AAMC FL 3 B/B Flashcards
osmotic pressure
the minimum pressure which needs to be applied to a solution to prevent the inward flow water across a semipermeable membrane
osmotic pressure equation
If solute concentration is relatively HIGH, then osmotic pressure is _____
HIGH
If solute concentration is relatively LOW, then osmotic pressure is _____
LOW
oxidoreductase enzyme
enzymes that catalyze the transfer of electrons from one molecule to another molecule
catalyze redox reactions
lyase enzyme
catalyzes the breaking of various chemical bonds by means other than hydrolysis and oxidation
isomerase enzyme
convert a molecule from one isomer to another
catalyze a structural rearrangement
hydrolase enzyme
use water to break a chemical bond, which typically results in dividing a larger molecule into smaller molecules
they catalyze hydrolysis
protease enzyme
break apart peptide bonds via hydrolysis
a subtype of hydrolases
primary vs secondary active transport
primary → directly pumps ions in or out using ATP
secondary → utilizes the gradient produced by a primary pump to drive transport
NADH dehydrogenase complex #
complex I
succinate dehydrogenase complex #
complex II
cytochrome C reductase complex #
complex III (3)
cytochrome C oxidase complex #
complex IV (4)
how are work and speed related?
they are NOT
work = force x distance
POWER = work / time
work (moving an object)
force x distance
(technically FDcosθ if there is an angle between these 2 vectors)
purine vs pyrimidine
purines → 2 rings / larger
pyrimidines → 1 ring / smaller
guanine → (purine or pyrimidine) ?
purine
adenine → (purine or pyrimidine) ?
purine
cytosine → (purine or pyrimidine) ?
pyrimidine
thymine → (purine or pyrimidine) ?
pyrimidine
uracil → (purine or pyrimidine) ?
pyrimidine
which nucleotide pair is stronger, A – T or G – C ?
G – C
(3 H-bonds)
high osmolarity means _____
high solute concentration
DNA replication: primase
synthesizes the short RNA primer to start replication (once on the leading strand and continuously on the lagging strand)
DNA replication: ligase
seals the ends of the DNA molecules together, creating one continuous strand of DNA
DNA replication: helicase
unwinds/separates the DNA
DNA replication: topoisomerase
introduce negative supercoils to alleviate torsional stress and reduce risk of strand breakage
prevents recoiling
DNA replication: polymerase III
synthesize the new daughter strands by adding complementary nucleotide bases to the parent strands
(add in a 5’ to 3’ direction)
DNA replication: polymerase I
replaces RNA primer with DNA nucleotides
direction of DNA replication
5’ to 3’ (new strand)
calcium involvement in muscle contraction
calcium binds to troponin which causes conformational change in tropomyosin, revealing the myosin binding site for the myosin head to bind to the actin/thin filament
ATP role in muscle contraction
binding of ATP releases the myosin head from the actin/thin filament
then when ATP hydrolyzes to ADP + Pi, the myosin head shifts back to its original position ready to bind again
muscle contraction steps
calcium binds to troponin causing shift in tropomyosin to revela myosin binding site
myosin binds to actin and the power stroke occurs as ADP + Pi dissociate from myosin
ATP binds to myosin to release it from actin
ATP hydrolyzes to ADP + Pi to recycle myosin head to resting position
histone acetylation vs deacetylation
acetylation → unwinding, increases transcription and expression of genes
deacetylation → tighter associations with histones; decreases transcription and expression of genes
epinephrine vs norepinephrine
aka “adrenaline” and “noradrenaline”
epinephrine → secreted from the adrenal medulla to act as a hormone
norepinephrine → acts locally as neurotransmitter
epinephrine and norepinephrine functions
the primary neurotransmitters of the sympathetic nervous system (fight-or-flight)
involved in alertness and wakefulness
microtubules
made of tubulin
largest diameter
transport substances within the cell (using motor proteins like kinesin and dynein)
form mitotic spindle, cilia, and flagella
microfilaments
made of actin → “actin filaments”
involved in gross movement of the cell from within (ex. cleavage furrow or amoeba movement)
dynamic → lengthen and shorten easily vs actin polymerization and depolymerization
intermediate filaments
made of many types of protein (keratin, desmin, etc.)
provide structural support / resist mechanical stress
permanent rather than dynamic → rarely lengthen/shorten often
restriction enzyme sequences must be ________
palindromic!
when copied, both strands of DNA will have the same sequence when read 5′ to 3′
how many base pairs do restriction enzymes cut?
4-8
genomic imprinting
an epigenetic phenomenon that causes genes to be expressed or not, depending on whether they are inherited from the mother or the father
via methylation to guide expression
polypeptide synthesis occurs in the _____ direction
N terminus (first) to C terminus (last)
retroviruses
carry RNA and reverse transcriptases
the enzymes convert the viral RNA to DNA which can then be integrated into the host genome for long term infection
the descending loop of henle is permeable to _______
water only
the ascending loop of henle is permeable to _______
salts (Na+, Cl-, K+, etc.)
the optimal temperature for MOST enzymes is _____
37 C (body temp)
what type of cells secrete mucus?
goblet cells (a type of epithelial cell)
connective tissue
supports, protects, and gives structure to other tissues and organs in the body
blood, fat, bone, cartilage, lymph, etc,
smooth muscle vs skeletal muscle
smooth muscle → involuntary control (ex. heart)
skeletal muscle → voluntary control (think “connected to skeleton”; ex. biceps)
functions of small and large intestine
small → digestion and absorption of nutrients
large → absorption of water and salts
competitive vs noncompetitive vs uncompetitive inhibitors
competitive → bind to the enzyme active site (same site as substrate)
noncompetitive → bind to a site other than the active site; bind equality well to the enzyme and enzyme-substrate complex
uncompetitive → bind only to the enzyme-substrate complex
osteoblasts
cells that make bones
synthesize bone matrix and coordinate the mineralization of the skeleton
osteoclasts
responsible for the breakdown of bone
(to release calcium?)
osteocytes
these are osteoblasts that lie within the substance of fully formed bone
involved in cell communication and mechanical sensing
maintain bone mass
