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132 Cards in this Set
- Front
- Back
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correct sequence of stages in mitosis
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Prophase, metaphase, anaphase, telophase
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the material that would be synthesised to
form the cell wall of the seedlings |
Cellulose
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the tissue that would form the vessels in a
root, following differentiation. A Chorion B Endothelium C Sclerenchyma D Xylem |
D Xylem
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Suggest how these results could be displayed in order to compare the effect
of temperature on the growth of seedlings of these two species. |
1. line (graph) ;
2. {Y / vertical} and {X / horizontal} axes correctly described. e.g. mass versus time / rate versus temperature ; 3. using same scale for axes for both plants; 4. plotting each temperature / species plant separately ; |
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Suggest why all of the seeds were germinated at 18 °C before being placed in
the temperature-controlled rooms. |
1. controlling a variable ;
2. suitable temperature for germination ; 3. using viable seedlings / making sure that seeds germinate 4. validity of the investigation ; |
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Suggest why temperatures below 0 °C or above 40 °C would be unsuitable for
most organisms. 2' |
1. metabolism stops / is slow
below 0C 2. enzymes are inactive / cells disrupted; 3. cause of inactivity / cell disruption e.g. water freezes, lower kinetic energy ; (above 40oC) 4. enzymes denature / change 3D shape ; 5. consequences of denaturation e.g. fewer enzyme-substrate complexes possible, change in active site, change in bonding ; |
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Explain how this range of temperatures has been maintained by the presence
of carbon dioxide and methane in the upper atmosphere. (3) |
1. carbon dioxide and methane are greenhouse gases;
2. which absorb heat & long wave radiation; 3. reflected from the Earth’s surface; 4. prevent heat & long wave radiation escaping ; 5. temperatures maintained higher than they would be; |
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Place a tick () in the box in each row to indicate whether each technique
could provide evidence of climate change having occurred in the past. Amniocentesis Dendrochronology Peat-bog pollen analysis Potassium-argon dating |
X
Y Y X |
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Suggest why these scientists do not agree that a reduction in the use of fossil fuels
will prevent further global warming. |
1. carbon dioxide produced by using fossil fuels ;
2. no direct evidence that increased carbon dioxide leads to global warming ; 3. carbon dioxide released from other processes 4. removal of carbon sinks also leads to increase in carbon dioxide ; 5. any other greenhouse gas released from another source e.g. CFC, water vapour, methane ; 6. description of source e.g. ruminant animals, paddy fields, melting ice, clearance of peat land ; 7. natural cycles may be involved in global warming e.g. solar, volcanoes ; 8. evidence from past is being used ; 9. past evidence is not in indicator of future events / limitations of climatic models; 10. scientists may be biased ; 11. description of bias e.g. employed by company / country with vested interest, self promotion; 12. specific example of problem with / disadvantage of alternative source of energy ; |
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Place a cross in the box next to the mineral ion that would need to be present if
plants, such as grasses and herbs, are to grow successfully on a bing. A Copper B Nitrates C Sodium D Sulphites |
Nitrates
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*(c) With reference to the information in the table, suggest why the type of plant
community growing on a bing changes over time. (5) |
succession described:
1. lichens and mosses as pioneer community ; they are able to grow in little / no soil ; they breaks up rock fragments and forms thin soil; 2. plants with small / short roots able to grow in thin soil; 3. changes in soil structure enable trees / shrubs to grow ; general points: 4. soil able to hold water / minerals ; 5. as plants die organic matter released 6. competition effects ; |
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After 100 years, the community on a bing becomes stable.
State the term used to describe this type of community and explain why it is stable. (4) |
1. climax (community) ;
2. includes (both) animals and plants / has many species / has high biodiversity ; 3. interaction between species; 4. balanced equilibrium of species ; 5. dominant plant or animal species ; 6. stable if no change to environment / human influence ; |
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State two differences between fibrous proteins, such as actin and myosin, and globular proteins, such as enzymes.
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1. fibrous – long / linear / straight (chains),
globular – compact / spherical / eq ; 2. globular are folded and fibrous are not / eq ; 3. globular are soluble and fibrous are not / eq ; 4. fibrous –involved in {structural / eq} and globular are not ; 5. globular – involved in {catalysis / metabolism / eq} and fibrous are not ; |
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Place a cross in the box next to the factor that might influence the rate of
progress of rigor mortis in a muscle immediately after death. A Degree of decomposition of the muscle B Oxygen concentration of the atmosphere C Presence of drugs in the body D Presence of egg laying insects |
C
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Suggest two environmental factors that influence the rate of progress of rigor
mortis in a muscle immediately after death. |
1. physical damage ;
2. immersion in water ; 3. (external) temperature ; 4. burning ; 5. electrocution ; 6. clothing ; 7. wind / air movements ; |
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Using the data in the graph, suggest why a forensic scientist would need to
consider rigor mortis in several muscles of a body when estimating the time of death. |
1. reference to not {all / both / eq} muscles
{contract / relax / reach (full) rigor / eq} at same {time / rate / eq} ; 2. idea of jaw muscle contracting before leg muscle / eq ; 3. idea of jaw muscle reaches {full contraction / rigor} before leg muscle / eq ; 4. jaw starts contraction {0.5 / 0.8 / 0.9} hours before leg OR jaw reaches (full) rigor 2.5 hours before leg ; 5. reference to {full contraction / rigor} in muscle does not last very long ; 6. idea of leg is still contracting while jaw is relaxing / eq ; |
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State two ways in which the skin flora can help to protect a person from
infection by pathogenic bacteria. |
1. competition for nutrients ;
2. competition for space ; 3. secretion chemicals / substances / lysozyme OR affects pH ; 4. stimulation of skin immune system |
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Place a cross next to the part of the skin that forms a physical barrier
against infection by pathogenic bacteria. A Epidermis B Erector pili C Malpighian layer D Sebaceous gland |
A Epidermis
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Influenza (flu) is caused by a virus.
