Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Biology > Chapter 2: Reproduction > Flashcards

Chapter 2: Reproduction Flashcards

(83 cards)

Start Studying
1
Q

diploid (2n)

A

Autosomal cells
Contain 2 copies of each chromosome
46 in humans

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

haploid (n)

A

Germ cells
Contain 1 copy of each chromosome
23 in humans

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

cell cycle

A

The cycle in which eukaryotic cells replicate
Specific series of phases during which a cell grows, synthesizes DNA, and divides
Derangements may lead to unchecked cell division and cancer
Consists of 4 stages: G1–>S–>G2–>M
Cells that do not divide spend their time in G0
***CELLS UNDERGO FINITE NUMBER OF DIVISIONS BEFORE PROGRAMMED DEATH

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

interphase

A

First three stages of cell cycle (G1, S, and G2)
Individual chromosomes are not visible with light microscopy, but in condensed chromatin form
DNA must 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
5
Q

G0 stage

A

Offshoot of G1 phase

Cell is not preparing for division, but simply living

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

chromatin

A

Less condensed form that individual chromosomes take during interphase
DNA must 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

Presynthetic gap
Cells create organelles for energy and protein production while increasing their size
Passage into S stage governed by restriction point
Main protein in charge of this is p53

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

restriction point

A

passage into S stage from G1 stage governed by certain criteria, such as proper complement of DNA

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

S stage

A

Synthesis of DNA
Cell replicates genetic material so each daughter cell will have identical copies
After replication each chromosome consists of 2 chromatids bound together at centromere
Cells entering G2 have twice as much DNA as the cells in G1
Humans in S stage have 46 chromosomes even though 92 chromatids are present

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

G2 stage

A

Postsynthetic Gap
Cell passes through another quality control checkpoint to ensure there are enough organelles and cytoplasm for two daughter cells and checks for errors
Checkpoint also moderated by p53

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

M stage

A

Mitosis + Cytokinesis
Mitosis: prophase, metaphase, anaphase, and telophase
Cytokinesis: splitting of cytoplasm and organelles into daughter cells

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

cyclin-dependent kinases (CDK’s)

A

Molecules responsible for the cell cycle (along with cyclins)
CDK’s require presence of right cyclins
Concentrations of various cyclins increase and decrease during specific stages, which bind to CDK’s, creating activated CDK-activated complex
This complex can then phosphorylate transcription factors

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

transcription factors

A

promote transcription of genes required for the next stage of the cell cycle after it’s phosphorylated by CDK-cyclin complexes

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

mitosis

A

Process by which 2 identical daughter cells are created from a single cell
One round of replication, one round of division
2 stages: prophase, metaphase, anaphase, telophase
Occurs in somatic cells (not involved in sexual reproduction)

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

somatic cells

A

Not involved in sexual reproduction

Divide by mitosis

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

prophase

A

First stage in mitosis
KEY CONCEPTS: CHROMOSOMES CONDENSE, SPINDLE FORMS
1. Condense chromatin into chromosomes, centriole pairs separate and move towards opposite poles of cells (responsible for correct division of DNA)
2. Centrioles begin to form spindle fibers, which are made of microtubles
3. Nuclear membrane dissolves, kinetochores appear
4. Nucleoli become less distinct
2n (2 chromosomes–4 sister chromatids paired)

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

kinetochore

A

Protein structures located on the centromeres that serve as attachment points for specific fibers of the spindle apparatus called kinetochore fibers
Appear at the centromere during prophase

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

metaphase

A

Second stage in mitosis
KEY CONCEPTS: CHROMOSOMES ALIGN
1. Centriole pairs are now at opposite ends of cell, and kinetochore fibers interact with TWO fibers of spindle apparatus to align the chromosomes at the metaphase plate, which is equidistant between the two poles of the cell
2n (2 copies of chromosome, 4 chromatids paired)

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

kinetochore fibers

A

Specific fibers of the of the spindle apparatus that attach at the kinetochore during prophase
Align the chromosomes at the metaphase plate during metaphase
Pull sister chromatids apart during anaphase

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

anaphase

A

Third stage in mitosis
KEY CONCEPTS: SISTER CHROMATIDS SEPARATE
Centromeres split so each chromatid has its own distinct centromere, thus allowing sister centromeres to separate
4n (4 copies of chromosome)

