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MCAT > Biology > Flashcards

Biology Flashcards

1
Q

4 tenets of cell theory

A

-all living things are composed of cells
-cell is basic functional unit of life
-cells only arise from preexisting cells
-cells carry genetic info in the form of deoxyribonucleic acid, the genetic material is passed from parent to daughter cell

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2
Q

Prokaryote vs eukaryote

A

Eukaryotes can be uni or multicellular and contain a true nucleus enclosed in a membrane with membrane bound organelles when prokaryotes do not

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3
Q

Nuclear pore definition

A

space in the nuclear membrane to allow for selective two way exchange of material between cytoplasm and nucleus

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4
Q

Linear DNA is wound around ___, which is further wound into strands called___

A

histones, chromosomes

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5
Q

Where is ribosomal RNA stored

A

nucleolus

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6
Q

inner membrane of mitochondria used for molecules and enzymes necessary for electron transport chain. What is the space inside this membrane called

A

cristae, the mitochondrial matrix

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7
Q

Extranuclear inheritance

A

Transmission of genetic material independent of the nucleus (think mitochondrial replication via binary fission

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8
Q

lysosomes

A

membrane bound structures containing hydrolytic enzymes capable of breaking down different substrates

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9
Q

Endoplasmic reticulum

A

series of interconnected membranes contiguous with nuclear envelope, double membrane of ER folded into numerous invaginations creating complex structures with central lumen, 2 varieties exist smooth (lipid and cell membrane synthesis) and rough (ribosomes)

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10
Q

golgi apparatus

A

stacked membrane bound sacs that receives material from ER and modifies them before repackaging and transferring to correct location

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11
Q

cytoskeleton

A

provides structure to cell to maintain shape and serves as a conduit for transport of materials around cells, 3 components microfilaments, microtubules, and intermediate filaments

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12
Q

microfilaments

A

solid polymerized rods of actin providing protection for a cell, actin filaments can also use ATP for generating movement by interacting with myosin. Also play a role in cytokinesis

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13
Q

microtubules

A

hollow polymers of tubulin proteins, radiate throughout the cell providing pathwasy ffor motor proteisn like kinesin and dynein to carry vesicles.

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14
Q

Cilia

A

Projections from a cell primarily involved in movement of materials along surface of the cell (think respiratory tract) composed of microtubules

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15
Q

flagella

A

involved in movement of the cell propelling composed of microtubules

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16
Q

9+2 structure

A

formation seen only in eukaryotic organelles of motility shared between cilia and flagella with 9 pairs of microtubules in outer ring and 2 in the center

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17
Q

intermediate filament

A

diverse group of filamentous proteins including keratin, help with structure of cell more rigid

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18
Q

4 tissue types

A

epithelial, muscle, connective, nervous tissue

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19
Q

parenchyma

A

functional tissue of an organ that is often epithelial cell in nature such as nephrons of kidney, hepatocytes, or acid producing cells of the stomach

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20
Q

basement membrane

A

joins epithelial cells together to an underlying layer of connective tissue

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21
Q

simple epithelium vs stratified vs pseudostratified

A

one layer of cells vs multiple layers vs appear to have multiple layers but are onlyone

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22
Q

stroma

A

support structure of organs composed of connective tissue

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23
Q

archea

A

single celled organism domain of life that are similar to bacteria but contain genes and metabolic pathways more similar to eukaryotes than to bacteria, they are notable to use alternative sources of energy, while some are photosynthetic many are chemosynthetic able to generate energy from inorganic compounds. Both eukaryotes and archea start translation with methionine, contain similar RNA polymerases, and associate their DNA with histones

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24
Q

Archea replication

A

they contain a single circular chromosome and divide by binary fission or budding

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25
Q

Examples of mutualistic symbiote bacteria

A

bacteria in the gut that produce vitamin K and biotin and also prevent overgrowht of harmful bacteria

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26
Q

Why are newborns given an injection of vitamin k

A

Because they have not been colonized with bacteria essential for producting vitamin k in the gut and thus clotting factors, they are at increased risk for hemorrhage

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27
Q

cocci vs bacilli vs spirilli

A

spherical vs rod shaped vs spiral shaped

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28
Q

facultative anaerobe

A

able to use oxygen for metabolism and switch to anaerobic metabolism if not

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29
Q

aerotolerant anaerobes

A

unable to use oxygen for metabolism but are not harmed by its presence in the environment

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30
Q

gram staining

A

a method to determine the type of cell wall in a bacteria of the 2 types, involves staining process with crystal violet stain follwed by a counterstain with safranin, if dark purple then gram positive, if pink red then gram negative

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31
Q

gram positive cell wall components

A

thick layer of peptidoglycan and lipoteichoic acid which the function is unkonwn but the human immune system may be activated by exposure to

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32
Q

gram negative cell wall components

A

thin peptidoglycan, abut directly to the cell membrane, also have outer membranes containing phospholipids and lipopolysaccharides that trigger immune inflammatory response very highly in humans

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33
Q

chemotaxis

A

ability of a cell to detect chemical stimuli and move tward or away from it

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34
Q

plasmids

A

additional dna acquired from exteneral sources not necessary for survival of prokaryote and therefore not part of the genome but may confer advantages

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35
Q

How do prokaryotes generate ATP?

