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biology Flashcards

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1
Q

what are nucleic acids and give examples

A

they are very acidic due to their phosphate groups and remain in the nucleus

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2
Q

nucleotide vs nucleoside

A

nucleoside is base with sugar WITHOUT phosphate group

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3
Q

1 nucleotide is equal to how many base pairs?

A

1

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4
Q

annealing / hybridization

A

joining the dna strands together again and usually occurs once cooling takes place

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5
Q

why is it called a right handed double helix

A

because it is coiled up in a clockwise fashion with only the phosphate groups being exposed

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6
Q

role of dna gyrase “gyrate” shakira

A

works for dna of proks twist and supercoil their dna to make less bulky

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7
Q

of chromosomes of prok?

A

1

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8
Q

diff btwn guanosine and adenosine

A

guan has carbonyl group

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9
Q

diff btwn the pyrimidines

A

uracil has two carbonyl groups and thymine has two carbonyl and a methyl group

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10
Q

nucleosomes

A

dna that wraps around histones and groups them in octamers

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11
Q

centromere

A

where the spindle fibers attach for cellular division

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12
Q

intergenic regions

A

noncoding RNA

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13
Q

what mitotic phase will be able to see chromosome the clearest?

A

metaphase

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14
Q

single nucleotide polymorphisms

A

essentially mutations and occur mostly in noncoding regions

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15
Q

benefit and cost of tandem repeats

A

the nucleotides of repeats can protect genes but if unstable or short or too long, can cause harmful mutations

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16
Q

codon

A

nucleic acid with three nucleotides

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17
Q

non sense codons

A

aka stop codons because they don’t code for any amino acid

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18
Q

origin of replication (ORI)

A

proteins that belong at least in the tertiary structure have to be able to recognize it so that helicase can begin. Once they regognize they are destroyed so that replic doesn’t occur in any other stage.

ORI AKA DNA A for proks

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19
Q

why is the lagging strand discontinuous?

A

it requires a RNA primer to continuously have dna polymerase add to the strand so it can only do lil by il causing the okazaki fragments

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20
Q

name 2 types of endonucleases

A

overall cuts the polynucleotide in the middle

repair enzymes remove damaged dna from chain

restriction enzymes remove damaged dna from viruses found in bacteria

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21
Q

DNA pol I

A

works slower than the dna pol III and requires an rna primer (ran primase must remove the primer so that DNA 1 to add nucleotides for the lagging strands

has a 3’ to 5’ proofreading activity

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22
Q

DNA POL III

A

works well in processing, focuses on the laeding strand,

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23
Q

what is a 3’ to 5’ exonuclease activity mean

A

had proffreading ability (usually works at the end of the chain)

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24
Q

define telomerase

A

adds extra nucleotides to the chromosome due to the fact that telomeres are not involved in replication so nothing else to keep them from shortening except telomerase

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25
Q

bad effect of telomerase with cancer

A

it keeps the cancer cell somewhat immortal by bypassing the apoptosis and continues to prolong their life by adding extra nucleotides to the cancerous cells

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26
Q

y is ethium bromide a mutagen?

A

bc it intercalates into DNA messing up the helix. usually used in cell molec labs to see visible dna during electrophoresis light

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27
Q

what are the 3 type of point mutations

A

missense , nonsense, and silent

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28
Q

define missense mutation

A

when u have point mutation and one nucleotide mismatching mistake may cause a diff aa but may not be serious IF AND ONLY IF an aa is replaced with an aa of the same character

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29
Q

nonconservative mutation

A

slight change in the genotype of polypeptide chain but goes undetected to not affect the phenotype

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30
Q

framseshift mutation includes ??

A

an insertion or deletion which can be very bad !

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31
Q

inversion

A

when the chromosome uses itself to get a segment of its own to reverse and then put insert in itself again

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32
Q

chromosome amplification

A

segment of the chromosome is duplicated

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33
Q

transloctaion

A

two nonhomologous chomosomes enter recombination with each other

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34
Q

what is the difference between primer, rna polymerase, and dna polymerase?

A

primer is needed to start replication and is made by dna primase

rna polymerase is needed to start transcription going into mrna

dna polymerase is made to add more nucleotides to the three end of the strand for replic

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35
Q

which strand matches the mrna when it is only replacing the t with u

A

coding strand

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36
Q

what group do introns belong to

A

nonsense

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37
Q

what is special about the hair pin loop in transcription

A

it causes the strands to change structure and causes the rna polymerase to drop off and stop transcription

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38
Q

what is the shine delgarno ?

A

in bacteria it is where the ribosome attaches to start the translation processes once the start codon AUG is attached as well

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39
Q

5 cap is used for protection but also for what

A

the ribosome will recognize it and start the translation processs for euks

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40
Q

how is bacteria start codon different from euk start codon?

A

it has formal methionine whch is interesting bc if found in the bloodstream of euk, it can trigger an alarm that causes inflammation response because something Is happening to the bacteria in the body

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41
Q

mismatch repair mechanism

A
  1. notices there is a problem bc the phosphate backbone appears distorted by sticking outwards
  2. mark incorrect base with a cut as a notice
  3. exonuclease removes it
  4. nuclease correctly matches it to a new nucleotide
  5. dna ligase

ALL OCCURS AFTER REPLICATION?

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42
Q

how does mismatch know which strand is which and which base is correct?

A

parental strands have their adenine methylated so it knows not to touch the parental strand in bacteria but not known how it knows in euks

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43
Q

mutation vs dna damage

A

mut is a change in sequence of the dna like wrong nucleotide matched

dna dam has correct order but can be damaged by engoenous (o2 radicals or h2o2) or exodgennbous factors like gamma xray

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44
Q

nucleotide excision repair

A
  1. endonuclease removes the dimers or any nucleotides that are not supposed to be there
  2. dna pol I will bring the correct nucleotide
  3. dna ligase to seal together
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45
Q

nuclease

A

enzyme that can remove the nucleotides

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46
Q

what happens to dna when mismatch doesn’t come into place

A

apoptiosis,

semsemsce

rapid cell division which leads to cancer

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47
Q

sensenscense

A

due to dna damage cell enters the dormant stage and no longer grows

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48
Q

what is acetylation and when does it occur

VS methylation

A

co translational protein modif and replaces methionine and of trying to replace histones, it removes the pos charge whch reduces the phosphate groups of dna from interacting well with the pos charge that was once on the histones

