MCAT Bio Flashcards

Question

semiautonomous

Answer 1

mitochondira replicate independently of nucleus via binary fission thought to have evolved from anaerobic prokaryote and establishment of symbiotic relationship

Answer 2

transmission of genetic material independent of nucleus

Answer 3

enzymes of ETC released by mitochondria

Answer 4

membrane bound structures containing hydrolytic enzymes

Answer 5

capable of breaking down many substrates, including substances ingested by endocytosis and cellular waste products sequestered by membrane to prevent damage to rest of cell

Answer 6

release of lysosome enzymes, results in apoptosis released enzymes lead to degradation of cellular components

Answer 7

series of interconnected membranes, contiguous with nuclear envelope double membrane folded into complex structures with central lumen

Answer 8

lacks ribosomes, utilized primarily for lipid synthesis (i.e. phospholipids in cell membrane) and detoxification of certain drugs/poisons transports proteins from RER to Golgi in vesicles

Answer 9

studded with ribosomes, which permits translation of proteins destined for secretion directly into lumen

Answer 10

consists of stacked membrane-bound sacs modifies cellular products of ER by addition of various functional groups (carbs, phosphates, sulfates, etc.) modifies cellular products by introducing signal sequences to direct delivery to specific cellular location

Answer 11

cellular products repackaged in vesicles and transported to proper location can be secreted by exocytosis

Answer 12

contain hydrogen peroxide breakdown of long fatty acid chains by beta-oxidation participate in synthesis of phospholipids, contain some enzymes of pentose phosphate pathway

Answer 13

provides structure to cell and helps maintain its shape provides conduit for transport of materials around the cell

Answer 14

microfilaments, microtubules, intermediate filaments

Answer 15

made of solid polymerized rods of actin organized into bundles and networks--resistant to compression and fracture, protect the cell

Answer 16

actin filaments can use ATP to generate force for movement by interacting with myosin--> muscle movement

Answer 17

division of material between daughter cells microfilament forms cleavage furrow, organize a ring at site of division between new daughter cells actin filaments contract, ring becomes smaller an eventually pinches off connection

Answer 18

hollow polymers of tubulin proteins radiate throughout the cell, provide primary pathways for kinesin and dyenin to carry vesicles

Answer 19

composed of microtubules projections form a cell that are primarily involved in movement of materials along cell surface i.e. line respiratory tract for movement of mucus

Answer 20

motor proteins examples of nonenzymatic protein function

Answer 21

composed of microtubules structures involved in movement of cell itself, i.e. of sperm cell through reproductive tract

Answer 22

cilia and flagella 9 pairs of MT form outer ring, 2 in center seen only in eukaryotic organelles of motility

Answer 23

found in centrosome organizing centers for MTs

Answer 24

nine triplets of MTs with hollow center

Answer 25

migrate to opposite poles of cell, organize mitotic spindle MTs emanating from centrioles attach to chromosomes via kinetochores, can exert force on sister chromatids and pull them apart

Answer 26

complexes that attach centrioles to chromosomes

Answer 27

diverse group of filamentous proteins, including keratin, desmin, ,vimentin, lamins many involved in cell-cell adhesion or maintenance of cytoskeleton integrity able to withstand tremendous tension, make cell structure more rigid help anchor other organelles i.e. nucleus

Answer 28

covers body and lines cavities, provide means for protection against pathogen invasion and desiccation involved in absorption, secretion, and sensation

Answer 29

layer of connective tissue that underlies and tightly joins epithelial cells--> remain cohesive unit

Answer 30

functional part of the organ epithelial cells in most organs i.e. nephrons (kidney), hepatocytes (liver), acid-producing (stomach)

Answer 31

polarized: one side faces lumen/outside world, other interacts with underlying blood vessels/structural cells

Answer 32

hollow inside of organ or tube

Answer 33

one layer of cells

Answer 34

multiple layers of cells

Answer 35

appear to have multiple layers because of height differences, but in reality one layer

Answer 36

cuboidal columnar squamous (flat, scalelike)

Answer 37

supports the body, provides framework for epithelial cells to carry out functions main contributors to stroma i.e. bone, cartilage, tendons, ligaments, adipose tissue, blood

Answer 38

support structure for epithelial cells

Answer 39

materials such as collagen and elastin, secreted by connective tissue cells

Answer 40

simplest of all organelles, include all bacteria do not contain any membrane bound organelles, do not have a nucleus single celled organisms but can live in colonies with other cells that can signal and share information about environment

Answer 41

organized into single circular molecule concentrated in nucleoid region not coiled around histones can also have plasmids

Answer 42

archaea and bacteria

Answer 43

single celled organisms, contain genes and several metabolic pathways that are more similar to eukaryotes than bacteria notable for ability to use alternative sources of energy-photosynthetic, chemosynthetic (inorganic compounds i.e. S or N based compounds)

Answer 44

historically considered extremophiles (extremely high temperatures, salinity, or not light) but more recent research has demonstrated greater variety of habitats

Answer 45

hypothesized that shared both start translation with Methionine, contain similar RNA polymerases, associate DNA with histones

Answer 46

contain single circular chromosome divide by binary fission or budding overall share similar structure to bacteria resistant to many antibiotics

Answer 47

cell membrane and cytoplasm, some have flagella or fimbriae

Answer 48

similar to cilia

Answer 49

Share very similar structure with archaea however, even similarly structures have enough biochem differences to allow targeting of one organism i.e. bacterial flagella and eukaryotic flagella distinct enough to be targeted many antibiotics target bacterial ribosome--much smaller than eukaryotic ribosome

