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Flashcards in Exam 2 Review Deck (26):
1

A karyotype is often used to identify _____.

rearrangements and large cytogenetic changes

2

Which of the following is true of X inactivation?

(A) It occurs late in embryonic life

(B) It is usually non-random which leads to skewing

(C) It affects 85-90% of one X-chromosome

(D) The inactive X varies from cellular generation to generation

(E) It is not affected by autosomal gene products

(C) It affects 85-90% of one X-chromosome

3

The genetic consequence of meiotic recombination between chromosomes in which one of the pair has either a pericentric or paracentric inversion is usually:

half defective gametes

4

A newly discovered gene is responsible for X-linked recessive susceptibility to premature COPD (Chronic obstructive pulmonary disease). A study reveals that disease prevalence is ~ 1/400. Assuming Hardy-Weinberg equilibrium, which statement is true?
(A) 1/20 of males carry the mutant allele
(B) 1/20 of females carry the mutant allele
(C) 1/400 of females have the disease
(D) 1/160,000 of females have the disease
(E) males never have this disease

1/400 gives you a direct measure of q.

(D) 1/1600000 of females have the disease

5

A woman is admitted to the hospital for excessive bleeding and is discovered to have an X-linked recessive form of hemophilia. Her doctors are perplexed since this is usually only seen in boys. You, the third year medical student, mention to them that there are certain circumstances under which a female may exhibit an X-linked recessive condition. All of the following are possible explanations for this presentation in a woman EXCEPT:

(A) a new (de novo) hemophilia mutation in one of her hemophilia genes
(B) Turner syndrome
(C) unfavorable or skewed X-inactivation
(D) receiving two copies of the hemophilia gene - one from each of her parents
(E) an X:autosome translocation resulting in inactivation of the X that has the normal or functional hemophilia gene

(A) a new (de novo) hemophilia mutation in one of her hemophilia genes

6

Which process in secretory epithelial lung cells is the primary cause of sticky mucus in cystic fibrosis patients?

(A) persistent infection by opportunistic bacteria
(B) aberrant chloride channel activity
(C) defective active transport of chloride ions
(D) high concentration of salt in sweat
(E) defective aquaporin membrane channels

(B) aberrant chloride channel activity

7

A cardinal feature of myotonic dystrophy is

locus heterogeneity
anticipation

8

All of the following are substrates for gluconeogenesis except

(A) lactate
(B) glycerol
(C) alanine
(D) glutamate
(E) glycogen

(E) glycogen

9

Phosphoenolpyruvate

(A) is formed from enolpyruvate by the addition of inorganic phosphate

(B) is formed from pyruvate by donation of electrons to FAD

(C) contains a high energy phosphate bond that can be used to phosphorylate ADP

(D) is formed from 1-phosphoglycerate by addition of water across a double bond

(E) is the immediate substrate needed for the formation of alpha glycerol phosphate

C) contains a high energy phosphate bond that can be used to phosphorylate ADP

10

In the conversion of pyruvate to glucose during gluconeogenesis

(A) biotin is required
(B) CO2 is added in one reaction and released in another
(C) energy in the form of GTP and ATP is utilized
(D) all of the above

(D) all of the above

11

Which of the following hormonal changes in plasma is likely to alter synthesis of fatty acids?

(A) increased glucagon concentration would favor increased fatty acid synthesis by elevating the rate of glucose oxidation in the liver
(B) increased insulin concentration would favor increased fatty acid synthesis by mediating the conversion of Acetyl CoA carboxylase to its phosphorylated form
(C) increased glucagon concentration would cause a decrease in fatty acid synthesis by mediating phosphorylation of active acetyl CoA carboxylase to its phosphorylated form
(D) increased insulin concentration would lower fatty acid synthesis by inhibiting glucose transport into the liver
(E) alteration of glucagon or insulin concentration has no effect on fatty acid synthesis

