Untitled Flashcards Set

Theca cells are the source of __________ and testosterone.

androstenedione

Phosphodiester bonds join the 5'-hydroxyl group of the deoxy-pentose of one nucleotide to the 3'-hydroxyl group of the deoxy-pentose of an adjacent nucleotide through a phosphate group. (T/F) __________.

True

Gout is a disorder characterized by low levels of uric acid—the end product of purine catabolism—in blood (hypouricemia). (T/F) __________.

False

DNA is negatively charged, histones and Mg2+ ions help to __________ the charge.

neutralize

Dopamine and norepinephrine are __________ in the brain and function as neurotransmitters.

synthesized

The main metalloporphyrin in the body is heme, which has a __________ Fe2+ iron atom coordinated by protoporphyrin IX.

ferrous

Polymerases use only __________ as a template.

ssDNA

Reduction of androstenedione at the C17 position results in the formation of __________, the most potent adrenal androgen.

Glucagon

Cholera and pertussis toxins catalyze the __________ of G proteins, affecting signal transduction.

ADP ribosylation

Estrogens are formed by the aromatization of androgens, which requires __________ and NADPH.

O2

Unconjugated bilirubin is normally __________.

secreted

The bile acids are __________ molecules that aid in lipid digestion.

amphipathic

The liver synthesizes more heme than most other organs in order to maintain its high content of __________.

cytochromes

Most of the urobilinogen is oxidized to __________, which turns the feces brown.

stercobilin

Bilirubin is not very __________, so most of it is carried to the liver bound to albumin.

water-soluble

Tyrosine is formed from __________ by phenylalanine hydroxylase.

phenylalanine

Inside a polysome, ribosomes are translating __________ types of proteins.

different

Niemann-Pick disease is caused by the inability to degrade __________.

sphingomyelin

Catecholamine degradation results in the synthesis of __________ (VMA).

vanillylmandelic acid

Heme is synthesized from glycine and succinyl-CoA in humans via a __________ pathway.

complex

In obstructive jaundice, it is mainly __________ bilirubin that increases, because the liver is intact.

conjugated

Creatinine is synthesized in the __________ and excreted by the kidney.

liver

Bilirubin and biliverdin are both products of __________ catabolism.

heme

The porphyrins are altered by decarboxylation and oxidation, and __________ IX is formed.

protoporphyrin

Infant RDS (Respiratory distress syndrome) is caused by a deficiency of __________ surfactant.

lung

Hormones are only synthesized in specialized organs called __________.

glands

The first step in pyrimidine synthesis is the formation of __________ phosphate, catalyzed by carbamoyl phosphate synthetase II.

carbamoyl

Citrulline is a non-protein amino acid that works as an intermediate in __________ biosynthesis.

urea

5-hydroxytryptophan is decarboxylated to serotonin in a reaction requiring __________ phosphate (PLP).

pyridoxal

Hyperuricemia is typically __________ and does not always lead to gout.

asymptomatic

The B chains of insulin are identical in all species, while the distinct __________-chain imparts hormone uniqueness.

alpha

Glycogen synthase and DNA synthase require a __________.

primer

Bilirubin is conjugated in the __________ by glucuronyl transferase.

gallbladder

Aminotransferases are intracellular enzymes, and their plasma concentration increases usually indicate __________.

pathology

Degradation of glycolipids happens in the __________.

lysosome

Cyclic AMP was the first intracellular second messenger signal identified in __________ cells.

mammalian

DNA polymerases cannot initiate the synthesis of a complementary DNA strand without an __________ primer.

RNA

Glutamate is converted to __________ by transamination reactions.

alanine

The purine ring is constructed primarily in the __________.

liver

Telomeres are complexes of noncoding DNA plus proteins located at the ends of __________ chromosomes.

linear

Hemin inhibits ALA synthase via __________ regulation.

allosteric

The urea cycle occurs only in the __________.

mitochondria

Enzymes increase reaction rates by lowering __________ energy.

activation

Fatty acid synthesis occurs in the __________.

cytoplasm

The electron transport chain is located in the __________ mitochondrial membrane.

inner

Peptide bonds are formed via __________ synthesis.

dehydration

Ribosomes are composed of __________ and proteins.

RNA

The pancreas secretes __________ to aid in fat digestion.

bile

Histidine is an __________ amino acid.

essential

DNA replication is __________.

semiconservative

ATP is the primary __________ currency of the cell.

energy

The lac operon is an example of __________ and negative gene regulation.

positive

Glycogen is stored in the __________ and muscle tissues.

liver

The main function of mitochondria is __________ synthesis.

ATP

Allosteric enzymes have __________ active sites.

multiple

The citric acid cycle produces __________, NADH, and FADH2.

ATP

Hemoglobin and myoglobin have the same __________-binding affinity.

oxygen

The Golgi apparatus modifies and __________ proteins.

packages

The smooth ER is involved in __________ synthesis.

lipid