A

lack mitochondria instead use cell membrane for ETC and generation of ATP

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36
Q

prokaryotic ribosome subunits vs eukaryoic

A

30s and 50s, eukaryotes are 40s and 60s (prokaryotes are much smaller)

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37
Q

binaryfission

A

form of asexual reproduction seen in prokaryotes, circular chromosome replicates attaches 1 to each side of cell wall and replicates while cell continues to grow in size eventually invaginating and forming 2 identical daughter cells, takes less steps than mitosis and thus is much more rapid

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38
Q

episomes

A

subset of plasmids able to integrate into genome of bacterium

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39
Q

transformation, conjugation, and transduction (3 methods of recombination for bacterial diversity)

A

transformation - integration of foreign genetic material into host genome often from spilled content of other bacteria
conjugation - bacterial form of mating sexual reproduction involving 2 cells forming a conjugation bridge that allows transfer of genetic material, the transfer is unidirectional with a donor male (+) to recipient female (-), the bridge is made of an appendage called a sex pili
Transduction - genetic recombo process that requires a vector such as a bacteriophage, involves the virus accidentally trapping a segment of host DNA during assembly and then releasing trapped DNA into a new host cell that it infects

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40
Q

Most well studied sex factor plasmid

A

F (Fertility) factor of e coli

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41
Q

High frequency of recombination

A

cells that have undergone a change where the sex factor plasmid (conjugation) also undergoes transformation integrating that plasmid into the DNA, now when a donor transfers they will attempt to send an entire copy of the genome into the recipient but this can cause the bridge to break before the full sequence is moved so there is random amounts DNA being sent between

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42
Q

bacterial growth pattern

A

in a new environment, first there is a lag phase as bacteria adapt to new conditions, then there is an exponential or log phase, and reduction of resources then causes a stationary phase, and then a death phase after resources are deplete

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43
Q

why are enveloped viruses easier to kill

A

the envelope surrounds the capsid protein coat and is very sensitive to heat, detergents, and desiccation

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44
Q

single stranded viruses may be positive sense or negative sense. meaning…

A

positive implies the genome may be directly translated to functiona proteins by the ribosomes of the host cell just like mRNA, negative sense RNA viruses require synthesis of an RNA strand complementary to a negative sense RNA strand which can then be used as a template for proteins ynthesis. These negative must carry RNA replicase in the virion to ensure the right strand is synthesized

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45
Q

retroviruses

A

enveloped, single stranded RNA viruses that carry an enzyme known as reverse transcriptase which synthesizes DNA from sinlge stranded RNA, that DNA then integrates with the host cell genome where it is replicated and transscribed as if it were the host cells own DNA

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46
Q

methods of infection by a virus

A

either injection of the genetic material alone through a tail sheath or enveloped viruses fuse with the cell membrane and enter the cell bringing in the entire viral capsid

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47
Q

extrusion

A

a method of virus leaving the cell by fusing with the plasma membrane, allows for survival of the host cell and continued use of said cell by the virus opposed to cell death and/or lysis that spills it out, that virus is in a productive cycle

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48
Q

lytic vs lysogenic cycles

A

lytic cycle is bacteriophage where it makes maximal use of cell machinery with little regard to survivial of host cell, lysing it and spreading and is virulent
lysogenic cycle the event a virus integrates into the host genome as a provirus it will replicate as part of the bacteria’s replication cycle and can remain indefinitely there but environmental factors such as light or radiation or chemicals can cause it to revert to lytic at some point

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49
Q

prions

A

infectious nonliving proteins that cause disease by triggering misfolding of other proteins usually conversion from alpha helical structure to beta pleated sheets, reduced solubility of the protein and the cells ability to degrade the misfolded protein causes function of the cell and eventually tissue to reduce

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50
Q

viroids

A

small pathogens composed of short circular single stranded RNA that can infect plants, a few examples of human viroids do exist that are innocuous but can cause disease with some coinfections

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51
Q

autosomal/somatic cells are ___ploid, while germ cells are ___ploid

A

diploid (2 copies of each chromosome) haploid (1 copy)

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52
Q

4 stages of the cell cycle and cells that do not divide live in this phase

A

G1, S, G2, (interphase about 90% of the time) and M. G0 is an offshoot of G1 that cells that live and serve function without any preparation for division

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53
Q

during interphase, are chromosomes visible with light microscopy?

