FINAL FINAL

Question 1

Glutamate and α-ketoglutaric acid, as well as oxaloacetic acid and aspartic acid, are especially important in carbohydrate metabolism because:

Answer 1

They allow a way to add intermediate molecules to the TCA cycle

Question 2

Tyrosine is a non-essential amino acid because we can synthesize it from:

Answer 2

Phenylalanine

Question 3

S-Adenosylmethionine is used in synthetic reactions to:

Answer 3

Provide methyl groups for synthesis reactions

Question 4

We need daily supplies of many vitamins, including folic acid. For what purpose or purposes do we need folic acid?

Answer 4

To carry one-carbon fragments during metabolism

Question 5

Transamination of amino acids results in products called:

Answer 5

α-keto acids

Question 6

Ketogenic amino acids are broken down to acetoacetate or

Answer 6

acetyl-CoA (or Pyruvate)

Question 7

The amino acids Ala, Cys, Gly, Ser, and Thr are all degraded to the metabolite

Answer 7

pyruvate

Question 8

Which of the following glycolytic intermediates is the common precursor to serine, cysteine, and glycine?

Answer 8

3-phosphoglycerate

Question 9

The neurotransmitters DOPA, dopamine, epinephrine, and norepinephrine are synthesized from the amino acid

Answer 9

tyrosine

Question 10

Nitrogenase carries out the reaction that reduces nitrogen to

Answer 10

NH3

Question 11

When glutamate is oxidatively deaminated by GDH, the products include

Answer 11

NAD(P)H + H⁺, NH4⁺, and a-ketoglutarate

Question 12

In which cellular compartment does the following reaction take place?

arginine —> urea + ornithine

Answer 12

cytosol

Question 13

In which cellular compartment does the following reaction take place?

ornithine + carbamoyl-phosphate —> citrulline

Answer 13

mitochondrial matrix

Question 14

In the reaction depicted below, choose the right answer:

A)The reaction is involved in the protein synthesis where 1=carbamoyl synthetase, and 2=carbamide phosphate

B)The reaction is the committed step of the urea cycle where 1=carbamoyl phosphate synthase, and 2=carbamoyl phosphate

C)The reaction is a side product of the urea cycle, and 1=carbamoyl phosphate synthase, and 2=carbamoyl phosphate

D)A) and C)

Answer 14

The reaction is the committed step of the urea cycle where 1=carbamoyl phosphate synthase, and 2=carbamoyl phosphate

Question 15

The metabolite chorismate

Answer 15

is an important intermediate in the production of Trp, Tyr, Phe

Question 16

Which of the following reactions is catalyzed by adenylate cyclase?

Answer 16

ATP → cAMP + PPi

Question 17

How do steroid hormones influence gene expression?

Answer 17

They bind receptor in the cytosol. These complexes then migrate to the nucleus where they bind hormone response elements to affect transcription

Question 18

Phospholipase C cleaves PIP2, generating

Answer 18

IP₃ and DAG (inositol-1,4,5-trisphosphate and 1,2-diacylglycerol)

Question 19

During fasting and prolonged starvation, skeletal muscle

Answer 19

Protein is degraded to provide amino acids to the liver for gluconeogenesis

Question 20

Which of the following are effects of insulin secretion?

A)Muscle and adipose tissue are stimulated to take up glucose;

B)Gluconeogenesis is inhibited in the liver and kidney;

C)Synthesis of glycogen, proteins, and triacylglycerols are stimulated, promoting cell growth;

D)A and B;

E)A, B, and C

Answer 20

E)A, B, and C

Question 21

The functions of the kidney include all of the following except

A) Blood pH regulation;

B) Body water regulation;

C) Reabsorption of electrolytes, sugars, and amino acids from the urinary filtrate;

D) Filtration of blood plasma which results in the excretion of water-soluble waste products;

E) Production of urea from ammonia

Answer 21

Production of urea from ammonia

Question 22

A simple system for information flow is composed of three components : reception, transduction and response. In multicellular organisms hormones play a role in which phase?

Answer 22

Reception

Question 23

The IP₃ receptor

Answer 23

Is a calcium channel

Question 24

What types of molecules serve as the starting materials for synthesis of uric acid?

Answer 24

Purine bases

Question 25

Ubiquinated proteins are transferred to large proteolytic machines for cleavage to smaller fragments. The proteolytic machine is known as a:

Answer 25

Proteasome

Question 26

Calmodulin is a

Answer 26

Calcium-binding protein

Question 27

The liver performs all of the following functions except

Answer 27

Storage of energy in the form of fat

Question 28

Degradation of proteins is facilitated by a process known as:

Answer 28

Ubiquination

Question 29

Brain tissue normally consumes glucose, but when glucose levels are low, nervous tissue can also consume:

Answer 29

β-hydroxybutyrate and acetoacetic acid

Question 30

Peptide hormones which bind to G-protein-coupled receptors stimulate the activity of adenyl cyclase, producing a second messenger called:

Answer 30

Cyclic-3'5'-adenosine monophosphate

Question 31

The schematic diagram of the signal transduction pathway is shown in the figure below. Please identify the best match for the labels.

Answer 31

1= reception; 2= transduction; 3= response; 4= signal-receptor binding; 5=secondary messenger.

