Biochem Exam 4

Question 1

What are the purine bases?

Answer 1

adenosine and guanine

Question 2

What are the pyrimidine bases

Answer 2

cytosine ,thymine, uracill

Question 3

ribonucleotides

Answer 3

structural units of RNA

Question 4

antiparallel

Answer 4

3 prime to five prime phosphodiester bonds run in opposite directions

Question 5

parallel

Answer 5

3 prime to five prime phosphodiester bonds run in the same direction

Question 6

phosphodiester linkage

Answer 6

covalent bond that joins successive nucleotides between DNA and RNA

Question 7

What is the spectrometry finding of nucleotide bases

Answer 7

all bases absorb UV light. peak at 260nm

Question 8

B form DNA

Answer 8

most stable for DNA molecules under physiological conditions Watson crick structure

Question 9

Z form DNA

Answer 9

left handed helix more slender and elongated in shape 12bp/turn

Question 10

A Form DNA

Answer 10

right handed helix . favored in the absence of water 11bp/turn. wider helix more tilted plane

Question 11

palindrome

Answer 11

region of DNA that is identical when read forwards or backwards. applied to regions of DNA with inverted repeats

Question 12

mirrored repeat

Answer 12

sequence when inverted repeat appears on the same strand

Question 13

Contigs

Answer 13

long, contiguous sequences that are assembled from overlaps

Question 14

Deamination

Answer 14

spontaneous loss of exocyclic amino groups

Question 15

Hypochromic effect

Answer 15

the observed decrease in the absorption of UV light when complementary strands are paired

Question 16

Hyperchromic effect

Answer 16

the observed increase in the absorption of UV light when a double-stranded nucleic acid is denatured

Question 17

Monocistronic

Answer 17

codes for one polypeptide mostly in eukaryotes

Question 18

Polycistronic

Answer 18

codes for 2+ different polypeptides bacteria and archaea

Question 19

Malate dehydrogenase

Answer 19

reduces oxaloacetate to malate

Question 20

Malic enzyme

Answer 20

oxidizes malate to pyruvate

Question 21

Citrate transporter

Answer 21

transports citrate through the inner mitochondrial membrane

Question 22

Citrate synthase

Answer 22

catalyzes the formation of citrate from acetyl-CoA and oxaloacetate

Question 23

Citrate lyase

Answer 23

= catalyzes cleavage of citrate to regenerate acetyl-CoA and oxaloacetate

Question 24

Statins

Answer 24

drug class used to treat patients with elevated serum cholesterol

Question 25

Low-density lipoprotein (LDL

Answer 25

Rich in cholesterol and cholesteryl esters
Carries cholesterol to extrahepatic tissues and macrophages

Question 26

HDL

Answer 26

lipoproteins that originate in the liver and small intestine as small, protein-rich particles
Mediates cholesterol scavenging and transport back to the liver to flush out

Question 27

Biliary cholesterol

Answer 27

cholesterol contained in bile

Question 28

What does bile do?

Answer 28

Bile removes excess cholesterol from the intestine and facilitates excretion

Question 29

Bile acids

Answer 29

the principal components of bile, a fluid stored in the gallbladder

Question 30

HMG-CoA reductase =

Answer 30

an integral membrane protein of the smooth ER that catalyzes the reduction of HMG-CoA to mevalonate

Question 31

Carnitine

Answer 31

compound that transports fatty acyl-CoAs destined for mitochondrial oxidation across the inner mitochondrial membrane

Question 32

Nucleotide-binding fold

Answer 32

single protein domain that binds adenosine

Question 33

The double helix is stabilized by:

Answer 33

Metal cations that shield the negative charges of backbone phosphates
Base stacking interactions between successive base pairs
G and C content

Question 34

Does hydrogen bond contribute to DNA stability

Answer 34

NO

Question 35

N glycosol bond

Answer 35

covalently joins the 1′ carbon of the pentose to the base (at N-1 of pyrimidines and N-9 of purines

Question 36

mRNA

Answer 36

portion of cellular RNA carrying the genetic information from DNA to the ribosome

Question 37

Transcription

Answer 37

process by which mRNAs are formed on a DNA template

Question 38

Carnitine shuttle =

Answer 38

transports long-chain fatty acids (containing 14+ carbons) through the mitochondrial membrane
Requires activation to a fatty acyl-CoA and attachment to carnitine

Question 39

Fatty acyl-CoA

Answer 39

contains a thioester linkage between the fatty acid carboxyl group and the thiol group of coenzyme A
high energy hydrolysis of 2 ATP bonds

Question 40

Carnitine acyl-transferase 1, CAT1 (carnitine palmitoyltransferase 1, CPT1

Answer 40

catalyzes a transesterification reaction to transiently attach a fatty acyl-CoA to the hydroxyl group of carnitine to form fatty acyl-carnitine

Question 41

Acyl-carnitine/carnitine cotransporter =

Answer 41

allows the passive transport of the fatty acyl-carnitine ester

Question 42

Carnitine acyltransferase 2 (CAT2, CPT2

Answer 42

transfers the fatty acyl group from carnitine back to coenzyme A to regenerate fatty acyl-CoA and free carnitine

Question 43

Coenzyme A in the cytosol is used in

Answer 43

biosynthesis of fatty acids

Question 44

Coenzyme A in the mitochondrial matrix is largely used in

Answer 44

oxidative degradation of pyruvate, fatty acids, and some amino acids

Question 45

Probiotics are

Answer 45

foods or supplements that contain live microorganisms intended to maintain or improve the “good” bacteria (normal microflora) in the body

Question 46

Prebiotics

Answer 46

foods (typically high-fiber foods) that act as food for human microflora.