A

No, they are in a less condensed form known as chromatin, during mitosis, however, it s prefererable to condense DNA into chromosomes to prevent loss of any genetic material

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54
Q

restriction point

A

preventative point to prevent passage from G1 to S phase that requires certain criteria suchas the proper complement of DNA

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55
Q

G1 phase processes

A

create organelles and protein production and increase in size

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56
Q

S stage processes

A

cell replicates its genetic material so each daughter will have identical copies, after replication, each chromosome consists of two identical chromatids bound at a centromere

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57
Q

Does the ploidy of a cell change during the S phase of the cell cycle?

A

No, even though 92 chromatids are present after, there are still only 46 chromasomes

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58
Q

G2 phase processes

A

Cell checks to make sure DNA replication proceeded correctly in S phase, checks there are enough organelles and cytoplasm to divide between 2 daugher cells

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59
Q

M phase

A

mitosis with its 4 phases and cytokinesis

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60
Q

4 phases of mitosis

A

prophase - chromatin condenses into chromosomes, spindle forms
metaphase - alignment of chromosomes at metaphase plate
anaphase - sister chromatids separate and are pulled to opposite poles of the cell by shortening kinetochore fibers
telephase and cytokinesis- spindle apparatus disappears, nuclear membrane reforms around each set of chromosomes, and nucleoli reappear, chromosomes uncoil, resuming interphase form, cytoplasm and organelles divide

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61
Q

the main protein in charge of g1/s phase transition and how is this related to cancer

A

p53, one of the most common mutations found in cancer is of the gene that produces p53 called TP53 that then results in cell cylce not stopping torepair cancerous DNA

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62
Q

meiosis 1 results in homologous chromosomes being separated generating haploid daughter cells, and is known as ____ division, meiosis ii is similar to mitosis in that it results in separation of sister chromatids, and is known as ___ divison

A

reductional, equational

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63
Q

crossing over

A

a process in meiosis prophase 1 in which chromatids of homologus chromosomes may break at a point of contact called a chiasma and exchange pieces of dna, increasing the diversity

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64
Q

mendels 2nd law of independent assortment

A

inheritance of one allele has no effect on the likelihood of inheriting certain alleles for other genes because of crossing over

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65
Q

stages of meiosis

A

meiosis 1 (prophase 1, metaphase 1, anaphase 1, telophase 1) and meiosis II (prophase 2, metaphase 2, anaphase 2, telophase 2)

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66
Q

difference between metaphase 1 of meiosis and mitosis metaphse

A

in mitosis, each chromosome is lined up at the metaphase plate by 2 spindle fibers, in meiosis, homologous chromosomes are lined up across from each other at metaphase plate and are held by one spindle fiber

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67
Q

mendels first law of segregation

A

accounts for the process of anaphase 1 of meiosis where homologous pairs separate and are pulled to opposite poles of the cell called disjunction, each chromosome therefore of paternal origin separates from homologue of maternal origin and either chromosome can end up in either daughter cell, randomly

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68
Q

mitosis n representation v s meiosis

A

2n to 2n, meiosis is 2n to n to n

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69
Q

difference between homologus chromosomes vs sister chromatids

A

homologous chromosomes are of each paternal and maternal origin, sister chromatids are identical copies

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70
Q

what pair of chromosomes determines biological sex

A

the23rd pair

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71
Q

what genetic information does the y chromosome carry

A

very little, the SRY gene which encodes transcription factor to initiate testis differentation and thus formation of male gonads, therefore in absence of y chromosome all zygotes will be female

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72
Q

two functional components of the testes

A

seminiferous tubules (produce sperm and nourished by sertoli cells), and interstitial cells (leydig cells) which secrete testosterone

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73
Q

where are formed sperm stored until ejacullation

A

epididymis

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74
Q

sperm pathway from epididymis

A

vas deferens to ejaculatory duct on posterior edge of the prostate gland called the ejaculatory duct, the two ejaculatory ducts fuse to form the prostatic urethra which caries sperm through the penis and out the body

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75
Q

3 glands that mix sperm with seminal fluid upon ejaculation

A

seminal vesicles (fructose), prostate gland (alkaline fluid)
bulbourethral glands - clear viscous fluid to lubricate urethra (precum)

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76
Q

diploid stem cells of males in the seminiferous tubules and what do these develop into

A

spermatogonia, after replicating genetic material are diploid primary spermatocytes, first division results in haploid secondary spermatocytes, then 2nd division causes haploid spermatids which then mature into spermatozoa

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77
Q

acrosome

A

cap on the sperm head that is derived from golgi apparatus and needed to penetrate ovum

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78
Q

components of ovaries

A

follicles, multilayered sacs that contain and protect immature ova

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79
Q

ovulation

A

process in which between puberty and menopause one egg is ovulated into the peritoneal sac lining the abdominal cavity that is then drawn into the fallopian tube or oviduct which is lined with cilia to propel the egg forward, the fallopian tubes are connected to the muscular uterus, lower end of this is the cervix, which connects the vaginal canal, outer genitalia are called vulva

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80
Q

unlike spermatogenesis, oogonia in a woman is…

A

not unlimited, by birth all the oogonia have already undergone DNA replication and are considered primary oocytes (2N), and are arrested in prophase 1

