Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MCAT 2015 > Reproduction > Flashcards

Reproduction Flashcards

You may prefer our related Brainscape-certified flashcards:
MCAT flashcards
1
Q

diploid

A

2n
contain two copies of each chromosome
i.e. autosomal cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

haploid

A

n
contain only one copy of each chromosome
i.e. germ cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

cell cycle

A

specific series of phases during which a cell grows, synthesizes DNA, and divides
derangements can lead to unchecked cell division and may be responsible for the formation of cancer
four stages: G1, S, G2, M

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

interphase

A

G1, S, G2 collectively
longest part of the cell cycle
chromatin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

G0 stage

A

cell is simply living and serving its function, without any preparation for division

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

chromatin

A

less condensed form of chromosomes

allows for DNA to be available to RNA polymerase so genes can be transcribed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

G1 stage

A

cells create organelles for energy and protein production (mitochondria, ribosomes, and ER), while also increasing size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

restriction point

A

governs passage into S (synthesis) stage

criteria (i.e. containing the proper complement of DNA) must be met

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

S stage

A

cell replicates its genetic material so that each daughter cell will have identical copies
after replication, each chromosome consists of two identical chromatids bound together at specialized region known as centromere

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

G2 stage

A

cell phases through another quality checkpoint
DNA already duplicated
cell checks to ensure that there are enough organelles and cytoplasm to divide between two daughter cells
makes sure DNA replication proceeded correctly to avoid passing on error to daughter cells that may further replicate error to progeny

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

M stage

A

consists of mitosis itself along with cytokinesis

divided into four phases: prophase, metaphase, anaphase, telophase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

p53

A

main protein in control of checking at restriction point (between G1/S) as well as at G2/M checkpoint to ensure that there is no damage to the DNA and that the cell has achieved adequate size and organelles have been properly replicated to support two daughter cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

cyclin-dependent kinases (CDK)

A

responsible for the cell cycle
require presence of right cyclins
conc’s of various cyclins increase/decrease during specific stages
cyclins bind to these creating an activated complex, which can then phosphorylate transcription factors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

transcription factors

A

promote transcription of genes required for the next stage of the cell cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

cancer

A

results when cell cycle control becomes deranged and damaged cells are allowed to undergo mitosis
one of the most common mutations found is of gene that produces p53 (TP53)
- cell cycle is not stopped to repair damaged DNA which allows for mutations to accumulate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

tumors

A

created when cancer cells undergo rapid cell division

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

metastasis

A

if cancer cell begins to produce the right factors, the damaged cells are then able to reach other tissues
distant spread of cancerous cells through the bloodstream or lymphatic systems

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

mitosis

A

process by which two identical daughter cells are created from a single cell
four phases: prophase, metaphase, anaphase, telophase
occurs in somatic cells–cells not involved in sexual reproduction
finite number of divisions before programmed death: 20-50 for human somatic cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

prophase

A

first phase in mitosis
condensation of the chromatin into chromosomes
centriole pairs separate and move toward opposite poles of the cell
centrioles form spindle fibers made of microtubules, which radiate outward
nuclear membrane dissolves, allowing spindle fibers to contact the chromosomes
nucleoli become less distinct, may disappear completely
kinetochores appear at the centromere

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

centriole pairs

A

cylindrical organelles located outside the nucleus in centrosome region
responsible for the correct division of DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

asters

A

formed from microtubules

anchor the centrioles to the cell membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

kinetochores

A

protein structures located on the centromeres that serve as attachment points for specific fibers of the spindle apparatus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

metaphase

A

centriole pairs are now at opposite ends of the cell

kinetochore fibers interact with the fibers of the spindle apparatus to align chromosomes at the metaphase plate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

metaphase plate

A

equatorial plate

equidistant between the two poles of the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

anaphase

A

centromeres split so that each chromatid has its own distinct centromere, allowing sister chromatids to separate
pulled toward the opposite poles of the cell by the shortening of the kinetochore fibers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

telophase

A

reverse of prophase
spindle apparatus disappears
nuclear membrane reforms around each set of chromosomes and nucleoli reappear
chromosomes uncoil, resuming interphase form
each of two new nuclei has received a complete copy of the genome identical to the original genome and to each other
cytokinesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

cytokinesis

A

separation of the cytoplasm and organelles so that each daughter cell has sufficient supplies to survive on its own

