Font size
WorksheetsBiochem Exam III Review: Max and Serena
Total questions: 48
Worksheet time: 29mins
Which of these is Not be considered a source of amino acids in humans
Urea carboxylation
De Novo synthesis
Protein turnover and recycling of amino acids
Dietary consumption of protein
A deficiency in vitamin B6 directly impairs the synthesis of ...(select all that apply)
Alanine
Glutamine
Glutamate
Aspartate
A patient has Vitamin B6 deficiency. Among their symptoms, they are unable to exercise for long periods of time, and a build up of pyruvic acid in the blood. How are these two symptoms related?
Due to the missing cofactor , PLP, the transamination reaction is in overdrive, creating toxic levels of alanine and pyruvate in the blood
The conversion of alanine in the muscles is inhibited by decreased levels of PLP. Less alanine is transported to the liver for gluconeogenesis
Gluconeogenesis in the muscles has decreased, resulting in decreased production of glucose and an increase conversion of pyruvate to alanine
Vitamin B6 allosterically slows the rate at which the transamnination reaction occurs. A deficiency would result in higher transamination rates, depleting glucose and producing excessive pyruvate
Which amino acid can be released by the muscle to the liver?
Asparate
Glutamate
Alanine
Tyrosine
A reduction in oxaloacetate would directly decrease the concentration of...
Urea
Aspartate
Valine
Alanine
Which amino acids are non-essential?
Alanine
Glutamate
Valine
Lysine
Leucine
Non-essential amino acids can be synthesized de novo
I'll bet my top dollar, that is true!
I would not bet my dollar, that is totally false.
What process oxidizes ammnonia to nitrates and nitrites?
Denitrification
Assimilation
Fixation
Nitrification
A bacteria is inoculated in the solution broth that contains only nitrates. After a few days, you observe a nitrogen gas bubble in the tube. What process are these bacteria capable of performing?
Fixation
Denitrification
Nitrification
Assimilation
Only a bacteria would know...
While sequencing the geneome of an unknown bacteria, you notice it has a gene that codes for nitrogenase. Based on this, which process is this bacteria capable of?
Denitrification
Assimilation
Nitrogen fixation
Nitrification
Would an individual with PKU be able to metabolize aspartame?
Sure! You can drink all the diet soda you want lol
Bro...do not drink that! You can't metabolize aspartame!
What happens in the body of an individual with PKU who drink diet soda? Select all that apply.
A build up of phenylalanine
A build up of aspartate
A build up of tyrosine
An abscence of alanine
An unhinged dependency on diet soda
Which krebs cycle intermediate is produced during the urea cycle?
Fumarate
Succinate
OAA
Arginosuccinate
What processes directly tie the TCA and Urea cycle together? Select all that apply
The glycerol phsophate shuttle
Carbamoyl phosphate synthesis
Malate aspartate shuttle
Aspartate-arginosuccinate shunt
A mutation causes the actiev site of arginase to become non-functional. What molecule is expected to be in higher concentrations until the cycle completely stalls?
Fumarate
Arginosuccinate
Succinate
Arginine
Urea
Which of these statements regarding the regulation of urea cycle is true?
Glutamate and acety CoA directly bind to carbamoyl phosphate to promote the synthesis if citrulline
High concentrations of arginine stimulate N-acetylglutamate synthase
Low concentrations of acetyl CoA increas N-acetylglutamate concentrations
Carbamoyl phosphate synthase 1 is not allosterically regulated. In contrast Ornithine transcarboxyalse is regulate by N-acetylglutamate.
The blood test of a diabetic patient shows a high concentration of ammonia in the blood. What might be the source of the ammonia?
Increased production of urea
Increased production of glutamine by cells
Increased production of glutamate by cells
Ammonia released through the degradation of proteins and amino acids
How does diabetes cause increase levels of ammonia in the blood?
Reduced uptake of glucose causing less allosteric control over urea hydrolysis , and thus an increase ammonia concentration in the blood
Excessive gluconeogenesis reduces the concentration of the TCA cycle intermediates, resulting in excessive activation of the urea cycle
Decrease uptake of glucose resulting in fewer TCA cycle intermediates that can undergo transamination, stalling the urea cycle
Decrease uptake of glucose resulting in fewer TCA cycle intermediates that can undergo deamination, decreasing ammonia concentrations
Which amino acids can be considered glucogenic?
Leucine
Alanine
Lysine
Threonine
Valine
Which is Not a true statement?
Nucleic acids are used to store genetic information
Nucleotides are usually not involved in energy generation
Nucleic acids are involved in protein synthesis
Nucleotides are involved in signal transduction
Pyrimidines have two rings in their structure.
True
False
Adenine and Guanine are the major pyrimidines
True
False
Adenosine is the primary precursor for RNA.
True
False
DNA has a major groove and a minor groove.
True
False
Which is the true statement?
Pyrimidines usually form covalent bonds with purines in the DNA
The pyrimidine salvage pathway is inhibited in people affected by Lesch-Nyhan syndrome
The A-form is the most abundant form of DNA
The A form is wider than the B and Z-from of DNA
Select the statements that are NOT true.
The B-form of DNA has a longer base-pair turn than the Z-form
All glycosidic bonds in DNA have a syn conformation
In contrast to the A and B forms, the Z-form is right-handed
The Z-form of DNA is more elongated than the A-form
Thioredoxin inhibits xanthine oxidase
True
False
Xanthine oxidase converts a ribonucleotide to a deoxyribonucleotide
True
False
De Novo pyrimidine synthesis is subject to feedback inhibition at the aspartate transcarbamylase level
True
False
Thymidylate synthase catalyzes the conversion of dCMP to dTMP
True
False
Dihydrofolate reductase converts dihydrofolate to tetrahydrofolate.
True
False
The end products of purine and pyrimidine biosynthesis are....(select all that apply).
AMP
CTP
GMP
UTP
Methotrexate directly targets thymidylate synthase.
True
False
Find the right matches.
Fluorouracil: TS
Glutamine analogs: HGPRT
Methotrexate: DHFR
In pyrimidine synthesis, the ring is assembled on the sugar molecule.
True
False
Atoms forming the purine ring can be derived from glycine.
True
False
Which of these does Not provide the atoms for the purine rings?
Glycine
CO2
Formate
Aspartate
Lysine
Although the biosynthetic process and end products are different for purines and pyrimidines, their starting materials are the same.
True
False
The difference between a nucleotide and a nuceloside is mainly about the type of ribose in their structure.
True
False
Which is Not usually found in eukaryotes?
Inosine
5-MethylCytidine
N6-Methyladenosine
7-methylguanosine
Which is Not correct in the Watson-Crick Model? Select all that apply.
The DNA strands are anti-parallel
The DNA is only stabilized by hydrogen bonding between base pairs
The model describes B-DNA
The model describes a left-handed helix
The Helix pitch is 20 Armstrong
Who is still alive?
Watson
Crick
While humans rely mostly on the salvage pathway of nucleotides, parasites can synthesize nucleotides de novo.
True
False
Find the right matches
Lys: Purine
Gln: amide groups
Asp:pyrimidine
Gly: amide groups
In purine biosynthesis, the end products are...(select all that apply)
AMP
GMP
IMP
ATP
GTP
Unlike other cellular processes, nucleotides synthesis does not consume energy.
True
False
Which is Not an intermediate in de novo pyrimidine synthesis?
TTP
UMP
UTP
Orotate
Find the right matches.
Xanthine oxidase: Gout
HGPRT: Gout
Allopurinol: Lesch- Nyhan
Lesch-Nyhan: pyrimidines
Allopurinol: Gout
