BCHM 4115 - Lectures 36-27

What two amino acids are essential in the diets of juveniles and not adults.

Answer explanation

Histidine and Arginine

What does glutamate aspartate aminotransferase essentially do?

Answer explanation

This enzyme transfers an amino group from glutamate to oxaloacetate to yield α-KG and aspartate.

Tags

NGSS.HS-LS1-6

Fill in the missing blanks regarding the molecules that allosterically inhibit glutamine synthetase through feedback inhibition (the images should help).

Answer explanation

_ is a major nitrogen donor in the biosynthesis of many organic nitrogen compounds such as purines, pyrimidines, and other amino acids.

Which prosthetic group found in assimilatory nitrite facilitates the six-electron reduction of nitrite (NO₂^-) to ammonia (NH₃).

Answer explanation

Siroheme

_ is a widely used drug known to activate AMPK and lower blood glucose by inhibiting gluconeogenesis in Type II diabetes.

If glucose is unavailable, what provides the brain with a source of acetyl-coA?

Answer explanation

Ketone bodies such as β-hydroxybutyrate. Because acetyl-CoA cannot cross the blood-brain barrier or freely circulate in the bloodstream, the liver converts it into ketone bodies like β-hydroxybutyrate, which serve as its transportable form.

Tags

NGSS.HS-LS1-7

What does creatine kinase essentially do?

Answer explanation

This enzyme catalyzes the conversion of phosphocreatine to creatine, generating ATP in the process. While creatine may enhance athletic performance by providing quick bursts of energy, its effects are short-lived, as intense muscular activity rapidly depletes ATP stores.

What is AMP-activated protein kinase (AMPK)? How many subunits does this enzyme have, and what are the general roles of each?

Answer explanation

AMPK is an enzyme that regulates energy balance in cells. It either activates catabolic pathways that generate ATP or inhibits anabolic pathways that consume ATP.

AMPK is an αβγ-heterotrimer. The α subunit is the catalytic subunit, where the substrate binds. The β subunit serves as the scaffold and contains the α–γ binding domain. The γ subunit is the regulatory subunit and contains a pair of allosteric sites where adenine nucleotides (AMP, ADP, and ATP) bind.

In the nitrogen cycle, _ prokaryotes concert nitrates to N_2.

• Nitrogen-fixing

• Denitrifying

• Nitrifying

Answer explanation