MCAT Bio/biochem

Nucleoside components

5-C pentose sugar, nitrogenous base, N-glycosidic linkage to link pentose and base

Reaction used to free substrate from enzyme

Hydrolysis

disulfide linkages cleaved exclusively by

oxidation/reduction

can both active site and substrate change shape?

yes

hyper polarization of neurons caused by

excess potassium efflux

depolarization of neurons caused by

sodium influx

Michaelis-mentin kinetics

concentration of compound impacts rate of transport at low not high concentrations

______ are some of the largest cells in the body

neurons

all viruses are/are not parasites

are

can bacteriophages infect eukaryotes

no

Gram negative bacteria structure

no thick peptidoglycan cell wall, yes external cell membrane

gram positive bacteria structure

yes thick peptidoglycan cell wall, no external cell membrane

Obligate aerobe

require O2 for growth

Facultative aerobe

grow under O2 or no O2 exposure

Aerotolerant anaerobe

doesn’t use O2 for growth but survives in presence of O2

obligate anaerobe

need complete absence of O2

(+) RNA

acts as mRNA, can be immediately translated

(-) RNA

complementary to mRNA, must be transcribed into positive strand before translation

Location of glycolysis

cytoplasm

first irreversible step of glycolysis

glucose to glucose 6-phosphate

second irreversible step of glycolysis (no turn back point)

fructose 6-phosphate to fructose 1,6-biphosphate

third irreversible step of glycolysis

PEP to pyruvate

function of kinase

add phosphate group to molecule

glucagon level relationship with blood sugar level

inverse

insulin (upregulates/downregulates) glycolysis

upregulates

glucagon (upregulates/downregulates) glycolysis

downregulates

third irreversible step of glycolysis inhibited by

ATP, acetyl CoA, fatty acids

pyruvate kinase inhibited by

ATP, acetyl CoA, fatty acids in glycolysis

how does glucokinase differ from hexokinase?

Low affinity for glucose, not inhibited by glucose 6-phosphate

what is the isoenzyme of hexokinase

glucokinase

where is glucokinase found

pancreas and liver

where can gluconeogenesis occur

liver and kidneys

gluconeogenesis can use these molecules to produce pyruvate

proteins, glycerol, lactate