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Flashcards in Pre Midterm Deck (18)
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1

Fibril forming collagen.

Type I, II, III

2

Fibril-associated collagen.

Type IX, XII

3

What type of OI is considered as the most severe, typically lethal in the perinatal period and is also associated with in utero fractures?

Type 2

Type 1: most common, mild
Type 3: multiple fx at birth

4

Pyruvate is the end product of glycolysis. What is the alternate fate of pyruvate?
A. Oxidative decarboxylation via pyruvated dehydrogenase complex is an important pathway in RBC
B. Carboxylation of pyruvate to oxaloacetate is a folate-dependent reaction.
C. Lacates is the final product of glycolysis in the cells of lens and cornea of the eye.
D. Decarboxylation of pyruvate predominantly occurs in humans.
E. B an C are accurate"

C. Lactate is the final product of glycolysis in the cells of lens and cornea of the eye.

Anaerobic glycolysis-lens/cornea, testes, renal medulla, leukocytes, rbc. Statement A refers to organs with high oxidative capacity (eg. Muscle), Statement B- it pyruvate carboxylase is a biotin dependent reaction. Statement C-Pyruvate decarboxylation is predominantly found in yeasts.

5

Enzyme that functions as glucose sensor in B cells of pancreas thus determine the threshold for insulin secretion, in the liver also facilitates glucose phosphorylation.
A. Hexokinase
B. Glucokinase
C. Aldolase A
D. Aldolase B
E. Isomerase

Glucokinase

Hexokinase phosphorylates glucose and permits metabolism even in low concentrations of glucose.

Aldolase A is the enzyme responsible in cleaving Fructose 1,6-bisphosphate to DHAP and Glyceraldehyde 3-phosphate.

Aldolase B is used in fructose metabolism. Isomerase, in the setting of glycolysis, interconverts glucose 6-phosphate and fructose 6-phosphate.

6

PFK-1 is the most important control point and the rate limiting and committed step in glycolysis. What is the most potent activator of PFK-1?

Fructose 2,6-biphosphate

F2,6 BP is the most potent activator of PFK 1. It is able to activate the enzyme even in high ATP concentrations. ATP and citrate(indicative of high energy states) both inhibit the enzyme. AMP is an allosteric activator which is an intracellular signal of depleted energy.

7

2y/o child presented with severe fasting hypoglycemia, lactic acidemia, and hyperuricemia. What is likely diagnosis?
A. McArdle
B. Pompe
C. Hers
D. Andersen
E. Von Gierke

Von Gierke disease

Glucose 6 phosphatase deficiency prevents liver from releasing free glucose into the blood, causing severe hypoglycemia, lactic acidemia, hyperuricemia and hyperlipidemia.

8

What property of water makes it universal solvent?
A. Water as a A1:E253
B. Formation of hydrogen bond
C. Water is amphoteric
D. Water is amphipathic
E. Water has a high dielectric constant

High dielectric constant.

water having a high dielectric constant, greatly decreases the force of attraction betweem charged and polar species

9

Measure of the change in randomness or disorder of the reactants and products. its unit of measurement is joules/kelvin.

Entropy

10

The following amino acids are considered basic:
A. Histidine,Arginine,Leucin
B. Histidine.Glycine, Gutamine
C. Leucine, lycine
D. Lycine,arginine, histidine
E. None of the above

Lycine, arginine, histidine

11

What amino acid can be synthesized from 3- phosphoglycerate?
A. Glutamine
B. Cysteine
C. Serine
D. Glycine
E. Tyrosine

Serine

Glutamine: synthesized from glutamate;
Cysteine: synthesized from methionine;
Glycine: synthesize from serine;
Tyrosine: synthesized from phenylalanine

12

What enzyme is deficient in alkaptonuria?
A. Homogentisic oxidase
B. Glucocerebrosidase
C. Ceramidase
D. Phenylalanine hydroxylase
E. BCAA dehydrogenase deficiency

Homogentisic oxidase

Gaucher: Glucocerebrosidase
Farber disease: Ceramidase
PKU: Phenylalanine hydroxylase
Maple syrup urine disease: BCAA dehydrogenase deficiency

13

Purine ring is constructed by adding C and N to preformed ribose-5-phosphate. Which amino acids act as sources of atoms in purine synthesis?

Aspartate and Glutamine

aspartic acid, glycine, glutamine, CO2 and formyltetrahydrofolate are the sources of atoms in purine synthesis.

14

The genetic code has different characteristics. Which characteristic describes that a given amino acid may have more than one triplet coding for it?
A. Degenerate
B. Specific
C. Redundant
D. Universal
E. A and C

E. A and C
Degenerate& Redundant

Degenerate and redundant means the same thing.

Universal: it has been conserved from the early stages of evolution with only slight differences in the mannerin which the code is translated;

Specific: a specific codon always codes for the same amino acid.

15

Which of the following enzymes participating in the TCA is capable of substrate level phosphorylation?
A. Citrate synthase
B. Isocitrate dehydrogenase
C. Malate dehydrogenase
D. Succinate thiokinase
E. Fumarase

D. Succinate thiokinase

The enzyme succinate thiokinase, converts succinyl coa to succinate and yields GTP

16

Which of the following statements accurately describe the properties displayed by amino acids?
A. Predominant form is the D-form
B. Only glycine is considered chiral
C. Simplest amino acid is glycine
D. Proline is an imino acid
E. C and D

E. C & D
C. Simplest amino acid is glycine
D. Proline is an imino acid

Amino acid occurs predominantly in the L-form. And all AA are chiral except for glycine. It is also the simplest amino acid.Proline is considered an imino acid.

17

Which of the following factors/conditions shifts the hemoglobin-dissociation curve to the left?
A. Increase in H+ concentration B. Acidosis
C. Inrease in pH
D. Hypothermia
E. C and D

E. C and D
C. Inrease in pH
D. Hypothermia

Alkalosis,decreased CO2, decreased temp all shifts the hb dissociation curve to the left.

18

Which group of antibiotic binds irreversibly to the 50s subunit of the bacterial ribosome, thus inhibiting translocation?
A. Clindamycin
B. Erythromycin
C. Tetracycline
D. A and B
E. All of the above

E. All

Tetracycline prevents binding of aminoacyl tRNAs to the A site.

Streptomycin binds to the 30s subunit and distorts its structure, interfering with the initiation of protein synthesis.

Chloramphenicol inhibits prokaryotic peptidyltransferase.