Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
40 Cards in this Set
- Front
- Back
|
Size of prokaryotes |
0.5-5 micrometers |
|
|
Plasmid characteristics |
Virulence Resistance to antibiotics Bacteriocin(natural antibiotic) Fertility(transferred in conjunction) |
|
|
Bacterophages |
Viruses that can infect gram negative bacteria reacting with specific proteins on cell surface |
|
|
Viroids |
Circular ssRNA loops with no capsid protein coat |
|
|
Prions |
Infectious proteins Occur spontaneously from mutation leading to a misfolded protein and a loss of the 3D structure |
|
|
How to Prions act on cells? |
Build up inside cell and poison it causing it to lyse and release the prions into the space around it can lead to degenerative diseases like mad cow disease |
|
|
Prophage |
When the bacteriophage genome is inserted and integrated into the host DNA. NB it circulizes first |
|
|
How does the change occur from the Lysogenic to the lytic cycle? |
Environmental or chemical triggers cause the release of the prophage from DNA leading it to control cell by degrading the host DNA. |
|
|
Reverse transcriptase |
Viral enzyme that sytheszies complementary DNA strands to viral RNA |
|
|
Viral envelope |
A lipid bilayer gained from plasma membrane when envelope type viruses leave their host cell Has surface glycoproteins allowing it to stay 'hidden' in the body whilst being specific for its host range |
|
|
Provirus |
Virus genome that is integrated into the DNA of a host cell |
|
|
Size of nucleus |
5-10 micrometers |
|
|
Nuclear envelope |
2 lipid bilayers |
|
|
Nuclear lamina 4 |
Lines inner surface of nuclear envelope Intermediate filaments Helps maintain shape of nucleus Also helps organise DNApacking |
|
|
Nuclear Pore Complex 4 |
Highly regulated Allows specific substances in and out RNAs allowed out control signals, materials and energy allowed in |
|
|
How is DNA packed? |
The DNA double helix is combined with histone proteins to form chromatin fibres that undergo multilevel packing |
|
|
First stage of DNA packing |
Double helix(d=2nm) interacts with histone proteins(H2-H4) forming chromatin fibers with nucleosomes(d=10nm) |
|
|
Nucleosomes |
Bead like structures on chromatin fiberss where Histone proteins 2-4 are attached to the double helix diameter of 10nm |
|
|
2nd stage of DNA packing |
Further interactions between DNA and histone 1 cause the fiber to coil forming a 30nm fiber |
|
|
How big is the fibre caused by further interactions of DNA and histones? What histone is involved here? |
30nm Histone 1 |
|
|
3rd stage of DNA packing |
The fibre the loops and is coiled more forming a 300nm fibre During cell division these coil more forming metaphase chromosomes(very dense visible form) |
|
|
Euchromatin |
Less dense area of chromatin More accessible More active - contains useful genes at present |
|
|
Heterochromatin |
More dense area of chromatin Less accessible Less active aka genetically inactive |
|
|
What is the relationship between euchromatin and heterochromatin? |
It is a dynamic relationship to suit cells needs as the genes needed change over time to suit cells demand. |
|
|
Chromosome location in nucleus is: |
Not random Chromosomes are anchored in place |
|
|
What resists compression in the ECM? |
Proteoglycans |
|
|
What can scanning electron microscopes view? |
Outer layers of cell |
|
|
What can transmission electron microscopes view? |
internal ultrastructure of cell |
|
|
Advantage of small cell size: |
A small cell has a large surface area relative to cytoplasmic volume |
|
|
Endospores |
Produced in adverse conditions. Heat, chemical and desiccation resistant |
|
|
Cholesterol |
Increases membrane fluidity at moderate Temps Decreases membrane fluidity at low Temps |
|
|
Fibronectins |
Glycoprotein attach cells to ECM |
|
|
Integrins |
Membrane receptor protein bound to microfilaments. Information changes in outside can be exchanged through a mechanical signaling pathway involving fibronectins, integrins and the cytoskeleton |
|
|
Microtubules |
Tubulin subunits Resist compression Organelle and whole cell motility Hav e a central organization centre - centrosome |
|
|
Microfilaments |
Double chain of actin forming spiraling intertwined strands Resists tension Maintains cell shape Involved in muscle contraction Cytoplasmic streaming Cell division |
|
|
Intermediate filaments |
Supercoiled fibrous proteins of keratin family Anchor nucleus Make up nuclear lamina Reinforce cell shape |
|
|
Cytoskeleton |
GIves mechanical support to cell and maintains or changes its shape Anchors or directs organelle movement Controls cilia, pseudopod movement(sometimes muscular contraction) Mechanically transmits signals from cells surface to interior Interacts with motor neurons(proteins) that change shape to produce cellular movement |
|
|
Resolution |
Minimum distance that can separate 2 points that still remain identifiable as separate when viewed under a microscope |
|
|
Magnification |
Ratio of an objects image size to its actual size |
|
|
Sexual Selection |
Individuals with certain inherited characteristics are more likely than other individuals to obtain mates |