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

gametocytes

A

germ cells in which meiosis occurs

results in up to four nonidentical sex cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

gametes

A

nonidentical sex cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

meiosis

A

occurs in germ cells to create four nonidentical sex cells (games
consists of one round of replication followed by two rounds of division

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

meiosis I

A

results in homologous chromosomes being separated, generating haploid daughter cells
reductional division

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

meiosis II

A

similar to mitosis
results in separation of sister chromatids
equational division

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

homologous pairs

A

considered separate chromosomes
human genome consists of 23
each contains one chromosome inherited from each parent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

prophase I

A

meiosis I
chromatin condenses into chromosomes, spindle apparatus forms, nucleoli and nuclear membrane disappear
homologous chromosomes come together and intertwine in synapsis
crossing over occurs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

tetrad

A

each chromosome consists of two sister chromatids, so each synaptic pair contains four chromatids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

chiasma (pl. chiasmata)

A

point of synapsis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

crossing over

A

chromatids of homologous chromosomes may break at point of synapsis and exchange equivalent pieces of DNA
occurs between homologous chromosomes and not between sister chromatids of the same chromosomes
genetic recombination, can unlink linked genes, thereby increasing the variety of genetic combinations that can be produced via gametogenesis
each daughter cell will have a unique pool of alleles from a random mixture of maternal and paternal origin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Mendel’s second law (of independent assortment)

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

metaphase I

A 
meiosis I
homologous pairs (tetrads) align at the metaphase plate and each pair attaches to a separate spindle fiber by its kinetochore (only ONE spindle fiber per pair of sister chromatids)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

anaphase I

A

meiosis I

homologous pairs separate and are pulled to opposite poles of the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

disjunction

A

accounts of Mendel’s first law (of segregation)
each chromosome of paternal origin separates from its homologue of maternal origin and either chromosome can end up in either daughter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

segregation

A

separating of the two homologous chromosomes

distribution to the two intermediate daughter cells is random with respect to parental origin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

telophase I

A

meiosis I
nuclear membrane forms around each new nucleus
each chromosome still consists of two sister chromatids joined at the centromere
cells are now haploid; once homologous chromosomes separate, only n chromosomes are found in each daughter cell (23 in humans)
cell divides into two daughter cells by cytokinesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

interkinesis

A

between cell divisions, there may be a short rest period during which the chromosomes partially uncoil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

meiosis II

A

very similar to mitosis in that sister chromatids, rather than homologues, are separated from each other
by completion, up to four haploid daughter cells produced per gametocyte (oogenesis an exception)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

prophase II

A

meiosis II

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

metaphase II

A

meiosis II

chromosomes line up on metaphase plate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

anaphase II

A

meiosis II
centromeres divide, separating chromosomes into sister chromatids
pulled to opposite poles by spindle fibers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

telophase II

A

meiosis II
nuclear membrane forms around each new nucleus
cytokinesis follows, and two daughter cells are formed

50
Q

X chromosome

A

carries sizable amount of genetic information

51
Q

sex-linked disorders

A

cause by mutations in genes of X chromosome
most are inherited recessively
females express them far less frequently than males

52
Q

hemizygous

A

males with respect to many of the genes on the X chromosome because they only have one copy

53
Q

carriers

A

females carrying a diseased allele on an X-chromosome, but not exhibiting the disease

54
Q

Y chromosome

A

contains very little genetic information

in its absence, all zygotes will be female, but in its presence a zygote will be male

55
Q

SRY (sex-determining region Y)

A

notable gene on Y chromosome

codes for a transcription factor that initiates testis differentiation and thus the formation of male gonads

56
Q

testes

A

primitive gonads develop into these
have two functional components: seminiferous tubules and interstitial cells (of Leydig)
located in scrotum

57
Q

sperm

A

produced in the highly coiled seminiferous tubules, nourished by Sertoli cells

58
Q

testosterone

A

secreted by cells of Leydig, which also secrete other male sex hormones (androgens)

59
Q

scrotum

A

external pouch that hangs below the penis and maintains a temperature 2˚ to 4˚C lower than the body

60
Q

epididymis

A

where flagella of sperm gain motility

stored until ejaculation

61
Q

ejaculation

A

sperm travel through the vas deferens to the ejaculatory duct at the posterior edge of the prostate gland

62
Q

urethra

A

formed from the fusion of the two ejaculatory ducts, carries sperm through the penis as they exit the body (reproductive and urinary systems share a common pathway)

63
Q

seminal fluid

A

mixed with sperm as they pass through the reproductive tract

produced through a combined effort by the seminal vesicles, prostate gland, and bulbourethral gland