Answer 50

5E30 outnumber all plants and animals combined

Answer 51

both humans and bacteria benefit from relationship i.e. bacteria in human gut produce vitamin K and biotin (Vitamin B7), also prevents overgrowth of harmful bacteria

Answer 52

also known as parasites provide no advantage or benefit to host, cause disease may live intracellularly or extracellularly

Answer 53

required for production of plasma proteins necessary for blood clotting newborns are not yet colonized by bacteria, cannot product clotting factors--> at risk for hemorrhage newborns given injection of Vitamin K to aid in production of clotting factors until colonization

Answer 54

cocci (spherical) i.e. streptococcus pyogenes bacilli (rod shaped) i.e. E Coli spirilli (spiral) i.e. causes syphilis

Answer 55

bacteria that require oxygen for metabolism

Answer 56

bacteria that use some other form of cellular metabolism that does not require oxygen i.e. fermentation

Answer 57

bacteria that cannot survive in oxygen-containing environment presence of oxygen leads to production of reactive oxygen-containing radicals--> cell death

Answer 58

bacteria that can toggle between metabolic processes (aerobic or anaerobic)

Answer 59

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

Answer 60

forms outer barrier of cell provides structure and controls movement of solutes into and out of bacterium

Answer 61

cell wall + cell membrane

Answer 62

plasma membrane, composed of phospholipids (similar to eukaryotes)

Answer 63

staining process with crystal violet stain, followed by cointerstain with safranin crystal stain absorbed by peptidoglycan

Answer 64

envelope absorbs crystal violet stain, appears deep purple cell wall consists of thick layer of peptidoglycan, contains lipoteichoic acid

Answer 65

very thin cell wall, also contains peptidoglycan but in much lower amount cell walls directly abut cell membrane also have outer membranes

Answer 66

polymeric substance made from amino acids and sugars structural/barrier functions may also aid pathogen by providing protection from host organism's immune system

Answer 67

unknown function for bacteria, but may activate human immune system

Answer 68

contains phospholipids and lipopolysaccharides

Answer 69

part of gram negative bacteria that triggers human immune response much stronger inflammatory response than to lipo acid

Answer 70

components of bacterial cell wall

Answer 71

long, whip like structures made of flagellin that can be used for propulsion can have 1 or many used to move towards food or away from toxins, immune cells

Answer 72

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

Answer 73

filament, basal body, hook *similar in gram positive and gram negative, slight differences due to different physical structures and chemical compositions of envelope

Answer 74

hollow, helical structure composed of flagellin

Answer 75

complex structure that anchors flagellum to cytoplasmic membrane and is the motor (rotates at rate up to 300 Hz)

Answer 76

connects filament and basal body so that as basal body rotates, exerts torque on filament which can then spin and propel bacteria forward

Answer 77

circular structures that carry DNA acquired from external sources carry DNA that are not necessary for prokaryotic survival (not considered part of genome) but may confer advantages such as antibiotic resistance

Answer 78

lack mitochondria use cell membrane for ETC and generation of ATP

Answer 79

contain a primitive one, but not nearly as complex as eukaryotes

Answer 80

smaller | 30S and 50S subunits (eukaryotic contain 40S and 60S)

Answer 81

simple form of asexual reproduction seen in prokaryotes circular chromosome attaches to cell wall and replicates while cell continues to grow in size eventually, plasma membrane and wall grow inwards along midline of cell to produce two identical daughter cells

Answer 82

requires fewer events, proceeds more rapidly

Answer 83

plasmids: extrachromosomal material often carry genes that impart some benefit to bacterium i.e. antibiotic resistance may also contain virulence factor

Answer 84

traits that increase how pathogenic a bacterium is, i.e. toxin production

Answer 85

projections that allow the bacterium to attach to certain kinds of cells or evasions of host's immune system

Answer 86

subset of plasmids capable of integrating into genome of bacterium

Answer 87

bacterial diversity permits evolution of bacterial species over time

Answer 88

results from integration of foreign genetic material into host genome foreign material frequently comes from other bacteria that spill contents upon lysing many gram negative rods are able to carry out this process

Answer 89

bacterial form of mating two cells form conjugation bridge transfer is unidirectional increases genetic variability

Answer 90

allows transfer of genetic material between bacterium made from appendages called sex pili

Answer 91

from donor male (+) to recipient female (-)

Answer 92

found on donor male

Answer 93

plasmids that contain necessary genes to form pilus

Answer 94

in E. coli bacteria that possess it termed F+, those that don't F-

Answer 95

F+ cell replicates its F factor, donates copy to recipient--> converts it to F+ cell enable cell obtaining new plasmid to transfer copies to other cells allows for rapid acquisition of antibiotic resistance, virulence factors throughout colony because other plasmids can also be passed through conjugation bridge

Answer 96

can be integrated into host genome in this case, when conjugation occurs, entire genome replicates because now contains sex factor donor cell will then attempt to transfer entire copy of genome into recipient, but bridge usually breaks before full DNA sequence can be moved

Answer 97

high frequency recombination entire copy of genome can be transferred to recipient before bridge breaks

Answer 98

only genetic recombination process that requires a vector when fragments of bacterial chromosome accidentally become packaged into viral progeny produced during viral infection, can subsequently be introduced into another bacterium by viral vector increases genetic variability

Answer 99

virus that corries genetic material from one bacterium to another

Answer 100

virusus cannot reproduce outside of host cell

Answer 101

viruses that infect bacteria can accidentally trap a segment of host DNA during assembly when bacteriophage infects another bacterium, can release trapped DNA into new host cell transferred DNA can integrate into genome, giving new host additional genes