Sometimes antibiotics are used as part of the treatment for a person with influenza. Suggest why antibiotics may be used as part of the treatment for influenza. |
1. influenza may allow development of other diseases e.g. opportunistic infections ;
2. antibiotics will kill / inhibit growth of bacteria ; |
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The target set by health authorities in the USA for the number of prescriptions
per 10 000 population by 2012 is 128, an overall reduction of 43.4% since 2000. Suggest whether this target will be achieved. Give an explanation for your answer. |
1. yes ;
2. idea that if current rate continues / eq ; 3. idea of achieving lower than the target / eq; 4. credit use of supporting figures ; |
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Suggest why health authorities in the USA are encouraging the reduction in
the number of prescriptions of antibiotics. |
1. some bacteria can resist / are resistant to antibiotics ;
2. resistance being genetic / can be passed on ; 3. reference to MRSA / other named example ; |
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The type of bond that links the amino acids in the primary structure of
osteocalcin is (1) A disulphide B hydrogen C ionic D peptide |
D
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The structure in which the amino acids in the primary structure of osteocalcin
would be linked together is a (1) A centriole B lysosome C nucleolus D ribosome |
D
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Suggest how DNA analysis could give further evidence for their conclusions.
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1. similarity of DNA indicates closeness of relationship ;
2. because genes are sections of DNA ; 3. genes are the codes for protein ; |
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Describe how gel electrophoresis can be used to analyse DNA. 3'
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1. source of DNA sample, e.g. blood, saliva, semen ;
2. small samples of DNA can be amplified by PCR ; 3. use of restriction enzymes to break DNA ; 4. use of electro potential / potential difference ; 5. treatment / staining ; 6. show up as bands ; 7. the number of bands that match indicates similarity of the DNA ; |
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Explain how oxygen is produced during the light-dependent reactions of
photosynthesis. |
1. energy from light ;
2. photolysis ; 3. of water ; |
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Y or N?
HIV infects b-lymphocytes in the human immune system |
N
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Y or N?
The genetic material in HIV is a form of RNA |
Y
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Y or N?
The enzyme, reverse transcriptase, is used by HIV |
Y
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Explain what is meant by the term genetic mutation.
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1. change in the nucleotides / bases ;
2. in RNA / DNA ; 3. which leads to change in the sequence of amino acids in primary structure of a polypeptide / protein |
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Suggest why effective treatment of HIV in human populations will require the continual development of a mixture of many new drugs.
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1. idea that HIV has many / variety of / new / strains / types /antigens / protein coats / in infected person;
2. some strains {are / become} resistant to {an individual / a specific / a particular drug ; 3. these would survive if only one drug used) ; 4. mixture of drugs has more chance of getting rid of {all / more strains / types ; 5. drugs used together because of mutation ; 6. rapid rate of mutation ; 7. rapid rate of multiplication of virus ; |
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Suggest reasons for each of the following.
(i) DNA polymerase from human sources is not suitable for use in a PCR machine. |
1. human enzymes will not work at high / these/ above 37oC ;
2. denaturation /change in shape of active site at temperatures in PCR) |
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(ii) Species of plants cannot be identified from woody (xylem) material using PCR
and DNA profiling. why? |
1. (xylem / wood) made of dead material / has no living material / cytoplasm / cell contents / nuclei / mitochondria ;
2. no {DNA / nucleic acid} present |
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what's the reaction break ATP into ADP and Pi?
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hydrolysis
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what's the reaction join ADP and Pi to ATP?
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phosphorylation
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Describe the structures in a chloroplast that are involved in this reaction.
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1. granum / grana ;
2. a granum is a stack of thylakoids / membranes OR grana are connected by lamellae ; 3. thylakoids contain electron carriers / chlorophyll / photosystems ; 4. membranes contain ATPase / ATPase channel ; 5. electron carriers / ATPase are associated with thylakoid / thylakoid membranes |
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how GALP/(glyceraldehyde 3-phosphate) may be used to synthesise cellulose.
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1. GALP is a 3C molecule ;
2. formation of {glucose / hexose/ 6C sugar} (from GALP) ; 3. enzymes involved in the synthesis of {glucose / cellulose} ; 4. cellulose consists of ß-glucose / beta glucose ; 5. joined by glycosidic bonds; 6. 1-4 (bonds) ; 7. condensation reactions (between glucoses) ; 8. cellulose is a long chain molecule e.g. polysaccharide, polymer ; 9. unbranched molecule |
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Compare the changes in mean environmental temperature between the
pre-monsoon and the post-monsoon periods from 1600 to 2000. |
1. no / little change in pre-monsoon temperature, post-monsoon has risen ;
2. both fluctuate ; 3. fluctuations match each other ; 4. fluctuations within / less than 1oC ; 5. a particular change in both e.g. both decreased between 1800 to 1850 ; 6. Credit correct manipulation of figures to compare pre-monsoon and post-monsoon changes units needed ; 7. the range of (mean) temperatures is greater OR greater fluctuations, in post-monsoon period ; |
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Suggest how scientists could use these data to predict future climate change.
