Kahn Academy MCAT Bio struggle topics

VH MILK WTF

essential amino acids

nucleophilic addition-elimination

what type of reaction forms peptide bonds linking amino acids?

hydrolysis

what type of reaction breaks peptide bonds between amino acids?

peptide bonds

links amino acids to form primary structure

H bonds

forms secondary structure of proteins

van der waals, hydrophobic interactions, disulfide bridges, h bonds

form tertiary interactions of proteins

SDS page

denatures proteins and coats them w/ a negative charge so they can be separated primarily by their weight and not their shape/charge

break disulfide bonds

reducing agents like B-mercaptoethanol are used in SDS- page to?

faster

smaller proteins move (slower or faster) in sds page

+electrode

what side of the electrode do proteins move towards in SDS-page?

chromatography

component that travels the least distance on TLC plate is most polar, since it binds to the silica most tightly

size-exclusion

chromatography in which smaller molecules enter pores and elute later

ion-exchange

chromatography in which resin beads bind proteins w/ opposite charges

affinity

chromatography in which proteins that don’t have affinity for the ligand are washed away

gas

chromatography which separates based on volatility

decrease

enzymes __ the free energy change of the transition state

zymogen

inactive enzyme that requires covalent modification to be active

phosphodiester bonds

link nucleotide monomers together in a DNA polymer

purines

adenine and guanine

pyrimidines

cytosine and thymine

topoisomeriase

unwinds strands; prevents supercoiling

helicase

breaks H bonds b/w strands

primase

synthesizes RNA primers complementary to DNA strand

DNA polymerase III

extends RNA primers by adding nucleotides

DNA polymerase I

removes RNA primers and replaces with newly synthesized DNA

DNA ligase

seals gaps b/w Okazaki fragments

telomeres

buffer zone that doesn’t contain important genes

mismatch repair mechanism

mark w/ a cut, exonuclease removes nucleotide, DNA polymerase inserts correct nucleotide, DNA ligase seals

nucleotide excision repair

endonuclease, DNA polymerase, DNA ligase

5’ cap and poly A tail

protect the mRNA transcript from attack by enzymes in the cytoplasm called exonucleases

splicing

removes introns

AUG

start codon

UAA, UGA, UAG

stop codons

30s, 50s

prokaryote ribosomal RNA subunit sizes

40s, 60s

eukaryote ribosomal RNA subunit sizes

operon

unit of genomic DNA containing a cluster of genes that are under control of a single regulatory signal or “promoter” (genes here are either expressed altogether or not at all)

histones

H2A, H2B, H3, H4

heterochromatin

densely packed chromatin

euchromatin

uncoiled chromatin

oncogenes

genes that code for proteins that normally direct cell-growth; can cause cancer by acting like a “stuck gas pedal”

tumor suppressors

genes whose protein products either have a halting effect on the regulation of the cell cycle or promote apoptosis

frameshift

number of inserted or deleted nucleotides is not a multiple of 3

mutagen

any chemical substance or physical event that can cause genetic mutations

endogenous mutagen

ROS are an example of

exogenous mutagens

intercalators and base analogues are examples of

prophase I

crossing over occurs during

higher

a ____ (higher or lower) recombination frequency between alleles means they are further apart

sanger sequencing

read sequence from bottom —> top, and then figure out the complementary template strand from there

no selection, no mutation, large pop, stable allele frequencies

conditions for hardy-weinberg principle

genetic drift

mechanism of evolution defined by random changes in gene variant (allele) frequencies over time, driven by pure chance rather than natural selection; more likely to happen w/ small populations

bottleneck effect

sudden disaster depletes a population, leaving only a small, random assortment of survivors to rebuild

founder effect

a small group of individuals breaks away from larger population to establish a new, isolated colony

allopatric speciation

groups from an ancestral population evolve into separate species due to a period of geographical separation

sympatric speciation

groups from the same ancestral population evolve into separate species without any geographical separation

ATP + H2O —> ADP + P

ATP hydrolysis

lactose

glucose + galactose

maltose

glucose + glucose

sucrose

glucose + fructose

pentose phosphate pathway

G6P + 2 NADP + H2O —> Ribose-5-phosphate + 2NADPH + 2H+ + 2CO2

2 ATP, 2 NADH, 2 pyruvate

net products of glycolysis

lactate + 2 ATP

lactic acid fermentation results in

ethanol + CO2 + 2 ATP

alcoholic fermentation results in

1 GTP + 3 NADH + 1 FADH2 + 2 CO2 + regenerated OAA

products of the citric acid cycle

NADH dehydrogenase

step 1 of ETC; moves electrons from NADH —> ubiquinone and pumps 4 protons

succinate dehydrogenase

step 2 of ETC; passes electrons from FADH2 —> QH2 while passing NO protons

Q-cytochrome c oxidoreductase

step 3 of ETC; transfers electrons from QH2 —> cytochrome c and pumps four protons

cytochrome c oxidase

step 4 of ETC; donates electrons to oxygen via copper while pumping 2 protons

107 ATP

beta oxidation of one 16-C Fatty Acid provides

cis

what types of double bonds create kinks in the membrane in phospholipids?

saturated

fluidity lower (can get closer together bc no kinks)

unsaturated

fluidity higher bc of kinks

hydrostatic pressure

pushes fluid out of a space

osmotic pressure

pulls fluid into a space

tight junctions

watertight seal in bladder, intestines, kidneys

desmosomes

spot welds in skin, intestines

gap junctions

tunnels in cardiac muscle, neurons

microfilaments

made of actin monomers; movement of whole cell

intermediate filaments

made up of different kinds of proteins; structural support; resist mechanical stress

microtubules

made of tubulin proteins; mitotic spindle, cilia/flagella, transport

gram +

purple stain, has thick peptidoglycan layer

gram -

pink stain; has LPS layer and thin peptidoglycan layer

transformation

bacteria takes up a piece of DNA floating in its environment

transduction

DNA accidentally moved from one bacterium to another by a virus

conjugation

DNA transferred between bacteria through a tube b/w cells

lytic cycle

phage infects bacterium, hijacks it to make lots of phages and then lyses it

lysogenic cycle

phage infects the bacterium and inserts its own DNA into the bacterial chromosome, allowing the phage DNA to be copied and passed along with the cell’s own DNA

retroviruses

enveloped ssRNA virus that uses reverse transcriptase to convert its RNA into dsDNA, which is then permanently integrated into the host genome

positive sense RNA

genome has a sequence that could be directly translated to make proteins

negative sense RNA

genome can’t be used for translation, so the reverse compliment encodes the viral proteins

Rb

activates DNA replication

p53

blocks cell cycle progression (defects in this lead to tumors)

p21

inhibits CDK

parathyroid

regulates calcium through PTH

thyroid

regulates metabolism

adrenal cortex

steroids (cortisol, aldosterone)

adrenal medulla

catecholamines (epi/norepi)

oxytocin and ADH/vasopressin

posterior pituitary hormones

thyroid hormone

which hormone acts like a steroid even though it isn’t one?

CN 9 (glossopharyngeal)

which cranial nerve is an important peripheral chemoreceptor for respiration?

bohr effect

high carbon dioxide and low pH decrease hemoglobin’s affinity for oxygen (occurs in peripheral tissues like muscles)