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81
Q

during menarche, what happens for meiosis

A

one primary oocyte will become a 2ndary oocyte and a polar body

82
Q

polar body

A

product of female meiosis in which there is unequall cytokinesis in telophase 1, this forms an inactive cell that does not divide further and will never produce functional gametes

83
Q

the 2ndary oocyte remains arrested in what phase until fertilization

A

metaphase 2

84
Q

zona pellucida

A

surrounds oocyte and is an acellular mix of glycoproteins that protect the oocyte and contain compounds necessary for sperm cell binding

85
Q

meiosis 2 in a female 2ndary oocyte

A

triggered whena sperm cell penetrates layers with help of acrosomal enzymes, then a 2nd meiotic divison splits into a mature ovum and another polar body, upon completion the pronuclei of the sperm and ovum join creating a diploid zygote

86
Q

prior to puberty, what restricts LH and FSH release

A

the hypothalamus which restricts production of GnRH

87
Q

FSH stimulates ___ in men, LH stimulates ___

A

sertoli cells and sperm maturaion, interstitial (leydig) cells to produce testosterone

88
Q

FSH stimulates __ in women

A

estrogen secetion

89
Q

progesterone

A

secreted by corpus luteum, remnant follicle that remains after ovulation, in response to LH, if pregnancy occurs then the placenta will secrete

90
Q

4 phases of the menstrual cycle

A

follicular phase, ovulation, luteal phase, menstruation

91
Q

follicular phase of menstruation

A

begins when menstrual flow, the shedding of the lining of the previous cycle, begins. GnRH secretion from hypothalamus increases due to decreased conscentrations of estrogen and progesterone, increasing FSH and LH. The follicles begin to produce estrogen which negative feedbacks on gnrh and LH and FSH, the estrogen regrows the endometrial lining, stimulating vascularization adn glandularization of the deicidua

92
Q

ovulation phase of menstruatioon

A

estrogen levels increase as late in follicular phase they secrete higher and higher concentrations that reach a threshhold that results paradoxiclaly in positive feedback, spiking gnrh, lh, and fsh, this surge of LH is important because it induced release of the ovum from the ovary into the abdominal cavity

93
Q

luteal phase of menstruation

A

after ovulation, LH causes ruptured follicle to form corpus luteum, which secretes progesterone, progesterone levels begin to rise maintaining uterine lining, high levels of progesterone cause negative feedback on GNRH, FSH , and LH preventing multiple eggs ovulating

94
Q

menstruation phase of menstruation

A

if implantation does not occur, corpus luteum loses its stimulation of LH and progesterone levels decline, uterine lining sloughs off, GNRH starts to rise due to loss of high levels of estrogen and progesterone

95
Q

hCG

A

released by a blastocyst if fertilization has occurred that will implant on the uterine lining, is an analog of LH which maintains corpus luteum important to keep uterine lining in place, by 2nd trimester these levels fall because placenta has grown sufficient size to secrete progesterone and estrogen by itself

96
Q

menopause hormone levels

A

estrogen and progesterone levels drop, FSH and LH rise

97
Q

When does sex differentiation occur in the womb? When can this be detected un u/s

A

6-8 weeks after fertilization, 16-17 weeks

98
Q

Ampulla

A

widest part of fallopian tube where sperm meets 2ndary oocyte

99
Q

cortical reaction

A

release of calcium ions after penetration of sperm thru cell membrane, preventing fertilization of ovum by multiple sperm cells and increasing metabolic rate of newly formed diploid zygote

100
Q

Dizygotic vs monozygotic twins

A

dizygotic are fraternal and occur with fertilization of 2 different eggs released during one ovulatory cycle by 2 diff sperm, each implants in uterine wall with own placenta, chorion, and amnion, fraternal twins are no more genetically similar than any other siblings. Monozygotic are when a single zygote splits into two, can share varying structures (monochorionic/diamniotic)

101
Q

Indeterminate cleavage vs determinate

A

division of a zygote, indeterminate results in cells that can still develop into complete organsims (think possibility for twins) and determinate determines the fate of each cell differentiated

102
Q

Steps of embryonic cell differentiation

A

zygote
morula
blastula (trophoblasts forming chorion and placenta and inner cell mass blastocoel gives rise to organism itself
gastrula and gastrulation (rise to germ cell layers)
neurulation (nervous system deelopment)

103
Q

chorion

A

extraembryonic membrane that develops into the placenta, has villi that penetrate into the endometrium

104
Q

how many umbilical arteries and veins

A

2 arteries carrying deoxygenated blood and waste, 1 vein carrying fresh blood rich in nutrients

105
Q

Amnion

A

tough inner membrane filled with amniotic fluid serving as a shock absorber during pregnancy

106
Q

Ectoderm components

A

epithelia, nervous system

107
Q

mesoderm components

A

muscle, circulatory, and excretory systems

108
Q

endoderm components

A

linings of digestive and respiratory tracts

109
Q

adrenal gland derivation from primary germ cell layers

A

adrenal cortex from mesoderm, adrenal medulla from ectoderm (contains nervous tissue)