Answer 102

genetic elements capable of inserting and removing themselves from the genome not limited to prokaryotes, also seen in eukaryotes

Answer 103

that gene may be disputed

Answer 104

lag exponential stationary death

Answer 105

in new environment, bacteria first adapt to new local conditions

Answer 106

as bacteria adapt, growth increases--> exponential increase in number of bacteria in the colony aka log phase

Answer 107

as number of bacteria in colony grows, resources often reduced reduction of resources slows reproduction

Answer 108

after bacteria have exceeded ability of environment to support number of bacteria, death occurs as resources have been depleted

Answer 109

genetic material, protein coat, sometimes envelope containing lipids

Answer 110

can be circular or linear, single or double stranded, DNA or RNA

Answer 111

protein coat of virus

Answer 112

surrounds capsid, composed of phospholipids and virus specific proteins sensitive to heat, detergents, and desiccation--> easier to kill *viruses without envelopes more resistant to sterilization, likely to persist on surfaces for extended period of time

Answer 113

obligate intracellular parasites must express and replicate genetic information within host cell replicate and produce virions, which can be released to infect additional cells

Answer 114

lack ribosomes

Answer 115

viral progeny released to infect other cells

Answer 116

viruses that specifically target bacteria do not actually enter bacteria--use tail to anchor to membrane and inject genetic material, leaving remaining structures outside infected cell

Answer 117

capsid, tail sheath, tail fibers

Answer 118

can act like syrings, inject genetic material into bacterium

Answer 119

help bacteriophage to recognize and connect to correct host cell some tail fibers have enzymatic activity, allowing penetration of cell wall and formation of pores in cell membrane

Answer 120

variety of shapes and sizes, any number of genes, single stranded DNA or RNA

Answer 121

positive sense or negative sense

Answer 122

genome may be directly translated to functional proteins by ribosomes of host cells, just like mRNA

Answer 123

single stranded RNA viruses require synthesis of RNA strand complementary to the negative sense RNA strand, which can then be used as template for protein synthesis must carry RNA replicase in virion

Answer 124

ensures that complementary strand of negative sense RNA virsus is synthesized

Answer 125

enveloped, single stranded RNA viruses in family Retroviridae usually, virion contains two identical RNA molecules carry reverse transcriptase

Answer 126

synthesizes DNA from single stranded RNA often makes errors that generates diversity into virus copies

Answer 127

Virsus fuses with cell, empties contents into cytoplasm Reverse transcriptase Integrase then inserts copy into host DNA, where replicated and transcribed as if host cell's DNA--> cell infected indefinitely, only way to cure infection is kill infected cell itself i.e. HIV cell machinery transcribes viral genes back into RNA, travels to cytoplasm, where ribosomes produce encoded proteins viral RNA and proteins move towards cell membrane, father into budding virus particle

Answer 128

virus binds to CD4 and CCR5 proteins on cell surface fuses, releases contents into cytoplasm reverse transcriptase, integrase viral genes back to RNA, then move to membrane and gather into budding particle in new immature virus copy, HIV protease enzymes modifies viral protein chains, enabling virions to mature into form that can infect new cell

Answer 129

receptor on white blood cells that HIV binds to people who lack CCR5 receptor--> HIV immune

Answer 130

in order to infect cell, virus has to bind to specific receptors on host cell (without proper receptors, cell is essentially invisible to virus) enveloped virus fuse with plasma membrane, allowing entry of virion into host cell *sometimes host cell will accidentally bring virus into cell via endocytosis (mistakes it for useful molecule)

Answer 131

translation must occur in order to reproduce requires translocation of genetic material to correct location in cell DNA viruses go to nucleus to be transcribed into mRNA mRNA then goes to cytoplasm, where translated to proteins positive sense: stays in cytoplasm, where directly translated to protein by host cell ribosomes negative sense: require synthesis of complementary RNA strand via RNA replicase, which is then translated to form proteins *DNA formed through reverse transcription in retroviruses also travels to nucleus, where integrated into host genome

Answer 132

using host cell ribosomes, tRNA, AAs, and enzymes, viral RNA-->proteins many proteins are structural capsid proteins, allow for creation of new virions in host cell cytoplasm once viral genome replicated, can be packaged within capsid (*must be returned to original form before packaging)

Answer 133

viral invasion may initiate cell death--> spilling of viral progeny host cell lyses because filled with extremely large number of virions extrusion-allows for survival of host cell and continued use of host cell by virus (productive cycle)

Answer 134

virus can leave cell by fusing with its plasma membrane

Answer 135

bacteriophage makes maximal use of cell's machinery with little regard for survival of host cell once host swollen with new virions, cell lyses and other bacteria infected

Answer 136

bacteria in lytic phase

Answer 137

if bacteria does not lyse bacterium, may integrate into host genome as provirus/prophage virus will be replicated as bacterium reproduces because now part of host's genome--may remain integrated into genome indefinitely, environmental factors (radiation, light, chemicals)--> provirus leaves genome and reverts to lytic cycle

Answer 138

allows transduction of genes from one bacterium to another

Answer 139

simultaneous infection infection with one strain of phage generally makes bacteria less susceptible to this

Answer 140

may be benefit to having them integrated into lysogenic cycle provirus is relatively innocuous, some be may evolutionary advantage to this association

Answer 141

infectious proteins--> non-living things cause disease by triggering misfolding of other proteins (usually alpha to beta) drastically reduces solubility as well as ability of cell to degrade misfolded protein--> aggregates form, cell function reduced ex: mad cow disease, creutzfeldt-jakob, familial fatal insomnia

