Amino Acid Metabolism

Question 1

amino acids are the _____ of proteins

Answer 1

building blocks

Question 2

some amino acids are converted into _______

Answer 2

acetyl-CoA

Question 3

What is nitrogen fixation

Answer 3

conversion of N2 to NH3 or NH4+

Question 4

how to leguminous plants incorporate nitrogen

Answer 4

from bacerially synthesized amino acids into their won

Question 5

how to nonleguminous plants inorcporoate NH4+

Answer 5

NH4 produced by nitrogen fixing soil bacteria directly into amino acids via nitrogen assimilation

Question 6

What are the two other nitrogen fixation processes that exist in the biosphere

Answer 6

industrial (the haber process) and atmospheric (lightning)

Question 7

most often, NH4+ is incorporated into the amino acids ____ and ____

Answer 7

glutamate and glutamine

Question 8

What are the key enzymes in nitrogen fixation and assimilation

Answer 8

nitrogenase complex, glutamine synthease, glutamate synthase, glutamate dehydrogenase

Question 9

What does hte nitrogenase complex do

Answer 9

uses redox reaction and ATP hydrolysis to convert N2 and 2NH3 and six redox reactions

Question 10

What does glutamine synthease do

Answer 10

found in all organisms, incorporates NH4 into glutamate to form glutamine in ATP-redox reaction

Question 11

What does glutamate synthase do

Answer 11

found in bacteria works with glutamine synthease to replenish glutamate

Question 12

what does glutamate dehydrogenase do

Answer 12

inconverts glutamate, NH4 and alpha-ketoglutarate using redox reactions

Question 13

how many redox centers in the nitrogenous complex

Answer 13

six

Question 14

which amino acids in infected plant cells are synthesized

Answer 14

Glu and Asp

Question 15

What is the intermediate in the glutamate synthease reaction

Answer 15

y-glutamyl phoshpate

Question 16

T or F: glutamate synthease reaction requrires ATP hydrolysis

Answer 16

T

Question 17

What does NH4 assimilation require

Answer 17

glutamine synthease and lgutamate synthase

Question 18

When can the glutamate dehydrogenase reaction assimilate NH4

Answer 18

when NH4 concentration are very high

Question 19

degredation of eukaryotic cellular protein is mediated by _____ and ____

Answer 19

lysosomes nad proteases

Question 20

How to lysosomes degrade proteins

Answer 20

contain acidic proteases that digest protein particles delivered by phagocytosis

Question 21

how to proteases degrade proteins

Answer 21

using three different protease activities located within the central core

Question 22

what is nitrogen used for in mammals

Answer 22

for urea or biosynthetic pathways

Question 23

what happens to the remaining carbon skeletons in mammals

Answer 23

metabolized to create ATP, glucose, fatty acids or ketone bodies

Question 24

amino acids transported to the liver use nitrogen to make _____

Answer 24

urea

Question 25

what does the alanine glucose cycle to for cells

Answer 25

removes excess nitrogen from muscles, using alanine as the carrier

Question 26

The urea cycle consists of ___ enzymatic reactions

Answer 26

5

Question 27

How many of the enzymatic reactions in the urea cycle occur in the cytosol

Answer 27

3/5

Question 28

where is the carbon in urea dervied from

Answer 28

HCO3- from citrate cycle

Question 29

What is the aspartate-arginosuccinate shunt

Answer 29

connects urea and the citrate cycle

Question 30

what connects urea and the citrate cycle

Answer 30

fumarate is used to make aspartate in the mitochondrial matrix

Question 31

what are gluconeogenic amino acids

Answer 31

have carbon skeletons that can be used to synthesize glucose

Question 32

what are ketogenic amino acids

Answer 32

give rise to acetyl-CoA and acetoacetyl-CoA which are precursors to keton bodies

Question 33

what is the difference between essential and nonessential amino acids

Answer 33

essential amino acids are more complex and take a greater number of enzymatic steps to synthesize

Question 34

what is the herbicide glycophosphate

Answer 34

blocks amino acid synthesis in plants by inhibiting the activity of EPSP synthase

Question 35

GLycophosphate is an _______ inhibitor of phophoeonol pyruvate

Answer 35

competitive

Question 36

what are hemes

Answer 36

hemoglobin and cytochromes

Question 37

what are nucleotides

Answer 37

purines and pyridimines

Question 38

what are signaling molecules

Answer 38

neurotransmitters, hormones and nitric oxide

Question 39

What is glycine

Answer 39

contributes the four nitrogen atoms to heme in a series of reactions that take place in both the matrix and cytosol

Question 40

What does tyrosine do

Answer 40

is the metabolic precursor to dopamine, norepinephrine and epinephrine

Question 41

What is tetrahydrobiopterin

Answer 41

key redox cofactor in a variety of amino acid metabolic pathways

Question 42

what does nitric oxide synthase do

Answer 42

uses a two step reaction to generate the vasodialator nitric oxide from arganine using O2 and NADPH

Question 43

nitric oxide leads to the relaxation of what

Answer 43

smooth muscle cells and blood vessel dialation

Question 44

nitroglycerin is what?

Answer 44

used to treat angina cause by vasoconstriction of cardiac blood vessels