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175 Cards in this Set
- Front
- Back
Which molecule is involved in the major step for the production of superoxide in the mitochondrial electrontransport chain?
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Ubiquinone
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The AB-sites (antigen reactive sites) are located on which of the following portions of the immunoglobulin chains?
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VL + VH
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What hormone is excreted from the chromaffin cells of the adrenal medulla?
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Epinephrine
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The protein that is defective in cystic fibrosis normally functions as:
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a chloride transporter protein
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If AUG is the codon for methionine, which sequences of bases (or theiranalogs) might be expected to be found somewhere on methionyl-tRNA?
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CAU
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Provides structural rigidity to the plasma membrane:
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cholesterol
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What are the complementary base pairs in DNA?
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Adenine : Thymine and Guanine : Cytosine
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What is the most reactive form of oxygen?
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OH.
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Glycogen breakdown in which of the following tissues can be used to support blood glucose levels during periods offasting?
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Liver
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NADPH is a two electron donor. Heme can only accept one electron. How is this accommodated in the microsomal electron transport chain?
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NADPH gives electrons to a flavoprotein with two flavin groups
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The enzyme which catalyzes the entrance of acetyl CoA into the Krebs cycle is
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citrate synthase
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What generates NADPH?
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hexose monophosphate shunt
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From what electron donor may the second electron that enters the microsomal cytochrome P450 cycle come?
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Cytochrome b5
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True or False? AUG is a initiation codon.
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True
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The alpha helix structure of a protein can be considered an example of:
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secondary structure
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Synthesis of the leading strand at the replication fork is carried out by ________________.
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DNA polymerase III
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During heavy exercise, the Cori Cycle employs the gluconeogenic pathway in the liver and the glycolytic pathwayin muscle. The major metabolites transported by blood to connect these pathways are ___________ and __________________.
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glucose and lactate
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Lactase catalyzes _________ + _______________.
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glucose + galactose
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A competitive inhibitor competes _______________________________________.
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with the substrate for the active site of an enzyme
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Which process is NOT increased in the presence of insulin?
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Gluconeogenesis in liver
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Which enzymes in the tricarboxylic acid cycle requires the same set of cofactors or coenzymes as the pyruvate dehydrogenase complex?
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Alpha-ketoglutarate dehydrogenase
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A 25 year old, healthy male has begun a treadmill exercise program. He has set the treadmill to a fast pace and hasbegun to run. As his physical activity continues for several minutes his heart rate would be expected to increase andthe levels of _______________ would be expected to rise significantly in his blood.
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lactic acid
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True or False? Synthesis of glucose from alanine does not occur in muscle.
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True
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Most nutrients are absorbed in the ____________.
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small intestine
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An important function of high density lipoproteins (HDL) is the __________________.
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acquisition of cholesterol from tissues and other lipoproteins
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Part of the structure of collagen consists of _________________.
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A triple helix
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True or False? Thiamine pyrophosphate is a component of the electron transport chain of the mitochondria.
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False
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The electron transport chain of mitochondria is specifically located in the ___________________.
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inner membrane
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The major nitrogenous product excreted in the urine is:
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urea
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Why do type II diabetics generally not develop ketoacidosis?
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There is enough residual insulin to suppress lipolysis.
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Niemann Pick disease results from a deficiency of...
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sphingomyelinase
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Okazaki fragments are associated with...
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replication of the lagging strand
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The heme group of myoglobin...
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is identical to that of hemoglobin
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When is hepatic glycogenolysis a primary source of blood glucose?
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Early fasted state, 3-12 hours postprandial
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Southern blots are used to analyze DNA that has been fractionated based on difference in...
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length
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Chemical damage to nuclear DNA from exposure to a mutagenic agent is most dangerous when:
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the resulting mutation is fixed through DNA replication and leads to the activation of a cellular oncogene and malignant transformation in a liver cell.
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The iron in the cytochromes function in biological systems by:
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undergoing oxidation and reduction
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Endocrine, paracrine, neuronal, and contact-dependent are all forms of:
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Extracellular signaling
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The synthesis of RNA complementary to one strand of the DNA is termed:
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transcription
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What is the main function of beta-oxidation?
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degradation of fatty acids
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The most serious consequence of failure of the urea cycle is:
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accumulation of ammonia (ammonium ion) in the blood
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Frameshift mutations are possible because of...
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non-overlapping code
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Two vitamins important in beta-oxidation are:
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Riboflavin and niacin
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The nucleotide sequence 5'-ATTGCAG-3' should base pair with _____________________.
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5'-CTGCAAT-3'
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The iron in the cytochromes function in biological systems by _____________ and ______________.
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undergoing oxidation and reduction
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What type of signaling are steroids and polypeptides involved in?
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Endocrine
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The TATA box is bound by _______________.
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RNA polymerase II
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Endocrine, paracrine, neuronal, and contact-dependent are all forms of ______________ ___________.
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extracellular signaling
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True or False? A characteristic of hormones is that they are considered to be secondary messengers. |
Fasle. They are not considered to be secondary messengers. |
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A common intermediate in the biosynthesis of both purine and pyrimidine nucleotides is __________________ _____________________. |
Phosphoribosyl pyrophosphate (PRPP) |
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In pyrimidine biosynthesis, the carbon atoms in the pyridmidine ring are supplied by ____________ and ______________. |
carbon dioxide and aspartic acid |
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True or False? The coenzyme biotin is NOT required for the activity of the pyruvate dehydrogenase complex. |
True |
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The surface of a lipoprotein synch as chylomicron or very low density lipoprotein (VLDL) is composed chiefly of _________________. |
phospholipid |
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The main organism responsible for keeping the blood glucose level stead between meals by making glucose via gluconeogenesis is the ________________. |
Liver |
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Very low density serum lipoproteins transport... |
triacylglycerol from the liver to the adipose tissues |
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True or False? Lipoproteins are covalent complexes of lipids and proteins. |
False |
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Chylomicrons: |
mainly carry dietary triglycerides |
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Carbon monoxide is toxic because: |
it binds competitively to the heme group and thus lowers the amount of oxygen bound. |
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What is the main carrier for the transport of digested fat? |
chylomicron |
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True or False? Lipid bilayer membranes can rotate end-over-end (flip flop) easily. |
False |
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How does the cell maintain a higher level of K+ than of Na+? |
Na+ is actively transported out of the cell and K+ actively transported in the cell |
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The stop codon(s) for protein synthesis are: |
UAA UGA UAG |
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A condition which favors increased ketone body synthesis is: |
increased lipolysis in adipose tissue |
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The enzymes responsible for the degradation of sphingolipids are localized in which subcellular structure? |
lysosomes |
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DNA synthesis is called: |
replication |
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The substrate for the committed step in glycolysis is ___________________. |
fructose 6-phosphate |
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A major control point of the Krebs cycle is exerted at the level of ____________ ________________. |
citrate synthase |
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How many amino acids would the following eukaryotic mRNA encode? 5'-cap-AGCUACCGUAUGCAUGAUAAAGUGACCAUGCUGACAUGAUAAUAGGAG-3'poly (A)? |
9 |
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True or False? 2 beta and 2 delta chains are part of the hemoglobin molecule. |
False |
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Which enzyme does amino acid degradation rely on? |
Pyridoxyl phosphate |
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Pyridoxal phosphate is involved in what type of reaction? |
production of new amino acids by transamination |
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A repressor attachment site is a _____________ __________________. |
operator gene |
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The result of a (an)________ reaction is that energy is released. Energy must be added to a (an) _______________ reaction to proceed. |
exothermic, endothermic |
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What is ubiquitin involved in? |
covalent coupling of ubiquitin to a protein can mark that protein for degradation |
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Which amino acid is considered the most polar? |
Threonine |
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What happens when cAMP binds to catabolite activator protein (CAP)? |
binding of RNA polymerase to the promoter is enhanced |
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The nucleotide intermediate common to the synthesis of all the pyrimidine mono nucleotides is: |
UMP |
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What substance binds to the lac repressor? |
allolactose |
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Catalysts that change the rate of reactions are what category of physiological proteins? |
enzymes, which don't alter the equilibrium |
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Which component of the system for protein synthesis actually translates the nucleotide code to an amino acid code? |
transfer RNA |
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Histones are: |
bound to DNA in the transcriptional units of both active and inactive genes |
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True or False? Aspartic acid is not a product of pyrimidine degradation. |
True |
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Protein modification which changes enzyme activity in a non-reversible manner is: |
zymogen activation |
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The protein that is defective in cystic fibrosis normally functions as: |
