MCAT: Biology(and some biochem)

Define the process of conjugation

Exchange of DNA between bacteria via an F factor plasmid through a sex pilus

Define the process of transformation(in bacteria)

Uptake of DNA by bacteria from their environment

Define the process of transduction

Transfer of genes by a virus

What is the function of a phosphotase?

Cleavage of phosphate bonds to remove a molecule of inorganic phosphate

What is the function of a kinsae?

Adding inorganic phosphate groups to molecules

What is the function of a transferase?

Transferring functional groups between molecules

What is the function of an isomerase?

Rearranging the structure of molecules to convert one isomer to another

What path do proteins usually follow to the golgi apparatus?

Cytoplasm to endoplasmic reticulum to golgi apparatus

How many electrons can cytochrome C carry?

1

How does cytochrome C transfer electrons?

It cycles between Fe2+ and Fe3+ during oxidative phosphorylation

What makes for an ideal primer for PCR?

High GC content and GC at the 5’ and 3’ ends

When in meiosis does nondisjunction occur?

Anaphase I

What is K_M in Michaelis-Menten kinetics?

Substrate concentration at which reaction rate is half the maximum capacity

Are L or D isomers of amino acids used to form proteins?

L only

What kind of filament is actin most of the time?

microfilament

A fatty acid is comprised of a long hydrocarbon tail and a head consisting of what?

A carboxylic acid

What is the function of protease?

Cleavage of peptide bonds

What germ layer does the mouth originate from?

Mostly ectoderm

What is indicated when apparent K_M is increased while the apparent V_max is unchanged after a compound is added to a substrate/enzyme mix?

The compound is a competitive inhibitor

What is the function of Na+K+ATPase during neuronal action potential?

Restoration of the resting potential(3 Na+ out & 2 K+ in)

How do glucocorticoids affect muscles?

They increase protein degradation which leads to muscle weakness

Where does most modification of proteins that are to be secreted happen?

the endomembrane system

What is an alpha glycosidic bond?

The anomeric carbon’s oxygen is going down

What is a beta glycosidic bond?

The anomeric carbon’s oxygen is going up

D-glucose

What enantiomers are most of the sugars in our body?

D

L-glucose

D-mannose

What is an epimer?

Sugars that differ at just one chiral carbon(C# to indicate carbon)

D-galactose

D-fructose

Ribose

alpha-D-glucose

beta-fructose

D-mannose

Lactose; galactose & glucose; beta-1,4

D-galactose

Maltose; 2 glucose; alpha-1,4

Sucrose; glucose & fructose; alpha-1,4; non-reducing

Features of glycogen

Chains of glucose; main chains: alpha-1,4; branches: alpha-1,6

Glycolysis equation

Glucose + NAD⁺ + 2ATP → 2 pyruvate + NADH + 4 ATP

Pyruvate dehydrogenase vs lactate dehydrogenase

PDH: High O2; LAF: Low O2

Pyruvate Dehydrogenase Complex equation

Pyruvate → Acetyl CoA + NADH + CO2

Citric Acid Cycle equation

Acetyl CoA + NAD⁺ + FAD⁺ → Acetyl CoA + NADH + FADH2 + CO2

How many total ATP from aerobic respiration?

30 in sk muscle and brain; 32 in liver and heart

Citric acid cycle location

Mitochondrial matrix

ETC location

Inner membrane of mitochondria

Lactic Acid Fermentation equation

pyruvate + NADH → lactate + NAD⁺

Gluconeogenesis rough equation

2 pyruvate → glucose

Glycogenesis rough equation

mass of glucose → glycogen

Glycogenolysis rough equation

Glycogen → mass of glucose

Where do gluconeogenesis, glycogenesis, and glycogenolysis occur?

liver cells(sometimes muscle)

Pentose Phosphate Pathway equation

Glycolytic intermediates + NADP⁺ → Nucleotides + NADPH

Beta oxidation rough equation

Fatty acids + O2 → Acetyl CoA

Fatty acid synthesis rough equation

acetyl CoA → citrate(to leave mitochondria) + NADPH → fatty acids

Ketogenesis rough equation

acetyl CoA + CAC intermediates → ketone bodies

Ketolysis rough equation

ketone bodies → acetyl CoA + CAC intermediates

Gastrin function

Stimulates stomach acid, pepsinogen, stomach churning

Control of gastrin

Stim by food in stomach, inhib by low pH

Control of secretin

Stim by acid in chyme in duodenum

Secretin function

Stim bicarb from pancreas, inhibit acid, pepsinogen, stomach churning

CCK function

Stim release pancreatic enzymes, contract gallbladder for bile; inhibits stomach churning

Control of CCK

Stim by fat in chyme in duodenum

Describe a phosphodiester bond

2 esters on either side of a phosphate

What is the Cori cycle?

Lactate to glucose(in the liver) and back(in the muscles)

The adrenal medulla is part of which branch of the peripheral nervous system?

Sympathetic only

What is required of a recognition sequence in a restriction enzyme?

A palindromic sequence(the complementing sequences are identical 5-3)

Features of ECC complex I

e- from NADH to CoQH2; pumps 4 protons

Features of ECC complex II

Succinate dehydrogenase; e- from succinate to FADH2 then to CoQH2; pumps no protons

Features of ECC complex III

e- from CoQH2 to cytochrome c; pumps 4 protons

Features of ECC complex IV

Cytochrome c oxidase; e- from cytochrome c to H2O; pumps 2 protons

Function of aconitase in the CAC

Citrate → Isocitrate

Function of Isocitrate dehydrogenase in the CAC

Isocitrate → alpha-ketoglutarate + CO2 (NAD+ → NADH)

Function of alpha-ketoglutarate dehydrogenase in CAC

alpha-ketoglutarate → succinyl-CoA + CO2 (NAD+ → NADH)

Function of Succinyl-CoA synthetase in CAC

Succinyl-CoA → Succinate (GDP → GTP)

Function of succinate dehydrogenase in CAC

Succinate → Fumarate (FAD → FADH2)

Function of Fumarase in CAC

Fumarate + H2O → malate

Function of malate dehydrogenase in CAC

Malate → oxalacetate (NAD+ → NADH)

Function of citrate synthase in CAC

Acetyl-CoA + oxalacetate → citrate

What is genomic imprinting?

The inactivation of one parental copy of genes via epigenetic alteration

What are some ways RNA viruses can replicate themselves?

Carry their own transcriptase or borrow polymerase from the host(no need to alter)

What does RT-PCR measure?

mRNA levels

What does a southern blot do?

analyzes genomic DNA

What does quantitative PCR do?

measures levels of DNA

What does a western blot do?

measures levels of protein translated

What does a northern blot do?

Analyse RNA

What does gel filtration chromatography do?

Separates proteins based only on size

What does a natural PAGE do?

separates molecules based on length, conformation, and charge