ch 46

Question 1

sexual reproduction

Answer 1

fusion of haploid gametes forms a diploid cell ( a zygote)

Question 2

asexual reproduction

Answer 2

new individuals are generated without fusion of egg and sperm

Question 3

ovulation

Answer 3

release of mature eggs - occurs at midpoint of each cycle

Question 4

fertilization

Answer 4

can be external or internal

external example - an amphibian female releases eggs into the environment where the male fertilizes them

internal - sperm are deposited in or near female reproductive tract. fertilization is inside fallopian tube. implantation is inside uterus

turns into a zygote if fertilized

only fertilized eggs go through all of meiosis

Question 5

testes

Answer 5

male gonads - organs that produce gametes

male gametes are made in testes

Question 6

spermatogenesis

Answer 6

formation and development of sperm, is continuous and prolific in adult human males

goes from outside to inside to create sperm. starts as diploid on outside

starts at puberty until death. cytokinesis is equal

occurs throughout seminiferous tubes. a single sperm takes about 7 weeks from start to finish to make.

Question 7

spermatogenesis differs from oogenesis in 3 ways

Answer 7

1. only in spermatogenesis do all 4 products of meiosis develop into mature gametes. In oogenesis, cytokinesis during meiosis is unequal
2. spermatogenesis occurs throughout adolescence and adulthood. In oogenesis, occurs before birth and then paused until puberty. production of mature gametes ceases at age 50
3. spermatogenesis produces mature sperm in a continuous sequence. where as in oogenesis, there are long interruptions

Question 8

oogenesis

Answer 8

development of mature oocytes (eggs), is a prolonged process in human females. made in ovaries

produces oogonia

immature eggs form in ovary of the female embryo (before birth) but do not complete until years/decades later

cytokinesis creates one large cell and one small cell. large cell becomes the egg and the smaller cell (polar bodies) degenerate/ reabsorbed

Question 9

how are sperm formed in spermatogenesis?

Answer 9

stem cells that give rise to sperm are situated near outer edge of seminiferous tubules. They move inward.

mature sperm are released into lumen.

Question 10

spermatogonia

Answer 10

in mature testes, divide mitotically to form spermatogonia which generate spermatocytes by mitosis

Question 11

structure of a sperm

Answer 11

head (nucleus and acrosome), neck, midpiece (mitochondria) and tail (plasma membrane)

mitochondria provides ATP for movement of flagellar tail

structure function

Question 12

acrosome

Answer 12

contains enzymes that help the sperm penetrate an egg

Question 13

oogonium

Answer 13

oogenesis produces this from germ cells

this is diploid (2n)

Question 14

female gametes are made where?

Answer 14

ovaries

Question 15

primary oocytes (in embryo)

Answer 15

developmentally arrested cells that reside within a small follicle

women are born with all their primary oocytes

this is diploid (2n)

Arrested in prophase I of meiosis I

Question 16

secondary oocytes

Answer 16

haploid!!

first polar body created

beginning at puberty, the follicle stimulating hormone (FSH) stimulates the follicles to resume growth.

arrested at MEIOSIS II in METAPHASE II

the secondary oocyte is released at ovulation when its follicle breaks open

Question 17

how do hormones control reproductive system?

Answer 17

sex hormones are steroid hormones.

coordinated action in both males and females come from hypothalamus and pituitary.

secretes (FSH) follicle stimulating hormone and (LH) luteinizing hormone

they regulate the activity of endocrine cells

Question 18

Peaks of LH and FSH production occur during

Answer 18

the period just before ovulation.

Question 19

For which of the following is the number the same in males and females?

Answer 19

meiotic divisions required to produce each gamete

Question 20

For which of the following is the number the same in spermatogenesis and oogenesis?

Answer 20

meiotic divisions required to produce each gamete

Both spermatogenesis and oogenesis go through two meiotic divisions to produce gametes (meiosis I and meiosis II).

Question 21

What hormones are used in female reproductive system?

Answer 21

hypothalamus produces GnRH, which causes the release of 2 important hormones: FSH and LH.

The pituitary gland produces these two hormones.

FSH is produced during firs half of menstrual cycle.
LH triggers ovulation and promotes development of corpus luteum.

Question 22

corpus luteum

Answer 22

hormone secreting structure in ovary; degenerates in a few days if there is no pregnancy

Question 23

male gametes are made where?

Answer 23

testes

Question 24

What are diploid and haploid in Spermatogenesis?

Answer 24

diploid (2n) =
Spermatogonium
Primary spermatocyte

haploid (n) =
Secondary spermatocyte
Spermatids
Sperm cell

Question 25

where are female gametes made?

Answer 25

ovaries

Question 26

Where is implantation?

Answer 26

uterus

Question 27

Where is fertilization?

Answer 27

fallopian tube

Question 28

Fertilization normally_____

Answer 28

reinstates diploidy.