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1. extrapolating data ;
2. use for modelling / investigation of correlations ; 3. providing evidence for global warming ; 4. using this data along with data from other sources ; |
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Suggest why some scientists may not be convinced that these data can be
used to predict future climate change. |
1. there is not enough data ;
2. data has only been collected from Nepal ; 3. no way of confirming data / no proof / not reliable ; 4. fluctuations too great / no real trend ; 5. means are a poor representation of raw data ; 6. scatter / spread of raw data is indicator of eliability ; 7. method of estimated temperature from growth rings is questionable ; 8. other environmental changes (affecting trees)not taken into account |
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Suggest one source of evidence, apart from growth ring studies, that could be
used to estimate changes in mean environmental temperature in Nepal during the past 400 years. |
1. (estimates of) carbon dioxide levels (in air)
2. (pollen) from peat 3. temperature records |
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*(b) In mountainous regions of mainland Europe, only S. europaea is found. Suggest
how a distinct species of nuthatch, S. whiteheadi, has evolved in the mountainous regions of the island of Corsica.5' |
1. geographical isolation e.g. physical barrier between Corsican and mainland birds / allopatric speciation ;
2. there are different selection pressures (between Corsica and the mainland) ; 3. an example of selection pressure e.g. food source, different habitats ; 4. mutations occurred ; 5. this results in adaptation to the conditions ; 6. these {alleles /genes} passed on to offspring; 7. change in gene pool e.g. increasing frequency of (these) alleles, changes in gene pool ; 8. reproductive isolation (of Corsican nuthatches from mainland nuthatches) ; 9. birds on mainland could live in all regions as there is no restriction on gene flow. |
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Suggest how environmental changes, such as those caused by global
warming, are more likely to cause extinction of S. whiteheadi than S.europaea. |
1. S. whiteheadi adapted to colder / mountainous regions ;
2. (if climate warms) {food supply / pine seeds / invertebrates} less available ; 3. small population / only 2500 pairs of S whiteheadi) ; 4. limited {gene pool / genetic diversity / variety of alleles} ; 5. all the S. whiteheadi will be adversely affected ; 6. the S. whiteheadi cannot fly to other regions ; |
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Suggest why S. whiteheadi might be able to survive an environmental change
such as global warming. |
1. S. whiteheadi have a variety of food sources e.g. can change their feeding habits, eat seeds and invertebrates} ;
2. more / different invertebrates /seeds / food /might become available ; 3. they have another allele that gives a survival advantage ; 4. they could migrate (NOT south, somewhere warmer) ; |
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Explain how the work of zoos could be important to the survival of S. whiteheadi.
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1. captive-breeding programmes ;
2. conserve / preserve alleles /genes / gene pools ; 3. re-introduction / releasing of S. whiteheadi into suitable habitats |
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Nucleic acid
B or V or Both? |
Both
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Cytoplasm
B or V or Both? |
bacteria
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Protein capsid
B or V or Both? |
Virus
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Suggest why patients with SCAG may be given antibiotics as part of their
treatment. |
1. SCAG is caused by a bacterium / bacteria ;
2. antibiotics kill / stop reproduction of bacteria / are {bactericidal / bacteriostatic} ; |
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*(ii) Using the information about SCAG and the data, describe and suggest
explanations for the trends shown in the table. (5) |
1. as age increases, acid secretion decreases ;
2. as age increases (above 30) , stomach cancer increase ; 3. as acid secretion decreases (below 120), stomach cancers increases ; 4. the {higher age groups (51+) have low acid and high cancer / lower age groups (up to 30) have high acid and low cancer} ; 5. acid / low pH in stomach kills bacteria 6. development of SCAG {inhibited / prevented / (by low pH / more stomach acid) ; 7. age affects the immune system ; 8. the older you are acid-producing cells are less effective e.g. fewer acid-producing cells / cancer cells replace the acid-producing cells ; 9. acid / low pH destroys cancer cells ; 10. mutations (leading to cancer) more likely to occur with age ; |
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net primary productivity
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1. rate of production of / energy incorporated into {biomass / organic material / organic molecules / tissue} ;
2. losses in respiration in producers / plants |
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Suggest why an increase in temperature may cause an increase in NPP.
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1. the rate of {(bio)chemical / metabolic / photosynthetic / named} reactions increases ;
2. increase in {movement / kinetic energy} of {enzyme / substrate / molecules / particles} ; 3. increase in reaction rate because of more enzyme substrate interaction |
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describe and explain the relative effects of
temperature and hours of sunlight on NPP in this grassland. |
1. (between January and April) NPP increases as light increases ;
2. a correlation between NPP and light ; 3. the changes in NPP are occurring after the changes in light / peak light is April and peak NPP is May ; 4. increase in light increases {(rate of) photosynthesis / (ATP) energy available for Calvin Cycle ; 5. credit correct details of photosynthesis e.g. light results in excitation of electrons ; 6. there is no real correlation between temperature and NPP / reference to temperature fluctuating ; 7. the temperature affects how quickly enzymes work ; 8. NPP falling (from May) but temperature remaining high ; 9. (light / temperature) limiting factor |
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(d) Temperature and hours of sunlight are abiotic factors.
