BCM 476 Exam 1 Study Guide
Degron
A specific sequence of amino acids that indicates that a protein should be degraded
Ketogenic amino acids are degraded to which of the following metabolites?
Acetyl-Coa
Glutamate is the carbon skeleton precursor for the amino acids glutamine, proline, and _______
Arginine
In the urea cycle, free NH3 is coupled with carboxyphosphate to form
Carbamic acid
What class of enzymes cleaves most aromatic rings in biological systems?
Dioxygenases
The purpose of the pentose phosphate pathway is to
Generate ATP & NADPH
The manganese center of photosystem II converts ____ to ____
H2O to O2
Which amino acid is solely ketogenic?
Leucine
Urea is synthesized in the
Liver
The C-terminal glycine of ubiquitin is covalently linked to _____ residues of the protein destined to be degraded.
Lys
Homocysteine is an intermediate in the synthesis of cysteine and ____
Methionine
In the light reactions of photosynthesis, the cooperation between photosystem II and photosystem I creates a flow of electrons from H2O to the final acceptor, ____
NADP+
In the overall equation for the Calvin cycle, two molecules of __________ and three molecules of ____________ are consumed in incorporating a single CO2 molecule into a hexose.
NADPH; ATP
Essential amino acids differ from nonessential amino acids in that:
Nonessential amino acids are synthesized in simple reaction pathways compared to complex pathways for most essential amino acids
What is the side product of light reactions
O2
Which amino acid(s) are metabolites in the urea cycle, but are not used as building blocks of proteins?
Ornithine & Citrulline
What are the special pairs in the reaction centers of plants?
P700 and P680
The inhibitor of photosystem I is:
Paraquat
Complete the following reaction for photosystem I (be sure to balance the reaction with regard to the electrons)
Pc(Cu+ ) + Fdox + light à Pc (Cu2+) + Fdred
Pepsin
Primary proteolytic enzyme of the stomach
In C4 plants, carbon dioxide is added to _____ to form oxaloacetate, which is reduced to malate, which carries CO2 to the bundle-sheath cells
Pyruvate
Serine dehydratase catalyzes the conversion of serine into NH4 + and _____
Pyruvate
A _______ intermediate is formed between the carbonyl group of the ketose substrate and the e-amino group of a lysine residue of transaldolase
Schiff base
Urea
The is the molecule that is formed from excess NH4 + by ureotelic organisms
Aminotransferases
These enzymes transfer an alpha-amino group from amino acids to alpha-ketoglutarate
Dioxygenases
This class of enzyme cleave most aromatic rings in biological systems
Glutamate Dehydrogenase
This enzyme catalyzes an oxidative deamination and can utilize either NAD+ or NADP+
Biopterin
This is the cofactor required by phenylalanine hydroxylase
S-adenosylmethionine
This methyl group donor is the product of the first step of methionine degradation
Oxaloacetate
This product results when aspartate is transaminated with alpha-ketoglutarate
Ubiquitin
This protein is used as a tag to identify proteins targets for destruction
Choose the reaction in which amino acids could be synthesized from alpha-ketoacids
Transamination reaction
_____ plays a major role in the regeneration of ribulose 1,5-biphosphate
Transketolase and aldolase
Amino acid synthesis is generally regulated by
Turnover, diet, and feedback and allosteric enzyme regulation
The half-life of a cytosolic protein is primarily determined by the
amino terminal residue.
In the first step of the urea cycle, CO2 and NH4 + are converted into _____
carbamic acid
In the urea cycle, the carbon skeleton of aspartate is preserved as
fumarate
Sodium bicarbonate secreted from the pancreas
neutralizes pH of the food.
The urea cycle is linked to gluconeogenesis through the TCA cycle intermediates fumarate and _______
oxaloacetate
The cause of formation of ATP in both photophosphorylation and oxidative phosphorylation is:
pH gradient
What prosthetic group do aminotransferases contain?
pyridoxal phosphate group
Where does the charge separation take place within each photosystem in chloroplasts?
reaction center
What is the name of the enzyme that is located on the stromal surface of the thylakoid membranes and catalyzes condensation of CO2 with the enediolate intermediate?
rubisco
In what part of the cell does the Calvin-Benson cycle occur?
stroma of the chloroplasts
The pathway of electron flow from H2O to NADP+ in photosynthesis is referred to as
the Z scheme of photosynthesis
Chorismate is a precursor to the amino acids
tryptophan, tyrosine, and phenylalanine
What does bacteriopheophytin have in its center?
two protons