110
Q

induction

A

ability of one group of cells to influence fate of nearby cells, allows cells with same genes to develop distinct functions thru selective transcription

111
Q

neurulation

A

process of nervous system development, begins with noochord forming along the long axis of the organism like a primitive spine, induces a group of overlying ectodermal cells to slide inward from the ectoderm to the neural folds forming a neural tube which gives rise to the CNS and neural crest which give rise to PNS

112
Q

During what stage of embryonic development does implantation occur

A

blastula stage

113
Q

Determination and differentiation

A

Determination is commitment of cell tohaving particular function in the future, commit to a specific lineage, differentiation is the changes that the cell must make to develop into the determined cell type

114
Q

Pathway of cell potency

A

Totipotent as en embryo, pluripotent after division into 3 germ cell layers in which cell can become any cell type except placental structure, and multipotent is cells only within specific groups

115
Q

autocrine vs paracrine vs juxtacrine vs endocrine signaling

A

signals that act on the same cell that secreted the signal in the first place vs signals that act in a local area vs signals that are a cell directly stimulating adjacent cell vs signals involved in secreted hormones that travel thru the blood stream

116
Q

morphogens

A

molecules that cause determination of cells

117
Q

apoptotic blebs

A

membranes containing cells that can be digested and recycled but also prevents release of potentially harmful substances into the environment

118
Q

Telomerase

A

enzyme released by germ cells, fetal cells,a nd tumor cells that is able to synthesize telomere’s the ends of chromosomes to prevent senescence

119
Q

Umbilical arteries carry ___ blood and umbilical veins carry ___

A

deoxygenated blood back to the placenta, oxygen rich blood toward the fetus from the placenta

120
Q

foramen ovale

A

one way valve that connects right an left atrium, allows blood entering right atrium to flow into left atrium instead of right ventricle and thereby be pumped thru aorta into systemic circulation directly, the right heart pressure is greater than left and after birth this reverses shutting foramen ovale

121
Q

ductus arteriosis

A

shunts leftover blood from pulmonary artery to aorta to allow for pumping into systemic circulation directly bypassing fetal lung circulation

122
Q

ductus venosus

A

shunts blood returning from placenta via umbilical vein directly to IVC bypassing liver which is not needed much in fetal development, liver still receives some supply from systemic circulation

123
Q

parts of a neuron

A

soma - body containing ER and ribosomes and nucleus
dendrites 0 appendages receiving incoming messages from other cells
axon - integrates incoming signals and depending on reaching threshold will initiate action potential, most are insulated by myelin with small breaks called the nodes of ranvier for rapid conduction (saltatory conduction)

124
Q

what cell produces myelin in the CNS and what cell does so in the PNS

A

oligodendrocytes, schwann cells

125
Q

PNS can see neurons bundled together in nerves that can contain both ____ and ___, while in the CNS tracts only are one type

A

sensory, motor

126
Q

resting potential

A

all neurons have an electrical potential difference (voltage) inside the cell and the extracellular space -70mV, implemented by the Na+/K+ ATPase that transfers 3 na out of the cell for every 2 k into a cell with use of 1 ATP, moves against concentration gradients active transport , where inside the cell K+ is high Na+ is low, and vise versa, with neg charged proteins in the cell and permability of the membrane to K+ compared to na+

127
Q

summation

A

additive effect of multiple inhibitory and stimulatory signals to reach the threshold of an action potential

128
Q

action potential MOA

A

when threshold is reached, voltage gated sodium channels open in the membrane, sodium cations go into the cell causing membrane potential to become more positive and less polar, once threshold hits +35 mV sodium channels are inactivated. potassium voltage gated channels are activated favoring efflux of potassium from the neuron causing restoratino of negative membrane potential called repolarziation, eventually overshooting the resting potential and hyperpolarizing the nuron creating a refractory period either absolute where no amount of stimulation can cuase another action potential or relative where there must be greater than normal action potential. Then na/k ATPase acts to restore the resting potential

129
Q

synapse MOA

A

neurotransmitters prior to release are stored in membrane bound vesicles in the nerve terminal, when action potential reaches nere terminal voltage gated calcium channels open allowing ca2+ to flow into the cell, sudden increase triggers fusion of membrane bound vesicles with cell membrane causing exocytosis of neurotransmitter, once released into the synapse they diffuse across the cleft and bind to receptors on the post synaptic membrane, this then triggers either ligand gated ion channels or g protein coupled receptors (to change levels of cAMP). After goal is achieved neurotransmitters are broken down by enzymatic rxns or brough back into the cell by reuptake carriers, or diffusion

130
Q

interneurons

A

found between other neurons and are most numerous compared to sensory or motor neurons, often linnked to reflexive behavior