Suggest two biotic factors that may influence NPP in this grassland. |
1. grazing / {consumers / herbivores / named herbivore;
2. trampling ; 3. shading by plants / named plant ; 4. competition from other plants ; 5. disease |
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Place a cross in the box next to the term used to describe each of the sub-units
in a molecule of RNA A amino acid B inorganic phosphate C nucleotide D saccharide |
nucleotide
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Name two types of cell that HIV enters in the immune system.
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1. T helper / CD4 (positive)} (cell / lymphocytes) ;
2. phagocytic cells e.g. macrophages, dendritic cell ; |
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Explain how HIV is able to enter these cells.
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1, (HIV) binds to (CD4) receptors on cell (surface) ;
2. CD4 (receptors on cells) ; 3. rglycoprotein / gp120 on virus (surface) ; 4. fusion of virus (envelope) with (cell surface) membrane ; 5. phagocytosis (in macrophage / |
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Describe the sequence of events following infection of these cells by HIV, that
may lead to the death of the patient. 6' |
1. viral RNA ;
2. production of (viral) DNA (using viral RNA as a copy) ; 3. reverse transcriptase ; 4. incorporation of viral DNA into host cell’s {DNA /genome } / reference to provirus ; 5. integrase ; 6. production of {viruses / viral RNA and proteins ; 7. infection of further (T helper) cells ; 8. destruction of (T helper) cells by T killer cells OR reference to cell lysis ; 9. lowering of immunity ;(to other diseases ; 10.role of T helper cells in immune response e.g. produce cytokines, activate B cells / killer cells ; 11. death is caused by e.g. opportunistic disease, pneumonia , TB, Kaposi’s sarcoma, cancer, dementia, extreme weight loss, meningitis, toxoplasmosis |
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B and T cells are formed in the bone marrow
T or F? |
T
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B cells stimulate T cells to produce clones of memory cells
T or F? |
F
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T helper cells produce chemicals that destroy pathogens
T or F |
F
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B and T cells are able to form clones by mitosis
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T
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Suggest two reasons why the bacteria that caused the infection are not visible in
the photograph. |
1. (bacteria are) too small / reference to limitation of {magnification / resolution} ;
2. (bacteria) not stained ; 3. bacteria already {removed / destroyed} e.g. phagocytosis ; 4. bacteria are not present in the blood e.g. only a small {region / sample} shown, reference to local infection ; |
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Suggest how a further sample of blood, taken a few days later, might differ from
the one shown in the photograph, in each of the following circumstances. Give a reason for each answer. (i) If the person is treated with antibiotic drugs. |
Either:
1. idea of fewer {lymphocytes / eq} ; 2. reference to {lymphocytes / eq} no longer needed / eq ; 3. (as) {antibiotics / drugs} {kill / destroy / eq} bacteria ; Or: 4. more {lymphocytes / eq} ; 5. idea of clonal expansion (of lymphocytes) / eq ; 6. idea that the antibiotics have not killed all the bacteria yet ; ( |
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Suggest how a further sample of blood, taken a few days later, might differ from
the one shown in the photograph, in each of the following circumstances. Give a reason for each answer. (ii) If the person is given a placebo. |
1. idea that a placebo has no effect ;
2. (therefore there will be) more bacteria / eq ; 3. (therefore there will be) more {lymphocytes / eq} ; 4. (more lymphocytes due to) clonal expansion / eq ; |
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Explain what is meant by the term niche, using the sea anemone Anthopleura
elegantissima as an example. |
1. the role / purpose / interaction of organism / sea anemone / species ;
2. trophic level(s) ; 3. it is a predator/ controls population of prey; 4. it is prey / provides food for other animals ; 5. provide shelter / home for some animals |
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Suggest and explain why the anemones contract when exposed at low tide.
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1. reduces surface area to volume ;
2. less water loss e.g. dehydration, drying out ; 3. reduces visibility (to predators) ; 4. protection from {predators / carnivores ; 5. there is no need for the tentacles to be exposed ; 6. energy will be conserved /will not be wasted |
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Describe and suggest explanations for the effects of these two abiotic factors
on the distribution of A. elegantissima on this shore. |
1. no indication that temperature has an effect e.g. little variation, only 2oC ;
2. distribution is influenced by height above low water mark; 3. more likely to dry out at higher levels; 4. food availability differs e.g. less at higher levels, more at lower levels ; 5. more likely to be eaten at lower levels; |
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Suggest how these data could be analysed to assess the relationship
between the two abiotic factors, shown in the table, and the distribution of A. elegantissima on this shore. |
1. plot graph(s) of numbers of anemones against {height and temperature / abiotic factors ;
2. correlation ; 3. using statistical analysis ; 4. named appropriate statistical test |
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Place a cross in the box next to the term used to describe the type of
chemical reaction involved in the digestion of cellulose by enzymes. (1) A autolysis B haemolysis C hydrolysis D photolysis |
C – hydrolysis ;
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Place a cross in the box next to the most likely product of the digestion of
cellulose by the bacteria. (1) A amino acids B fatty acids C glucose D glycerol |
C – glucose ;
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Suggest why these bacteria need to have special adaptations to live in the
stomach of a cow. |
1. low pH / (hydrochloric) acid / HCl ;
2. acid destroys bacteria ; 3. low / no oxygen ; 4. using anaerobic respiration ; 5. resistant to stomach enzymes / protease / named protease ; 6. bacterial cell resistant to digestion ; 7. adaptation to cow’s temperature |
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*(ii) Scientists have estimated that if all cattle in Britain were fed on a diet with
added chopped hay and straw, there would also be an annual reduction of at least 1.6 million tonnes of carbon dioxide released into the atmosphere. With reference to your answer in (c)(i) and the information on carbon dioxide release, suggest why the new diet may be supported by organisations that are concerned about global warming. (5) |
1. less greenhouse gas / methane / carbon dioxide ;
2. carbon dioxide and methane are both greenhouse gases that can absorb heat / infra red / longer wavelengths radiation reflected from the Earth ; 3. decrease in these gases / carbon dioxide / methane leads to reduced greenhouse effect ; 4. methane having a greater greenhouse effect than carbon dioxide ; 5. temperature of Earth’s surface / atmosphere less likely to rise ; 6. reduced possibility of climate change ; 7. description of example of effect of this (e.g. ice caps melting, crop failure |
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(a) Describe what might happen to the clear areas in forests, over a long period of
time, if the numbers of rabbits and deer decreased. (3) |
1. taller growing plants could grow in the clear areas ;
2. loss of low-growing plants / clear zones ; 3. different animals appear ; 4. secondary succession ; 5. climax community of the taller plants |
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(i) The distribution of plants in a forest is affected by many abiotic factors.