Answer 142

small pathogens consisting of very short circular single-stranded RNA that infect plants can bind to large number of RNA sequences, silence plant genome--> prevents synthesis of necessary proteins, can subsequently cause metabolic and structural derangements in plant cell

Answer 143

HDV (Hepatitis D) alone innocuous but when paired with Hep B, can exert silencing function on human hepatocytes

Answer 144

human liver cell

Answer 145

synthesis of ribosomal RNA

Answer 146

conjugation transduction

Answer 147

``` milk producing mammary glands three bones in middle ear, one in lower jaw fur/hair heterodont dentition sebaceous and sudoriferous glands ```

Answer 148

different kinds of teeth

Answer 149

oil producing

Answer 150

prototherians and metatetherians

Answer 151

monotremes encase developing embryos within hard-shelled amniotic eggs and lay them to hatched (oviparity) i.e. platypus, echinada (spiny anteater)

Answer 152

method of birth for protherians amniotic eggs laid to be hatched

Answer 153

marsupials i.e. koalas, kangaroos fetus (joey) undergoes some development in mother's uterus, climbs out of birth canal into marsupium (pouch)

Answer 154

2n contain two copies of each chromosome

Answer 155

(n) contain only one copy of each chromosome

Answer 156

a series of phases during which cell grows, synthesizes DNA, and divides euokaryotic replication

Answer 157

first three stages of cell cycle G1, S, G2 longest part of cell cycle--actively dividing cells spend 90% of time in it

Answer 158

stage that cells do not divide spend all time in cell is simply living and serving function, without any preparation for division

Answer 159

less condensed form of chromosomes during interphase not visible with light microscopy

Answer 160

DNA must be available to RNA polymerase so that genes can be transcribed

Answer 161

condensed into tightly coiled chromosomes to avoid losing any genetic material during division

Answer 162

presynthetic gap cells create organelles for energy and protein production while also increasing size

Answer 163

restriction point criteria such as proper complement of DNA must be met, otherwise cell cycle goes into arrest until DNA has been repaired

Answer 164

synthesis of DNA cell replicates genetic material so that each daughter cell will have identical copies after replication, each chromosome consists of two identical chromatids *ploidy of cells does not change even though double the number of chromatids (same number of chromosomes despite double chromatids)

Answer 165

created during S phase bounds together at centromere composed of complete double stranded molecule of DNA sister=identical

Answer 166

specialized region that binds chromatids together

Answer 167

number of sets of chromosomes

Answer 168

postsynthetic gap cell passes through another quality control checkpoint checks to ensure that there cell is big enough and there are enough organelles and cytoplasm to divide between two daughter cells makes sure that DNA replication occurred correctly to avoid passing error to daughter cells

Answer 169

mitosis and cytokineseis

Answer 170

prophase metaphase anaphase telophase

Answer 171

splitting of cytoplasm and organelles into 2 daughter cells

Answer 172

main protein in control of restriction point also plays role in G2/M checkpoint

Answer 173

cyclins and cyclin dependent kinases

Answer 174

requires presence of correct cyclins bound cyclin activates compound which can then phosphorylate transcription factors

Answer 175

promote transcription of genes required for next stage of cell cycle

Answer 176

when cell cycle control becomes deranged and damaged cells are allowed to undergo mitosis

Answer 177

of gene TP53 that produces p53 cell cycle is not stopped to repaired damaged DNA, allows for mutations to accumulate and results in cancerous cell that divides continuously without regard to quality or quantity of cells produced

Answer 178

cells undergo rapid cell division and create mass of abnormal tissue

Answer 179

spread of cancerous cells through blood steam or lymphatic system possible if cell produces factors such as proteases that can digest basement membranes or factors that encourage blood vessel formation

Answer 180

process by which two identical daughter cells are created from single cell occurs in somatic cells

Answer 181

not involved in sexual reproduction

Answer 182

oncogenes: when mutated, actively promote cell division tumor suppressor: when mutated, lose ability to regulate or pause cell cycle

Answer 183

first phase in mitosis condensation of chromatin in chromosomes centriole pairs separate and move towards opposite poles of cells, begin to form spindle fibers nuclear membrane dissolves nucleoli become less distinct, may even disappear completely kinetochores appear at centromere

Answer 184

paired cylindrical organelles, located outside nucleus in centrosome region and responsible for correct division of DNA

Answer 185

one of the two microtubule organizing regions of the cell (other is basal body of flagellum/cilium)

Answer 186

made of MTs radiate outwards from centrioles, some form asters and other extend towards middle once membrane dissolved, can make contact with chromosomes

Answer 187

anchors centrioles to cell membrane

Answer 188

appear at centromere during prophase protein structures located on centromeres that serve as attachment points for fibers of spindle apparatus to attach to chromosomes

Answer 189

specific fibers of spindle apparatus

Answer 190

centriole pairs now at opposite ends of cell kinetochore fibers interact with fibers of spindle apparatus to align chromosomes at metaphase plate

Answer 191

equatorial plate equidistant between two poles of cell

Answer 192

centromeres split so that each chromatid has own distinct centromere--> sister chromatids separate chromatids pulled to opposite poles of cell by shortening kinetochore fibers

Answer 193

reverse of prophase spindle apparatus disappears nuclear membrane forms around each set of chromosomes, nucleoli reappear chromosomes uncoil (resume interphase form) each of two new nucleoli has received complete copy of genome identical to original and each other

Answer 194

germ cells

Answer 195

four gametes

Answer 196

non-identical sex cells

Answer 197

prophase I homologous chromosomes come together and intertwine

Answer 198

