清华大学生物化学1本科测试题

I.

1: how many carbons does Arachidic acid have? (20 carbons)

2: how many double bonds does Arachidonic acid have? (4 double bonds)

3: list two advantages that fats have over sugars as stored fuels (more energy gram

for gram; no hydration needed)

4: where inside the cells are most of the phospholipids degraded (lysosomes)

5: oligosaccharide head groups determine the blood type of an individual. How are they attached to the plasma membrane? (glycosphingolipids or lipids and surface proteins) 6: list at least one genetic disease that could result from abnormal accumulation of membrane lipids (Tay-Sachs, Sandhoff’s, Fabry’s, Gaucher’s, or Niemann-Pick diseases) 7: list the three main eicosanoids that produced from arachidonic acid (prostaglandins; thromboxanes; and leukotrienes).

8: list one NASID you know (aspirin, ibuprofen, or acetaminophen or meclofenamate)

9: list two fat-soluble vitamins (A, D, E, K)

10: which vitamin can be derived from beta-carotene (A).

11: which year was the fluid mosaic model proposed? (1972)

12: why the thickness of most biological membranes is thicker than 3nm, the standard thickness of lipid bilayer? ( due to association of proteins to the membrane and carbohydrates on the membrane)

13: Please define the transition temperature of the lipid bilayer (the temperature above which the paracrystalline solid changes to fluid)

14: If a membrane protein has its N-terminus exposed to the outside of the cell while its C-terminus resides in the cytosolic compartment, is it a type I transmembrane protein ? (yes).

15: How can you predict if a protein has a transmembrane domain? (hydropathy or hydropathy index, or hydropathy plot).

16: Name the two cell surface receptors that HIV use to enter cells (CCR5 and CD4). 17: For the Na+ K+ ATPase, how many Na+ and K+ can it move across the membrane for the hydrolysis of one ATP (2 K+ in, 3 Na+ out).

18: what drives F-type ATPases to synthesize ATP? (proton or proton gradients) 19: The acetylcholine receptor is a _____-gated channel (Ligand)

20: The neuronal Na+ channel is a _____-gated channel (voltage)

II.

D and H

(3 points) The antiparallel orientation of complementary strands in duplex DNA was elegantly determined in 1960 by Arthur Kornberg by nearest-neighbor analysis. In this technique, DNA is synthesized by DNA polymerase I from one (alpha-32P)-labelled and three unlabelled deoxynucleoside triphosphates. The resulting product is then hydrolyzed by a Dnase that cleaves phosphodiester bonds on the 3’ sides of all deoxynucleotides. For example, in the labeled dATP reaction,

ppp*A + pppC + pppG +pppT --Æ …pCpTp*ApCpCp*ApGp*Ap*ApTp… -

Æ …+Cp+Tp*+Ap+Cp+Cp*+Ap+Gp*+Ap*+Ap+TpT…