Name one of these factors and suggest how this factor could affect the distribution of the low-growing plants within the clear areas of a forest. |
1. named abiotic factor ;
2. appropriate description of how named factor affects the {number / distribution / growth / eq} of these plants ; 3. appropriate explanation |
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reproductively-isolated populations
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1. no inter breeding / reproduction / mating / between the B. Selene because geographical / physical barrier ;
2 different behaviour ; 3. incompatible genitalia ; 4. each population having a discrete gene pool e.g. restricted gene flow, different mutations, different alleles |
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Suggest why it is unlikely that any individuals within a population of B. selene would survive if the numbers of rabbits and deer decreased.
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1. low-growing plants would die out / taller plants would outgrow the lowgrowing plants ;
2. B. Selene unable to feed e.g. no nectar for the adults ; 3. (B.selene) unable to lay eggs ; 4. no suitable plants for caterpillars to feed on ; 5. very little variation / genetic diversity in a small population |
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(a) Place a cross in the box next to the region of the chloroplast that would be
involved in the fixation of carbon dioxide. (1) A crista B granum C matrix D stroma |
D - stroma;
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(i) Suggest two reasons why a suspension of cells of a unicellular alga, in a
solution, is more suitable for this investigation than using leaves. |
1. samples of cells can be taken easily ;
2. no damage to plant / leaf / other cells during sampling; 3. carbon dioxide level in water can be adjusted / maintained / changed / easily ; 4. RuBP / GP / products / cannot pass into other cells / rest of plant ; 5. only one kind of cell ; 6. controlling the mass / number/surface area} of cells ; 7. genetically-similar cells used |
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Suggest why it would be advisable to illuminate the cells at a high light intensity during this investigation.
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1. light is needed for light-dependent reaction ;
2. light intensity will not be a limiting factor; 3. the effect of carbon dioxide concentration can be seen / carbon dioxide concentration is only limiting factor; 4. ATP / NADPH / produced during light dependent reactions ; 5. ATP / NADPH / light-dependent products / required for light-independent reactions / Calvin cycle / carbon dioxide fixation |
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Describe and suggest an explanation for the changes in the concentrations of
RuBP and GP shown in the graph. |
1. both RuBP and GP levels constant until carbon dioxide lowered ;
2. RuBP and GP in Calvin cycle ; RuBP 3. at lower carbon dioxide levels the RuBP increases and drops and then stays constant ; 4. rises because being regenerated ; 5. falls as being used to fix / carbon dioxide ; 6. RuBP level remains constant once new equilibrium reached ; GP 7. at lower carbon dioxide levels the GP drops and then stays constant ; 8. drops because less carbon dioxide available to convert into GP / less carbon fixation ; 9. levels out at a lower level as carbon dioxide still available but at lower level; 10. credit correct manipulation of figures for a description of either RuBP or GP |
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Suggest how the pathologist might use the information in the table and the
flow diagram to estimate the time of death of the young man.3' |
1. the body has been dead for a while ;
2. because more than one species of insect present ; 3. succession of insect species; 4. life cycle times / stages of the insects are known / used ; 5. life cycle times depend on environmental temperature ; 6. credit specific ref to information in table e.g. blowfly cycle complete ; |
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(c) Suggest how useful each of the following additional sources of evidence would be
for the pathologist in determining the time of death of this young man. Give an explanation for each of your answers. (i) Body temperature 2' |
1. a drop in body temperature is linked to time after death e.g. algor mortis ;
2. factors affect temperature drop e.g. environmental temperature, body size, clothing ; 3. useful because time of death can be calculated if (ambient) temperature known ; 4. only useful for short period of time following death e.g. 24 hours, a day ; |
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(c) Suggest how useful each of the following additional sources of evidence would be
for the pathologist in determining the time of death of this young man. Give an explanation for each of your answers. (ii) State of decomposition 2' |
1. body decomposes in a specific sequence with time;
2. factors affect decomposition e.g. environmental temperature, wounds ; 3. (not useful) if all the body has decomposed |
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Describe how the vaccine gives active immunity against PWMS.
