MCAT BIO 1
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MCAT BIO 1
biology flashcard mcat
my studies for the big exam
what is saltatory conduction?
the jump of an action potential between unmyelinated node of ranvier
what happens when a action potential reaches a synapse (in a mammal)?
when an action potential reaches a synapse, the electrical signal causes the release of neurotransmitters from the presynaptic membrane into the synapse.
which types of neuron serves as a link between motor and sensory neurons?
what is the function of cerebral cortex?
processes and integrates sensory input and motor response, and controls memory
whats the function of hypothalamus
responsible for visceral functions such as hunger, thirst, and sex drive
what are the components of the hindbrain
cerebellum, pons, medulla oblongata
what part of the brain controls autonomic activities
(t/f) sensory nerves enter the spinal cord ventrally and motor nerves leave dorsally
false, sensory enter dorsally; motor leaves ventrally
the heirarchy of the division of the peripheral nervous system
PNS-- sensory, motor
Automatic--- parasympathetic, sympathetic
whats the difference btwn polysynaptic and monsynaptic relfex?
mono-only one sensory and one motor neuron
poly-one or more interneurons and one sensory and one motor neurons
what types of photoreceptor cell is specialized in color?what specialized in low light?
cones for for colors
rods are for low light
what is fovea
an area of high density of cones
component of middle ear?
tympanic membrane, malleus, incus, and stapes
component of inner ear?
cochlea (contains organ of Corti) and semicircular canals
what are alleles
different form of the same gene. they occupy the same position on homologous chromosomes
mendal's first law (segregation)
genes exist in alternative form (alleles)
one inherits two alleles of each trait... one from each parent.
alleles segregates during meiosis
if two different alleles are present only one will be fully expressed
Mendal's 2nd law (independent assortment)
alleles of unlinked genes assort independently during meiosis
P= purple, p= white... whats the ratio of each:
1.phenotype PP x pp
2.phenotype Pp x Pp
3.phenotype Pp x pp
4.genotype Pp x pp
5.genotype Pp x Pp
2.75% purple, 25% white
4.50% Pp, 50% pp
5.25% PP, 50% Pp, 25% pp
Given: X and Y recombinant freq =5%
X and Z recombinant freq =13%
1.what is Y and Z rec freq if gene order is XYZ
2. if it is YXZ?
red flower and white flower crossed to have pink flowers... what kind of dominance?
what is penetrance of a genotype?
percent of individuals in a population who actually express its phenotype
what is expressivity of a genotype
degree to which the phenotype is expressed in an individual
what percent of daughters will inherit their father's sex linked gene
what percent of sons will inherit father's sex linked gene
what percent of sons will inherit their mother's sex linked gene (heterozygous mother)
what is nondisjunction
failure of homologous chromosomes (or sister chromatids) to separate properly during cellular reproduction
three different result of chromosomal breakage
1.duplication- fragment joins with its homologous chromosome
2.translocation-fragment joins with a non-homologous chromosome
3.inversion-fragment rejoins its original chromosome but in reverse position
name purines and pyrimidines
pyrimidines- Cyotsine, Uracil, Thymine
what are the 4 types of RNA, what are their functions?
mRNA-contains the codons for peptide chain synthesis
tRNA-transport amino acids to the ribosome during protein synthesis
rRNA-strutural component of ribosome
hnRNA-precursor of mRNA
what are 3 stages of polypeptide synthesis
initiation, elongation, termination