Developmental Biology

Question 1

What is the difference between Fission and Budding?

give example of organisms:

Answer 1

Fission: separation of an organism into 2 new cells; clones (amoebas)

Budding: New organism splits off from existing
(hydra)

Question 2

What is the difference between Fragmentation and Parthenogenesis?

Answer 2

Fragmentation + Regeneration (sponges):
-single parent breaks off into many parts that develop

Parthenogenesis (honey bees, lizards):
-development of egg w/ out fertilization; resulting adult is haploid

Question 3

What are Gonads and what is their duty in human reproduction?

Answer 3

gonads are reproductive structures responsible for production of gametes

Male = testes
Female= ovaries

Question 4

What is an ova, ovary, oviduct, and uterus?

Answer 4

Ovary - responsible for the production of Ova (eggs); each female have 2 ovaries

Oviduct- eggs move from ovaries –> uterus via oviduct

Uterus- where embryo development occurs until birth; fertilized ovum implants on the inside wall, ENDOMETRIUM, of uterus

Question 5

What is the cervix of the uterus?

Answer 5

the opening in the uterus

Question 6

What do testes consist of and what are those structures responsible for producing?

Answer 6

testes consist of seminiferous tubules that produce sperm and interstitial cells (leydig cells) which are responsible for production of male hormones (testosterone = androgen) and are secreted in the presence of LH

Question 7

What is the difference between interstitial cells (leydig cells) and sertoli cells?

What sex are these only found?

Answer 7

MALES

Interstitial cells are responsible for production of male hormones (testosterone = androgen) in presence of LH

Sertoli cells surround and nurture sperm in the presence of FSH

Question 8

What structure are the testes located in and what is that structure’s duty?

Answer 8

scrotum: site of sperm production;

- usually 2 degrees lower than body temp for sperm production

Question 9

What structure is responsible for the storage of sperm in males?

Answer 9

Epididymis: coiled tube attached to testes

Question 10

What transfers sperms from one epididymus to urethra in human males?

Answer 10

Vas deferens

Question 11

What do the seminal vesicles do for you when you ejaculate?

Answer 11

Provides: 3 things:

1. mucus (liquid for sperm) to the vas deferens,
2. fructose as ATP
3. prostaglandins (stimulate uterine contractions that help sperm move into uterus)
   “when you bust, sperm squirts out)

Question 12

What is the prostates duty?

Answer 12

secretes milky alkaline fluid to neutralize acidity of urine, and seminal fluid

Question 13

What is important about the head of a sperm?

Answer 13

it is called the acrosome (kinda like lysosomes) and contains enzymes to penetrate the female egg

Question 14

What does SEVEn UP refer to in the male reproductive system?

Answer 14

SEVEn UP

Seminiferous tubules—> Epididymis—> Vas deferens—> Ejaculatory duct—> urethra—> penis

Question 15

What is Oogenesis vs Spermatogenesis?

Answer 15

Oogenesis: meiotic cell divisions that produce eggs’

oogonia (fetal cells)–mitosis–> primary oocyte–28 days in follicle–> 2ndary oocyte–> ovulation–LH surge–> 2ndary oocyte released from vesicular follicle –fertilization–> ovum,egg (diploid + polar body)

Spermatogenesis: meiotic cell division that produce sperm

Spermatogonia cells—mitosis—> primary spermatocytes—meiosis ll—> 4 spermatids—sertoli cells nourish—-> spermatozoa (sperm)

Question 16

What are the steps in the menstrual cycle?

Answer 16

Hypothalamus and anterior pituitar initiate: monitor and estrogen and progesterone in blood

Low level—> hypothalamus—> GnRH—> FSH and LH———–> Follicle develops —>FSH stimulate follicle to release lots of estrogen—-> LH surge —> Ovulation (follicle is now corpus luteum -maintained by LH [which along w/ estrogen begins to decrease after ovulation], secretes –> estrogen + progesterone— Development of endometrium–> thickens in prep for implantation of fertilized egg

Question 17

What happens if there is no implantation occurs during the menstrual cycle?

Answer 17

(negative feedback on AP from increased e+p) terminates production of FSH + LH -due to decreased GnRH from hypothalamus —> *corpus luteum disintegrates ( cause no longer maintained by LH)

Question 18

What occurs if there is implantation during the menstrual cycle?

Answer 18

embryo (placenta) secretes chorionic gonadotropin
(HCG) —> maintains corpus luteum—> production of e+p remain high —> endometrium stays —> HCG is later replaced by progesterone from placenta

Question 19

What are the steps of the Ovarian cycle in females?

Answer 19

1. Follicular phase: development of egg and secretion of estrogen from follicle
2. Ovulation: midcycle release of egg
3. Luteal phase: secretion of estrogen and progesterone from the corpus luteum after ovulation

Question 20

What are the net duties of estrogen and progesterone during the ovarian cycle?

Answer 20

estrogen - thicken endometrium

progesterone - development and maintenance of endometrial wall

Question 21

What are the steps in the male reproductive cycle?

Answer 21

GnRH–> FSH + LH (also called ICSH, interstitial cell stimulating hormone—> testosterone and androgens from testes).

FSH and testosterone —> influence sertoli cells to promote development of sperms (nourish sperms during development -spermatogenesis).

*Hormone and gamete production are constant unlike females

Question 22

What are the 4 big stages in growth and development of animals?

Answer 22

1. Gametogenesis (sperm/egg formation)
2. Embryonic development (fertilization of egg until birth)
3. Reproductive maturity (puberty)
4. Aging process to death

Question 23

What is a fetus in embryonic development?

Answer 23

is an embryo that resembles an infant form

Question 24

What is the duty of both the vitelline layer of sea urchin-echinoderm and the zona pellucida in humans?

Answer 24

prevents fertilization of sperm from other species

Question 25

What is a very important part of the acrosome reaction?

Answer 25

(sperm release contents of acrosome as it approaches egg; contributes to charge fast block of polyspermy

Question 26

What is the duty of the blastocyst 5 days after fertilization?

Answer 26

perform zone hatching

zona pellucida degenerates + replaced by underlying layer of tropoblastic cells so it can implant in the uterus

Question 27

How does fertilization for frogs and amphibians differ from humans?

Answer 27

fertilization doesn’t take place inside a frogs body…

it occurs externally in water

***external fertilization = more eggs and less parental care than internal fertilization due to a less change in fertilization

Question 28

The vitelline layer forms the fertilization membrane and blocks addition sperm due to the _________ RXN.

Answer 28

Cortical RXN

Question 29

What is the difference between the Acrosome RXN and the Cortical RXN?

Answer 29

Acrosome rxn: FAST block of polyspermy

Cortical rxn : SLOW block of polyspermy

Question 30

What is the north pole and south pole of an egg referred to as?

Answer 30

Animal pole = Top of egg

Vegtal pole = Bottom of egg (contains more yolk which is heavier and sinks to the bottom, which then differentiates into extraembryonic membranes that protect + nourish embryo

Question 31

What occurs during cleavage in embryonic development?

Answer 31

rapid cell divisions w/ out cell growth,

each cell = blastomere (less cytoplasm than original zygote)

Question 32

What is the difference between indeterminate and determinate cleavages?

Answer 32

Indeterminate cleavage- blastomeres can individually complete normal development even if separated

Determinate cleavage- can NOT develop into complete embryo if separated; each is differentiated into part of the embryo