chromatin condenses into chromosomes, spindle apparatus forms, nucleoli/nuclear membrane disappear

Answer 199

chromosomes come together and intertwine during prophase I

Answer 200

two chromosomes that consist of two sister chromatids

Answer 201

group of proteins called synaptonemal complex

Answer 202

point of contact between homologous chromosomes where chromatids may break and exchange equivalent pieces of DNA

Answer 203

number of cross over events that occur in one strand of DNA

Answer 204

occurs between homologous chromosomes, not between sister chromatids chromatids involved are left with altered but structurally complete set of genes provides genetic diversity

Answer 205

can unlink linked genes, thereby increasing the variety of genetic combinations that can be produced via gametogenesis

Answer 206

the tendency for genes to be inherited together and more likely to undergo crossing over relative to each other

Answer 207

a unique pool of alleles from a random mixture of maternal and paternal origin

Answer 208

Law of Independent Assortment the inheritance of one allele has no effect on the likelihood of inheriting certain alleles for other genes

Answer 209

tetrads align at metaphase plate, each pair attaches ot separate spindle fiber by kinetochores

Answer 210

mitosis: each chromosome lined up on metaphase plate by two spindle fibers (one from each pole) meisosis: homologous chromosomes lined up across from each other at metaphase plate and held by one spindle fiber

Answer 211

`homologous pairs separate and pulled to opposite poles disjunction

Answer 212

Accounts for Mendel's First Law (of segregation) each chromosome of paternal origin separates from its homologue of maternal origin and either can end up in either daughter cell

Answer 213

is random with respect to parental origin

Answer 214

the separating of two homologous chromosomes

Answer 215

nuclear membrane forms around each new nucleus each chromosomes stills consists of two sister chromatids hoinged at the centromere haploid: only n chromosomes found in each daughter cell cell divides into 2 daughter cells by cytokineses

Answer 216

short rest period that may occur between meiosis I and II during which the chromosomes partially uncoil

Answer 217

sister chromatids rather than homologues are separated from each other

Answer 218

nuclear envelope dissolves, nucleoli disappear, centrioles migrate to opposite poles, spindle apparatus begins to form

Answer 219

chromosomes line up on metaphase plate

Answer 220

centromeres divide, seaprating chromosomes into sister chromatids chromatids pulled to opposite poles by spindle fibers

Answer 221

nuclear membrane forms around each new nucleus cytokineses follows and two daughter cells are formed

Answer 222

up to four haploid daughter cells are produced per gametocyte

Answer 223

23rd chromosomes XX female XY male

Answer 224

carry sizable amount of genetic information

Answer 225

sex-linked disorders most are recessively inherited

Answer 226

only have one copy of a gene males with X chromosome genes --> male with disease causing allele on unpaired part of X chromosome will express the allele

Answer 227

females carrying a diseased allele on an K chromosome but not exhibiting it

Answer 228

contains comparatively little genetic information

Answer 229

notable gene on Y chromosome codes for transcription factor that initiates testis differentiation and thus formation of the male gonads

Answer 230

zygotes will be female

Answer 231

seminiferous tubules interstitial cells

Answer 232

where sperm are produced highly coiled

Answer 233

seminiferous tubules/ Sertoli cells

Answer 234

secrete testosterone and other androgens

Answer 235

male sex hormones

Answer 236

where testes are located external pouch that hangs below penis maintains temperate 2-4 C below body temp

Answer 237

layer of muscle around vas deferens that can raise and lower testis to maintain proper temperature for sperm development

Answer 238

where sperm are passes as they are formed: gain flagella motility and stored until ejaculation

Answer 239

sperm travel through vas deferens to ejaculatory duct

Answer 240

at posterior end of prostate gland two ducts fuse to form urethra

Answer 241

carries sperm through the penis as they exit the body

Answer 242

share a common pathway not the case in females

Answer 243

mixed with sperm as they pass through the reproductive pathway produced through combined effort by seminal vesicles , prostate gland, and bulbourethral gland

Answer 244

contribute fructose to nourish sperm, gives fluid mildly alkaline property to be able to survive acidity of female reproductive tract (alongside prostate gland)

Answer 245

alongside seminal vesicles, gives mildly alkaline property to survive acidity of female reproductive tract

Answer 246

produce clear viscous fluid that cleans out any remnants of urine and lubricates urethra during sexual arousal

Answer 247

combination of sperm and seminal fluid

Answer 248

formation of haploid sperm through meiosis occurs in seminiferous tubules results in four functional sperm for each spermatagonia

Answer 249

diploid stem cells in males

Answer 250

what spermatagonia become after after replicating genetic material in S stage

Answer 251

result of first meitotic division in primary spermatocytes haploid

Answer 252

generated when secondary spermatocytes undergo meiosis II haploid

Answer 253

spermatazoa

Answer 254

very compact head (contains genetic material), midpiece (generates ATP from fructose), and flagellum (motility)

Answer 255

filled with mitochondria that generate energy to be used as sperm swims through fallopian tubes to reach ovum

Answer 256

cap that covers sperm head derived from Golgi apparatus and necessary to penetrate the ovum enzymes enable to head of the sperm to penetrate through the corona radiata and ZP

Answer 257

female gonads produce estrogen and progesterone located in pelvic cavity, consists of 1000s of follicles

Answer 258

multilayered sacs that contain, nourish, and protect immature ova (eggs)

Answer 259

once a month between puberty and menopause though peritoneal sac (lines abdominal cavity), then drawn into fallopian tube or oviduct (contains cilia to propel egg forward)

Answer 260

muscular structure connected to the fallopian tubes site of fetal development

Answer 261

lower end of the uterus, connects to vaginal canal

Answer 262