(C) increased glucagon concentration would cause a decrease in fatty acid synthesis by mediating phosphorylation of active acetyl CoA carboxylase to its phosphorylated form

think of insulin (ANABOLIC) as leading to fatty acid synthesis

12

Fatty acids are oxidized
(A) in the cytosolic compartment of the cell
(B) in the intermembrane space of mitochondria
(C) in the rough endoplasmic reticulum
(D) as fattyacyl CoA esters
(E) answers C and D are both correct

(D) as fattyacyl CoA esters

13

The glycerol phosphate shuttle

uses an FAD linked enzyme in the mitochondria

14

Cytochrome c

(A) is the most tightly bound cytochrome in the electron transport chain

(B) undergoes release from the mitochondria in order to protect cells from apoptosis

(C) accepts electrons from NADH but not from FADH2

(D) is an intermediary electron carrier between complexes III and IV

(E) is the ultimate donor of electrons to FAD in mitochondrial electron transport

A. It is the least tightly bound cytochrome and even can be released from mitochondria signaling apoptosis.

15

The accumulation of glycogen with short outer branches can be demonstrated in cells from patients with Glycogen Storage Disease Type

Type III

16

The most abundant plasma protein is

albumin

17

Accumulation of H2O2 causes ulcerations and an increased plasma level of methemoglobin. Which of the following enzymes are responsible for the elimination of H2O2?
(A) pyruvate carboxylase and catalase
(B) pyruvate carboxylase and hydrogen peroxide
(C) nitric oxidase and catalase
(D) catalase and glutathione peroxidase
(E) nitric oxidase and pyruvate carboxylase

(D) catalase and glutathione peroxidase

18

Which of the following blood clotting factors operates in the extrinsic pathway?

(A) VII
(B) VIII
(C) IX
(D) XII
(E) XI

(A) VII

19

Hemopexin is a plasma protein that

(A) Maintains the colloid osmotic pressure
(B) Binds and transports copper
(C) Binds to heme
(D) Is required for the oxidation of iron
(E) Is the major transport protein for fatty acids

(C) Binds to heme

20

A boy with recurrent episodes of hypoglycemia and ataxia, microcephaly, mental retardation, permanent lactic acidemia, intermittent 2-oxoglutaric aciduria as well as elevation of serum branched chain amino acids was investigated. Dihydrolipoamide dehydrogenase and pyruvate dehydrogenase complex activities in muscle were 29% and 14% of the lowest control values, respectively. In this patient the lactic acidemia is most directly related to

A. conversion of leucine to lactic acid.
B. decarboxylation of oxaloacetate.
C. increased reduction of pyruvate.
D. decreased reduction of lipoamide residues in the pyruvate dehydrogenase complex.
E. increased contractility in muscle tissue.

C. increased reduction of pyruvate.

D. decreased reduction of lipoamide residues in the pyruvate dehydrogenase complex.

21

GTP is formed in the tricarboxylic acid (Krebs) cycle in a reaction that also results in the formation of

A. succinate.
B. malate.
C. citrate.
D. oxaloacetate.
E. fumarate.

A. succinate

22

The enzymes in the tricarboxylic acid cycle occur in the

A. nucleoli.
B. mitochondrial matrix.
C. cytosol.
D. plasma membranes.
E. outer mitochondrial membranes.

B. mitochondrial matrix.

23

The malate-aspartate shuttle

A. generates an NADH inside the mitochondria for every NADH that is oxidized outside.

B. requires the action of an FAD-linked dehydrogenase.

C. requires the diffusion of oxaloacetate through the inner mitochondrial membrane.

D. is coupled to the transport of ATP into mitochondria.

E. facilitates the reduction of pyruvate in the cytosol

A. generates an NADH inside the mitochondria for every NADH that is oxidized outside.

24

A deficiency in what enzyme causes chronic granulomatous disease?

NADH oxidase

25

In the Fenton reaction, ferrous iron and hydrogen peroxide react to form

a hydroxyl radical.

26

A 2-month -old child was taken to his family doctor because of lethargy, feeding difficulties, and yellowish skin. Physical examination revealed jaundice, cataracts and hepatomegaly. Growth and development were in the fifth percentile. These symptoms would be most characteristic of the accumulation of

Galactose 1 phosphate