So the DNA is not getting acetylated: it’s the histones that are.
Acetylation occurs at lysine residues on the histone, which removes the (+) charge off of the R-group. This causes the DNA to open up (since the favorable interaction between (+) charged histone and (-) charged DNA is lost), hence why it’s associated with gene activation.
Deacetylation has the opposite effect.
Here’s an image I found from google images of histone acetylation that might help further with this

With methylation, both the DNA and histones can be methylated.
DNA methylation is associated with gene repression, as the addition of a methyl group onto the cytosine of CpG islands can mess up the binding of TFs onto the regulatory parts of a gene. So you’ll get less transcription at a gene that has lots of DNA methylation.
Histone methylation can have either an activating or a repressing effect (I doubt they’ll test this on the MCAT). It’s weird enough where I’ve read of cases where if you add one methyl group, it activates, but when you add another methyl group, it becomes repressive… And then you add a third methyl group, and it’s back to being activating. I think just knowing that it has an effect on gene expression is sufficient for the MCAT

Acetylation is also a temporary DNA modification
Methylation is a permanent DNA modification

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49
Q

define glycosylation

A

adding of a carbohydrate to a protein that ends up being embeded in the cell membrane

helps for identification process like in ABO blood groups
happens after translation

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50
Q

define lipidation

A

add lipids to a protein which occurs after translation

usually for GPI anchors that helps to attach protein to cell membrane

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51
Q

discuss relationship btwn phosphorylation and sodium potassium pump?

A

when bring sodium out of the cytolplasms (about 3) there needs to be a phosphate group attached to the pump BUT that phosphate MUST BE REMOVED when bringing potassium back in

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52
Q

why is proteolysis not necessarily a bad thing

A

sometimes cutting a protein helps to activate it which is common in activating insulin

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53
Q

ubiquination

A

marks the protein for destruction and the protein parts will be recycled

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54
Q

why is a virus known as a obligate intracellular parasite?

A

in order to reproduce and “live”, it needs to live within the host to survive

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55
Q

can a virus have rna and dna nucleic acids at the same time?

A

no only one at a time

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56
Q

if a virus just made two proteins of diff sizes, what does that mean?

A

it is using more than one reading frame which causes there to be overlap of diff protein sizes

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57
Q

what does it mean if you see that the virus dna has more adenine than thymine in its code?

A

basically because they are not equal in ratio as they should be when they pair up for double stranded dna, it must be single stranded dna bc of the unequal distrib

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58
Q

what does the capsid have

A

couple of proteins, coat, and the head may have the genome

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59
Q

shaft / sheath

A

used to input its genome into the host but bacteria has special quality to break cell walls

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60
Q

what is important about the envelope of viruses? and why are phage and plant viruses naked envelpopes

A

envelopes have the host carbohydrates and phospholipids which trick the host so that the virus can enter and leave better

bacteria viruses already have to break down the cell wall so when they leave the host will rupture (lytic) anyways because their cell walls are destroyed

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61
Q

what does early state of virus mean?

A

one of the group of genes that immediately gets expressed when the virus infects the host

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62
Q

what does late state of the virus mean

A

things that occur and help virus right b4 the host ruptures

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63
Q

how is hydrolase unique to virsuses

A

early state that immediately destroysthe genome of the host so that the virus can start making its own genome

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64
Q

how are lysoszy,es unique to viruses

A

late state that destroys the bacteria cell wall whch causes the host to rupture and the copies of the virus to escape

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65
Q

what comes in and out of the nuclear pore

A

mrna comes out and the proteins come in

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66
Q

nucleolus

A

site of ribosome assemble that makes r rna so that’s why it has a lot of heterochromatin

once ribosomes are made they leave the pore

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67
Q

smooth er

A

metabolizes carbohydrates, take care of toxins, synthesize lipids

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68
Q

rough er

A

make proteins

post translational occurs

disulfide bonds r formed in the lumen but not the cytosol part

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69
Q

secretory pathway for proteins

A

synthesized in rough er but has signal sequence

rough er , cis stack Golgi , medial stack, trans Golgi (furthest away from er) , vesicle

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70
Q

endocrine vs exocrine

A

exocrine releases directly to organ and endocrine release to blood stream

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71
Q

simple epithelium vs stratified

A

simple is for diffusion (alveoli) gas exchange

stratified acts as protective layer to deal with stress like esophagus when food comes in

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72
Q

how do epithelial cells get nutrients

A

doesn’t have blood vessels so it gets it from nearby tissue

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73
Q

cytoskeleton

A

serves as
structural support
movement
transport of substances in the cell

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74
Q

microtubules

A

involved in
mitotic spindsle
make up cilia (hairlike projections to help sweep things up out of the cell)

help with flagellum (tail)
help to move things ioverall

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75
Q

intermediate fillaments

A

structural support
help resist mechanical stress similar to springs inside a mattress

focuses with movement to move out of cell

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76
Q

microfilaments

A

movement of cell within
dynamic (can lengthen and shorten frequently)

lengthen with actin polymerization
shorter in actin depolarization

found in cell division when pinching occurs to separate into two diff cells

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77
Q

where does hydrophobic waste and hydrophilic waste occur

A

hydrophobic is liver

hydrophilic like solvent and solutes

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78
Q

internal urinary sphincter

A

under involuntary smooth muscle (some skeletal) because u don’t want to pee all the time

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79
Q

as u move from outside of kidney to inwards what incr

A

osmolarity which causes ions to move where they are so cause inside to be more hypertonic (more salts)

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80
Q

kidney functions

A

reabsorption of water, nutrients like glucose from filtrate to blood

secretion is move substance from blood to filtrate like drugs toxins and wastes

filtration

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81
Q

creatinine

A

acts as a waste product so if high it is bad

indicator of poor kidney function

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82
Q

what do arteries have that veins don’t have ?