where sperm are deposited during intercourse

Answer 263

known collectively as vulva

Answer 264

production of female gametes all the oogenia a woman will ever have are formed during fetal development

Answer 265

all oogenia have undergone DNA replication by birth 2n arrested in prophase I

Answer 266

product when primary oocyte completes mitosis I (1 per month) also produces polar body remains arrested in metaphase II, does not complete remainder of meiosis unless fertilized

Answer 267

first menstrual cycle

Answer 268

characterizes division between secondary oocyte and polar body ample cytoplasm to to oocyte and nearly none to polar body

Answer 269

does not usually divide further after meiosis I will never produce any functional gametes

Answer 270

zona pellucida | corona radiata

Answer 271

surrounds to oocyte itself, acellular mixture of glycoproteins that protect the oocyte and contain compounds necessary for sperm cell binding

Answer 272

lies outside ZP | layer of cells that adhered to oocyte during ovulation

Answer 273

sperm penetrates layers around oocyte with the help of acrosomal enyzmes

Answer 274

mature ovum and polar body

Answer 275

large cell consisting of large quantities of cytoplasm, organelles contributes nearly everything to zygote (half of DNA, all cytoplasm, organelles, RNA for early cellular processes, and physical space)

Answer 276

diploid created upon creation of meiosis II haploid pronuclei of sperm and ovum join

Answer 277

prior to puberty, hypothalamus restricts production of GnRH at start of puberty, restriction is released as hypothalamus produces GnRH --> anterior pituitary synthesizes LH and FSH LH and FSH trigger production of other sex hormones that develop and maintain the reproductive system

Answer 278

during fetal period, Y chromosome allows for production of androgens

Answer 279

low during infancy and childhood

Answer 280

produced by testes dramatically increases during puberty, sperm production begins also results in development of secondary sexual characteristics

Answer 281

FSH stimulates Sertoli cells --> sperm maturation LH causes interstitial cells to produce testosterone

Answer 282

remains high through adulthood declines as men age exerts negative feedback on hypothalamus and anterior pituitary, limits production to normal levels

Answer 283

secreted in response to FSH result in development of female reproductive system and secondary sexual characteristics stimulate development of reproductive tract in embryo leads to thickening of endometrium each month in preparation for zygote implantation

Answer 284

lining of the uterus

Answer 285

secreted by corpus luteum in response to LH involved in development and maintenance of endometrium but not in initial thickening

Answer 286

remnant follicle that remains after ovulation

Answer 287

required for the generation, development, and maintenance of endometrium capable of supporting a zygote

Answer 288

by end of fist trimester, supplied by placenta corpus lutuem atrophies and ceases to function

Answer 289

estrogen and progesterone rise and fall in cyclic cycle leading to growing and shedding of endometrial lining

Answer 290

follicular phase ovulation luteal phase menstruation

Answer 291

begins when menstrual flow begins GnRH secretion increases in response to decreased levels of estrogen and progesterone, leads to increase in FSH and LF FSH and LH work in concert to develop several ovarian follicles--> production of estrogen follicles produce estrogen exerts NFB and GnRH, LH, FSH level off estrogen works to regrow endometrial lining, stimulating vascularization and glandularization of decidua

Answer 292

estrogen can exert NFB and PFB late in follicular phase, follicles secrete high levels of estrogen, concentration reach a threshold that results in PFB (GnRH, LH, and FSH spike) surge in LH induces ovulation

Answer 293

release of ovum from ovary in abdominal (peritoneal) cavity

Answer 294

after ovulation, LH causes ruptured follicle to form corpus luteum which secretes progesterone *progesterone maintains endometrium for implantation progesterone levels rise and estrogen remain high high progesterone exerts NFB on GnRH, FSH, LH which prevents ovulation of multiple eggs

Answer 295

assuming implantation does not occur, corpus luteum loses its stimulation from LH, progesterone levels decline, and uterine lining sheds loss of high levels of estrogen and progesterone removes block on GnRH so that next cycle can begin

Answer 296

if fertilization has occurred, resulting zygote develops into blastocyst that will implant into uterine lining and secrete hCG which maintains corpus luteum

Answer 297

human chorionic gonadotropin analog of LH and can stimulate LH receptors, maintains corpus luteum critical in first trimester because estrogen and progesterone from corpus luteum keep the uterine lining in place

Answer 298

decline because the placenta has grown sufficiently to secrete progesterone and estrogen itself high levels of estrogen and progesterone continue to serve as NFB to prevent further GnRH secretion

Answer 299

ovarian atrophy results from ovaries becoming less sensitive to estrogen and progesterone with age estrogen and progesterone drops also leads to endometrium atrophy, menstruation stops NFB on LF and FSH removed, blood levels rise accompanied by profound physical and physiological changes such as flushing, hot flashes, bloating, head aches, irritability usually ages 45-55

Answer 300

widest part of fallopian tube where fertilization usually occurs

Answer 301

tubelike structure that extends to and penetrates cell membrane once sperm comes into direct contact with secondary oocyte cell membrane

Answer 302

after penetration of sperm through cell membrane, release of calcium ions that serves to depolarize and prevent fertilization of ovum by multiple sperm cells and increase metabolic rate of newly formed zygote

Answer 303

depolarized and impenetrable membane

Answer 304

fraternal result from fertilization of two different eggs released during one ovulatory cycle by two difference sperm each implants on uterine wall 2 placenta, 2 chorion, 2 amnion *if too close to each other, placentas may overgrow onto each other

Answer 305

single zygote splits in two results in identical genomes in offspring can be monochorionic, monoamniotic, dichorionic, diamnonic (which type is a result of when separation occurred) as more gestational structures are shared, more risks

