Biology Ch. 2 Flashcards
(115 cards)
1
Q
List the four stages of the cell cycle
A
1) G1
2) S
3) G2
4) M
2
Q
Interphase includes what stage(s)?
A
G1, S, G2
3
Q
____ is the longest stage of the cell cycle
A
Interphase
4
Q
Describe the events of interphase
A
The cell grows, replicates its chromosomes, and prepares for cell division
5
Q
Describe the events of G0
A
Cells aren’t dividing or preparing for division
6
Q
Describe the events of G1.
A
Pre-synthetic gap: cells create organelles for energy and protein production and increase in sizee
7
Q
Describe the events of S
A
Synthesis of DNA: cells replicated genetic material, forming 2 identical chromatids
8
Q
The passage from the G1 to S phase is governed by ___
A
the restriction point
9
Q
Define chromosome
A
2 definitions: a single stranded chromatid before S phase or pair of chromatids attached by centromere after S
10
Q
Describe the events of G2
A
Post synthetic gap: cell s pass through checkpoints to ensure there are enough organelles and cytoplasm for 2 daughter cells and ensures DNA replication does not have errors
11
Q
Cells entering ___ have twice as much DNA as cells in G1
A
G2
12
Q
Cells in G2 have ___ chromosomes
A
46
13
Q
Cells in G1 have ___ chromosomes
A
23
14
Q
Describe the events of M
A
Mitosis: mitosis and cytokinesis
15
Q
List the 4 phases of mitosis
A
1) prophase
2) metaphase
3) anaphase
4) telophase
16
Q
Describe the events of prophase
A
1) chromatin condenses into chromosomes
2) centriole pairs separate to opposite poles
3) nuclear envelope dissolves
4) nuclei disappears or diminishes
17
Q
Centrioles are located ____
A
Outside of the nucleus at the centrosome
18
Q
___ form spindle fibers
A
Centriole pairs
19
Q
Define aster
A
Microtubule that radiates toward the middle of the cell and anchors centrioles to the membrane of the cell during cell division
20
Q
Spindle fibers are made of ____
A
Microtubules
21
Q
List the two microtubule organizing centers of the human body
A
Centrosome and basal body of cilia/flagella
22
Q
Describe the events of metaphase
A
Kinetochore fibers interact with fibers of spindle apparatus to align chromosomes at metaphase plate
23
Q
Describe the events of anaphase
A
1) Centromeres split so each chromatid has own distinct centromere
2) Sister chromatids separate and pulled to opposite sides of cell by shortening kinetochores
24
Q
Describe the events of telophase and cytokinesis
A
1) Spindle apparatus disappears
2) Nuclear membrane reforms around each set of chromosomes
3) Nucleoli reappear
4) Chromosomes uncoil
5) Cytoplasm and organelles separate
25
The cell cycle is controlled by ___ and ____
G1/S and G2/M checkpoints
26
Describe the events of the G1/S restriction point
The cell determines if DNA is good enough for synthesis. If DNA damaged, cell goes into arrest until DNA is repaired
27
What is the main control protein of the G1/S restriction point?
p53
28
What is the gene that produces p53
TP53
29
Mutations in gene TP53 can cause ___
cancer
30
What happens if there's a mutation in TP53? describe the events
The cell cycle doesn’t stop to repair damaged DNA, causing cancer
31
Describe the events of the G2/M restriction point
ensures the cell is the correct size and has organelles replicated for 2 daughter cells
32
List the molecule(s) responsible for the cell cycle
1) cyclin-dependent kinase (CDK)
| 2) cyclins
33
Cyclin-dependent kinases are activate by ___
certain cyclins
34
The cyclin-CDK complex phosphorylate _____, which promotes ____________
transcription factors; the transcription of genes needed for next stage of cell cycle
35
_____ promotes the transcription of genes needed for next stage of cell cycle
cyclin-CDK complex
36
Describe the function(s) of cyclin
Bind to and activate CDK
37
____ is reductional division
Meiosis I
38
Meiosis I results in ____
homologous chromosomes separated to form haploid daughter cells
39
Describe the events of prophase I
1) Chromatin condenses into chromosomes and spindle apparatus forms
2) homologous chromosomes intertwine
40
During meiosis I, each synaptic pair has ___ chromatids, forming ___
4; tetrad
41
During prophase I, homologous chromosomes are held together by ____
synaptonemal complex
42
Crossing over is what and occurs where?
Homologous chromosomes may break and exchange DNA; at the chiasma
43
Describe Mendel's 2nd law of independent assortment
Inheritance of 1 allele doesn’t impact inheritance of other alleles
44
Describe the events of metaphase I
Tetrads align at metaphase plate and each pair attaches to separate spindle fiber by kinetochore
45
Describe the events of anaphase I
Homologous pairs separate and pull to opposite poles of cell: disjunction
46
Define disjunction
Homologous pairs separate and pull to opposite poles of cell during anaphase I
47
Describe Mendel's 1st law of segregation
Distribution of homologous chromosomes to daughter cells is random (can come from dad or mom)
48
What phase/events demonstrates Mendel's 1st law of segregation?
Disjunction, occurring during anaphase I
49
Describe the events of telophase I
1) Nuclear membrane forms around new nucleus
2) Chromosomes are still 2 sister chromatids
3) Haploid daughter cells formed via cytokinesis
4) Chromosomes partially uncoil during interkenisis
50
Define interkinesis
rest period between divisions where chromosomes partially uncoil
51
Meiosis II is ___ and results in ____
equational division; results in separation of sister chromatids without change in ploidy
52
Describe the events of prophase II
Nuclear envelope dissolves, nucleoli disappear, centrioles migrate to opposite poles, spindle apparatus forms
53
Describe the events of metaphase II
Chromosomes line up at metaphase plate
54
Describe the events of anaphase II
1) Centromeres divide, separating chromosomes into sister chromatids
2) Chromatids pulled to opposite poles by spindle fibers
55
Describe the events of telophase II
1) Nuclear membrane forms around new nucleus
| 2) Cytokinesis forms ~4 haploid daughter cells
56
what and where is the SRY gene located
Sex-determining region found on Y chromosome
57
What is the function of the SRY gene?
Codes for transcription factor that initiates testis differentiation
58
List the sperm pathway
SEVE UP:
1) Seminiferous tubules
2) Epididymis
3) Vas deferens/ductus deferens
4) Ejaculatory duct
5) Urethra
6) Penis
59
Sperm is produced in ____ and nourished by ____
seminiferous tubules; Sertoli cells
60
Sperm flagella gain motility in _____
the epididymis
61
Sperm is stored in the ____ until ejaculation
epididymis
62
Seminal fluid is produced by _______
seminal vesicles, prostate gland, and bulbourethral gland
63
____ provide fructose to nourish sperm
Seminal vesicles
64
_____ give seminal fluid alkaline properties
The prostate gland and seminal vesicles
65
______ produce fluid to clean out urine and lubricate urethra during arousal
The bulbourethral glands
66
___ + ___ = semen
Sperm + seminal fluid
67
Leydig cells secrete ______
testosterone and other androgens
68
How is the optimal temperature for sperm development maintained?
By the testes: a layer of muscle around vas deferens raises and lowers testis to regulate temperature
69
Define spermatogenesis
formation of haploid sperm via meiosis
70
Where does spermatogenesis occur?
In the seminiferous tubules
71
Define spermatogonia
Diploid stem cells
72
The primary spermatocytes are ____
diploid
73
Meiosis ___ produces haploid secondary spermatocytes
I
74
Haploid spermatids are produced during meiosis ____
II
75
Spermatids mature into ___
Spermatozoa
76
1 spermatogonium produce ___ sperm
4
77
Provide a rough overview of sperm differentiation, including mitotic/meiotic phases
2n spermatogonium --> mitosis --> 2n primary spermatocyte --> meiosis I --> 1n secondary spermatocyte --> meiosis II --> 4 1n spermatids --> spermatid mature into spermatozoa
78
Ovaries produce ___ and ____
Estrogen and progesterone
79
Ovum is ovulated into __ and down ___
Peritoneal sac; the fallopian tube
80
The fallopian tube is lined with ___ to propel the ova
Cilia
81
Define oogenesis
Production of female oogonia
82
All female oogonia are formed during:
a) fetal development
b) conception
c) puberty
d) menopause
A
83
```
All oogonia have developed into primary oocytes by:
A) conception
B) fetal development
C) birth
D) puberty
```
C
84
Primary oocytes are ___ (haploid/diploid)
Diploid
85
Primary oocytes are arrested in ___ until first menarche
Prophase I
86
Primary oocytes undergo ___ to produce secondary oocytes
Meiosis I
87
After meiosis I, a primary oocyte will produce ___ and ___
Secondary oocyte and polar body
88
The secondary oocyte is arrested in ___ and only completes ___ if fertilized
metaphase II; meiosis II
89
Define zona pellucida, it's structure, and function
An acellular mix of glycoproteins that surround and protect the oocyte and help with sperm binding
90
Define the corona radiata, it's function, and structure
A layer of cells adhered to the oocyte during ovulation
91
Meiosis II is triggered a sperm penetrates the layers of the ___
Corona radiata
92
After completing meiosis II, a secondary oocyte produces ___ and ___
Zygote and second polar body
93
Polar bodies are (diploid/haploid)
Haploid
94
Sexual development is controlled by
gonadotropin-releasing hormone (GnRH
95
GnRH is limited before ____
Puberty
96
Describe the function and mechanisms of GnRH
triggers anterior pituitary to synthesize and release follicle stimulating hormone (FSH) and luteinizing hormone (LH)
97
Y chromosome leads to production of ____ which results in male sexual differentiation during fetal development
androgens
98
Androgen production in men increases at ____
Puberty
99
Describe the function of FSH in men
Stimulates Sertoli cells and triggers sperm maturation
100
Describe the function of LH in men
Causes interstitial cells to produce testosterone
101
How does testosterone work with the hypothalamus and anterior pituitary?
Exerts negative feedback
102
Women produce ___ and ___ in response to FSH and LH
Estrogen; progesterone
103
Progesterone is secreted by ___ in women in response to ____
Corpus luteum; LH
104
Define corpus luteum
remnants of ovarian follicles after ovulation
105
Estrogen is secreted in response to ___ in women
FSH
106
After conception and the first trimester, progesterone is secreted by ____
The placenta
107
List the three phases of the menstrual cycle
1) follicular phase
2) ovulation phase
3) luteal phase
108
Describe the events of the follicular phase
Menstrual flow;
1) GnRH secreted from hypothalamus increases due to decreased estrogen and progesterone levels
2) GnRH increase increases secretions of LH and FSH, which develop ovarian follicles
3) Follicles produce estrogen to negatively feedback on GnRH, LH, and FSH
4) Toward end of phase, estrogen levels result in positive feedback of GnRH, LH, and FSH (this will cause ovulation)
109
Describe the events of the ovulation phase
Ovulation triggered by LH in response to high estrogen levels
110
Describe the events of the luteal phase
1) Ruptured follicle forms corpus luteum
2) Corpus luteum releases progesterone in response to LH
3) Progesterone feeds back negatively on LH, GnRH, and FSH to prevent ovulation of multiple eggs
111
A blastocyst secretes ____
Human chorionic gonadotropin (hCG)
112
Describe the function of hCG
Maintains corpus luteum to maintain estrogen and progesterone levels
113
hCG levels decline during the ____
second trimester, when the placenta begins to secrete its own estrogen and progesterone
114
What causes menopause?
As ovaries become less sensitive to FSH and LH over times, this causes ovarian atrophy, reduced progesterone and estrogen levels, endometrial deterioration, and eventually menopause
115
Crossing over/recombination occurs:
A) During prophase 1
B) During prophase 2
C) During both prophase 1 and 2
D) During neither prophase 1 and 2
A