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

telophase

A

Fourth stage in mitosis
KEY CONCEPTS: NEW NUCLEAR MEMBRANES FORM
Essentially a reverse of prophase
1. Spindle apparatus disappears
2. Nuclear membrane reforms around each set of chromosomes, nucleoli reappear
3. Chromosomes uncoil, resuming interphase form
4n (4 copies of chromosome)

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

cytokinesis

A

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

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

meiosis

A

Occurs in gametocytes (germ cells) and results in up to 4 nonidentical sex cells (gametes)
One round of replication followed by 2 rounds of division
Number of chromosomes is halved; each daughter cell has 23 chromosomes
Occurs only in sex cells

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

meiosis I

A

Homologous chromosomes being separated, generating haploid daughter cells
AKA reductional division
2n–>n

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
meiosis II
Similar to mitosis Separation of sister chromatids AKA equational division
26
homologous pairs
23 in total in human genome Each contains one chromosome inherited from each parent 15 maternal and 15 paternal Similar but not identical After S phase, 92 chromatids organized into 46 chromosomes
27
sister chromatids
identical strands of DNA connected at the centromere
28
prophase I
First stage of meiosis 1. Chromatin condenses into chromosomes 2. Spindle apparatus forms 3. Nucleoli and nuclear membrane disappear 4. Homologous chromosomes come together and intertwine in synapsis, resulting in crossing over
29
centromere
``` Holds two chromatids together Contain kinetochores (attachment point for spindle fibers) ```
30
synapsis
Occurs during prophase I; homologous chromosomes come together and form a tetrad May break at point of synapsis (chiasma) and cross over, exchanging pieces of DNA
31
chiasma
Point of synapsis and crossing over
32
genetic recombination
When chromosomes exchange pieces of DNA during crossing over Increases variety of genetic combinations that can be produced via gametogenesis if unlinks linked genes Linkage: tendency for genes to be inherited together
33
Mendel's second law (of independent assortment)
States that inheritance of one allele has no effect on the likelihood of inheriting certain alleles for other genes
34
metaphase I
1. Tetrads align at metaphase plate and each pair is attached to ONE spindle fiber by its kinetochore
35
anaphase I
Homologous pairs separate and are pulled to opposite poles (disjunction and segregation)
36
disjunction
Occurs during anaphase I Homologous pairs are disjointed (from tetrad); maternal chromosome goes one way, paternal goes the other Accounts for Mendel's first law (of segregation)
37
Mendel's first law (of segregation)
Caused by disjunction | Each paternal chromosome is separated from maternal chromosome and either chromosome can end up in either daughter cell
38
telophase I
Nuclear membrane forms around each new nucleus Each chromosome still consists of two sister chromatids Cell is now haploid
39
mitosis II
Similar to mitosis Sister chromatids, as opposed to homologues, are separated from each other No change in ploidy; haploid to start, haploid to finish (n-->n)
40
prophase II
Nuclear envelope dissolves Nucleoli disappear Centrioles migrate to opposite poles Spindle apparatus begins to form
41
metaphase II
Chromosomes line up on metaphase plate
42
anaphase II
``` Centromeres divide, separating chromosomes into two sister chromatids Spindle fibers (2) attach to kinetochores and begin to pull apart sister chromatids from each other to opposite poles ```
43
telophase II
Nuclear membrane forms around each new nucleus Cytokinesis follows Up to four haploid daughter cells produced
44
sex
Determined by 23rd pair of chromosomes | XX-female, XY-male
45
sex-linked
x-chromosome linked
46
hemizygous
Possessing only one copy of the X chromosome (males)
47
Y chromosome
Contains very little genetic information Notable region: SRY (sex-determining region Y)-formation of male gonads Absence of Y=female zygotes Presence of Y=male zygotes
48
SRY
Sex-determining region Y Notable region on Y chromosome Codes for a transcription factor that initiates testis differentiation and, thus, formation of male gonads
49
testes
Males: what primitive gonads develop into | Two functional components: seminiferous tubules and interstitial cells
50
seminiferous tubules
In testes Sperm are produced here Highly coiled Nourished by Sertoli cells
51
Sertoli cells
Nourish sperm in testes | Specifically, in seminiferous tubules, where they (sperm) are produced
52
cells of Leydig