Answer 306

incomplete division of monozygotic twins

Answer 307

zygote must travel from fallopian tubes to uterus for implantation if too late, no longer an endometrium capable of supportin gembryo

Answer 308

rapid mitotic cell divisions as zygote moves to uterus for implantation size of embryo remains same during first few divisions

Answer 309

official embryo | nullifies defining unicellular characteristics of zygote

Answer 310

increases nuclear to cytoplasmic increases surface area to volume leads to increased area for gas and nutrient exchange relative to overall volume

Answer 311

results in cells that can still develop into complete organisms MZ twins originate from indeterminately cleaved cells of same embryo

Answer 312

results in cells with fates that are already determined committed to differentiating into certain type of cell

Answer 313

solid mass of cells that results from several divisions of embryo

Answer 314

forms blastula from morula

Answer 315

hollow ball of cells with fluid-filled inner cavity

Answer 316

fluid-filled inner cavity of blastula

Answer 317

mammalian blastula contains trophoblast and inner cell mass

Answer 318

surround blastocoel and give rise to chorion and later the placenta specialized to create interface between maternal blood supply and developing embryo

Answer 319

protrudes into blastocoel and gives rise to organism itself

Answer 320

blastula moves through fallopian tubes to uterus, where burrows into endometrium

Answer 321

extraembryonic membrane that devlops into placenta, arises from trophoblast cells also forms outer membrane around amnion

Answer 322

formed by trophoblast cells microscopic fingerlike projections that penetrate endometrium as develop into the placenta, support maternal-fetal gas exchange

Answer 323

connects embryo to placenta consists of two arteries and one vein encased in gelatinous substance vein carries freshly oxygenated blood with nutrients from placenta to embryo arteries carry deoxygenated blood and waste to placenta for exchange

Answer 324

supports embryo until placenta is in place site of early blood cell development

Answer 325

extraembryonic membrane involved in early fluid exchange between embryo and tolk sac

Answer 326

extraembryonic membrane that surrounds the allantois thing, though membrane filled with amnionic fliud

Answer 327

serves as shock absorber during pregnancy, lessening the impact of maternal motion

Answer 328

generation of three distinct cell layers

Answer 329

two membranes merge after invagination, resulting in tube through the middle of the blastula

Answer 330

membrane invagination into the blastocoel, later develops into the gut

Answer 331

opening of the archenteron

Answer 332

dueterostomes: anus protosomes: mouth

Answer 333

three layers of the cell ectoderm, mesoderm, endoderm

Answer 334

outermost layer gives rise to the integument, eye lens, nervous system (including adrenal medulla), inner ear

Answer 335

epidermis, hair, nails, epithelia of nose, mouth, lower anal canal

Answer 336

middle layer develops into musculoskeletal, circulatory, and most of excretory system gives rise to gonads, muscular and connective tissue layers of digestive and respiratory systems and adrenal cortex

Answer 337

innermost layer forms epithelial linings of digestive and respiratory tracts, including lungs pancreas, thyroid, bladder, distal urinary tracts, parts of liver

Answer 338

only the genes needed for that particular cell type are transcribed allows for differentiation related to induction

Answer 339

ability of one group of cells to influence the fate of other nearby cells mediated by inducers ensures proximity of different cell types that work together within an organ

Answer 340

diffuse from the organizing cells to the responsive cells responsible for processes such as guidance of neuronal axons

Answer 341

development of nervous system can being once three germ layers are formed

Answer 342

rod of mesodermal cells that forms along the long axis of the organism like a primitive spine induces neural folds

Answer 343

formed by group of overlying ectodermal cells that slide inward, surround neural groove

Answer 344

neural folds grow towards one another and fuse, giving rise to CNS

Answer 345

at the tip of each neural fold migrate outwards to form PNS and specific cell types in other tissues

Answer 346

ectodermal cells will migrate over neural tube and crests to cover rudimentary nervous system

Answer 347

additive effects are based on number and location of incoming signal i.e. large number of signals on soma will have greater effect than a few signals on the dendrites

Answer 348

membrane potential +35 mV have to be brought back to near resting potential to be deinactivated

Answer 349

closed: before cell reaches threshold and once inactivation has been reversed open: threshold-35 mV inactive: +35 mV to resting potential

Answer 350

broken down by enzymatic reactions i.e. acetylcholinesterase brought back into neurons using reuptake carreirs i.e. 5-HT, DA, NE may simply diffuse out of cleft i.e. NO

Answer 351

sensory neurons motor neurons interneurons

Answer 352

afferent neurons transmit info from receptors to CNS

Answer 353

efferent neurons transmit motor information from CNS to muscles and glands

Answer 354

located between sensory and motor most numerous of three types located predominantly in CNS and are often linked to reflexive behavior

Answer 355

used in reflexes that require input from brain or brainstem

Answer 356

protects the spinal cord transmits nerves at the space between adjacent vertebrae

Answer 357

in from the periphery enter on dorsal side of spinal cord

Answer 358

cell bodies of sensory neurons

Answer 359

the spinal cord ventrally

Answer 360

connects CNS to the rest of the body includes 31 pairs of spinal nerves and 10/12 pairs of cranial nerves

Answer 361

sensory and motor neurons distributed throughout skin, joints, and muscles

Answer 362

generally regulates heartbeat, respiration, digestion, glandular secretions manages involuntary muscles associated with many internal organs and glands helps regulate body temp by activating sweating or piloerection

Answer 363

peripheral component of ANS contains 2 neurons motor neuron in somatic goes directly from spinal cord to muscle without synapsing ANS has two neurons work in series to transmit message (preganglionic and postganglionic)

