1. Unesterified cholesterol is taken-up to serum lipoprotein and delivers to the
ID: 865471 • Letter: 1
Question
1. Unesterified cholesterol is taken-up to serum lipoprotein and delivers to the liver. Which serum lipoprotein plays this role?
a. Very-low-density lipoprotein
b.Low-density lipoprotein
c.High-density lipoprotein
d. Chylomicron
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2. The first step of de novo synthesis of fatty acids is synthesis of citrate from acetyl CoA and oxaloacetate in mitochondria. Citrate in mitochondria must move out to cytosol to continue de novo synthesis of fatty acids. Translocation of citrate occurs when citrate concentration in mitochondria is high. What does cause citrate concentration to rise in mitochondria?
a. High AMP concentration in mitochondria
b. High ADP concentration in mitochondria
c. High ATP concentration in mitochondria
d. High Ca++ concentration in mitochondria
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3. When fatty acids are used for generation of ATP, it produces number of Acetyl CoA, NADPH and FADH2.
a. All enter the TCA cycle to generate more ATP.
b. Only Acetyl CoA enters the TCA cycle to generate more NADPH.
c. All enter the pentose phosphate pathway to generate more ATP.
d. Only acetyl CoA enters the TCA cycle to generate more GTP, NADH and FADH2.
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4. Receptor for glucagon is
a. Located in nucleus and has kinase activity.
b. Located on cell surface and has kinase activity.
c. Located on cell surface and is G-protein coupled receptor type.
d. Located on mitochondria and is G-protein coupled receptor type.
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5. Very-low-density lipoprotein (VLDL) contains apolipoproteins E and C-II. However, when VLDL changes to low-density lipoprotein, apolipoprotein E and C-II are not found anymore. Where do they come from and where do they go?
a. They come from high-density lipoprotein, but digested by lipoprotein lipase in capillaries.
b. They come from high-density lipoprotein, but transferred back to high-density lipoprotein in capillaries.
c. They come from chylomicron, and returned to chylomicron in capillaries.
d.They come from chylomicron, and returned to high-density lipoprotein in capillaries.
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6. Insulin receptor is a member of tyrosine kinase receptors. What is the initial kinase activity to initiate insulin signal transduction?
a. Insulin binding to its receptor recruits another kinase to initiate signal transduction.
b. Insulin binding to its receptor initiates phosphatase activity and initiate signal transduction
c. Insulin binding to its receptor initiates autophosphorylation of own receptor and initiate signal transduction
d. Insulin binding to its receptor cause change in membrane structure and initiate signal transduction
Explanation / Answer
1.High-density lipoprotein play an important rule in transferring unesterified cholesterol to serum lipoprotein and delivers back to the liver for their breakdown and excretion
2.High ATP concentration in mitochondria formed during TCA cycle causes the citrate concentration to rise in mitochondria and hence their translocation occurs to cytosol.
3.(d)Only acetyl CoA enters the TCA cycle to generate more GTP, NADH and FADH2.
4.(c) Glucagon receptors are located on cell surface membrane and is G-protein coupled receptor type.
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