Question 32

The figure below shows one of the major receptors involved in signal transduction. Please identify the best matches for the labels:

Answer 32

1= G protein coupled receptor (GPCR); 2= alpha subunit; 3= GDP; 4=gamma subunit; 5= trimeric G proteins

Question 33

Which of the following describes the flow of genetic information as stated in the central dogma of molecular biology? ## Footnote A) RNA → Protein → DNA; B) DNA → RNA →Protein; C) DNA → Protein → RNA; D) Protein →RNA → DNA; E) None of the above are correct

Answer 33

DNA → RNA →Protein

Question 34

The DNA “backbone” is composed of

Answer 34

A phosphodiester bond between 3” and 5’ hydroxyl groups of adjacent deoxyribose residues

Question 35

Nucleosomes are composed of all of the following except \_\_\_\_\_\_\_\_. ## Footnote A) H1; B) H2; C) H3; D) H4; E) H5

Answer 35

H5

Question 36

\_\_\_\_\_\_ are gene sequences that code for a gene product.

Answer 36

Exons

Question 37

A genome is

Answer 37

The complete DNA base sequence in an organism

Question 38

Protein synthesis is called

Answer 38

Translation

Question 39

In which of the following is a sequence of bases termed anticodon located?

Answer 39

transfer RNA

Question 40

A codon in a segment of mRNA is shown below. Which of the following is the corresponding anticodon? (5') G-A-U (3')

Answer 40

(5') A-U-C (3')

Question 41

The codon sequences on a segment of mRNA are shown below. Which of the following amino acid sequences is coded by this mRNA segment? (Recall: the mRNA chain runs 5' to 3'. Of the genetic code) -UAC-GCA-CCC-ACG-AGC-CAG-

Answer 41

tyr-ala-pro-thr-ser-gln

Question 42

In the reversible chemical reaction depicted below (a transamination) choose the best answer for the labeled compounds:

Answer 42

1=alanine, 2=alpha-ketoglutarate, 3=pyruvate, 4=glutamate

Question 43

The stability of the DNA helix is mainly due to

Answer 43

hydrogen bonding between phosphate groups &stacking and hydrophobic interactions

Question 44

Determine the mRNA sequence for the following DNA sequence. 5’-GCCATTTCCCGTTA-3’;

Answer 44

5’-UAACGGGAAAUGGC-3’

Question 45

Chromatin is:

Answer 45

DNA complexed with histones

Question 46

Nitrogen assimilation is the incorporation of inorganic nitrogen compounds into organic molecules. Which of the following statements is true for glutamine synthetase: ## Footnote A) Glutamine synthetase catalyzes the conversion of glutamate into glutamine using the nitrate (NO3-); B) Glutamine synthetase catalyzes the ATP-dependent reaction of glutamate with NH4+ to form glutamine

Answer 46

Glutamine synthetase catalyzes the ATP-dependent reaction of glutamate with NH4+ to form glutamine

Question 47

Enzymes catalyzing the transaminations reactions require which of the following prosthetic groups:

Answer 47

Pyridozal-5'-phosphate

Question 48

The figure below shows the biosynthetic routes for some amino acids. Which are the glycolytic intermediates which are converted into chorismate, a precursor in the biosynthesis of Phe, Tyr and Trp?!

Answer 48

phosphoenolpyruvate and fructose-6-phosphate

Question 49

The figure below shows the biosynthetic routes for some amino acids. The kidney and small intestine use glutamine as an energy source because:

Answer 49

Glutamine can be converted into glutamate which is further transaminated to alpha-keto-glutarate, which supplies the TCA cycle;

Question 50

Both of the NADPH-requiring reactions necessary to convert folate to tetrahydrofolate are catalyzed by which enzyme:

Answer 50

dihydrofolate reductase

Question 51

In the figure below interconversions of the one-carbon units are shown. Many one-carbon units enter the pathway as N5,N10-methylene THF which is further used in which biosynthetic pathway?

Answer 51

Thymine nucleotides

Question 52

S-Adenosylmethionine (SAM) is an important metabolite in the one-carbon metabolism because:

Answer 52

It is involved in methyl-transfer reaction where the activated methyl group is transferred to many methyl acceptors

Question 53

In the reaction of dopamine conversion to epinephrine (depicted below), the following chemical transformations most probably take place:

Answer 53

Hydroxylation followed by methyl transfer to a amino group acceptor (methylation)

Question 54

The balanced equation depicted below represents: CO2 + NH4+ + Aspartate + 3 ATP + 2 H2O → Urea + Fumarate + 2 ADP + 2 Pi + AMP + PPi + 5 H+

Answer 54

urea cycle

Question 55

. Amino acids that are degraded into pyruvate or citric acid cycle intermediates are known to be:

Answer 55

Glucogenic

Question 56

Chromatin contains several levels of structure which include

Answer 56

Nucleosomes, 200 nm filaments, and 30 nm fiber

Question 57

The DNA strand that acts as a template during transcription is referred to as the ______ strand.

Answer 57

Antisense

Question 58

In a transversion mutation

Answer 58

A purine base is substituted for a pyrimidine base and A pyrimidine base is substituted for a purine base

Question 59

Mitchell's chemiosmotic theory suggested that a high concentration of protons outside the mitochondrial membrane

Answer 59

Generated a voltage and a protonmotive force which helped drive the ATP synthase

Question 60

Reactive oxygen species such as hydrogen peroxide and superoxide radicals may be generated by scavenger cells and used to destroy unwanted invaders or metabolic fragments. The ROS are generated by a process called the:

Answer 60

Respiratory burst

Question 61

Obligate anaerobes have difficulty living in environments containing:

Answer 61

Oxygen.

Question 62

The endoplasmic reticulum usually functions in an oxidative environment. In ER stress, low oxygen concentration results in inability of the ER to properly facilitate protein folding. Which of the following reactions is likely to be compromised?

Answer 62

Cysteine molecules between regions of the protein are not joined by disulfide bonds .

Question 63

A single reduced molecule or NADH is considered to be equivalent in energy to 2.5 ATP molecules. Oxidation of a mole of FADH 2 yields 1.5 ATP. In chemical terms, this would mean that: