AAMC FL3 BBCF

Question 1

five types of inheritance

Answer 1

autosomal dominant: requires only one allele; both sexes affected
autosomal recessive: requires both alleles; both sexes affected

x linked dominant: requires only one allele; affects all children bc one parent donates one chromosome
x linked recessive: requires both alleles; males affected more than females

y linked: male exclusive; all male offsprings will be affected

Question 2

imprinted genes

Answer 2

gene will only be expressed from the maternal or paternal chromosome; thus expression of only one copy despite having two bc one is “silenced” as a result of epigenetic marking,

Imprinted genes are re-marked according to the individual’s own sex in their gametes.

i.e. in Angelman’s syndrome, only the maternally-inherited copy of the gene is active. For a male, the active Angelman’s gene (inherited from his mom) will be marked as silent in his sperm (since that gene copy will be paternally inherited by the resulting zygote).

Question 3

types of evolution

• convergent
• divergent
• parallel
• coevolution

Answer 3

Convergent - two different species in same environment adapt in similar ways

Divergent - same animals are separated by geographics and adapt to those environment, making new species

Parallel - Same lineage, evolving closer together to be similar, using similar mechanisms.

Coevolution - Two species evolve in response to each other

Question 4

sympatric speciation vs allopatric

Answer 4

sympatric speciation: two species occupy the same area; biological barrier prevents them from merging

allopatric speciation: two species occupy different areas; physical barrier prevents them from merging

Question 5

how do isoforms form in prokaryotes vs eukaryotes

Answer 5

in pro: an operon containing two genes in prokaryotic cells is transcribed from a single promoter upstream of the first gene in the operon

in eu: alternative splicing allows diff amts of exons to be expressed from the same gene, thus yielding diff isoforms

Question 6

what increases the contractile force of the heart

Answer 6

increased levels of intracellular calcium

Question 7

histone acetylation

Answer 7

histone acetylation would promote transcription as it would result in the histone becoming “less positive” and unable to interact as strongly w the negatively charged phosphates on DNA

loosening of DNA around histones allows transcription to occur more readily bc of the increased exposure of the transcribable sites

Question 8

DNA methylation

Answer 8

dna methylation would inhibit transcription as it would prevent the binding of transcription factors to that specific gene of the DNA sequence

this leads to less expression of that gene

Question 9

what system do these brain parts interact with

• adrenal medulla
• hypothalamus

Answer 9

ADRENAL MEDULLA: secretes epinephrine and norepinephrine in response to short-term stress; reactions to short-term stress are mediated by the sympathetic branch of the autonomic nervous system.

HYPOTHALAMUS: controls the pituitary gland, initiating the stress response; regulates temperature, thirst, and appetite via the endocrine system

Question 10

restriction enzymes recognize what

Answer 10

a four-base sequence or a six-base sequence

Question 11

ideal conditions for an enzyme

Answer 11

while the optimum pH value varies greatly from one enzyme to another, the optimum temperature for enzymes is normally 37 °C

Question 12

epithelial cells

Answer 12

specialized cells for secretion, esp of mucous (thus can be found in any area of the body that is exposed to the environment)

Question 13

a decrease in ions in the blood results in what

Answer 13

decrease in osmotic pressure, also decrease of ion concentration relative to the tissues

based on osmosis, water will flow from the blood to the tissues in order to reestablish osmotic pressure in the blood

Question 14

an excess of unabsorbed fats in the intestine will ____

Answer 14

inhibits normal water and electrolyte absorption, resulting in increased osmotic pressure and diarrhea

Question 15

what inhibitors reversibly bind? (3)

which ones bind irreversibly? (4)

Answer 15

reversible: eventually fall off or can be outcompeted w excess substrate
eg. competitive, non-, un-

irreversible: covalently bonds to the enzyme at the active site, denaturing it
eg. group-specific reagents, reactive substrate analogs, affinity labels and suicide inhibitors

Question 16

What is the order in which filtrate passes through the tubular regions of a nephron?

Answer 16

Bowman’s capsule → proximal tubule → loop of Henle → distal tubule → collecting duct