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MCAT > Biology Ch. 2 > Flashcards

Biology Ch. 2 Flashcards

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MCAT flashcards
1
Q

List the four stages of the cell cycle

A

1) G1
2) S
3) G2
4) M

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2
Q

Interphase includes what stage(s)?

A

G1, S, G2

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3
Q

____ is the longest stage of the cell cycle

A

Interphase

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4
Q

Describe the events of interphase

A

The cell grows, replicates its chromosomes, and prepares for cell division

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5
Q

Describe the events of G0

A

Cells aren’t dividing or preparing for division

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6
Q

Describe the events of G1.

A

Pre-synthetic gap: cells create organelles for energy and protein production and increase in sizee

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7
Q

Describe the events of S

A

Synthesis of DNA: cells replicated genetic material, forming 2 identical chromatids

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8
Q

The passage from the G1 to S phase is governed by ___

A

the restriction point

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9
Q

Define chromosome

A

2 definitions: a single stranded chromatid before S phase or pair of chromatids attached by centromere after S

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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

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11
Q

Cells entering ___ have twice as much DNA as cells in G1

A

G2

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12
Q

Cells in G2 have ___ chromosomes

A

46

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13
Q

Cells in G1 have ___ chromosomes

A

23

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14
Q

Describe the events of M

A

Mitosis: mitosis and cytokinesis

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15
Q

List the 4 phases of mitosis

A

1) prophase
2) metaphase
3) anaphase
4) telophase

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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

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17
Q

Centrioles are located ____

A

Outside of the nucleus at the centrosome

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18
Q

___ form spindle fibers

A

Centriole pairs

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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

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20
Q

Spindle fibers are made of ____

A

Microtubules

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21
Q

List the two microtubule organizing centers of the human body

A

Centrosome and basal body of cilia/flagella

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22
Q

Describe the events of metaphase

A

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

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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

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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

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25
Q

The cell cycle is controlled by ___ and ____

A

G1/S and G2/M checkpoints

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26
Q

Describe the events of the G1/S restriction point

A

The cell determines if DNA is good enough for synthesis. If DNA damaged, cell goes into arrest until DNA is repaired

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27
Q

What is the main control protein of the G1/S restriction point?

A

p53

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28
Q

What is the gene that produces p53

A

TP53

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29
Q

Mutations in gene TP53 can cause ___

A

cancer

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30
Q

What happens if there’s a mutation in TP53? describe the events

A

The cell cycle doesn’t stop to repair damaged DNA, causing cancer

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31
Q

Describe the events of the G2/M restriction point

A

ensures the cell is the correct size and has organelles replicated for 2 daughter cells

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32
Q

List the molecule(s) responsible for the cell cycle

A

1) cyclin-dependent kinase (CDK)

2) cyclins

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33
Q

Cyclin-dependent kinases are activate by ___

A

certain cyclins

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34
Q

The cyclin-CDK complex phosphorylate _____, which promotes ____________

A

transcription factors; the transcription of genes needed for next stage of cell cycle

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35
Q

_____ promotes the transcription of genes needed for next stage of cell cycle

A

cyclin-CDK complex

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36
Q

Describe the function(s) of cyclin

A

Bind to and activate CDK

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37
Q

____ is reductional division

A

Meiosis I

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38
Q

Meiosis I results in ____

A

homologous chromosomes separated to form haploid daughter cells

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39
Q

Describe the events of prophase I

A

1) Chromatin condenses into chromosomes and spindle apparatus forms
2) homologous chromosomes intertwine

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40
Q

During meiosis I, each synaptic pair has ___ chromatids, forming ___

A

4; tetrad

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41
Q

During prophase I, homologous chromosomes are held together by ____

A

synaptonemal complex

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42
Q

Crossing over is what and occurs where?

A

Homologous chromosomes may break and exchange DNA; at the chiasma

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43
Q

Describe Mendel’s 2nd law of independent assortment

A

Inheritance of 1 allele doesn’t impact inheritance of other alleles

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44
Q

Describe the events of metaphase I

A

Tetrads align at metaphase plate and each pair attaches to separate spindle fiber by kinetochore

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45
Q

Describe the events of anaphase I

A

Homologous pairs separate and pull to opposite poles of cell: disjunction

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46
Q

Define disjunction

A

Homologous pairs separate and pull to opposite poles of cell during anaphase I

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47
Q

Describe Mendel’s 1st law of segregation

A

Distribution of homologous chromosomes to daughter cells is random (can come from dad or mom)

48
Q

What phase/events demonstrates Mendel’s 1st law of segregation?

A

Disjunction, occurring during anaphase I

49
Q

Describe the events of telophase I

A

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
Q

Define interkinesis

A

rest period between divisions where chromosomes partially uncoil

51
Q

Meiosis II is ___ and results in ____

A

equational division; results in separation of sister chromatids without change in ploidy

52
Q

Describe the events of prophase II

A

Nuclear envelope dissolves, nucleoli disappear, centrioles migrate to opposite poles, spindle apparatus forms

53
Q

Describe the events of metaphase II

A

Chromosomes line up at metaphase plate

54
Q

Describe the events of anaphase II

A

1) Centromeres divide, separating chromosomes into sister chromatids
2) Chromatids pulled to opposite poles by spindle fibers

55
Q

Describe the events of telophase II

A

1) Nuclear membrane forms around new nucleus

2) Cytokinesis forms ~4 haploid daughter cells

56
Q

what and where is the SRY gene located

A

Sex-determining region found on Y chromosome

57
Q

What is the function of the SRY gene?

A

Codes for transcription factor that initiates testis differentiation

58
Q

List the sperm pathway

A

SEVE UP:

1) Seminiferous tubules
2) Epididymis
3) Vas deferens/ductus deferens
4) Ejaculatory duct
5) Urethra
6) Penis

59
Q

Sperm is produced in ____ and nourished by ____

A

seminiferous tubules; Sertoli cells

60
Q

Sperm flagella gain motility in _____

A

the epididymis

61
Q

Sperm is stored in the ____ until ejaculation

A

epididymis

62
Q

Seminal fluid is produced by _______

A

seminal vesicles, prostate gland, and bulbourethral gland

63
Q

____ provide fructose to nourish sperm

A

Seminal vesicles

64
Q

_____ give seminal fluid alkaline properties

A

The prostate gland and seminal vesicles

65
Q

______ produce fluid to clean out urine and lubricate urethra during arousal

A

The bulbourethral glands

66
Q

___ + ___ = semen

A

Sperm + seminal fluid

67
Q

Leydig cells secrete ______

A

testosterone and other androgens

68
Q

How is the optimal temperature for sperm development maintained?

A

By the testes: a layer of muscle around vas deferens raises and lowers testis to regulate temperature

69
Q

Define spermatogenesis

A

formation of haploid sperm via meiosis

70
Q

Where does spermatogenesis occur?

A

In the seminiferous tubules

71
Q

Define spermatogonia

A

Diploid stem cells

72
Q

The primary spermatocytes are ____

A

diploid

73
Q

Meiosis ___ produces haploid secondary spermatocytes

A

I

74
Q

Haploid spermatids are produced during meiosis ____

A

II

75
Q

Spermatids mature into ___

A

Spermatozoa

76
Q

1 spermatogonium produce ___ sperm

A

4

77
Q

Provide a rough overview of sperm differentiation, including mitotic/meiotic phases

A

2n spermatogonium –> mitosis –> 2n primary spermatocyte –> meiosis I –> 1n secondary spermatocyte –> meiosis II –> 4 1n spermatids –> spermatid mature into spermatozoa

78
Q

Ovaries produce ___ and ____

A

Estrogen and progesterone

79
Q

Ovum is ovulated into __ and down ___

A

Peritoneal sac; the fallopian tube

80
Q

The fallopian tube is lined with ___ to propel the ova

A

Cilia

81
Q

Define oogenesis

A

Production of female oogonia

82
Q

All female oogonia are formed during:

a) fetal development
b) conception
c) puberty
d) menopause

A

A

83
Q 
All oogonia have developed into primary oocytes by:
A) conception
B) fetal development
C) birth
D) puberty
A

C

84
Q

Primary oocytes are ___ (haploid/diploid)

A

Diploid

85
Q

Primary oocytes are arrested in ___ until first menarche

A

Prophase I

86
Q

Primary oocytes undergo ___ to produce secondary oocytes

A

Meiosis I

87
Q

After meiosis I, a primary oocyte will produce ___ and ___

A

Secondary oocyte and polar body

88
Q

The secondary oocyte is arrested in ___ and only completes ___ if fertilized

A

metaphase II; meiosis II

89
Q

Define zona pellucida, it’s structure, and function

A

An acellular mix of glycoproteins that surround and protect the oocyte and help with sperm binding

90
Q

Define the corona radiata, it’s function, and structure

A

A layer of cells adhered to the oocyte during ovulation

91
Q

Meiosis II is triggered a sperm penetrates the layers of the ___

A

Corona radiata

92
Q

After completing meiosis II, a secondary oocyte produces ___ and ___

A

Zygote and second polar body

93
Q

Polar bodies are (diploid/haploid)

A

Haploid

94
Q

Sexual development is controlled by

A

gonadotropin-releasing hormone (GnRH

95
Q

GnRH is limited before ____

A

Puberty

96
Q

Describe the function and mechanisms of GnRH

A

triggers anterior pituitary to synthesize and release follicle stimulating hormone (FSH) and luteinizing hormone (LH)

97
Q

Y chromosome leads to production of ____ which results in male sexual differentiation during fetal development

A

androgens

98
Q

Androgen production in men increases at ____

A

Puberty

99
Q

Describe the function of FSH in men

A

Stimulates Sertoli cells and triggers sperm maturation

100
Q

Describe the function of LH in men

A

Causes interstitial cells to produce testosterone

101
Q

How does testosterone work with the hypothalamus and anterior pituitary?

A

Exerts negative feedback

102
Q

Women produce ___ and ___ in response to FSH and LH

A

Estrogen; progesterone

103
Q

Progesterone is secreted by ___ in women in response to ____

A

Corpus luteum; LH

104
Q

Define corpus luteum

A

remnants of ovarian follicles after ovulation

105
Q

Estrogen is secreted in response to ___ in women

A

FSH

106
Q

After conception and the first trimester, progesterone is secreted by ____

A

The placenta

107
Q

List the three phases of the menstrual cycle

A

1) follicular phase
2) ovulation phase
3) luteal phase

108
Q

Describe the events of the follicular phase

A

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
Q

Describe the events of the ovulation phase

A

Ovulation triggered by LH in response to high estrogen levels

110
Q

Describe the events of the luteal phase

A

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
Q

A blastocyst secretes ____

A

Human chorionic gonadotropin (hCG)

112
Q

Describe the function of hCG

A

Maintains corpus luteum to maintain estrogen and progesterone levels

113
Q

hCG levels decline during the ____

A

second trimester, when the placenta begins to secrete its own estrogen and progesterone

114
Q

What causes menopause?

A

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
Q

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

A

MCAT (13 decks)

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