2013 biochem endterm Flashcards
Which of the following zygomens is activated by autocatalysis in our body?
A) Pepsinogen
B) Chymotrypsinogen
C) Proelastase
A) Pepsinogen
How does our body appose ketoacidosis during prolonged starvation?
A) increase production of ketone bodies
B) increase activity of urea cycle
C) increase release of ammonia from glutamine by the kidneys
D) Increase lipogenesis
C) increase release of ammonia from glutamine by the kidneys
Where can you find complex carbohydrates in the plasma membrane? A) Inner core B) extracellular surface C) Core leaflet D) Intracellular surface
B) extracellular surface
Phenylketonuria is what type of inborn error of metabolism? A) amino acid metabolism B) carbohydrate metabolism C) lipid metabolism D) purine metabolism E) pyrimidine metabolism
A) amino acid metabolism
What kind of mutation is mostly found in phenylalanine hydroxylase in PKU? A) Deletion B) Missense C) Insertion D) Splice
B) Missense
Cystic fibrosis is what type of inborn error of metabolism? A) amino acid metabolism B) carbohydrate metabolism C) lipid metabolism D) purine metabolism E) pyrimidine metabolism
A) amino acid metabolism
What is the genetic cause of cystic fibrosis? A) Missense B) Insertion C) Deletion D) Splice
C) Deletion
What is the use of ketones bodies during prolonged starvation?
A) Energy production in the brain
B) Energy production in the liver
C) Gluconeogenesis
A) Energy production in the brain
Which of the following can be converted to 2-deoxyribose? A) Adenosine B) AMP C) ATP D) ADP
D) ADP
What produces ketone bodies during prolonged starvation ( >21 days)?
A) Glycerol from adipose
B) fatty acids from adipose
C) Lactic from RBC
D) Branches chain amino acids from skeletal muscle
B) fatty acids from adipose
What increases the fluidity in the plasma membrane?
A) Cis-unsaturated fatty acids
B) Trans-unsaturated fatty acids
C) Integral proteins
A) Cis-unsaturated fatty acids
What is the most common product of transamination reactions? A) Alanine B) Pyruvate C) Leucine D) Glutamate E) Trytophan
D) Glutamate
What is the characteristic of aminotransferase?
A) must have glutamine or alpha-ketoglutarate
B) always net production of glutamate
C) can’t catalyze essential amino acids
D) uses pyridoxal phosphate as a cofactor
D) uses pyridoxal phosphate as a cofactor
What carbohydrates is used in both de-novo synthesis of purine & salvage pathways?
A) Ribose-5-phosphate
B) Phosphribosylpyrophosphate
C) Adenosine
B) Phosphribosylpyrophosphate
What is the most acidic phospholipid in the cell? A) cardiolipin B) sphingomyelin C) PS D) PC
A) cardiolipin
Which of these is a feature of Trans fats? A) Absence in the mother’s milk B) good substrate for lipase C) Long half life D) Can’t be absorbed by small intestine E) Rapid degradation in the saliva
C) Long half life
which set of desaturases are present in our body?
A) ∆ 4,5,6,9 desaturases
B) ∆ 3,5.6.9 desaturases
C) ∆ 4,6,9,12 desaturases
A) ∆ 4,5,6,9 desaturases
which lipase needs a colipase? A) pancreatic lipase B) phospholipase C C) hepatolipase D) hormone sensitive lipase
A) pancreatic lipase
What facilitates the packing of good cholesterol into HDL? A) Cardiolipin B) Leukotrienes C) Phosphotidylcholine D) LCAT
D) LCAT
What is the effect of prolonged trans-fat consumption?
a. Suppressing the activity of LDL receptors
b. Activating the activity of LDL receptors
a. Suppressing the activity of LDL receptors
Inhibition of which protein function results in an increase in HDL cholesterol & decrease in LDL cholesterol simultaneosly? A) ApoE receptor B) CETP C) INSIG D) LDL receptors E) SCAP
B) CETP
Which of these substances cannot be absorbed from the GI tract?
A) Trans Fatty acid
B) Olestra
C) cis fatty acid
B) Olestra
Which substance enhances the oxidation of odd-chain fatty acid? A) ATP B) Citrate C) Vitamin B12 D) NAD+
C) Vitamin B12
What is the normal physiological function that will be affected if we block farnesylation of RAS protein to slow down cancer rate?
A) Alpha oxidation
B) Beta oxidation
C) glycosyl phosphatiydl inositol formation
D) HDL receptor acylation
E) Cholesterol formation
E) Cholesterol formation
What is the main regulator of the Pentose Phosphate Pathway? A) NADP+/NADPH B) AMP/ATP C) NAD+/NADH D) Glucose 6-Phosphate
A) NADP+/NADPH
The lack of fructokinase causes fructose intolerance even though hexokinase catalyzes the phosphorylation of fructose. What property of hexokinase causes fructose intolerance?
A) high Km for fructose
B) low Vmax
C) feedback inhibition by fructose 6 phosphate
D) feedback inhibition by glucose 6 phosphate
A) high Km for fructose
What is produced in Fenton reaction? A) Hydroxyl radical B) Hydrogen peroxide C) Superoxide radical D) Peroxinitrite
A) Hydroxyl radical
What are ketone bodies used for? A) Energy production in the brain B) Energy production in the liver C) Gluconeogenesis in the kidney D) Fatty acid synthesis in adipose tissue
A) Energy production in the brain
What increases respiration? A) ADP B) NADH C) FADH2 D) queinone
A) ADP
What product of PPP is critical for antioxidants function in the cell?
A) NADPH
B) ATP
C) Ribose-5-phosphate
A) NADPH
What property of the enzyme that catalyzes the first step of glycolysis allows the liver to buffer blood glucose?
A) high Km
B) inhibition by ATP
C) inhibition by glucose-6-phosphate
D) activation by fructose 1,6 bisphosphate
A) high Km
What is the free electron carrier in the inner mitochondrial membrane? A) coenzyme A B) FADH2 C) NADH2 D) Fe-S chain
A) coenzyme A
How are 2 phases of glycolysis synchronized?
A) feedback inhibition of PFK-1
B) feed-forward activation of pyruvate kinase
C) feedback inhibition of Pyruvate dehydrogenase
D) phosphorylation of PFK-1
B) feed-forward activation of pyruvate kinase
What is the function of Acyl CoA synthase?
Activate fatty acids for metabolic reactions
What is increased when uncouplers are expressed? A) ATP synthesis B) Glucogenesis C) Proton gradient D) Thermogenesis
D) Thermogenesis
Pyruvate carboxylase is activated by acetyl CoA. The effect is:
A) pyruvate oxidation
B) activation of gluconeogenesis
B) activation of gluconeogenesis
From which component are ketone bodies produced? A) Acetyl CoA B) Lactate C) Glucose D)Triacylglycerol
A) Acetyl CoA
What is the endogenous source for ROS in aerobic organisms?
A) Radiation
B) Quinones
C) Respiration
C) Respiration
Patients with peroxisomal disorders can’t break down which of the following?
A) very long chain fatty acids (C=20)
B) fatty acids with branches on Beta Carbon
C) short chains of fatty acid
A) very long chain fatty acids (C=20)