131
Q

white matter vs grey matter

A

nervous tissue containing axons encased in myelin sheaths, grey is unmyelinated cell bodies and dendrites, in the brain the white matter is deeper than the grey matter but in the spinal cord the whtie matter is outside the cord and grey matter deep within it

132
Q

dorsal root ganglia

A

cell bodies of sensory neurons that receive signals from afferent pathways, the cell bodies for motor neurons are in the spinal cord itself and exit ventrally

133
Q

a motor neuron in the somatic nervous system goes directly from spinal cord to muscle without synapsing. In the autonomic nevous system, there are…

A

… 2 neurons, a preganglionic whose soma is in the CNS and postganglionic neuron whose soma is in the PNS,

134
Q

main neurotransmitter for Parasympathetic nervous system

A

acetycholine

135
Q

main neuroransmitters for the sympathetic nervous system

A

acetycholine for preganglionic neurons, postganglionic norepi

136
Q

monosynaptic reflex aarc

A

single synapse between sensory neuron that receives stimulus and motor neuron that respons such as knee jerk reflex

137
Q

polysynaptic reflex arc

A

at elast one interneuron between sensory and motor neurons such as withdrawal reflex when stepping on a nail, where the interneuron in the spinal cord provides connections from the incoming sensory info to the different relevant motor neurons

138
Q

peptide hormones

A

made up of amino acids, synthesized at translation and modified in the golgi apparatus before packed for exocytosis into vesicles, because they cannot pass the plasma membrane as they are charged they must bind an extracellular receptor, they are considered primary messengers, relatively rapid but short lived response because of the secondary messenger system they require

139
Q

steroid hormones

A

derived from cholesterol and synthesized primarily from gonads and adrenal cortex, they can easily cross cell membrane as they are not polar and their receptors are usually intracellular or intranuclear, can even act directly on DNA, cause slower but longer lived response, must be carried by proteins in the bloodstream (such as sex hormone binding globulin which is specific or albumin which is nonspecific)

140
Q

amino acid derivative hormones

A

less common but important hormones including epi, norepi triiodothyronine and thyroxine, variable in how they bind some bind to receptors (catecholamines) while others bind intracellularly

141
Q

hypophyseal portal system

A

blood vessel system directly connecting hypothalamus with anterior pituitary, thus hormones released from the hypothalamasu trael directly here and cannot be found in appreciable concentrations in systemic circulation

142
Q

hormones released from hypothalamus (5)

A

GnRH, GHRH (growth hormone releasing hormone), TRH (thyroid releasing hormone), CRF (corticotropin releasing factor), dopamine (which deceases prolactin secretion)

143
Q

posterior pituitary hormones

A

neurons from hypothalamus send axons directly to posterior pituitary releasing oxytocin and ADH

144
Q

anterior pituitary hormones (7)

A

FSH, LH, ACTH, TSH, prolactin, endorphins, growth hormone

145
Q

oxytocin is unusual in that…

A

…it is a positive feedback loop where its release promotes stronger uterine contractions which promotes more release

146
Q

__ cells of the thyroid produce thyroid hormone and ___ cells produce calcitonin

A

folicular, c cells or parafollicular cells

147
Q

calcitonin MOA

A

degreases plasma calcium in 3 ways, increased excretion from the kidneys, decreased absorption from the gut, and increased storage of calcium in the bone, high levels of calcium in the blood stimulate secretion of this

148
Q

parathyroid hormone MOA

A

responds to low calcium levels and decreases excretion of calcium by kidneys, increases absorption of calcium in the gut thru converting vit D3 to 25-oh-d3 which then increases GI ca2+ and GI phosphate absorption, and increases bone resorption thereby freeing up ca2+.
Also resorbing phosphate from the bone (increases) and reducing reabsoprtion of phosphate in the kidney (decreases)

149
Q

adrenal gland components

A

cortex and medulla, cortex releases corticosteroids and medulla is derivative of nervous system releasing sympathetic system hormones

150
Q

zona glomerulosa

A

part of adrenal cortex releases mineralocorticoids used in salt and water omeostasis, aldosterone beign primary of this, increases sodium reabsorption in distal convouted tubule and collecting duct of nephron, thus water follows

151
Q

renin angiotensin aldosterone system

A

decreased blood pressure causes juxtaglomerular cells of kidney to release renin which cleaves inactive angiotensiongen produced by liver into active form angiotensin I, which is then converted to angiotensin II by ACE in the lungs, angiotensin II stimluates adrenal cortex to secrete aldosterone, and itself causes vasoconstriciton and increased heart rate which hopefully increass blood pressure to neg feedback this system

152
Q

zona faciulata

A

part of the adrenal gland that releases glucocorticoids mainly cortisol and cortisone that raise blood glucose by increasing glucoenogenesis and decrease inflammation and immunologic responses

153
Q

zona reticularis

A

part of the adrenal gland that releases cortical sex hormones mainly androgens, because men already secrete at the testees adrenal testosterone plays small role but females are sensitive to this such as excess androgen production due to enzyme deficiences causing female fetus to be born with ambiguous or masculinized genitalia