A

more muscle to contract

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83
Q

high adh causes may be due to

A

exercise
LOWbp
dehydrated

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84
Q

what does renin and ace inhibitors do

A

former incr bp and latter decr bp

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85
Q

how to treat high bp

A

low salt
ace inhib
low salt

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86
Q

when bp is normal what does that helps

A

promote filtration

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87
Q

juxtular glomularar apparatus

A

controls bp

connector btwn afferent and distal convoluted

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88
Q

afferent arteriole in kidney

A

notice pressure changes

too low, incr
too high do dilate

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89
Q

distal convoluted tubule

A

ions moving in and out like calcium goes to urine
reasoption of other ions that we don’t want to pee away like nacl

measures osmolarity through chemoreceptors

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90
Q

aldosterone

A

na reabsorbance and potassium secretion

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91
Q

atriole naturetic protein

A

high bp that causes the atriums to get bigger and stretch and acts to lower bp bc it is a vasodilator…

inhibit aldosterone

works as opp of renin angionin bc cant go at same time bc that is bad

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92
Q

ph respiration vs renal regulation

A

ph is slow in renals

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93
Q

when it comes to ph getting lower, what happens to the protrons

A

they go through the blood stream

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94
Q

glomerulus

A

leaks out fluid like glucose, aa, and sodium and h20 but fluid is then captured in bowmans capsule

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95
Q

mouth exocrine parts

A

salive to moisturize the mouth

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96
Q

auxotroph

A

cant do the thing so ex of histadine meanes they cant make it so they have to be given it bc cant make on own

would be called histadine - minus

lactose - means DONT GIV IT TO THEM (EXCEPTION) BC CANT DIGEST IT

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97
Q

Sertoli

A

give sperm nutrition and have androgen (male hormone) binding

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98
Q

spermatonia

A

immature sperm that live in Sertoli cells

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99
Q

interstitual cells aka leydig

A

make testosterone

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100
Q

fsh stimulates what for males

A

stimulate Sertoli and spermatogonia cells

101
Q

where is fsh and lh made

A

anterior pituitary and act on gonads

102
Q

lh stimulates what for males

A

stimulates Leydig cells

103
Q

epidymmis

A

sperm learn to swim (motility ) and will have mitochondria to generate energy to swim

also fiver nutritents

104
Q

what does the seminule tubles and the prostate have in common

A

both fructose levels but prostate has less semen volume and has a thick fluid clotting factor for sperm

105
Q

bulbourthean glands aka cowspers

A

stimulated when arousall occurs

106
Q

arousal is sympathet vs parasympathetic

A

parasympathetic

107
Q

orgasm, emission (sperm goes to urethra) /ejaculation (semen into vagina) is para or sympath

A

sympathet

108
Q

cilia vs microvilli

A

cilia moves things but microvilli is to absorb things like in digestion

109
Q

blastula

A

hollow ball of cells

110
Q

morula

A

comes b4 blastula and has hard ball

111
Q

trophoblast

A

outer ring of blastula that sectretes hcg

also makes the placenta

112
Q

inner cells mass of blastula

A

becomes embryo, amniotic cell,

113
Q

hematocrit formula

A

number of rbc / total blood volume

normal is 45% but if less than anemic

114
Q

how is o2 delivered to the muscles

A

basically has to fall off of hemoglobin by 3 ways:

  1. low pressure of o2 in muscles so through diffusion
  2. H+ competes with o2 for hemoglobin so hydrogens will take space on hemoglobin so o2 is left to fall off or be left in muscles
  3. competing with co2 the same way that o2 competes with h+ bc high pressure of co2 in muscles
115
Q

what is carbonic anhydrase

A

enzyme that helps this rxn occur to make carbonic acid and to go back in reverse if too much hco3/h + (I say / bc has 1 to 1 ratio in normal conditions)

h2o + co2 -> H2CO3 < => H+ + HCO3-

116
Q

oxyhemoglobin vs carbaminohemoglobin

A

oxygen is bound to former and co2 is bound to the latter

117
Q

how is co2 delivered to lungs

A

basically has to fall off of hemoglobin by 3 ways:

  1. low pressure of co2 in lungs so through diffusion wants to jump off of hemoglobin and go to low pressure in lungs
  2. H+ competes with co2 for hemoglobin so hydrogens will take space on hemoglobin so co2 is left to fall off or be left in muscles
  3. competing with o2 for hemoglobin spot because there is high pressure of o2 in lungs
118
Q

Haldane vs bohr effect

A

borh means that the co2 and h+ are eff the affinity to o2 (more eff in muscles and shifts to the right of the normal hemoglob level but delivers more o2)

the Haldane eff means that the o2 disrupts the affin for hemoglobin to co2 / h+ (no cooper so no sigmoidal but regular / constant shape) just a lower slope and more co2 delivery

119
Q

units for kw

A

[oh-][ph] = M^2

120
Q

glycolipids

A

the protein coat of blood types

121
Q

gram pos/ neg bacteria

A

pos has the thick peptidoglycan layer and is harmless

neg is thin and has the lipolysacharides that can set off immune sys (- ) bc sucks since no one likes being sick

122
Q

how do platelets form clumps to form plug

A

collagen which is founbd outside of the blood vessel

123
Q

fibrin

A

protein that strengthen platelet plug by making them tighter together with its strands by polymerizing

found in blood vessels but as inactive fibrinogen to avoid causing platelets from sticking together to avoid clots

124
Q

pro thrombin vs thrombin

A

pro thrombin is the inactive form of thrombin and thrombin is enzyme in blood plasma which causes the clotting of blood by converting fibrinogen to fibrin.

125
Q

life span for rbs and platelets

A

rbs up to 4 months

platelets are couple of days

126
Q

monocyte of spleen

A

eats up the bad rbs to get the iron out and recycle it

127
Q

erythropoietin

A

stimulates the making of erthropoisis to make more rbs and this enzymes acts when o2 is low and takes place in the kidneys

128
Q

what causes constriction of respiratory airway

A

parasympat and histamine (keep in mind that histadine dilates blood vessels which lowers resistance which will slow air flow)

129
Q

what does sympathet, epinephrine (think of epi pen) and adrenaline do to airway?

A

dilate so more air flow

130
Q

The diaphragm plays an important role in respiration. During inspiration, the diaphragm:

A

when u inhale, chest get bigger so more vol will mean less pressure

contracts, causing alveolar pressure to drop below atmospheric pressure.