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1. using virus / PCV2 as vaccine ;
2. which is modified / attenuated / harmless / similar / part of / ; 3. the vaccine contains the antigen ; 4. activation / proliferation of specific B cell / T cell / lymphocyte ; 5. production of B / T memory cells ; 6. body now able to produce specific antibody faster / at higher concentration / on another exposure to PCV2 ; |
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Apart from having no vaccine, suggest how group B should be treated during
the test. Give reasons for your answer. (3) |
1. giving a placebo to group B ;
2. all other variables should be controlled / same as group A; 3. stated example e.g. food, temperature of housing ; 4. group B is a control group ; 5. so that only the effect of vaccine / vaccination is tested ; 6. valid / validity |
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Compare the changes in concentrations of PCV2 antibodies in the blood of the two groups of gilts during pregnancy.
(3) |
1. Greater change / higher in group A than B;
2. group A rises for first 30 days, group B rises (slightly) for first 20 days ; 3. (this) rise for group A is {faster / greater} than for group B ; 4. (after the rise) group A falls, group B levels off / (until day 140) ; 5. after day 140, group A rises, group B falls ; 6. credit use of comparative manipulated figures (with units) |
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Suggest reasons for the changes in the concentrations of PCV2 antibodies in
group A and group B piglets. |
1. antibodies present at birth as both groups received antibodies from mother ;
2. via placenta / blood / milk / breast feeding ; 3. passive immunity ; 4. group A concentration falls because piglets not infected by (PCV2) virus/ antibodies excreted / passive immunity is short term ; 5. group B concentration rises because {PCV2 / virus} present |
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Compost formation involves respiration by
microorganisms. Y N? |
Y
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I added nitrate fertiliser so that the
microorganisms could synthesise nucleic acids. Y or N? |
Y
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There is only one trophic level in my compost
heap. Y or N? |
N
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Describe the changes in temperature shown in the graph.
Suggest explanations for these changes. |
1. increase in temperature for first 4 weeks ;
2. heat energy related to temperature change ; 3. metabolism / respiration / named metabolic reaction ; 4. appropriate comment on changes in numbers of microorganisms ; 5. decrease in temperature after 4 weeks ; 6. comment on enzymes denaturing ; 7. substrate is running out |
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Suggest why the student took temperature measurements by using a long
thermometer at several points. |
1. heat is lost from outer surface of compost heap / temperature will vary in different parts of the compost heap ;
2. long thermometer measures internal / core / temperature of heap ; 3. this improves validity of the method ; 4. repeated readings to obtain mean / average ; 5. this improves reliability of the results |
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Explain why a molecule of DNA can be described as a double-stranded
polynucleotide. (3) |
1. Double-stranded because made of two strands ;
2. strands joined by hydrogen bonds between bases ; 3. polynucleotide of many / nucleotides ; 4. nucleotides linked by phospho(di)ester bonds |
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*(b) Describe how the sequence of bases in a DNA molecule would be used to form
the primary structure of a protein. (5) |
1. sequence of bases forming the genetic code / determines the amino acid sequence ;
2. one triplet codes for an amino acid; 3. DNA acting as a template ; 4. transcription OR detail of transcription e.g. DNA unzips, mRNA synthesis ; 5. mRNA moves from nucleus to cytoplasm ; 6. translation OR detail of translation e.g. role of ribosome, codonanticodon interaction ; 7. tRNA carries an amino acid ; 8. formation of peptide bonds between amino acids ; 9. primary structure is the sequence /order / of amino acids ; 10.comment on post-transcriptional modification of mRNA (between transcription and translation)e.g. removal of introns, splicing ; |
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Gross primary production (GPP)
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Gross primary production (GPP) is the rate at which an ecosystem's producers capture and store a given amount of chemical energy as biomass in a given length of time.
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Suggest why cephalosporins are bactericidal antibiotics.
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1. killing of bacteria cells ;
2. bacteria cells burst ; |
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Suggest why quinolones are bacteriostatic antibiotics.
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1. cells cannot reproduce / increase in number /
produce new cells / multiply / replicate ; 2. no cell division |
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Explain how the appearance of the nutrient agar plates, after incubation,
would have enabled the scientists to reach these conclusions. |
1. A and C resistant as no clear zone / zone of inhibition / around A and C ;
2. clear zone / indicates where antibiotic inhibits growth / kills bacteria ; 3. {clear zone around B smaller than clear zone around D ; 4. size of clear zone indicates effectiveness ; |
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In this investigation, several nutrient agar plates were used for
(1) A accuracy B precision C reliability D validity |
C reliability
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In this investigation, each disc had the same concentration of antibiotic for
(1) A accuracy B precision C reliability D validity |
D validity;
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Suggest how this hospital could improve the prevention and control of the
spread of infections. |
1. hospitals changing a code of practice / protocol / policy / standards / for dealing with hospital acquired
infections ; 2. clothing rules for hospital workers ; 3. improved laundry of bed linen e.g. increased frequency / higher washing temperature ; 4. use of special pillow cases / treatment of pillow cases e.g. microfilters, treated with antibacterials, sterilisation, disposable pillow cases ; 5. use of special procedures when carrying {pillow cases / bed linen} to laundry e.g. sealed plastic bags ; 6. screening of patients / isolation of infected patients / ; 7. hand washing regimes; |
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Place a cross ( ) in the box next to the name of the type of cell in the human
immune system that is infected by HIV. (1) A B effector cell B B memory cell C T helper cell D T killer cell |
C T helper cell
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Place a cross ( ) in the box next to the name of the enzyme used to produce
DNA from viral RNA in an infected cell. (1) A DNA polymerase B RNA polymerase C restriction endonuclease D reverse transcriptase |
D reverse transcriptase
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State two characteristic features of antibodies.
