Exam 4

Question 1

What are the sources of NADPH for fatty acid synthesis?
Lactic fermentation
Oxidative decarboxylation of malate by malic enzyme in cytoplasm.
Pentose phosphate pathway.
Oxidative phosphrylation.
Citric acid cycle.

Answer 1

Oxidative decarboxylation of malate malic enzyme in cytoplasm.
Pentose phosphate pathway.

Question 2

What is the common precursor for biosynthesis of Valine, Leucine, and Alanine.

Answer 2

Pyruvate

Question 3

Predict which product of phosphoglucomutase reaction predominates when insulin levels are high.

Answer 3

Glucose-1-phosphate

Question 4

At what stage of protein synthesis an aminoacyl-tRNA binds to AUG of the A-site of a ribosome?

Answer 4

Elongation

Question 5

Ribonucleotide reductase catalyzes the conversion of ribonucleotides into deoxyribonucleotides. What is the product of ribonucleotide reductase reaction?

Answer 5

dADP

Question 6

In order for RNA polymerase II to create a transcript, what is necessary? Mark ALL the correct statements.
NTPs.
Primers.
DNA template.
Magnesium.
dNTPs.

Answer 6

DNA template.
Magnesium.
NTPs.

Question 7

Mark all the molecules that are amino acid precursors.
alpha-ketoglutarate.
3-phosphoglycerate.
ribose-5-phosphate.
glucose-6-phosphate.
succinate.
oxaloacetate.
UDP-glucose.
pyruvate.
erythrose 4-phosphate.
phosphoenolpyruvate.

Answer 7

alpha-ketoglutarate.
3-phosphoglycerate.
ribose-5-phosphate.
oxaloacetate.
pyruvate.
erythrose 4-phosphate.
phosphoenolpyruvate.

Question 8

mRNA is translated in the ____ direction, new proteins are synthesized in ____ direction.

Answer 8

5’ –> 3’; N –> C

Question 9

The amino acid is attached to the tRNA molecule at ____.

Answer 9

CCA 3’

Question 10

Deoxyribonucleotides are ____.

Answer 10

Made by the reduction of the ribose component of ribonucleotide phosphates.

Question 11

What is the main regulator for the pentose phosphate pathway?

Answer 11

Concentration of NADP+

Question 12

The committed step of fatty acid synthesis is formation ____.

Answer 12

malonyl CoA

Question 13

Mark common precursors for both de novo purine and pyrimidine nucleotide synthesis.
PRPP.
aspartate.
glycine.
formate.
orotate.

Answer 13

PRPP.
aspartate

Question 14

Acetyl groups to be used for fatty acid biosynthesis are transferred across the mitochondrial membrane in what form?

Answer 14

citrate

Question 15

Which metabolic pathway is NOT a source of carbon skeletons for amino acid biosynthesis?

Answer 15

beta-oxidation

Question 16

The 5’-terminal cap structure of eukaryotic mRNAs is a(n):

Answer 16

7-methylguanosine joined to the mRNA via a 5’-5’ triphosphate linkage

Question 17

Which type of bacterial RNA does not require any modification?

Answer 17

messenger RNA

Question 18

True or false: Eukaryotic mRNA is monocistronic

Answer 18

True

Question 19

Mark all the true statements about mRNA splicing:
One mRNA can sometimes code for more than one protein by splicing at alternative site.
Splicing of mRNA does not involve any proteins.
Splicing occurs while the mRNA is still in the nucleus.
Splicing occurs while the mRNA is attached to the nucleosome.
In splicing, intrones sequences are removed from the mRNA and degraded

Answer 19

One mRNA can sometimes code for more than one protein by splicing at alternative site.
Splicing occurs while the mRNA is still in the nucleus.
In splicing, intrones sequences are removed from the mRNA and degraded

Question 20

Aminoacyl-tRNA synthetases:

Answer 20

Recognize specific tRNA molecules and specific amino acids

Question 21

The wobble base of tRNA is ____

Answer 21

The 5’ base of anti-codon

Question 22

ATP is called the energy currency. The currency of biosynthetic reducing power is ____.

Answer 22

NADPH

Question 23

Identify the enzymes that are required for the synthesis of a glycogen particle starting from glucose 6-phosphate
Glycogen phosphorylase.
UDP-glucose pyrophosphorylase.
Glycogen synthase kinase.
Glycogen synthase.
Branching enzyme.

Answer 23

UDP-glucose pyrophosphorylase.
Glycogen synthase.
Branching enzyme

Question 24

Enhancer sites are often located

Answer 24

At a distance from the transcription start site

Question 25

In which direction does RNA polymerase read DNA strand?

Answer 25

3' --> 5' on the template strand

Question 26

Signals that define the beginning and end of protein synthesis are contained in

Answer 26

mRNA

Question 27

Which of the following is not a component of the pentose phosphate pathway?

Answer 27

Phosphoenolpyruvate

Question 28

RNA synthesis (tRNA, mRNA, and rRNA) is called ____

Answer 28

Transcription

Question 29

What kind of organisms convert molecular nitrogen into NH4+ through nitrogen fixation?

Answer 29

Bacteria

Question 30

Identify the 5 enzymes that take part in the process of DNA replication: Topoisomerase. Helicase. Aminotransferase. ATP synthase. Pyruvate kinase. Histone acetyltransferase. Ligase. Primase. Enteropeptidase. DNA polymerase.

Answer 30

Helicase Topoisomerase Primase DNA polymerase Ligase

Question 31

After 6 rounds of fatty acid synthase activity, what size is the fatty acyl intermediate?

Answer 31

14 carbons long

Question 32

During replication, Okazaki fragments elongate ____.

Answer 32

Lagging strand away from the replication fork

Question 33

Glycogen synthesis is primarily regulated by modulating the activity of ____.

Answer 33

Glycogen synthase

Question 34

Which statement is true regarding the introns? Introns are neither transcribed, spliced, nor translated. Introns are transcribed and spliced but translated separately from the exons. Introns are transcribed, spliced, translated, and removed after translation. Introns are transcribed and spliced out before translation. Introns are transcribed, spliced, and translated with the exons.

Answer 34

Introns are transcribed and spliced out before translation

Question 35

Red blood cells lack mitochondria. These cells process glucose to lactate, but they also generate CO2. How can they generate CO2 if they lack mitochondria?

Answer 35

Pentose phosphate pathway coupled with glycolysis

Question 36

True or false: glycogen is reducing sugar

Answer 36

False