154
Q

adrenal medulla

A

derivative of nervous system responsible for production of epi and nor epi

155
Q

islets of langerhands

A

hormone producing cells of the pancreas with 3 types of cells, alpah for glucagon, beta for insulin, and delta for somatostatin

156
Q

glucagon

A

secreted during times of fasting when glucose elvels are low stimulating conversion of glycogen to glucose and production of new glucose via gluconeogenesis, inhibited by blood sugar concentrations being high

157
Q

insulin

A

secreted when blood sugar is high inducing muscle and liver cells to take up glucose and store it as glycogen

158
Q

pineal gland

A

deep in the brain secretes melatonin, involved in circadian rhythm

159
Q

erythropoeitin

A

stimulates bon marrow to increase production of erythrocytes, secreted in response to low o2 levels in blood

160
Q

atrial natriuretic peptide

A

when cells of atria are stretched due to excess blood folume they release ANP, promotesexcretion of sodium and therefore increases urine volume, antagonistc to aldosterone

161
Q

aldosterone and ANP differ from vasopressin (ADH) in that…

A

…they do NOT affect blood osmolarity

162
Q

boyles law

A

at a constant temp the pressure and volume of gases are inversely related

163
Q

negative pressure breathing

A

standared quiet respiration where intrathoracic volume increases as well as intrapleural volume leading to a decrease in intrapleural pressure, the air is then sucked from a higher pressure environment of the outisde world into the lungs, then during exhalation which does not have to be active, relaxation of iintercostal muscles cause cheset cavity to decrease in volume, intrapleural volume decreases and intrapleural pressure increases, greater than the pressure in the lungs pushign air out

164
Q

gas transfer is a ____ tpe of transport

A

passive

165
Q

thermoreguation of the respiratory system

A

as capillaries expand, more blood passes thrut hem and larger amount of thermal energy can be dissipated, consstriction conserves thermal

166
Q

control of pH of respiratory system

A

thru the bicarbonate buffer system oof the blood: CO2 gas + h2o liquid <=> H2CO3 aqueous <=> H+ aqueous + HCO3 aqueous

167
Q

control of pH of respiratory system MOA

A

body likes pH between 7.35-7.45, when pH is lower, in acidemia, chemoreceptors send signal to brain to increase respiratory rate, further, this hydrogen ion concentration increase will cause shift in bicarb buffer system generating additional co2, which then is blown off, causing the H+ to drop to want to compensate for low CO2 now.

168
Q

how many leaflets in semilunar valves

A

3

169
Q

cardiac output is the measure of total blood volume pumped by A SINGLE VENTRICLE per minute. Volume of each must be the same. What is the equation

A

CO= HRxSV

170
Q

normally blood will only pass 1 capillary bed before returning to the heart however there are 3 portal systems in the body that are exceptions

A

1) hepatic portal system where blood leaving capillary beds in walls of gut pass thru hepatic portal vein before going thru capillary beds of the liver
2) hypophyseal portal system where blood leaving capillary beds of hypothalamus ravel to capillary bed in anterior pituitary for signaling
3) renal portal system where blood leaving the glomerulus travels thru an efferent arteriole before surrounding the nephron in a capillary network called vasa recta

171
Q

macrophages have different names depending on the organ they dwell in. what is their name in bone and in CNS?

A

osteoclasts, microglia

172
Q

why do people make anti-A or B antigen antibodies before exposure to that blood type even occurring?

A

It is thought that E coli in the colonmay have proteins that match the A and B alleles

173
Q

Other proteins relevant for blood typing

A

C, E, kell, lewis, duffy antigens, the more antigens that are correctly matched the lower likelihood of hemolysis

174
Q

Rh factor refers to what protein

A

D protein

175
Q

where does the largest drop in blood pressure occur in circulation

A

arteries to arterioles

176
Q

pressure differential across the circulation equation

A

deltaP= CO x TPR (total peripheral resistance)

177
Q

oxyhemoglobin dissociation curve

A

the first o2 that binds a heme group induces conformational shift increasing affinity for further o2 binding positive feedback, and removal of 1 molecule of o2 increases conformational shift decreasing overall afinity makin git easier for the remaining o2 to leave, this is cooperative binding and has an S shaped sigmoidal curve

178
Q

how does the vast majority of co2 exist in the blood and what enzyme do RBC’s use to catalyze this

A

as bicarbonate ion (HCO3-), carbonic anhydrate which causes rxn between co2 and water to form carbonic acid H2CO3 which dissociates into H+ and HCO3-

179
Q

bohr effect

A

increased co2 production will cause shift right in the bicarbonate buffer equation resulting in decreased pH of blood due to increased H+ such as during times of higher celllar metabolism and accumulation of lactic acid, these protons bind hemoglobin reducing hemoglobins affinity for o2, causing shift of o2 hemoglobin curve to the right which results in more o2 to be unloaded at tissues