131
Q

neg vs pos pressure breathing

A

neg is when u are breathing for yourself causing a low pressure but pos is like a ventilator (blasts the air into youto breath for u) so pos pressure bc getting much more than u can do on own

132
Q

is there slightly more o2 or co2 in the veins

A

co2

133
Q

what does acidosis have to do with respire sys

A

co2 is main acidic waste in body so when that accumulates like in hypoventilation, too little o2 but soooo much co2

134
Q

ketoacidosis

A

not a problem of too much co2 in body like a respire acidosis because it is a metabolic acidosis

135
Q

Bronchodilators are a class of drug often used in the treatment of asthma and COPD, which act on β-adrenergic receptors of the airways to induce smooth muscle relaxation. The anatomic distribution of these receptors is closely correlated to the function of each structural component of the lungs. What structural component(s) of the airway would be most affected by the use of a bronchodilator, and in what functional zone(s) are they found?

A

The conducting zone is simply a series of tubes through which gases travel, while the respiratory zone directly participates in gas exchange.
Hint #22 / 5
The respiratory zone is made up of only the alveoli and the respiratory bronchioles/ alveolar ducts.
Hint #33 / 5
The walls of the airways contain smooth muscle, which is the site of action of bronchodilators.
Hint #44 / 5
The alveoli are made of only a single layer of cells, and their walls do not contain smooth muscle. Bronchodilators do not directly affect the alveoli.
Hint #55 / 5
The lobar bronchi would be most affected by the use of a bronchodilator, and they are found in the conducting zone.

136
Q

conducting vs respiratory zone

A

The conducting zone is simply a series of tubes through which gases travel, while the respiratory zone directly participates in gas exchange.

137
Q

What is the pressure of gas within the alveoli at the peak of inspiration, just before expiration, relative to that of atmospheric air?

A

At the peak of inspiration or expiration, the airflow momentarily stops. However, the airway is still open to the atmosphere.
Hint #55 / 6
The halt of airflow is because the alveolar pressure is ‘zero’ relative to the atmosphere.
Hint #66 / 6
The pressure within the alveoli at the peak of inspiration is the same as atmospheric air.

138
Q

henrys law

A

as the partial pressure of has rises, the more amount of gas will go into liquid phase

Kh (jenry constant = P (concentration) think of price Charles

139
Q

henrys law and formula

A

as the partial pressure of has rises, the more amount of gas will go into liquid phase

Henry’s Law has to do with the principles involving dissolved gas and pressure. It states that the amount of gas dissolved under equilibrium in a certain volume of liquid is in direct proportion to the pressure of the gas that makes contact with the liquid’s surface.

Kh (henry constant = Partial pressure that is going in (concentration) think of price Charles

units: L x atm / mol
kh is what solutes are going out of water

temp dep bc influences solubility concen

140
Q

a dot above a variable means what

A

rate

141
Q

ficks law of diffusion and formula

A

V of particles moving= [ (P1-P2) x Area x Diff constant ] / Thickness
V=PAD/ Thickness

following helps diff:
smaller mw
less thick (so more thin)
more solubilty (co2 diffuses faster than o2 bc of this reason)
incr area
incr partial pressure (due to more molecules)

142
Q

flux

A

net gain rate of particles moving through an area… V/A

143
Q

formula for gradient

A

delta pressure / temp

144
Q

mechanoreceptors

A

deal with pressure and a baroreceptor is s type of mechanoreceptor

145
Q

renal vein

A

reabsorbs the ions that we want such as sodium

146
Q

renal calyx

A

1rst part in nephron where the urine is collected and the plural gather together to form the renal pelvis waiting to go to the urether

147
Q

basement membrane

A

prevent proteins from leaving the glomerulus

148
Q

how does the diameters of the afferent or efferent arteriole affect the glomeruls filtration

A

if u incr the affer diameter there will be more things to be filtered so filtration will incr as well

if u incr the effer, more things will be even thrilled to leave bc door is wider so filtration will decr since that is the spot they are b4 they leave

149
Q

proximal convoluted tubule

A

reabsorbs the sodium and water

150
Q

descending vs ascending limb of the loop of henle

A

found in the salty medulla due to ions reapsorption
descending reabsorbs only water NO IONS
ascending reabsorbs na, k, and NO WATER

151
Q

Countercurrent multiplication in the kidney

A

they go in opp directions so countercurrent

Remember that water moves in the direction of the higher solute concentration. So if we have a porous balloon, for example, FILLED with salt, water will flow into the balloon. What is happening in the kidney takes advantage of this. In the ascending loop of henle, ions are ACTIVELY being pumped into the interstitial space. This creates a reaaaally salty environment, like that in our balloon example. Since the descending loop of henle is permeable to water, water will want to flow into the high concentration of salt in the interstitial space.

The reason this is so cool, is the kidney doesn’t have to actively pump water AND salts out. By actively pumping salts out, water can passively follow by piggybacking on the active transport of salt.

152
Q

collecting duct

A

after the distal tubule

reabsorb h20 and urea (waste proponent usually but when kept it helps to drive more water towards it so helps to maintain osmolarity in medulla portion)

153
Q

Secondary active transport in the nephron

A

atp is used to make the sodium go against its gradient but binds to protein

potassium will bind to open part of protein until protein changes conformational shape and potassium falls off after the shape changes but note that potassium will come passively down its gradient

this pump helps to cotransport (sym) glucose in same dir as sodium

154
Q

juxtomerular cells

A

incr renin production in kidneys when:

sodium or bp decr
potass incr

155
Q

renin

A

released into blood stream and acts on protein angiotenisogen by activating it so it can turn into angiostenin I

156
Q

ACE

A

angiostensin converting enzyme

changes the I into the II

157
Q

angiostenin II activates what to secrete what

A

activates adrenal cortex to secrete aldosterone
it also constricts blood vessels

keep in mind acth will be used to secrete cortisol

158
Q

adrenal cortex vs medulla

A

The adrenal medulla, the inner part of an adrenal gland, controls hormones that initiate the flight or fight response. The main hormones secreted by the adrenal medulla include epinephrine (adrenaline) and norepinephrine (noradrenaline), which have similar functions.

The adrenal cortex produces three main types of steroid hormones: mineralocorticoids, glucocorticoids, and androgens. Mineralocorticoids (such as aldosterone) produced in the zona glomerulosa help in the regulation of blood pressure and electrolyte balance.