a chloride transporter protein |
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An amino acid found in large amounts in collagen is _____________. |
proline |
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Primary sequencing of proteins are determined mainly by _______________ ________________. |
sequential degradation |
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Transposition is |
the movement of a stretch of DNA from one genetic locus to the other |
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The excretion of ammonia in urine results directly from action of the enzyme _____________. |
glutaminase |
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The lac repressor protein from E. Coli: |
binds to the lac operon and physically blocks RNA polymerase from initiating transcription from the lac promoter |
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____________ nucleic base does not have a KETO group. |
Adenine |
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Substances that bind with domain sites and alter the activity of regularity enzymes are called ____________ ______________ or ______________. |
Allosteric effectors OR modulators |
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True or False? NADH is formed in the pentose phosphate pathway. |
False |
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When is hepatic glycogenolysis a primary source of blood glucose? |
early fasting state, 3-12 hours post-prandial |
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An enzyme present in saliva which hydrolyzes starch to produce free maltose is _____________. |
alpha-amalyse |
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Glycogen in muscle: |
serves as a primary source of ATP synthesis in that tissue |
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Amino acids from muscle breakdown provide the chief substrate for which metabolic process? |
gluconeogensis |
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What makes hyaluronic acid different from the other proteoglycans? |
it does not have a sulfur |
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The effects of insulin on glucose uptake by muscle tissues is most directly opposed to by ____________. |
glucagon |
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Which two cell types are NOT dependent on insulin for glucose transport? |
brain and kidney |
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What regulatory hormone stimulates liver glycogenolysis and gluconeogenesis? |
Glucagon |
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Cellulose is not digested by humans because: |
we do not have the enzyme to breakdown the polymer |
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Cyanide is toxic because it inhibits _____________ ________________. |
cytochrome oxidase |
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What is the principal physiological function of bile salts? |
to permit GI absorption of dietary lipids |
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The net products of anaerobic glycolysis are _________ and __________. |
ATP and lactate |
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A rise in blood glucose triggers the release of ____________ hormone. |
insulin |
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The largest amount of glycogen in humans is stored in __________. |
skeletal muscle |
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True or False? Glycogen to glucose conversion utilizes the intermediate UDP-glucose. |
False |
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Glucose-6-phosphate dehydrogenase catalyzes the first step in the ___________________________ pathway. |
Pentose phosphate |
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In what part of the cell does the electron transport chain take place? |
inner membrane of the mitochondria |
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The substrate normally utilized as the major energy source in the brain is _____________. |
glucose |
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Which type of reaction BEST characterizes the process of digestion? |
hydrolysis |
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The major site for digestion of dietary fats is the ____________ _______________. |
small intestine |
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True or False? The formation of citrate from oxaloacetate in the Krebs cycle is not physiologically reversible. |
True |
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How many ATP are required for the reaction through lactic acid is converted into glucose in the liver? |
6 ATP |
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Sucrose is composed of _________ and _____________. |
glucose and fructose |
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True or False? Only the liver is available for blood sugar maintenance. |
True, tissue glycogen stores in the liver can help to maintain normal blood sugar. |
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The substrate for the committed step in glycolysis is _________________. |
fructose-6-phosphate |
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The TCA cycle is initiated by the condensation of ________________ and ____________________. |
acetyl-CoA and oxaloacetate |
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Bile salts are stored in the ________________. |
gallbladder |
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Which hormones cause the liver to break down glycogen and carry out gluconeogenesis? |
glucagon and epinephrine |
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Blood glucose levels cannot by increased by muscle glycogen degradation because muscle lacks __________________. |
glucose-6-phosphatase |
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Most nutrients are absorbed in the _____________. |
small intestine |
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The glucose-alanine cycle serves to: |
transport carbons and nitrogen from skeletal muscle to liver |
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The enzyme which catalyzes the entrance of acetyl-CoA into the Krebs Cycle? |
citrate synthase |
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The hormone ____________ works primarily in the muscle. |
epinephrine |
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The hormone __________ works primarily in the liver. |
glucagon |
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In the pyruvate dehydrogenase complex... |
it catalyzes the conversion of pyruvate into acetyl-CoA and CO2 |
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True or False? Pepsin helps to digest protein in the small intestine. |
False |
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The TCA cycle does not occur in which cells of your body? |
red blood cells |
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The main organ that is responsible for keeping blood glucose levels steady between meals by making glucose via gluconeogenesis is the ___________. |
liver |
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Which hormone has the primary responsibility for directing energy metabolism in the fed state? |
insulin |
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Which of the following compounds should be eliminated from the diet of a patient suffering from galactosemia? |
lactose |
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What hormone is excreted from the chromaffin cells of the adrenal medulla? |
epinephrine |
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What is considered to be a major regulatory control point of the Krebs Cycle? |
citrate synthase |
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When simple compounds are combined into larger more complex molecules the reaction is considered: |
anabolic endergonic |
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Which hormone triggers the muscle to breakdown glycogen and carry out glycolysis? |
epinephrine |
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The beta-oxidation of fatty acids: |
occurs in the mitochondrial matrix |
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Enzymes for the synthesis of oleic acid from palmitic are located in the ________________ ________________. |
endoplasmic reticulum |
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De novo fatty acid synthesis occurs in the ___________________. |
cytosol |
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What apoproteins serves as a cofactor (activator) for lecithin: cholesterol (LCAT)? |
APO AI |
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True or False? Linoleic fatty acid is synthesized in humans. |
False |
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Fatty oxidation is a major source of energy in many tissues EXCEPT the ______________. |
brain |
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In humans, fatty acids... |
can be synthesized from excess dietary carbohydrates and protein |
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Membrane fluidity: |
increase as the percentage of unsaturated fatty acids increases |
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Citrate regulates fatty acid metabolism by: |
stimulating acetyl-CoA carboxylase |
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What is not a lipid type found in the membrane? |
Triglycerides |
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Lipids are most efficient forms of biologically stored energy because they are: |
highly reduced |
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The coenzyme involved in the synthesis of malonyl-CoA from acetyl-CoA is ______________. |
Biotin |
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The function of fatty acytl-CoA dehydrogenase of beta-oxidation is most similar to that of ___________________ __________________. |
Succinate dehydrogenase |
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The principal apoprotein in LDL is: |
apo B-100 |
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Which phospholipid would migrate closer to the "+" plus electrode in an electrophoresis gel cell at the pH of 7? |
Phospatidylserine |
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Which lipoprotein possesses the highest concentration of protein? |
HDL |
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An important function of high density lipoproteins (HDL) is the: |
acquisition of cholesterol from tissues and other lipoproteins |
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A ceramide is composed of _____________ and _________________. |
sphingosine and fatty acid |
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True or False? Chylomicrons are synthesized in the liver. |
False |
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True or False? Alpha-keto-glutarate is NOT a ketone body. |
True |
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During biosynthesis of saturated fatty acids, the addition of every two-carbon unit requires? |
2 NADPH+2H+1ATP |
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Lipoprotein lipase is found in ______________. |
lysosomes |
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Transfer of cholesterol from membranes to HDL requires ________ ______________ _______________. |
lecithin cholesterol acyltransferase |
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For transport across the inner mitochondrial membrane, long chain fatty acids are attached to ____________. |
carnitine |
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__________ ___________ biosynthesis does not occur in the mitochondria. |
Fatty acid |
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Cholesterol is metabolized in the mammalian body primarily by conversion to ____________ ____________. |
bile acids |
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Most of the triglyceride in serum is contained in __________ and ______________. |
VLDL and chylocmicrons |
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The lipoproteins made de novo in the intestine or liver and secreted into the bloodstream are ___________, ________________ and _____________. |
chylomicrons, VLDL and HDL |
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What is the main function of beta-oxidation? |
Degradation of fatty acids |
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Chylomicrons mainly carry _____________. |
dietary triglycerides |
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The major site of formation and release of acetoacetate is ____________. |
liver |
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The steps of beta-oxidation parallel portions of: |
Krebs cycle |
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In the metabolism of cholesterol in the human: |
cholesterol conversion to bile salts involves shortening of the side chain of cholesterol |
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A condition that favors increased ketone body synthesis is : |
increased lipolysis in adipose tissue |
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The mobilization of fat from adipose tissue requires the enzymatic activity of _________________ __________________. |
hormone-sensitive lipase |
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Differences in bilayer fluidity among human cell membranes are due to: |
the ratio of cholesterol to phospholipids |
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What is the rate limiting step in the conversion of triglyceride to free fatty acid in adipose tissue? |
hydrolysis by the hormone-sensitive lipase |
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Very low density serum lipoproteins transport: |
triacylglycerol from the liver to adipose tissues |
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In the cell, squalene is... |
a hydrocarbon that may undergo attack by oxygen to tom an epoxide |