180
Q

what other 2 processes shift the oxyhemoglobin curve to the right

A

increased temp and increased 2.3 BPG productoin side product of glycolysis

181
Q

Why does fetal hemoglobin HbF have higher affinity for oxygen than adult hemoglobin

A

it is a more left shifted because red blood cells must literally pull o2 off materanl hemoglbin and onto fetal hemoglobin

182
Q

the kidney’s function in the bicarb buffer system

A

it can create compensatory changes by excretion depending on the situation, for example during hyperventilation, drops co2 content shifting bicarb system left, decreasing concentration of protons leading to alkalosis, kidney can increase excretion of bicarb to bring pH to normal

183
Q

hydrostatic pressure

A

force per unit area blood exerts against the vessel wall generated by contractin of heart and elasticity of teh arteries, pushes fluid out of the blood stream thru leaky capillary walls, higher on arteriole side than venule side

184
Q

osmotic (oncotic) prssure

A

caused by plasma proteins to suck water into the blood sream drawn by solutes, constant between each side of a arteriole and venule but due to hydrostatic pressure dropping below it on the venule side sees movement

185
Q

coagulation mechanism

A

endothelium of blood vessel is damaged exposing underlying connective tissue contains collagen and tissue factor, when platelets come into contact they release contents and begin aggregation, coagulation factors in the blood released by liver sense tissue factor and initiate a complex activation cascade, end point is activation of prothrombin to form thrombin by thrmboplastin, and thrombin converts fibrinogen to fibrin which forms the “scab”. Clot is eventually broken down by plasmin generated by plasminogen

186
Q

2 divisions of immune system and characteristics of both

A

innate immunity or nonspecific (faster, cannot target specific pathogens over others, macrophages and neutrophils and basophils etc. and cytokine inflammatory response), and adaptive or specific (slower to act but can maintain memory of infection and mount a faster attack with subsequent infections, B and T cells)

187
Q

what organ produces all whie blood cells, what organ is storage of blood and maturation of of B cells, what organ matures T cells, what organ is the hub of the immune system

A

bone marrow, spleen, thymus, lymph nodes and others such as gut asssociated lymphoid tissue and tonisls and adenoids and peyer’s patches

188
Q

antibodies are considered ____ immunity, while T cells provide ___ immunity

A

humoral immunity, cell mediated

189
Q

divisions of the hematopoietic stem cell

A

myeloid stem cell (granulocytes) or lymphoid stem cell (agranulocytes)
granulocytes include monocytes that become dendritic cells and macrophages, neutrophils, eosinophils, basal cells, ast cells, megakaryocyte (precurser to platelet) and erythrocytes.
Agranulocytes include NK cells, B cells (that become plasma cells and memory cells), and T cells (helper and cytotoxic T cells)

190
Q

complement and the two pathways of activation

A

a system of proteins that act as nonspecific defense against bacteria, can be activated by classical pathway binding of antibody to a pathogen or alternative pathway not requireing antibodies, complement punches holes in walls of bacterial cells

191
Q

interferons

A

produced by cells of the body infected with cells that prevent viral replication and dispersion, decrease permeability of cells as well and upregulate MHC class I and II molecules resulting in antigen presentation of the viral capsid to make better detection by immune system

192
Q

MHC and their classes

A

major histocompatibility complex that bind pathogenic peptide antigens and carries it to cell surface to be recognized by cells of adaptive immune system. MHC class I is on all nucleated cells in the body (endogenous pathway binds intracellular antigens)and MHC class II is only on professional APC’s, present extracellular antigen so exogenous pathway

193
Q

professional APC’s

A

macrophages, dendritic cells, and B cells

194
Q

natural killer cells

A

nonspecific lymphocytes that are able to detect downregulation of MHC and induce apoptosis in a cell that is infected with virus that causes said downregulation or cancer cells that cause this

195
Q

neutrophils are most common to target ___ infection

A

bacterial

196
Q

eosinophils most often target

A

allergic and parasitic infections

197
Q

basophils most commonly target

A

allergic responses

198
Q

opsonization, agglutination, and degranulation

A

whereantibodies covering a pathogen mayallow phagocytosis by other leukocytes, form insoluble complex that can be broken down and phagocytized, and trigger release of granule contents such as histamine causing allergic rxn

199
Q

B cells response to try to find the proper antien binding region

A

hypermutation and only those b cells that can bind the antigen with high affinity survive called clonal selection

200
Q

CD4 (helper) T cells respond to MHC class ____ and serve what function

A

II, they secrete lymphokines to recruit other immune cells

201
Q

CD8 (cytotoxic) T cells respond to MHC class __ and serve what function

A

I, they kill directly viral infected cells by injecting cytotoxic chemicals to induce apoptosis

202
Q

active vs passive immunity

A

active is the immune system is stimulated to produce antibodies, passive is ransfer of antibodies such as placenta transfer of antibodies during pregnancy or breast milk or treatment with immunoglobulin

MCAT (7 decks)

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