159
Q

once aldosterone keep sodium and along with water since water usually follows salt closely, and bp incr what happens to the renin

A

the blood volume of body will incr bc now more water that followed the sodium that was reabsorbed (cl is also reabsorbed as side eff)… once the bp incr, neg feedback will occur and cause the renin to deactivate the angiostenin II and go back to angiostenogen (inactive form)

160
Q

relationship between aldosterone and distal convoluted tube

A

aldosterone will cause the atp secondary pump to be activated in the distal

161
Q

diabetes insipidus

A

production of large volumes of urine excretion of isotonic urine or hypotonic urine (equal salt/h20 or low salt) due to adh not working properly bc udh is an antidiuretic

162
Q

circulatory shock

A

major decr in bp

163
Q

why is hyperkalemia associated with over depolarizing the cells rather than hyperpolarizing

A

it depolarizes bc due to so much potassium, the cell membrane potential has less time to be in refractory and will cause the voltage gates to open sooner and then let the depolarization occur

164
Q

Mice subjected to a very high sodium diet were found to have a significant increase (p<0.05) in plasma renin concentration; in order to test the hypothesis that this increase is due to the sensing of increased sodium by macula densa cells, an assay designed to detect which of the following signalling molecules should be performed?

A

Hormones are blood-borne molecules produced by specific organs that are used to send long-range signals between different organ systems.

Neurotransmitters are molecules that send short-range signals between neurons.

Prostaglandins are molecules that send short-range signals between cells; unlike hormones, they are not produced by specific organs, but rather throughout the body.

Macula densa cells send local, short-range signals to juxtaglomerular cells via release of prostaglandins.

165
Q

beta inhibitors and ace inhibitors

A

treat high bp by lowering it

166
Q

Macula densa cells are in what part of the nephron?

A

in the distal convoluted bc of the sodium

167
Q

A biochemical analysis of the conversion of angiotensinogen to angiotensin 1 in the presence of renin (treatment), as compared to a reaction carried out with renin not present (control), is most likely to produce which of the following experimental observations?

A

A statistically significant (p<0.05) increase in reaction rate, with a statistically insignificant (p=0.08) decrease in delta G

Statistical significance (p-value) is the probability that an observed difference in means between the treatment group and the control group is due to random chance
Hint #22 / 4
Renin is an enzyme. It catalyzes the conversion of angiotensinogen to angiotensin 1.
Hint #33 / 4
Enzymes increase reaction rate but do not alter the thermodynamics of a reaction (delta G is a thermodynamic quantity).
Hint #44 / 4
The most likely observation is a statistically significant (p<0.05) increase in reaction rate, with a statistically insignificant (p=0.08) decrease in delta G
168
Q

A student postulated that the sodium pump directly causes action potentials along neurons. Is this hypothesis reasonable?

No; action potentials result in an increased permeability of the plasma membrane to sodium.
No; the myelin sheaths of neurons prevent movement of ions across the plasma membranes of the neurons.
Yes; sodium is transported out of neurons during action potentials.
Yes; action potentials are accompanied by the hydrolysis of ATP.

A

The sodium pump does not cause the actual action potential. The sodium pump is used to create the resting potential. The opening of Na+ gates from voltage-gated ion channels is what causes the action potential. The opening of these gates causes increased permeability, as through them Na+ ions can enter the axon.

169
Q

what does the immune systems do when an inflammation is detected?

A

Inflammation leads to an adaptive response, where leukocytes come to fight an infection. Remember that leukocytes are WBCs, so it makes sense that triggering an immune response leads to WBC action.

170
Q

effect of inflammation on the arterioles?

A

Inflammation leads to vasodilation, so blood can remove necrotic tissue as well as provide immune responses and nutrients for healing.

171
Q

what exactly is the lymphatic sys responsible for doing when it comes to fluids?

A

near the arteries, the pressure is so high that fluids come out out of endothelial cells causing hydrostatic pressure. it is lymp node job to incr osmotic pressure near the veins where the hydrostatic is low

puts the fluids back in one direction

172
Q

what are lacteals

A

lymph vessels in the small intestine that helps to carry bulky chylomicrons (grouped fatty acids) into the vessels again

173
Q

ex of antigen presenting cells

A

phagocytes that present some identification of the bacteria that they just killed to part of the non innate that may have specific responses against the certain bacteria

non inate are called adaptive

174
Q

type of phagocytes

A

neutrophils (fast and abundant, release chemicals or dna nets)

macrophages
dendritic cells (nothing nervous sys about them but are best activators for specific immune sys)
175
Q

what do B lymphocytes (B cells) do

A

antibodies with each having diverse combinations of variable portions … but so many combinations causes at least one of the many antibodies to bind to foreign object at the epitope and will become activated by helper T cells… onmce activated the b cell will make multiple versions of himself to fight or become memory cells with the variable portion on their receptor

what is the difference between MHC 1 and MHC 2?effector cells are the ones that fight aka plasma cells and will turn into antibodies

176
Q

opsonization

A

antibodies attach to foreign objects which makes it easier for phagocytes to eat

177
Q

what is the difference between MHC 1 and MHC 2?

A

All cells with a nucleus contain MHC I. Whereas APCs (Antigen Presenting Cells) contain MHCII.

178
Q

example of cell mediated cells of the immune sys

A

t helper t cells and cytotoxic t cells

179
Q

naïve b or t cell means what

A

has not been activated yet, not an effector cell yet, and not bound to anything yet…. but once activated, make a bunch of copies of itself and then becomes three previous things that it was not yet

180
Q

what activates t helper cells

A

from antigen presenting cells like dendritic cells that will then be activated and bind to the mhc2 complex

181
Q

I have a doubt regarding the MHC I. I was under the impression that all cells in the body constantly “show” what they are doing inside themselves by presenting it on their surface through their MHC I. Then if the pathogen takes over and begins to produce something else then this new unknown process will be shown on the MHC and attract the Tc cells to start the process you speak of here.

Do cells only use their MHC I when infected or always?

A

It’s true, every nucleated human cell expresses MHC I (except sperm cells and trophoblasts). If they don’t, Natural Killer cells would it them up, thinking they’re infected (it’s interesting how some viruses downregulate MHC I to hide from the Cytotoxic T-cells, but invoke the wrath of NK-cells instead)

182
Q

cytotoxic t cells

A

effector cells that can release a type of toxin or perforins which make little holes in the cell that needs to be killed or ganulizimes which will kills the cell also

183
Q

cd4 and cd8 are?

