Cellular Biochemistry

Question 1

Function of RT-PCR

Answer 1

Detects and Quantifies mRNA

Question 2

Function of Rough Endoplasmic Reticulum

Answer 2

Cell membrane Protein Synthesis

Question 3

Function of Smooth Endoplasmic Reticulum

Answer 3

Lipid Synthesis

Question 4

Function of Fibronectin

Answer 4

Binds to integrins, serving as mediator of cell adhesion and migration

Question 5

RAS Gene Inactive in

Answer 5

Inactive in GDP bound state

Question 6

RAS Gene Active in

Answer 6

GTP bound state

Question 7

Function of Ubiquitin

Answer 7

Labelling proteins for degradation by Proteasomes

Question 8

Fasting State Hormones

Answer 8

Glucagon and Epinephrine

Question 9

Prolonged Fasting State Hormones

Answer 9

Cortisol

Question 10

Amino Acids Needed for Purine Synthesis

Answer 10

Glycine, Aspartate and Glutamate

Question 11

Action of 5 Flurouracil

Answer 11

Inhibition of Methylation of Uracil to Thymine

Question 12

Nucleosome

Answer 12

Negatively charged DNA loops twice around positively charged histone octamer

Question 13

Which phase does DNA and histone synthesis occur

Answer 13

S phase

Question 14

HISTONE METHYLATION

Answer 14

Histone Methylation Mostly Makes DNA Mute.

Question 15

HISTONE ACETYLATION

Answer 15

Histone Acetylation makes DNA Active.

Question 16

Mitochondrial DNA

Answer 16

Most common non-nuclear DNA found in eukaryotic cells
Small circular chromosomes.

Question 17

Mitochondrial DNA mutation

Answer 17

Diseases arising from mutations in mtDNA are transmitted from the mother to all of her offspring.

Question 18

What are the amino acids needed for pyrimidine synthesis

Answer 18

Aspartate and Glutamine

Question 19

What are the amino acids needed for Purine synthesis

Answer 19

Glycine
Aspartate
Glutamine

Question 20

Precursor for all pyrimidines

Answer 20

Orotic acid

Question 21

What are Telomeres

Answer 21

Long stretches of repetitive sequences at the end of chromosomes.

Question 22

Importance of telomeres

Answer 22

When the length of telomeres is exhausted, the cells often become quiescent or undergo apoptosis

Question 23

Exons

Answer 23

Contain the actual genetic information coding for
protein.

Question 24

Introns

Answer 24

Intervening non coding segments of DNA.

Question 25

Function of NADPH

Answer 25

1. Cholesterol and Fatty acid synthesis 2. Antioxidant mechanism for RBC

Question 26

Function of Telomerase

Answer 26

Adds TTAGGG to 3’ end of chromosome

Question 27

Topoisomerase function

Answer 27

Prevents supercoiling and strand breakage

Question 28

Nucleotide Excision Repair

Answer 28

Remove large distortion (Answer if *UV Light Damage* in question)

Question 29

Base Excision Repair

Answer 29

Removal of Single base (Answer if question mention glycosylases)

Question 30

Recombinational dsDNA repair

Answer 30

Defect repaired using complimentary strands from homologous dsDNA (Answer if question mentions BRACA or Fanconi Anemia)

Question 31

Splice Site mutation

Answer 31

Intron retained in mRNA (Answer if question with mutation of intron sequence)

Question 32

Smooth Endoplasmic Reticulum function

Answer 32

Synthesises steroids and lipids

Question 33

Rough Endoplasmic Reticulum function

Answer 33

Protein synthesis for use outside cell

Question 34

Free Ribosome function

Answer 34

Produce proteins which are used intracellularly

Question 35

Golgi body function

Answer 35

Process and package proteins

Question 36

Location of enzyme defect in I cell disease

Answer 36

Golgi body

Question 37

Enzyme inhibited by Arsenic

Answer 37

Pyruvate Dehydrogenase

Question 38

Enzyme affected in Mushroom Poisoning (Amanita phalloides)

Answer 38

RNA Polymerase 2

Question 39

Wnt Pathway

Answer 39

Controls migration of cells essential for embryogenesis

Question 40

NF-k beta pathway

Answer 40

Leads to activation of immune cells

Question 41

Action of Insulin

Answer 41

Increase Lipogenesis Increase glycolysis Increase glycogenesis Decrease Gluconeogenesis

Question 42

Lab values in Vitamin D deficiency

Answer 42

Decreased calcium Decreased Phosphate Decreased Calcitriol Increased PTH

Question 43

Which DNA repair mechanism can repair neurons

Answer 43

Non Homologous End Joining

Question 44

What is the result of methylation of CpG islands within the promoter region?

Answer 44

Repression of gene transcription (CpG methylation makes DNA mute)

Question 45

What process changes the expression of a DNA segment without changing the sequence

Answer 45

DNA methylation

Question 46

Which enzyme is affected in orotic aciduria?

Answer 46

UMP synthase

Question 47

What enzyme do mycophenolate and ribavirin inhibit?