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1. reference to glycoprotein ;
2. credit detail of structure e.g. specific (3D) shape, L and H regions, Y-shape, 4 (peptide) chains, disulphide bridges between peptides, hinge region; 3. antigen-binding site / variable region / Fab (region) ; 4. antibodies have a similar / constant / Fc / region; 5. produced by plasma cells / present on B cells ; 6. role of antibody described e.g. opsonisation, immobilisation, agglutination, lysis ; |
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*(ii) The antibody 2G12 is produced in response to part of a glycoprotein found
on the surface of HIV. Synthetic molecules have been made that resemble this part of the glycoprotein. The antibody 2G12 binds to these synthetic molecules. Using the information, suggest how this may enable scientists to develop a means of producing active immunity to HIV infection. (5) |
1. artificial active immunity ;
2. vaccine containing synthetic molecule / (synthetic) antigen / (synthetic) glycoprotein } ; 3. stimulation of the {specific/ humoral} immune response (to the synthetic antigen) ; 4. credit detail of process of producing effector B cells e.g. clonal expansion of B cells, involvement of cytokines, T helper cells activate B cells ; 6. production of B memory cells ; 7. 2G12 antibodies are produced {faster / in greater concentration} on reinfection ; |
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Suggest why data about HIV infections are often estimates.
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1.HIV infection does not always produce symptoms ;
2. provirus / latency ; 3. test needed to detect (symptomless) HIV ; 4. only people who suspect they may have contracted HIV would have a test ; 5. some people would not want to be tested / impossible to test everyone} ; 6. symptoms are common to other diseases ; 8. new strains of virus arising |
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Describe how small samples of DNA can be amplified.
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1. polymerase chain reaction / PCR ;
2. polymerase enzyme added }; 3. need for primers and nucleotides ; 4. {90-98} (oC) {50-65} (oC) {70-75} (oC) ; 5. cycle needs to be repeated {several times / to make several copies of DNA |
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Name one technique that could be used to analyse the amplified DNA
samples. |
(DNA) {profiling / fingerprinting / (gel) electrophoresis} ;
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Suggest how the scientists who conducted the study had their results accepted by other scientists.
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1. work appearing in a (Scientific) journal or being presented at a conference ;
2. validity or reliability is considered ; 3. by other scientists / ref to peer review |
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(c) Suggest how each of the following may have contributed towards the divergence
of polar bears and Irish brown bears into two separate species. (i) Separation of the Arctic and Irish regions by sea |
1. different conditions /environments in each region;
2. different selection pressures; 3. restricted gene flow / separate gene pools} ; 4. reproductive isolation |
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(ii) Genetic mutation
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1. different alleles/ gene pool ;
2. this leads to new / different phenotypes ; 3. new allele / gene can be advantage / disadvantage; 4.advantageous mutated gene / new allele passed onto offspring |
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Explain why body temperature affects the rate of development of animals.
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1. increase in metabolic rate / enzyme activity as temperature rises ;
2. increase in kinetic / energy of molecules as temperature rises ; 3. increase in enzymesubstrate complexes / energy of collisions as temperature rises ; 4. inactivation at lower temperatures/ denaturation at higher temperatures of enzymes; 5. temperature affects differentiation / growth /division |
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Using the information, suggest why the lower and upper lethal temperatures limit
the range of latitudes inhabited by each species of frog. |
1. temperature affects survival / development / growth
/ metabolism / cell division; 2. enzymes affect development / growth / metabolism / cell division ; 3.temperature affects enzymes ; 4. different frogs have different enzymes |
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Populations of the different species overlap on the boundaries of each latitude
range. Suggest why interbreeding does not take place between these populations. |
1. different species are reproductively isolated ;
2.different breeding times / seasons ; 3. different {breeding / courtship / eq} {behaviour / rituals / displays / colour / songs / croaks ; 4. population at northerly / southerly} limit of range may not develop (to adulthood) ; 5.breeding between different species results in infertile offspring |
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Suggest how global warming may affect the distribution of these species of Rana in North America.
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1.global warming will increase the temperature (at the
latitudes ; 2. temperatures at these latitudes may become too high for any of the species ; 3. new temperature may be above the maximum to complete development or above the upper lethal limit ; 4. species move north / to cooler regions ; 5. change in food source / predators / competition |
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Explain why the light-independent stage cannot take place without the light-dependent stage.