A

both are t cells but cd4 is inactive form of helper cell and binds to mhc 2…
cd8 are inactive form of cytotoxin so will kill

keep in mind that effector cells don’t always have to kill directly but also indirectly like t helper cells to activate or set alarm to get other cells attentiion

184
Q

what causes pus

A

neutrophils will eat the bad bacteria and will then die after a couple of days causing pus

185
Q

direction of movement of wbc

A

goes from blood to the tissue

186
Q

layers (strata) of epidermis skin from superficial to deep

A

stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum

come, lets get some beer

187
Q

basale strata layer

A

keratinocyte cell division and melanocytes

188
Q

langerhan cells

A

basically like macrophages in the spinosum layer

189
Q

lamellar bodies

A

form lipid layer in granulosum layer which is helpful to reduce pathogens

190
Q

where are cells dead or lose nuclei/ organells like what epidermis strata

A

lucidum however dead things are in corneum as well

191
Q

epidermis vs dermis vs hypodermis

A

dermis is deeper and has vessels and hypodermis has subcutaneous fat and help insulate body

papillary dermis has loose (allow 4 o2 collection) and reticular for sweat glands
arrector pilli is in loose dermis

192
Q

type os burns and wat layers effected

A

1rst deg is epidermis redenning
2nd is dermis so nerve damage
3rd deg is hypo and beyond nerve damage and may damage and darken bone and muscles below hypo

193
Q

merocrine vs holocrine vs apocrine swet glands

A

The holocrine gland releases its secretions by disintegrating the whole cell to break down to release what’s called sebum. found on the face, the chest, and the back. lubricates the skin with sebum so it slows bacterial growth by making it difficult for bacteria to move around and divide.

Now apocrine glands release secretions from the apex of the cell or the top of the cell breaks off So the top of your cell breaks off to release a mixture of proteins, lipids, and steroids . apocrine glands are mostly concentrated in your armpits, the groin, and around the nipples the armpits, the groin, and around the nipples and the main thing here that’s unique about the apocrine sweat glands is that they release their contents into the hair follicle. until after puberty and the reason why could be better understood when we talk about animals because apocrine glands in animals release things like pheromones and warning signals and even territorial marking signs

merocrine glands release their secretions which is mostly the watery sweat we think of these are the main sweat glands we talk about they release watery sweat by a process you may be familiar with it’s called exocytosis. found literally everywhere else mostly concentrated in our palms of our hands and our soles of feet .They help us eliminate waste products as well. so any extra nitrogenous waste products that we might have or water or electrolytes we don’t need. also release things like lysozymes lysozymes which are enzymes that will lyse bacteria and even antibodies which are immunologic proteins so antibodies that will help tag bacteria and other foreign pathogens or bad stuff that could cause damage to our skin and our bodies tag these things for elimination

194
Q

What is the main function of the Meissner’s corpuscle mechanoreceptors?

A

in order to fire, requires to constantly changing stimuli bc u don’t want to constantly feel light touch like your clothes

Meissner corpuscles, respond to superficial light touch; and is found in the papillary )loose) dermis

195
Q

Pacinian’s Corpuscle and Merkel’s Disk mechanoreceptors function

A

the next two, Merkel endings and Ruffini endings.. located in stratum basale in epidermis and deals with action potentials so deals with a lot of ions… delas with light touch as well but keeps on firing as long as stimulus is present so it is different from Meisner

Pacinian corpuscles responds to vibration, or poking touch or pushing.. found in hypodermis

196
Q

pain vs temp

A

pain aka nocireception
temp aka thermoreception
both rely on the trpV1 receptor founf all over the body in cells even the dying ones

197
Q

TrpV1 receptor

A

whenever change in temp or even pain, heat will also cause conformational change

198
Q

A delta fibers (fast) vs medium beta fiber vs c fiber

A

delta respond very quickly, mylenated in response to pain to burning

So the fast-acting fiber is the A-delta, and the medium sized fiber that sends info to the brain is the A-beta

c fiber are the slow ones that respond to pain and are slow bc it is unmyelinated… ex will be the lingering pain for a couple of min after removing finger that was burned.

199
Q

cold vs warm temp relationship to hypothalamus and vesssels

A

if warm, the anterior hypo will be incharge and smooth muscle will be in charge to dilate vessels blood flow so that heat can go through skin as sweat

smooth muscle in cold will contract (vasoconstriction).. if cold, posterior hypo will be in charge

skeletal will break down atp to get energy when cold like shivering

200
Q

tympanic membrane function

A

starts vibration from the sound waves coming into the auditory canal and these vibrations will cause the 3 bones in ear (malleus, incus, and stapes ) to vibrate

201
Q

oval elipitical window

A

pushes fluid into the cochlea so that it can reach the apex of the cochlea and then the fluid goes out of the cochlea into the circular round oval

the fluid back and forth motion will cause the auditotu nerve to generate

202
Q

organ of corti function

A

The organ of Corti, or spiral organ, is the receptor organ for hearing and is located in the mammalian cochlea. This highly varied strip of epithelial cells allows for transduction of auditory signals into nerve impulses’ action potential. located in basilar membrane of the cochlea

203
Q

why is the endolymph fluid in ear so unique

A

The K+ channels in hair cells do similar functions as the Na+ channels on neurons, but hair cells alone cannot generate an action potential.

Hair cells aren’t neurons, so they don’t produce action potentials. They are found within the cochlear duct, which has a fluid called “endolymph” filling it. Endolymph is special because it is high in K+ unlike most extracellular fluids. When the stereocilia move in a way to open up the mechanogated K+ channels, K+ enters the cell. The resulting depolarization also opens Ca2+ channels, which are needed for neurotransmitter (NT) release. The NT travel across the synapse to the receptors on an afferent neuron, which will conduct the action potential to the brain.

204
Q

relationship btwn freq and basilar membrane of cochlea

A

base has high freq and apex has low freq

205
Q

what is the point of cochlear implants

A

no action potential reaches the auditory nerve=deafness.