Answer 364

in the CNS axon travels to ganglion in PNS

Answer 365

conserve energy associated with resting and sleep states, acts to reduce heart rate and constrict bronchi manages digestion by increasing peristalsis and exocrine secretions ACh released by pre and post ganglionic neurons

Answer 366

responsible for parasympathetic innervation of thoracic and abdominal cavities

Answer 367

activated by stress, associated with rage and fear reactions (fight or flight) increases heart rate, redistributes blood to muscles of locomotion, increases blood glucose concentration, relaxes bronchi, decreases digestion and peristalsis, dilates eyes to maximum light intake, releases epi into blood stream

Answer 368

release ACh

Answer 369

release NE

Answer 370

neural circuits that control reflexive behavior sensory neurons connect with interneurons, which then relay pain impulses to brain interneurons (spinal cord) also send signals directly to legs (one withdraws, other balances) two types: mono and poly

Answer 371

single synapse between sensory neuron that receives stimulus and motor that responds i.e. knee jerk

Answer 372

patellar tendon is stretched, information travels up afferent neuron to spinal cord interfaces with motor neuron that contracts quad muscle Net result: extension of leg (lessons tension on patellar tendon) serves to protect muscles

Answer 373

at least one interneuron between sensory and motor neurons i.e. withdrawl reflex

Answer 374

stepping on nail stimulates foot to flex, uses hips and hamstrings to pull foot away from nail (this part is monosynaptic) to maintain balance, other foot has to plant firmly--motor neurons of quads must be stimulated, extending it interneurons in spinal cord provide connections from incoming sensory info to motor neurons in supporting limb

Answer 375

damage to organs such as retina, glumeruli of kidneys, coronary vessels of heart, cerebral vessels of brain, nerves in the extremeties left untreated: blindness, kidney failure, heart attacks, strokes, amputation

Answer 376

organs that secrete hormones

Answer 377

signaling molecules that are secreted directly into the blood stream to travel to distant target tissue binds to receptors to induce change in gene expression or change in cellular functioning

Answer 378

made of amino acids range from small (ADH) to relatively large (insulin) all derived from larger polypeptide precursors that are cleaved during post translational modification smaller units transported to Golgi for modification that activates and directs it to correct cellular location released by exocytosis water-soluble, travel freely in bloodstream

Answer 379

peptides are charged and cannot pass through plasma membrane so they bind to extracellular receptor hormone considered first messenger, receptor triggers transmission of second signal (second messenger) type of receptor determines what happens once hormone has stimulated receptor

Answer 380

connection between hormone at surface and effect brought about by the second messenger

Answer 381

amplification

Answer 382

hormone may bind to multiple receptors before its degraded each receptor may activate multiple enzymes, which triggers production of large amounts of second messengers

Answer 383

cAMP, IP3, calcium

Answer 384

activation of G protein triggered by binding of peptide hormone G protein either activates or inhibits adenylate cyclase, raising or lowering cAMP levels accordingly cAMP can bind to intracellular targets i.e. protein kinase A PKA phosphorylates transcription factors like cAMP response binding element protein (CREB) to exert hormone's ultimate effect *PKA can also modify enzymes and have rapid or slow effect on cell

Answer 385

quick response lats shorter because operates through transient second messenger systems

Answer 386

derived from cholesterol produced primarily by gonads and adrenal cortex derived from non-polar molecules so easily pass through cell membrane receptors in cytosol (intracellular) or intranuclear

Answer 387

upon binding, receptor undergoes conformational changes receptor can then bind directly to DNA, resulting in increased or decreased transcription of particular genes

Answer 388

common form of conformational change pairing of two receptor-hormone complexes

Answer 389

slower longer lived than peptide because cause alteration in amount of mRNA and protein present in cell by direct action in DNA

Answer 390

steroid hormones not eater soluble so must be carried in blood to travel around body some highly specific and carry only one kind of protein i.e. sex-hormone binding globulin nonspecific proteins i.e. albumin hormones generally inactive while attached to carrier protein, must dissociate to function levels of carrier can change levels of active hormone

Answer 391

thyroxine-binding globulin some condition increase the quantity of protein that carries thyroid hormones causes body to perceive a lower level of thyroid hormone because increased TBG binds larger proportion of the hormone, meaning there is less free hormone available

Answer 392

less common than peptide or steroid include epi, NE, T2, T3 derived from one or two AAs with additional modification catecholamines bind extracellularly (G-coupled) and thyroid hormones bind intracellularly

Answer 393

Tyrosin + iodine molecules

Answer 394

secreted and then act directly on target tissue i.e. insulin secreted by pancreas causes increased glucose uptake in muscles

Answer 395

require an intermediary to act i.e. GnRH stimulates LH and FSH usually originate in brain and anterior pituitary gland (both structures involved in coordination of multiple processes within body)

Answer 396

acts on gonads to stimulate testosterone production in male, estrogen in female

Answer 397

high levels of estrogen and progesterone cause increased production of TBG in order to compensate, secretes much higher level of thyroid hormones IOT diagnose thyroid disease in pregnant woman, different reference values must be used

Answer 398

extremely fast onset short lived

Answer 399

slower onset, longer duration regulate metabolic rate over long period of time

Answer 400

bridge between nervous and endocrine systems regulated pituitary gland through tropic hormones, capable of having organism wide effects

MCAT Bio Flashcards

(430 cards)