64
Q

seminal vesicles

A

combine fructose to nourish sperm, give the seminal fluid mildly alkaline properties so the sperm will be able to survive in the relative acidity of the female reproductive tract

65
Q

prostate gland

A

gives the seminal fluid mildly alkaline properties so the sperm will be able to survive in the relative acidity of the female reproductive tract

66
Q

bulbourethral (Cowper’s) glands

A

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

67
Q

semen

A

the combination of sperm and seminal fluid

68
Q

spermatogenesis

A

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

69
Q

spermatogonia

A

diploid stem cells in males

70
Q

primary spermatocytes

A

after replicating their genetic material (S stage) spermatogonia develop into these

71
Q

secondary spermatocytes

A

first meiotic division of primary spermatocytes, results in haploid cells

72
Q

spermatids

A

secondary spermatocytes undergo meiosis II to generate these haploid cells

73
Q

spermatozoa

A

after spermatids undergo maturation

74
Q

midpiece

A

sperm
filled with mitochondria, which generate the energy to be used as the sperm swims through the female reproductive tract to reach the ovum in the fallopian tubes

75
Q

acrosome

A

cap that covers each sperm head

derived from the Golgi apparatus and is necessary to penetrate the ovum

76
Q

ovaries

A

female gonads
produce estrogen and progesterone
located in the pelvic cavity
each consists of thousands of follicles

77
Q

follicles

A

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

78
Q

peritoneal sac

A

lines the abdominal cavity

through which one egg per month is ovulated

79
Q

fallopian tube (oviduct)

A

lined with cilia to propel the egg forward

connected to the uterus

80
Q

uterus

A

muscular

site of fetal development

81
Q

cervix

A

lower end of the uterus

connects to the vaginal canal

82
Q

vaginal canal

A

where sperm are deposited during intercourse

also passageway through which childbirth occurs

83
Q

vulva

A

external female anatomy known collectively

84
Q

ovaries

A

female gonads
produce estrogen and progesterone
located in the pelvic cavity
each consists of thousands of follicles

85
Q

follicles

A

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

86
Q

primary oocytes

A

once oogonia undergo DNA replication (happens by birth)

cells are 2n and are arrested in prophase I

87
Q

fallopian tube (oviduct)

A

lined with cilia to propel the egg forward

connected to the uterus

88
Q

uterus

A

muscular

site of fetal development

89
Q

cervix

A

lower end of the uterus

connects to the vaginal canal

90
Q

vaginal canal

A

where sperm are deposited during intercourse

also passageway through which childbirth occurs

91
Q

vulva

A

external female anatomy known collectively

92
Q

oogenesis

A

production of female gametes

93
Q

zygote

A

2n

produce upon completion of meiosis II where haploid pronuclei of the sperm and ovum join

94
Q

primary oocytes

A

once oogonia undergo DNA replication (happens by birth)

95
Q

menarche

A

first menstrual cycle

begins the process of one primary oocyte completing meiosis I per month

96
Q

secondary oocyte

A

completion of meiosis I by primary oocyte produces this and a polar body
division characterized by unequal cytokinesis
remains arrested in metaphase II and does not complete the remainder of meiosis II unless fertilization occurs

97
Q

polar body

A

gets very little cytokinesis at the end of meiosis I

generally does not divide further and will never produce functional gametes

98
Q

zona pellucida

A

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

99
Q

corona radiata

A

lies outside the zone pellucida and is a layer of cells that adhered to the oocyte during ovulation

100
Q

estrogens

A

secreted in response to FSH
result in development and maintenance of the female reproductive system and female secondary sexual characteristics (breast growth, widening of the hips, changes in fat distribution)
in embryo, stimulate development of the reproductive tract
in adults, lead to thinking of lining of uterus each month in preparation for implantation of a zygote

101
Q

zygote

A

2n

produce upon completion of meiosis II where haploid pronuclei of the sperm and ovum join

102
Q

hypothalamus

A

prior to puberty, restricts production of GnRH

at start of puberty, restriction is lifted–releases pulses of GnRH

103
Q

gonadotropin-releasing hormone (GnRH)

A

released by hypothalamus

triggers the anterior pituitary gland to synthesize and release FSH and LH

104
Q

follicular phase

A

begins when menstrual flow begins
GnRH secretion from the hypothalamus increases in response to the decreased concentrations of estrogen and progesterone, which fall off toward the end of each cycle
higher concentrations of GnRH cause increased secretions of both FSH and LH
work in concert to develop several ovarian follicles
begin to produce estrogen, which has negative feedback effects and causes the GnRH, LH, and FSH concentrations level off
estrogen works to regrow the endometrial lining, stimulating vascularization and glandularization of the decidua
late in phase, developing follicles secrete higher and higher concentrations of estrogen

105
Q

ovulation phase

A

estrogen concentrations reach a threshold that paradoxically results in positive feedback, and GnRH, LH, and FSH levels spike
surge in LH induces the release of the ovum from the ovary into the abdominal (peritoneal) cavity

106
Q

testosterone

A

produced by the testes
dramatically increases during puberty, sperm production begins
not only develops and maintains the male reproductive system but also results in the development of secondary sexual characteristics
production remains high through adulthood and declines as men age
exerts negative feedback on hypothalamus and anterior pituitary so that production is limited to appropriate levels

107
Q

secondary sexual characteristics

A

i.e. facial and axillary hair, deepening of voice, and changes in growth patterns

108
Q

estrogens

A

secreted in response to FSH
result in development and maintenance of the female reproductive system and female secondary sexual characteristics (breast growth, widening of the hips, changes in fat distribution)
in embryo, stimulate development of the reproductive tract
in adults, lead to thinking of lining of uterus each month in preparation for implantation of a zygote

109
Q

progesterone

A

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

110
Q

corpus luteum

A

remnant follicle that remains after ovulation

secretes progesterone in response to LH

111
Q

menstrual cycle

A

menarche to menopause
cyclic pattern of estrogen and progesterone levels rising and falling
in response, endometrial lining will grow and be shed
can be divided into four events: follicular phase, ovulation, the luteal phase, and menstruation

112
Q

ovulation

A

estrogen concentrations reach a threshold that paradoxically results in positive feedback, and GnRH, LH, and FSH levels spike
surge in LH induces the release of the ovum from the ovary into the abdominal (peritoneal) cavity

113
Q

luteal phase

A

after ovulation, LH causes ruptured follicle to form the corpus luteum with secretes progesterone
maintains uterine lining for implantation
progesterone levels begin to rise while estrogen levels remain high
high levels of progesterone again cause negative feedback on GnRH, FSH, and LH, preventing the ovulation of multiple eggs

114
Q

menstruation phase

A

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

115
Q

human chorionic gonadotropin (hCG)

A

if fertilization has occurred, resulting zygote will develop into a blastocyst that will implant in uterine lining and secrete this hormone
analog of LH, looks very similar chemically and can stimulate LH receptors
maintains corpus luteum
critical during first trimester development because it is the estrogen and progesterone secreted by the corpus luteum that keep the uterine lining in place
by second trimester, levels decline because placenta has grown to a sufficient size to secrete progesterone and estrogen by itself

116
Q

menopause

A

as a woman ages, ovaries become less sensitive to FSH and LH, resulting in ovarian atrophy
as estrogen and progesterone levels drop, endometrium atrophies and menstruation stops
because negative feedback on FSH and LH is removed, blood levels of these rise
accompanied by profound physical and physiological changes (flushing, hot flashes, bloating, headaches, and irritability)
occurs between the ages of 45-55

117
Q

luteal phase

A

after ovulation, LH causes ruptured follicle to form the corpus luteum with secretes progesterone
maintains uterine lining for implantation
progesterone levels begin to rise while estrogen levels remain high
high levels of progesterone again cause negative feedback on GnRH, FSH, and LH, preventing the ovulation of multiple eggs

118
Q

menstruation phase

A

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

119
Q

human chorionic gonadotropin (hCG)

A

if fertilization has occurred, resulting zygote will develop into a blastocyst that will implant in uterine lining and secrete this hormone
analog of LH, looks very similar chemically and can stimulate LH receptors
maintains corpus luteum
critical during first trimester development because it is the estrogen and progesterone secreted by the corpus luteum that keep the uterine lining in place
by second trimester, levels decline because placenta has grown to a sufficient size to secrete progesterone and estrogen by itself

120
Q

menopause

A

as a woman ages, ovaries become less sensitive to FSH and LH, resulting in ovarian atrophy
as estrogen and progesterone levels drop, endometrium atrophies and menstruation stops
because negative feedback on FSH and LH is removed, blood levels of these rise
accompanied by profound physical and physiological changes (flushing, hot flashes, bloating, headaches, and irritability)
occurs between the ages of 45-55

MCAT 2015 (66 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions