PART 2: mixed topics Flashcards
Cyanide poisoning is fatal. This is because cyanide has this effect of the electron transport chan:
inhibits cytochrome oxidase
The precursor of the sugar-phosphate moieties in the de novo synthesis of both purine and primidine nucleotide is
ribose 5 phosphate
The highest reservoir of calories in muscle tissue is
proteins
Deficiency in the intake of carbohydrates and fats can lead to:
increase protein requirements
Gluconeogenesis is the major source blood sugar during _________
prolonged fasting
The receptor involved in the G-protein coupled signal transduction pathway:
Beta-adrenergic receptor
This is the mechanism of action by which PENICILLIN kills bacterial cells:
it covalently binds to the active site of the enzyme for cell wall synthesis
TRUE of Vitamin K
it functions as a cofactor to carboxylase that acts on glutamate residues of clotting factor precursors proteins
Kwashiorkor occurs when there is
lack of calories and protein in diet
Cancer can be attributed to mutation in the DNA. A mutation that converts an amino acid codon to a stop codon is
nonsense
The process by which a polypeptides destination in the cell is determined by
signal peptides
The type of histones: uniquely associated with the linker DNA
H1
Cytidine is a _______
nucleoSIDE
TRUE about the salvage pathway of purine nucleotide synthesis is correct?
Deficiency of hypoxanthine-guanine phosphoribosyl transferase is the cause of Lesch-Nyan syndrome (overproduction of uric acid)
______ is the source of MOST blood glucose during starvation:
alanine
An individual who has fasted for more than 24 hours will have increased production of
glutamine and alanine
excessive ingestion of raw eggwhite is detrimental because it inhibits this step in extramitochondrial lipogenesis:
formation of malonyl coA
Semi-conservative replication of DNA means:
each new DNA strand forms a pair with the template strands
Ribosomal RNA contain
The anticodon
During RNA replication, which enzyme joins the okazaki fragments?
DNA ligase
Familial hypercholesterolemia is due to
deficiency or defective LDL receptors
most metabolically active plasma lipid
non-esterified fatty acid
Deficiency of lipoprotein lipase will result in a increased plasma level
VLDL
needed for transport of long-chain FAs from the cytosol to the mitochondrial matrix
carnitine
major enzyme that digest dietary triacylglycerol
pancreatic lipase
In the liver cholesterol is mainly disposed by:
being converted to bile acids
Immediate source of energy of ATP synthesis
electrochemical gradient
the link between the catabolic and anabolic reactions in the energy cycle is
ATP
function of pyridoxal phosphate
prosthetic group of transaminases
vitamin is solely synthesized by bacteria and is thus absent from all plants
Biotin (B7)
This vitamin is required for the synthesis of NTs like epinephrine:
Ascorbic Acid
deficiency of this mineral is prevalent among pregnant women living in mountainous areas:
Iodine
______ accumulates in carnitine deficiency in humans
odd-numbered fatty acids
The regulatory action involves a reversible covalent modification of an enzyme
phosphorylation of Ser hydroxyl on the enzyme
BEST explains why oxidation of FADH(2) produces less ATP than NADH
FADH(2) enters ETC via complex II
BEST applies to isoelectric pH of a protein
net charge is zero
what kind of reaction is interconversion of aldose and ketose?
isomerization
The beta pleated sheet of a protein is classified as which level of protein
secondary
What is the cause for the lactic acidosis that develops in thiamine deficiency?
conversion of pyruvate to acetyl-coA is blocked
collagen is _____ helix
triple helix
BEST explains the role of hydrochloric acid in the stomach
denature proteins
bond that stabilizes the primary structure of a protein
hydrogen
products of the action of salivary amylase on glycogen
maltose
A zwiterion is a molecule that contains ________
a cation and anion
The anemia that develops in patients on anti-malarial therapy may be due to deficiency of enzymes belong to what metabolic pathway?
hexose monophosphate
TRUE of the TATA box
binds RNA polymerase
SRS-A, the slow reacting substance of anaphylaxis, is composed of ______
leukotrienes
The regulation of cholesterol synthesis primarily occurs at which enzymatic site
3-hydroxy-3methylglutaryl coA reductase
What is the major source of reducing equivalents used for fatty acid synthesis
pentose phosphate pathway
Patients suffering from familial defect in ApoB 100 have significantly elevated levels of plasma LDLs. The reason for this is
inability of LDL to interact with the LDL receptor
What is the pharmacological benefit of the drug Lovastatin?
inhibits HMG-coA reductase
What vitamin combines with the opsin to form the visual pigment in the eye?
vitamin A
the cause of muscle fatigue following vigorous exercise
accumulation of lactate
an intermediate of pyrimidine biosynthesis is common to the urea cycle
carbomyl phosphate
Function of non-sense codons
they may be used in the cell as termination signals
Phase of protein synthesis does the release of newly synthesized polypeptide from the ribosome take place
termination
directs the polypeptides ultimate destination in the cell
signal peptides
What is the primary action of methotrexate, a chemotherapeutic agent?
displaces cells of folate
First reaction in the metabolism of all sugars
phosphorylation
site on the operon is the site of RNA polymerase binding
promoter
What is the cellular site of synthesis of messenger RNA?
ribosome
BEST applies to transfer RNA
exists in at least 20 different forms
Biological function of DNA synthesis
assures viability of the specie
the enzymes in replication that functions as proof-reading device
3 exonuclease
it constitutes the second level of organization of DNA
nucleosome
TRUE of okazaki fragments
fragments of DNA that are copied in direction away from replication fork
the post-transcriptional processing prevents 5 exonuclease attack
poly A tail
What reaction does the RNA-directed DNA polymerase catalyze?
synthesis of DNA complimentary to the RNA strand
During protein synthesis, which reads information in mRNA and transfers AA to a growing polypeptide chain?
transfer RNA
What is the cause of polyuria in diabetes mellitus?
osmotic diuresis