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1. products of lightdependent stage are needed for /
used in light-independent stage / Calvin cycle; 2. products of lightdependent stage are reduced NADP / and ATP ; 3. use of reduced NADP / for reduction of carbon dioxide / GP / 4. use of ATP as source of energy |
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Place a cross ( ) in the box next to the statement that describes what could
be measured to find the rate of photosynthesis in this investigation. (1) A increase in mass of Elodea B mass of nitrate absorbed C volume of carbon dioxide produced D volume of oxygen produced |
D volume of oxygen produced
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The temperatures used in this investigation were 0°C, 10°C, 20°C, 30°C, 40°C
and 50°C. Suggest what the results of the investigation show about the minimum temperature required for photosynthesis in Elodea. Give a reason for your answer. |
1. (minimum temperature) is between 0 oC and 10 oC
0 oC but less than 10 / 10 oC} ; 2. no photosynthesis at 0oC but photosynthesis is taking place at 10 oC ; 3. no data / readings / measurements / evidence / between 0 oC and 10 oC ; 4. at 0 oC water is frozen |
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Explain the meaning of the following statement.
“All other abiotic factors were controlled.” |
1. abiotic factors are non-living / non-biological / do not
involve organisms ; 2. other factors need to be kept constant |
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The student, who carried out this investigation, wrote the following as part of
her conclusion. Enzymes control the rate of photosynthesis in Elodea. Discuss how far the results of this investigation support her conclusion. |
Supporting conclusion:
1. shape of graph is typical of an enzyme-temperature graph; 2. rate increases (up to 30 oC) because more {enzyme-substrate complexes / collisions between enzymes and substrates} ; 3. rate decreases (after 30oC) due to enzyme denaturation ; Not supporting conclusion: 4.other factors could be affecting photosynthesis ; 5. gas / oxygen / carbon dioxide solubility changing with temperature ; 6. correlation / not causation |
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Succession
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1. a sequence of changes in a community / organisms /
species / plants ; 2. over a period of time |
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Climax community
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1. final stage / sere / community ;
2. feature of community described e.g. self-sustaining , stable, one dominant species, a few codominant species |
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Suggest why it is important to conserve rare and endangered plants.
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1. conservation of genetic diversity / genetic variation /biodiversity ;
2. extinction ; 3. aesthetic reasons ; 4. these plants may be useful e.g. as medicines ; 5. other animals depend on these plants as a {source of food / habitat |
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suggest one management strategy
that could have been used to conserve the heathland |
grazing / remove saplings / mowing
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A statistical analysis of the data obtained gave a correlation value of 0.565
between height and width of Petty Whin. This correlation was not statistically significant. Suggest reasons why the correlation was not statistically significant. |
1. comparison of the value to the critical value indicates no significance / stronger correlation
the nearer the value is to 1.0 / 0.565 is too low / eq ; 2. sample size too small; 3. there is no correlation between height and width / other factors affect height / other factors affect width |
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Suggest why many scientists consider that the use of protected reserves is likely
to be more successful for the conservation of some animals than captive breeding programmes in zoos |
1.less stress / trauma / discomfort / depressed (for the animals) ;
2. animals are more likely to breed in natural environment ; 3. animals may require large areas ; 4. problems of releasing animals back into the wild is avoided eg habituation ; 5. disease is less likely /disease will not wipe out population} ; 6. allowing (natural) {interspecific relationships / communities} to exist ; 7. allowing (natural) {intraspecific relationships / family / social / structure/ behaviour ; 8. (because) large numbers of animals needed / wider gene pool / eq ; 9. (natural) {diet / food / available |
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*(b) The illegal killing of white rhinoceros (poaching), to obtain their horns, is a serious
problem in many of the reserves in southern Africa. When the body of a white rhinoceros is discovered, determination of the time of death is an important part of the police investigation to catch the poachers. After several days, body temperature and rigor mortis cannot be used to determine the time of death. Suggest how the time of death of a white rhinoceros could be determined if it is discovered several days after being killed. (5) |
1. succession ;
2. forensic entomology; 3. example of {insect / eq} e.g. fly, beetle, wasp ; 4. types / species / life cycle stages} (of insects) are used; 5. decomposition / decay ; 6. there are different stages of {decomposition / decay /; 7. detail of decomposition / decay / e.g. production of gases, liquefaction of tissue, bloating, discolouration ; 8. rate of {succession / insect development / decomposition} influenced by external factor / appropriate named factor ; 9. insect and decomposition information is used to determine time of death ; |
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Describe how the production and action of interferon differs from the production and action of lysozyme.
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1. interferon involved viral infections, lysozyme affects bacteria;
2. interferon produced by infected cells, lysozyme present in secretions / phagocytes / neutrophils / macrophages ; 3. interferon inhibits / replication / of viruses, lysozyme kills bacteria; |
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Suggest why the protein structure of lysozyme is important to the way in
which it acts against pathogens. |
1. lysozyme is an enzyme ;
2. proteins / active sites / enzymes have a specific shape ; 3. lysozyme acts on cell wall; 4. of bacteria |
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Explain why an insect bite, which breaks the surface of the skin, may lead to
inflammation around the injury. |
1. histamine released as a result of damaged {tissue /
cells} ; 2. (histamine released from) {basophils / mast cells / platelets}; 3. effect of histamine e.g arterioles dilate, vasodilation, increased blood flow, capillaries more permeable ; 4. named effect of inflammation e.g. oedema / swelling /redness / heat / pain |
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Suggest why applying this cream might be better than taking tablets
containing antihistamines. |
1. only a local reaction produced / histamines produced around bite area ;
2. cream has been applied to actual site of production of histamine ; 3. effect / treatment / relief / more rapid / immediate /; 4. higher concentration of antihistamine at site ; 5. the antihistamines will not be {digested (by enzymes) / destroyed (by acid / enzymes) /; 6.tablets may lower immune response generally / lead to side-effects ; |