Answer 47

Inosine monophosphate dehydrogenase

Question 48

What drug inhibits dihydroorotate dehydrogenase

Answer 48

Leflunomide

Question 49

Dihydrofolic acid (DHF) is converted to tetrahydrofolic acid (THF) by which enzyme

Answer 49

Dihydrofolate reductase

Question 50

Name 2 drugs that decrease deoxythymidine monophosphate (dTMP)

Answer 50

5-Fluorouracil (5-FU) Methotrexate (MTX)

Question 51

(dUMP) is converted to deoxythymidine monophosphate (dTMP) by which enzyme?

Answer 51

Thymidylate synthase

Question 52

mechanism of action of drug 6-mercaptopurine and azathioprine

Answer 52

blocking conversion of phosphoribosyl pyrophosphate (PRPP) to inosine monophosphate

Question 53

Name the key intermediate that is common to the de novo synthesis pathway of both purines and pyrimidines.

Answer 53

Phosphoribosylpyrophosphate (PRPP)

Question 54

Lesch-Nyhan syndrome

Answer 54

self-mutilation behaviors, intellectual disability, gout and lactic acidosis

Question 55

Lesch-Nyhan syndrome finding on blood smear is

Answer 55

Hyper segmented neutrophils

Question 56

severe combined immunodeficiency disease (SCID) is due to

Answer 56

Deficiency of adenosine deaminase

Question 57

SCID clinical features

Answer 57

Absence of a thymus Failure to thrive Recurrent infections A low WBC count

Question 58

Mechanism of rasburicase

Answer 58

Converting uric acid to soluble allantoin

Question 59

7-year-old complaining of frequent, severe, debilitating episodes of pain in her arms and legs that resolve after a few days. The patient appears fatigued and has pale conjunctivas. Her abdomen is soft with palpable splenomegaly.

Answer 59

Sickle cell anemia (Missense mutation)

Question 60

What 2 processes occur during the M phase

Answer 60

Mitosis (splitting of the nucleus) and cytokinesis (splitting of the cytoplasm)

Question 61

Site of synthesis of Insulin

Answer 61

Rough endoplasmic reticulum.

Question 62

Ataxia, scaly skin, long-standing night blindness, and shortened 4th toes

Answer 62

Refsum disease

Question 63

Zellweger syndrome - clinical manifestations

Answer 63

Hepatomegaly, hypotonia, and seizures

Question 64

Which enzyme regenerates UDP-glucose from UDP-galactose

Answer 64

4-epimerase

Question 65

Why might high succinyl-CoA levels still be noted after treatment of anemia due to vitamin B12 deficiency?

Answer 65

decreased vitamin B6 (which is required for the conversion of succinyl-CoA to heme)

Question 66

Which cofactor is used in the conversion of dopamine to norepinephrine

Answer 66

Vitamin C

Question 67

How does the presence of excess ammonia result in inhibition of the tricarboxylic acid cycle (TCA)

Answer 67

Hyperammonemia depletes α-ketoglutarate stores, a key TCA intermediate

Question 68

What are the 3 direct electron transport inhibitors of complex IV?

Answer 68

Cyanide, carbon monoxide, and azide (the -ides);

Question 69

What compound directly inhibits complex I

Answer 69

Rotenone (inhibits complex one)

Question 70

How does oligomycin affect ATP production in the electron transport chain

Answer 70

Inhibits mitochondrial ATP synthase

Question 71

What compound directly inhibits complex III

Answer 71

Antimycin A

Question 72

Enzymes inhibited in Lead Poisoning

Answer 72

δ-aminolevulinic acid dehydratase and ferrochelatase

Question 73

Thyroid hormone is made from which Amino Acid

Answer 73

Tyrosine, and the amino acid phenylalanine is a precursor to tyrosine.

Question 74

What is the main component of pulmonary surfactant

Answer 74

Phosphatidylcholine

Question 75

milky-white plasma on Blood draw

Answer 75

Type 1 familial dyslipidemia

Question 76

skin blistering on sun-exposed areas of his body Tea-colored urine mildly elevated transaminases

Answer 76

porphyria cutanea tarda (PCT)

Question 77

porphyria cutanea tarda (PCT) deficiency of

Answer 77

uroporphyrinogen decarboxylase

Question 78

Function of Vitamin K

Answer 78

Carboxylation of glutamic acid residues

Question 79

Mechanism of Absorption of Vitamin A

Answer 79

Micelle-mediated transport

Question 80

Mechanism of Absorption of Iron

Answer 80

apoferritin-mediated transport

Question 81

Mechanism of Absorption of Vitamins B7, B5 and C

Answer 81

Sodium-dependent cotransport

Question 82

Mechanism of Absorption of Calcium

Answer 82

Vitamin D–dependent binding protein–mediated transport

Question 83

Why Niacin is used with caution to control dyslipidemia in Diabetics

Answer 83

Excess Niacin can result in Hyperglycemia

Question 84

Findings in Vitamin K Deficiency

Answer 84

Increased PT Increased APTT Normal BT

Question 85

What is the marker for Nucleus

Answer 85

DNA, RNA Polymerase

Question 86

What is the marker for Lysosome

Answer 86

Acid Phosphatase

Question 87

What is the marker for Peroxisome

Answer 87

Catalase

Question 88

What is the marker for Cytosol

Answer 88

LDH

Question 89

What is the marker for Rough ER

Answer 89

Glucose 6 Phosphatase