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MCAT Journey > Biology Chapter 2: Reproduction (3 Stars) > Flashcards

Biology Chapter 2: Reproduction (3 Stars) Flashcards

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MCAT flashcards
1
Q

Diploid (2n) cells have ____ copies of each chromosome; ______ cells have one copy.

A

Two
haploid (n)

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2
Q

The cell cycle contains five stages. The G1, S, and G2 stages are collectively called _____, during which the DNA is uncoiled in the form of chromatin.

A

Interphase

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3
Q

In the _____ stage, cells create organelles for energy and protein production, while also increasing their size.

A 
G1 stage (presynthetic gap),
The restriction point, during which the DNA is checked for quality, must be passed for the cell to move into the S stage.
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4
Q

In the S stage (synthesis), DNA is _______.

A

DNA is replicated. The strands of DNA, called chromatids, are held together at the centromere.

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5
Q

In the G2 stage (postsynthetic gap), there is further ____ and replication of ______ in preparation for mitosis. Another quality checkpoint must be passed for the cell to enter into mitosis.

A

cell growth and replication of organelles
Checkpoint must be passed for the cell to enter into mitosis.

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6
Q

In the ____ stage , mitosis and cytokinesis occur.

A

M stage (mitosis)

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7
Q

In the ____ stage, the cell performs its function without any preparation for division.

A

G0 stage

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8
Q

p53 plays a role in the ____ major checkpoints of the cell cycle A & B

A

2v major checkpoints of the cell cycle
(G1 to S, and G2 to M).

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9
Q

Cyclins bind to _____, phosphorylating and activating transcription factors for the next stage of the cell cycle.

A

CDKs

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10
Q

Cancer occurs when cell cycle control becomes deranged, allowing damaged cells to undergo _____ without regard to quality or quantity of the new cells produced. Cancerous cells may begin to produce ______ that allow them to escape their site and invade or metastasize elsewhere.

A

mitosis
factors

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11
Q

Mitosis produces two genetically identical haploid or diploid ______ cells from a single cell and occurs in somatic cells.

A

identical diploid daughter

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12
Q

In _______, (CNNCS)
chromosomes condense
nuclear membrane dissolves
nucleoli disappear,
centrioles migrate to opposite sides of the cell,
spindle apparatus begins to form.

A

prophase
The kinetochore of each chromosome is contacted by a spindle fiber.

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13
Q

What happens in metaphase?

A

In metaphase, chromosomes line up along the metaphase plate (equatorial plate).

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14
Q

In _______, sister chromatids are separated and pulled to opposite poles.

A

Anaphase

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15
Q

What happens in telophase? NSC

A

In telophase,
the nuclear membrane reforms,
spindle apparatus disappears,
cytosol and organelles are split between the two daughter cells through cytokinesis.

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16
Q

Meiosis occurs in _______ and produces up to_____ nonidentical haploid sex cells (gametes).

A

gametocytes (germ cells)
4

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17
Q

Meiosis has ____# round of replication and____ # rounds of division

A

1 round of replication
2 rounds of division (the reductional and equational divisions)

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18
Q

In meiosis I, ______ pairs of chromosomes are separated from each other.

A

Homologous: are chromosomes that are given the same number, but are of opposite parental origin.

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19
Q

In prophase I, the same events occur as in prophase of mitosis, except _______.
The # chromatids are referred to as a tetrad
This accounts for Mendel’s _____ law (of independent assortment).

A

that homologues come together and intertwine in a process called synapsis.
4 chromatids are referred to as a tetrad
Mendel’s second law (of independent assortment).

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20
Q

In metaphase I, _______ chromosomes line up on opposite sides of the metaphase plate.

A

homologous

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21
Q

In ______ I, homologous chromosomes are segregated to opposite poles of the cell.
Mendel’s ____ law (of segregation).

A

anaphase I
Mendel’s first law (of segregation).

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22
Q

In ________ I, the chromosomes may or may not fully decondense, and the cell may enter interkinesis after ______.

A

telophase I
cytokinesis.

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23
Q

In meiosis II, _______ are separated from each other in a process that is functionally identical to mitosis. Sister chromatids are copies of the same DNA held together at the centromere.

A

sister chromatids
Sister chromatids are copies of the same DNA held together at the centromere.

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24
Q

Biological sex is determined by the _____ pair of chromosomes in humans, with XX being female and XY being male.

A

23rd pair

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25
Q

The _ chromosome carries a sizeable amount of genetic information

A

X chromosome

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26
Q

The __ chromosome carries little genetic information, but contains the SRY gene

A

The Y chromosome
(sex-determining region Y) gene, which causes the gonads to differentiate into testes.

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27
Q

Sperm develop in the ________ in the testes. They are nourished by Sertoli cells.

A

Seminiferous tubules

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28
Q

Interstitial cells (of Leydig) secrete _______ and other male sex hormones (androgens).

A

testosterone

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29
Q

The testes are located in the _____, which hangs outside of the abdominal cavity and has a temperature 2° to 4°C lower than the rest of the body.

A

Scrotum

30
Q

Once formed, sperm gain motility in the ______and are stored there until ejaculation.

A

Epididymis

31
Q

During ejaculation, sperm travel through the ________to the ejaculatory duct to the ______ and out through the penis.

A

vas deferens
urethra

32
Q

The seminal vesicles contribute _____ to nourish sperm and produce alkaline fluid.

A

fructose

33
Q

The ______ gland also produces alkaline fluid.

A

Prostate gland

34
Q

The bulbourethral glands produce a clear _____ fluid that cleans out any remnants of urine and lubricates the urethra during sexual arousal.

A

clear viscous fluid

35
Q

Semen is composed of sperm and _______ from the glands above.

A

seminal fluid

36
Q

In spermatogenesis, ____ haploid sperm are produced from a spermatogonium.

A

4

37
Q

After S stage, the germ cells are called ______ spermatocytes.

A

primary

38
Q

After ______, the germ cells are called secondary spermatocytes.

A

meiosis I

39
Q

After meiosis II, the germ cells are called _____

A

spermatids.

40
Q

After _______, the germ cells are called spermatozoa.

A

maturation

41
Q

Sperm contain a head, ______, and flagellum.

A

midpiece

42
Q

The_____ contains the genetic material and is covered with an acrosome— a modified Golgi apparatus that contains enzymes that help the sperm fuse to and penetrate the ovum.

A

head

43
Q

The midpiece generates _____ from fructose and contains many mitochondria.

A

ATP

44
Q

The flagellum promotes ______.

A

motility

45
Q

The female reproductive system only contains ______structures.

A

internal

46
Q

Ova (eggs) are produced in ______ in the ovaries.

A

follicles

47
Q

Once each month, an egg is ovulated into the _______ and is drawn into the fallopian tube or oviduct.

A

peritoneal sac

48
Q

The fallopian tubes are connected to the _____, the lower end of which is called the cervix.

A

uterus.

49
Q

The vaginal canal lies below the ______ and is the site where sperm are deposited during intercourse. Birth also occurs here.

A

cervix

50
Q

The external female anatomy is known as the _____.

A

vulva

51
Q

In oogenesis, one _____ ovum and a variable number of polar bodies are formed from an oogonium.

A

haploid

52
Q

At birth, all oogonia have already undergone replication and are considered _____ oocytes. They are arrested in ______ I.

A

primary oocytes
prophase I.

53
Q

The ovulated egg each month is a secondary oocyte, which is arrested in ________ II.

A

metaphase II.

54
Q

If the oocyte is fertilized, it will complete meiosis II to become a _______.

A

true ovum.

55
Q

Cytokinesis is uneven in oogenesis. The cell receiving very little cytoplasm and organelles is called a _____

A

polar body.

56
Q

Oocytes are surrounded by the _______, an acellular mixture of glycoproteins that protect the oocyte and contain the compounds necessary for sperm binding, and the corona radiata, which is a layer of cells that adhered to the oocyte during ovulation.

A

zona pellucida

57
Q

Gonadotropin-releasing hormone (GnRH) from the hypothalamus causes the release of follicle-stimulating hormone (FSH) and __________, the functions of which depend on the sex of the individual.

A

luteinizing hormone (LH)

58
Q

In males, _____ stimulates the Sertoli cells and triggers spermatogenesis, while ____ causes the interstitial cells to produce testosterone.

A

FSH
LH

59
Q

In females, _____ stimulates development of the ovarian follicles, while LH causes ovulation. These hormones also stimulate production of ____ and _____

A

FSH
estrogens and progesterone.

60
Q

The menstrual cycle is a periodic growth and _____ of the endometrial lining.

A

shedding

61
Q

GnRH secretion stimulates FSH and LH secretion, which promotes ______ development.

A

follicle development. Estrogen is released, stimulating vascularization and glandularization of the decidua.

62
Q

Ovulation is stimulated by a sudden surge in _____. This surge occurs because estrogen stops having negative feedback effects at a certain threshold and begins to have positive feedback effects.

A

LH.

63
Q

In the luteal phase, ____ promotes the ruptured follicle to become the corpus luteum, which secretes progesterone that maintains the uterine lining. High estrogen and progesterone levels cause ______ feedback on GnRH, LH, and FSH.

A

LH
negative feedback

64
Q

Menstruation occurs if there is no fertilization. As the estrogen and progesterone levels drop, the endometrial lining is sloughed off, and the block on _____ production is removed.

A

GnRH

65
Q

If fertilization does occur, the _____ produces______which, as an LH analog, can maintain the corpus luteum.

A

blastula
human chorionic gonadotropin (hCG)
Near the end of the first trimester, hCG levels drop as the placenta takes over progesterone production.

66
Q

Menopause occurs when the ovaries stop producing ____ and ______, usually between ages 45 and 55. Menstruation stops and ____ and _____ levels rise. Physical and physiological changes accompanying menopause include flushing, hot flashes, bloating, headaches, and irritability.

A

estrogen and progesterone,
FSH and LH levels rise.

67
Q

Mutations of ____-linked genes can cause sex-linked disorders.

A

X-linked

68
Q

_____ are hemizygous with respect to the unpaired genes on the X chromosome, so they will express sex-linked disorders, even if they only have one recessive disease-carrying allele.

A

Males

69
Q

_____ with one copy of the affected allele are called carriers.

A

Women

70
Q

What is Testosterone responsible for?

A

Maintenance and development of the male reproductive system
male secondary sex characteristics (facial and axillary hair, deepening of the voice, and changes in growth patterns).

71
Q

Difference between Mitosis & Meosis:

A
72
Q

How is Metaphase I different from Metaphase (Mitosis)?

A

Homologous chromosomes line up on opposite sides of the metaphase plate, rather than individual chromosomes lining up on the metaphase plate

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