In testes | Secrete testosterone and other male sex hormones (androgens)
53
androgens
male sex hormones (other)
54
scrotum
External pouch that contains the testes Maintains temp 2-4 degrees C below body temp Layer of muscle around vas deferens that can raise and lower the testis to maintain proper temp for sperm development
55
epididymis
Sperm gaim motility and stored until ejaculation
56
ejaculation
Sperm travel from epididymis (where they were stored) to vas deferens-->ejaculatory duct-->urethra-->penis
57
semen
combination of sperm and seminal fluid
58
spermatogenesis
Formation of haploid sperm through meiosis Occurs in the seminiferous tubules spermatogonia-->primary spermatocytes-->secondary spermatocytes-->spermatids-->spermatozoa Results in four functional sperm for each spermatogonium
59
spermatogonia
Diploid stem cells in males Replicate genetic material during S stage, then become diploid primary spermatocytes Four functional sperm for each spermatogonium after spermatogenesis
60
primary spermatocytes
Diploid What spermatogonia develop into after S stage (replication) Develop into haploid secondary spermatocytes after first meiotic division
61
secondary spermatocytes
Haploid What primary spermatocytes develop into after first meiotic division Develop into spermatids after meiosis II
62
spermatids
Haploid What secondary spermatocytes develop into after meiosis II Develop into spermatozoa after maturation
63
spermatozoa
Mature spermatids
64
sperm head
Contains the genetic material | Covered by acrosome (cap)
65
sperm midpiece
FIlled with mitochondria, which generates energy to be used as the sperm swims through the female reproductive tract Generates ATP from fructose
66
acrosome
Covers sperm head | Derived from Golgi apparatus and needed to penetrate the ovum
67
sperm
Head (genetic material) + midpiece (energy via ATP from fructose) + tail (motility)
68
ovaries
Female gonads | Produce estrogen and progesterone
69
primary oocyte
Arrested in prophase I Once a woman reaches menarche, each primary oocyte per month will complete meiosis I, producing a secondary oocyte and a polar body Characterized by unequal cytokinesis, which doles out almost all cytoplasm to secondary oocyte and none to polar body
70
secondary oocyte
Arrested in metaphase II and does not complete meiosis II unless fertilization occurs
71
zygote
Haploid pronuclei of sperm + ovum=diploid cell
72
gonadotropin-releasing hormone (GnRH)
Release is restricted by hypothalamus prior to puberty Restriction lifted after puberty GnRH triggers anterior pituitary to synthesize and release
73
oogenesis
No unending supply of stem cells like in males | By birth, all of the oocytes have already undergone DNA replication and are already considered primary oocytes
74
testosterone
Produced by testes | Increases dramatically during puberty
75
FSH (follicle stimulating hormone)
Produced and released by anterior pituitary Stimulates Sertoli cells and triggers sperm maturation Causes the secretion of estrogen from ovaries
76
anterior pituitary
Synthesizes and releases FSH and LH in response to GnRH production by hypothalamus
77
LH (luteinizing hormone)
Produced and released by anterior pituitary Causes interstitial cells to produce testosterone Causes secretion of progesterone by corpus luteum (remnant follicle that remains after ovulation)
78
estrogen
Secreted from ovaries in response to FSH | Involved in initial thickening of endometrium (lining of uterus) in preparation of implantation of zygote
79
progesterone
Secreted by corpus luteum in response to LH Involved in development and maintenance of endometrium After first trimester of pregnancy, progesterone is supplied by placenta and corpus luteum atrophies
80
follicular phase
Begins with menstrual flow (beginning of uterine lining shedding) GnRH from hypothalamus increases in response to decreased concentrations of estrogen and progesterone, FSH and LH increase, which develop ovarian follicles Follicles produce estrogen GnRH, LH, FSH level off b/c of estrogen negative feedback Estrogens starts to regrow endometrial lining
81
ovulation
Late in follicular phase, estrogen levels reach a level so high it paradoxically causes a spike in GnRH, LH, and FSH LH spike causes release of ovum from ovary
82
luteal phase
LH causes ruptured follicle to form corpus luteum Corpus luteum releases progesterone Progesterone levels rise and maintain uterine lining Estrogen levels remain high
83
hCG
Analog of LH Secreted when zygote implants in uterine lining Critical during first semester because progesterone and estrogen keep lining in place High levels of progesterone and estrogen form a block on GnRH

Biology (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions