Reproduction

Question 1

in animals, autosomal cells are said to be _ , which means they contain two copies of _

Answer 1

diploid (2n)

each chromosome

Question 2

What are the four stages of the cell cycle also known as _

Answer 2

G1, S, G2, and M

interphase

Question 3

Cells that do not divide spend their time in?

Answer 3

G0

Question 4

during interphase individual chromosomes are not visible with light microscopy because they are in a less condensed form known as _ . and why

Answer 4

chromatin

bc DNA must be available to RNA polymerase so that genes can be transcribed

Question 5

Describe the G1 stage

Answer 5

cells create organelles for energy and protein production while increasing their size. passage into the S phase is governed by a restriction point.

Question 6

Describe the S stage

Answer 6

During the Synthesis phase the cell replicates its genetic material so that each daughter cell will have a copy.

Question 7

describe the chromosomes During the S stage

Answer 7

replicates to two sister chromatids bound by a centromere

Question 8

Describe the ploidy and amount of DNA in S stage

Answer 8

ploidy is still diploid. Humans still have 46 chromosomes but DNA is doubled because there are 92 chromatids present

Question 9

Describe the G2 stage

Answer 9

cells pass through another restriction point making sure there are enough organelles for two daughter cells. And checks DNA replication

Question 10

Describe the M stage

Answer 10

mitosis and cytokinesis. Mitosis is divided into 4 stages

Question 11

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

Answer 11

p53

Question 12

What are the molecules responsible for the cell cycle

Answer 12

cyclins and cyclin-dependent kinases (CDK)

Question 13

How do cyclins and CDKs work

Answer 13

cyclins bind to CDKs creating an activated CDK-cyclin complex. this complex can phosphorylate transcription factors that promote the transcription of genes required for the next stage of the cell cycle

Question 14

what is metastasis

Answer 14

local invasion and distant spread of cancerous cells through the bloodstream or lymphatic system

Question 15

What are the 4 phases of mitosis

Answer 15

prophase, metaphase, anaphase, and telophase.

Question 16

mitosis occurs in _ whereas meiosis occurs in _

Answer 16

somatic cells; gametocytes (germ cells)

Question 17

Describe prophase

Answer 17

first phase of mitosis;
first step; involves condensation of the chromatin into chromosomes and the centriole pairs separate and move toward opposite poles of the cell.
2nd step; spindle fibers form (made of microtubules), some form asters. the nucleoli become less distinct and may disappear.

Question 18

where are centriole pairs located

Answer 18

in a region called the centrosome; a region located outside the nucleus

Question 19

Describe metaphase

Answer 19

the centriole pairs are at opposite sides of the cell. kinetochore fibers interact with spindle fibers and align the chromosomes at the metaphase plate or equatorial plate.

Question 20

Describe anaphase

Answer 20

sister chromatids separate to opposite sides of the cell

Question 21

Describe Telophase

Answer 21

reverse of prophase; spindle fibers disappear. nuclear membrane reforms around each set of chromosomes. chromosomes then uncoil resuming interphase form.

Question 22

Describe cytokinesis

Answer 22

separation of the cytoplasm and organelles

Question 23

Meiosis results in four nonidentical _

Answer 23

gametes

Question 24

Meiosis I results in

Answer 24

homologous chromosomes being separated generating haploid daughter cells. (reductional division)

Question 25

Meiosis II results in

Answer 25

reparation of sister chromatids without change in ploidy (equatorial division)

Question 26

Whats different in Prophase 1 compared to Prophase

Answer 26

homologous chromosomes come together and intertwine in a process called synapsis. chromatids may break at the point of contact called a chiasma and exchange equivalent pieces of DNA.

Question 27

importance of the synaptonemal complex

Answer 27

a group of proteins that holds homologous chromosomes together in prophase 1.

Question 28

Mendel's second law

Answer 28

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

Question 29

What is different in Metaphase 1 compared to Metaphase

Answer 29

in meiosis, homologous chromosomes are lined up at the metaphase plate and held by one spindle fiber. in mitosis they're held by 2 spindle fibers

Question 30

What is different in Anaphase 1 compared to Anaphase

Answer 30

In anaphase 1 in meiosis, homologous pairs are separated but sister chromatids stay joined together. In anaphase 1 of mitosis the sister chromatids do separate.

Question 31

What is different in Telophase 1 compared to Telophase

Answer 31

At the end of Telophase 1 during meiosis, we get a haploid set of chromosomes with complete homologous chromosomes separated at each pole. At the end of Telophase during Mitosis, we get a haploid set of chromosomes with discrete homologs (sister chromatids) of homologous chromosomes separated at each pole.

Question 32

What is SRY

Answer 32

sex determining region

Question 33

Pathway of sperm through the male reproductive system

Answer 33

``` Seve(n) up Seminiferous tubules epididymis vas deferens ejactulatory duct (nothing) urethra penis ```

Question 34

What is the function of the interstitial cells of Leydig

Answer 34

secrete testosterone and androgens

Question 35

what are androgens

Answer 35

male sex hormones

Question 36

function and purpose of the ductus deferens

Answer 36

a layer of muscle around the vas deferens that can raise and lower the testis to maintain a proper temperature

Question 37

Describe the physiology of a mature sperm

Answer 37

compact; consist of a head containing genetic material. a midpiece which generates ATP from fructose, and a flagellum.

Question 38

What is an acrosome

Answer 38

covers the sperm head and is necessary to penetrate the ovum.

Question 39

What hormones do the ovaries produce

Answer 39

estrogen and progesterone

Question 40

fallopian tubes are connected to the muscular _ and are lined with _ that propel the egg foward

Answer 40

uterus; cilia

Question 41

what are spermatogonia

Answer 41

stem cells that make sperm

Question 42

primary oocytes versus secondary oocytes; arrested phases

Answer 42

primary oocytes; are 2n, at birth are considered primary, arrested in prophase 1 secondary oocytes; 1 primary oocyte per month will undergo meiosis 1 producing a secondary oocyte; than arrested in metaphase 2 until fertilization (meiosis II)

Question 43

what layers surround the oocyte and what is their purpose

Answer 43

zona pellucida; glycoprotein layer that protect the oocyte and allow sperm cell binding. corona radiata; lies outside the zona pellucida, layer of cells that adhere to the oocyte during ovulation.

Question 44

when is meiosis 2 triggered

Answer 44

when a sperm cell penetrates the layers around the oocyte

Question 45

Before puberty the hypothalamus restricts production of this hormone, but after releases it in pulses

Answer 45

gonadotropin-releasing hormone (GnRH)

Question 46

the anterior pituitary gland is triggered by GnRH and releases

Answer 46

follicle-stimulating hormone (FSH) | and luteinizing hormone (LH)

Question 47

What hormones trigger the production of other sex hormones that develop and maintain the reproductive system

Answer 47

GnRH FSH LH

Question 48

_ leads to the thickening of the lining of the _ or _ each month in preparation for the implantation of a zygote

Answer 48

Estrogen | uterus or endometrium

Question 49

What secretes progesterone in response to LH

Answer 49

corpus luteum

Question 50

by the end of the first trimester, progesterone is supplied via the _ and the _ atrophies and ceases to function

Answer 50

placenta | corpus leutem

Question 51

Explain the follicular phase of the menstrual cycle. including the hormones involved

Answer 51

the follicular phase (preovulatory) begins when the menstrual flow begins. GnRH secretion increases in response to the decreased concentrations of estrogen and progesterone. High [GnRH] cause increased [FSH] and [LH]. FSH and LH work in concert to develop several ovarian follicles. The follicles produce estrogen, which has a negative feedback and causes GnRH, LH, and FSH to level off. Endometrial lining regrows.

Question 52

Explain the ovulation phase of the menstrual cycle. including the hormones involved

Answer 52

estrogen then begins to act in a positive feedback loop where [LH], [GnRH] , and [FSH] spike. The surge in LH induces ovulation.

Question 53

Explain the luteal phase of the menstrual cycle. including the hormones involved

Answer 53

after ovulation, LH causes the ruptured follicle to form the corpus luteum. progesterone levels rise while estrogen level remain high. High progesterone causes negative feedback on GnRH, FSH, and LH.

Question 54

_ helps regenerate the uterine lining, but _ maintains it for implantation

Answer 54

estrogen | progesterone

Question 55

Assuming implantation doesnt occur; explain hormones in luteal phase

Answer 55

the corpus luteum loses stimulation from LH, and progesterone and estrogen levels decline. GnRH rises and next cycle begins.

Question 56

a blastocyst will implant in the uterine lining and secrete _

Answer 56

human chorionic gonadotropin (hCG)

Question 57

Why does menopause occur

Answer 57

ovaries become less sensitive to FSH and LH, causing ovarian atrophy.

Question 58

Upon ovulation, the oocyte is released into the _ than the _

Answer 58

abdominal cavity; fallopian tube

Question 59

What is the last point in the meiotic cycle in which the cel has a diploid number of chromosomes

Answer 59

During telophase 1