My understanding of cochlear implants is that they are designed to overcome an issue in which the hairs within the cochlea are not able to transmit the action potential to the nerve axons that feed into the auditory nerve. The implant stimulator stretches into the cochlea and directly stimulates these nerves, removing the need for the hair cells to accomplish this part of the pathway. Since the stimulator can’t reach all the way to the apex of the cochlea, and therefore can only directly stimulate some of the nerve axons that stretch into the auditory nerve, the sound that is generated from cochlear implants is not exactly the same as natural sound.

206
Q

intrinistic and extrinistic movements of the tongue

A

extrinistic is when u can move the tongue up down in and out

intrinistic is when u can shorten or widen the tongue to lengthen it or make it narrow

207
Q

von ebners gland

A

releases less than 5% of the saliva and releases lingual lipase so that it can be broken down into free fatty acids

208
Q

g cells

A

secrete gastrin

209
Q

chyme

A

is the highly acidic semifluid material that results from your digestive juices chemically breaking down food. Chyme is the product of two forms of digestion, mechanical digestion and chemical digestion, and is a prerequisite for the process of nutrient absorption.

chime will be released into the dudodenum of the small intestine

210
Q

chief cells

A

secrete pepsinogen which then needs hcl to break it down into pepsin

211
Q

what do mucus cells do in stomach

A

release mucin and will sit on top of stomach as a layer so that it is not that acidic

212
Q

order of the small intestine for digestion

A
  1. duodenum (breaking down stuff and chime/bile/ hcl are delivered here)
  2. jujenum (most absorption)
  3. vitamin adek and b12 are absorbed here
213
Q

order of the small intestine for digestion

A
  1. duodenum (breaking down stuff and chime/bile/ hcl are delivered here)
  2. jujenum (most absorption of monomers) and helps to secrete bile
  3. illium vitamin adek and b12 and bile are absorbed here
214
Q

cytochrome 450

A

enzyme will react with a bunch of substrates and helps with detoxification that takes place in the liver

215
Q

hepatic artery vs hepatic vein vs portal vein

A

portal vein is nutrient rich and
the hepatic artery is o2 rich and supplies the o2 for rbc
both ENTER the liver

hepatic vein leaves the liver and carries o2 poor

together make up the liver triad

216
Q

cholecystokinin

A

tells gall bladder to release bile to the common bile duct so that it can then be released ti the duodenum to emulsify fat

217
Q

diarrhea vs constipation

A

for former the large intestine didn’t absorb a lot of water so pooping most of it out

for latter, large intestine absorbed too much h20 so when popping, it is hurts without water

218
Q

gastrin function

A

food in stomach causes gastrin to be released to then release digestive juices like hcl, pepsinogen, chime

when ph of stomach acid reaches 3, gastrin will be inhibited

219
Q

how do muscles contract

A

the filaments on the sarcomere slide past each other
(myosin pulls along the actin along its length)

ATPase is needed in order for myosin to form bridge with actin and to pull actin which causes the sarcomere to shorten (bc z and m line become closer to each other) but without actin or myosin changing their lengths

ADP amd phosphate griup will be released

220
Q

myosin

A

thick fillaments at the M line in the sarcomere

221
Q

actin

A

thin filaments at the z line (end of the sarcomere)

has tropomyosin (when muscle is relaxed, the myosin cross bridge will be blocked) and troponin (displaces tropomyosin when troponin is bound to calcium)

222
Q

sarcoplasmic reticulum

A

full of calcium when muscle is at rest but when ready to contract it will release the calcium so that it can bind to troponin

223
Q

Is the movement of Calcium out of the SR active transport?

A

no it’s passive transport via diffusion.
This is because there is a large concentration of Ca+ inside the SR. So they’re moving form high concentration to a low concentration (diffusion)so no energy is used.

224
Q

describe diff bands in sarcomere

A

Z-lines: define the ends of the sarcomere, Z is at the end of the alphabet.
I bands: region with only thin filaments (I is a thin letter).
H zone: region with only thick filaments (H is a thick letter)
A has all bands

The I band is composed of only actin filaments, and will begin to overlap with the myosin filaments, shortening the band. The A band, however, is the section composed of myosin filaments. Since this section is not altered by contraction, it stays the same length.

225
Q

Osteoprogenitor cells

A

undifferentiated mesenchymal precursors to osteoblasts. They are not yet specialized to produce new bone tissue.

226
Q

osteocytes

A

mature forms of osteoblasts that are no longer active.

227
Q

haversian cells

A

Haversian canals travel through bone tissue and allow for innervation and vascularization of bone. most directed blood supply for bone

228
Q

The following may or may not be steps included in the endochondral ossification of long bones:

I . Ossification of the epiphyses
II.  Ossification of the diaphysis
III.  Intramembranous ossification
IV. Formation of the epiphyseal plate
V. Formation of a hyaline cartilage model

What is the correct sequence of events in ossification of a long bone?

A

Correct (selected)
V → II → I → IV

Endochondral ossification is the process by which long bones develop through the ossification of cartilage. The first step in this process formation and growth of a hyaline cartilage model.
Hint #2
2 / 5
Intramembranous ossification is the process by which flat bones like the skull form from a membrane of mesenchymal tissue. This is not a step in endochondral ossification but rather a separate process of ossification.
Hint #3
3 / 5
The first place where bone tissue develops on a long bone is at the primary ossification center, which can be found near the center of the shaft of a long bone.
Hint #4
4 / 5
After primary ossification begins in the shaft, or diaphysis, of a long bone, secondary ossification begins on both ends, in the epiphyses.
Hint #5
5 / 5
The epiphyseal plate is an area of hyaline cartilage that remains between the diaphysis and each epiphysis through adolescence; in adults the epiphyseal plate becomes the epiphyseal line. The correct sequence of events in ossification of a long bone are: V → II → I → IV.

229
Q

bone matrix contains

A

an organic portion composed of collagen and a protein mixture called osteoid as well as an inorganic portion composed of hydroxyapatite, which are basically calcium phosphate crystals.

230
Q

lacunae

A

(empty spaces in the matrix), this characteristic is unlikely to add tensile strength to the bone.

231
Q

prokaryotes vs eukaryotes

A

Eukaryotic cells contain membrane-bound organelles, including a nucleus. Eukaryotes can be single-celled or multi-celled, such as you, me, plants, fungi, and insects. Bacteria are an example of prokaryotes. Prokaryotic cells do not contain a nucleus or any other membrane-bound organelle.

prokaryotes have haploid only

232
Q

synapsis

A

the pairing of homologous chromosomes, occurs in meiosis I but not mitosis.

233
Q

In mammals, which of the following events occurs during mitosis but does NOT occur during meiosis I?

Synapsis
The splitting of centromeres
The pairing of homologous chromosomes
The breaking down of the nuclear membrane

A

One of the key differences between mitosis and meiosis occurs during their respective anaphases. During anaphase of mitosis, sister chromatids are pulled apart at the centromeres, each becoming an independent chromosome in the two diploid daughter cells. During anaphase I of meiosis I, homologous pairs of chromosomes are separated into the two daughter cells. However, each chromosome still consists of two sister chromatids joined to each other at the centromere. It is not until anaphase II of meiosis II that the centromere is split and the sister chromatids separate. Thus, B is the best answer.

234
Q

why are water resorption and concentrating ability are the same,

A

ADH values near the upper limit of normal of the PHYSIOLOGICAL range will decrease urine output. ADH is supposed to retain water, and does this by INCREASING water reabsorption in the collecting duct. As water collects from the proximal to distal collecting duct (another way of saying cortical collecting duct to medullary collecting duct), the environment is more concentrated. Only with ADH present, the collecting duct is permeable to water, and allows water to flow out of the collecting duct and into the more concentrated environment. In this way, the presence of water transports in the collecting duct in the presence of ADH concentrates urine, reabsorbs water, decreases urine output, and increases body volume (probably blood pressure slightly).

he tubules are in contact with the renal interstitium, not exchanging directly with blood. Additionally, increased blood pressure of the vasa recta capillaries in the renal interstitium might actually decrease the rate at which water re-enters the circulation, possibly being a reason water reabsorption would be slowed SOLELY WHEN CONSIDERING BLOOD PRESSURE.

235
Q

incr the bo will do what to glomerulus rate

A

incr it as well but have to be careful not to have too high of bp bc less time for proper blood flow or water resportption

236
Q

ejaculatory duct is aka

A

prostate gland

237
Q

seminal vesicle does what

vs seminal tubules

A

former makes semen which has sugar and fluids to nourish the sperms

latter makes the sperm which is aka spermatagonia

238
Q

where does fertilazation occur

A

in the fallopian tubes

239
Q

ampulla of vas deferens

A

Ampulla of vas deferens is the expansion of the vas deferens closer to ejaculatory duct.

240
Q

spermiogenesis vs spermatogenesis

A

Meiosis in males is called spermatogenesis
Hint #2
2 / 4
Spermiogenesis occurs in epididymis
Hint #3
3 / 4
Spermiogenesis is not selection of spermatogonia
Hint #4
4 / 4
During spermiogenesis, maturation of the sperm, unnecessary cytoplasm is shed off

The main difference between spermatogenesis and spermiogenesis is that spermatogenesis is the formation of sperm cells whereas spermiogenesis is the maturation of the spermatids into sperm cells. … Spermiogenesis, on the other hand, is the final differentiation and maturation process of the spermatids into sperm cells.

241
Q

How many chromatids and chromosomes should one expect to find in a secondary spermatocyte in a human?

A

Non-gametic cells have 46 chromosomes and 46 chromatids prior to replication.
Hint #2
2 / 4
At the beginning of meiosis, DNA duplication occurs and 92 chromatids are found.
Hint #3
3 / 4
Meiosis I reduces the number of chromosomes by half; meiosis II is responsible for separation of sister chromatids.
Hint #4
4 / 4
A secondary spermatocyte is formed after completion of meiosis I; it has 46 chromatids and 23 chromosomes.

242
Q

Which penile tissues remain pliable during an erection? Which tissues become firm? What is the function of the pliable (easily bent/flexible) tissues?

A

The pliable tissues are not responsible for secretion of seminal fluid
Hint #2
2 / 3
Corpus spongiosum remains pliable during an erection.
Hint #3
3 / 3
During an erection the corpus spongiosum remains pliable, corpora cavernosa(when blood enters penis, becomes firm, and the pliable tissues maintain the urethra open.

243
Q

What would be a direct result of an enzymatic deficiency on the acrosome?

A

Acrosome is formed after differentiation of the primary spermatocyte
Hint #2
2 / 3
Acrosome is formed after differentiation of the secondary spermatocyte
Hint #3
3 / 3
Acrosome is responsible for sperm penetration in the egg, if that does not occur the egg would not complete metaphase II.

244
Q

flacidity

A

. A state characterised by a complete loss of muscle tone like it has less blood like when the penis is not erected

you will see more veins and vessels present bc there is no erection so no blood being engorged in penis and arterioles are constricted

245
Q

glans of the penis aka

A

head or the tip of the penis

246
Q

Could you please clarify whether it is Nitrus Oxide from the Parasympathetic nervous system or Norepinephrine from the Sympathetic nervous system that is released to cause an erection?

A

NE is responsible for constricting vessels.

1) by contricting the BLOODvessels it hinders blood from entering these vessels, hence the flacid state.
2) When there is an erection and it’s time for the ejaculation, NE is produced –> it once again constricts vessels (this time the vas deferens, the different glands and a few muscles) to shoot the semen out –> ejaculation.

You are correct in saying that NO causes the erection (NO causes vessels to dilate, one of the reasons it is used in e.g. agina pectoris) but to actually cause ejaculation. the vessels need to constrict. Thats where NE comes in play.

a tool we use in med school is to think about the erection & ejaculation stages as “Point & Shoot.”

  • To P oint (erection), we use the P arasympathetic nervous system.
  • To S hoot (ejaculate and return to a flaccid state), we use the S ympathetic nervous system.
247
Q

norep vs epi

A

Epinephrine and norepinephrine are very similar neurotransmitters and hormones. While epinephrine has slightly more of an effect on your heart, norepinephrine has more of an effect on your blood vessels

248
Q

tunica albaganea

A

prevent the penis from filling up or overexpanding so it is really supportive connective tissue for the chambers

249
Q

what is testosterone converted into

A
  1. dht (dihydroxy testosterone) and only 7% converted into this
  2. estrogen

MCAT PREP (14 decks)

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