Reproduction & Development Flashcards Preview

SAT II BIOLOGY > Reproduction & Development > Flashcards

Flashcards in Reproduction & Development Deck (50)
Loading flashcards...
1

Binary Fission

 

 

  • Prokaryotes, algae, bacteria
  • Key step - DNA replication 
  • Only 1 chromosome in a single long circular DNA;
  • Gets attached to cell membrane and replicated as the cell grows
  • DNAs are drawn apart when cell grows and adds more membrane between the DNAs

2

Conjugation

  • primitive form of sexual reproduction used by bacteria
  • move genes between cells by exchanging a circular extrachromosomal DNA with eachother
  • individuals exchange genetic information

3

Transduction

  • viruses that infect bacteria can accidentally carry bacterial genes with them into a new cell they infect
  • introduce new genes into bacteria 

4

Cell Cycle

Interphase

  • Stage G1 - intense biochemical and biosynthetic activity - growth - cell doubles in size - new organelles are produced
  • Stage S - synthesis - DNA replication - chromosomes each consist of 2 identical sister chromatids held by centromere, ends are called telomeres
  • Stage G2 - prepares for mitosis 

Stage M (Mitosis and Cytokinesis) 

5

Advantages of Asexual reproduction

  1. enables animals living in isolation to reproduce without a mate
  2. creates many offsprings quickly
  3. no expenditure of energy to maintain complex reproductive systems or hormonal cycles
  4. when the environment is stable and favorable 
  5. mechanism for perpetuating primitive organisms and plants, especially in times of low population density

6

Budding

  • unequal division of cytoplams, but equal division of the nucleus
  • yeast, hydra
  • parent cell forms smaller daughter cell that sprouts off with less cytoplasm
  • the daughter organism becomes independent and is released 
  • splitting off new idnividuals from existing ones

7

Parthenogenesis

  • Asexual Reproduction (in animals)
  • egg develops without fertilization by sperm 
  • occurs naturally in bees
    • fertilized eggs develop into worker bees and queen bees
    • unfertilized eggs become male drone bees

8

Regeneration

• Asexual Reproduction

Ability to regrow a missing body part

• Fragmentation – single parent breaks into parts that regenerate into new individuals
• Ex/ Sponges, planaria, earthworm, lobster, sea star, plants

9

Gonads

specialized organs that produce gametes through meiotic cell division 

  • Male - testes - produce sperm
  • Female - ovaries - produce ova

10

Germ cell

• A cell that is committed to the production of gametes
• Diploid; not a gamete
• Its genome contributes to gametes and offspring
• Mutations in somatic cells won’t be passed on

11

Testes

• Male gonads
• Site of sperm formation
• Produce male hormones(testosterone)
semniferous tubuoles - support the stem

12

Vas deferens

 Duct that carries sperm during ejaculation from the epididymis to the penis

13

Prostate gland

secretes semen directly into the urethra

14

Scrotum

  • sac outside the abodminal cavity that holds the testes
  • cooler temperature enables sperm to survive

15

Urethra

• Tube that carries urine and semen

 

16

Spermatogenesis

- Begins as luteinizing hormone(LH) induces the testes to produce testosterone

- FSH and testosterone stimulate sperm production

• Produces 4 mature sperm; each sperm has an X or Y chromosomes and doesn’t donate mitochondria to the embryo
• Continuous process
• Produces fresh sperm daily
• Spermatogonium(2n) –(Mitosis)--> Primary Spermatocyte(2n) –(Meiosis I)--> 2 Secondary spermatocyte(n) –(Meiosis 2)--> 4 spermatids(n) ----> 4 spermatozoa(n)
o Specialized sac called acrosome on sperm tip has enzymes that break through protective layers around the egg

17

Oogenesis

• produces 1 egg and 3 polar bodies
• begins prior to birth; a female is born with all the primary oocytes she will ever have
• produces ova with only X chromosomes and donates mitochondria to the embryo
• discontinuous process
• ova progress to meiosis I and gets stuck at this stage; ova that mature during each menstrual cycle progress through this meiotic block
• primary oocyte remains inactive within follicles in the ovaries until puberty, when they become reactivated by hormones
• Oogonium(2n) –(mitosis)--> Primary Oocyte(2n) –(Meiosis I)--> Secondary Oocyte(n) & 1st polar body(n) –(Meiosis II)--> Ovum(n) & 2 2nd Polar Bodies(n)

18

Ovaries

female gonad

where meiosis occurs and where the secondary oocyte forms prior to birth

one ova develops each month within a follicle in an ovary

19

Fallopian tube/ Oviduct

  • where fertilization occurs
  • after ovulation, egg moves through the oviduct to the uterus

20

Uterus

where the blastula stage of the embryo will implant and develop during the nine-month gestation

21

vagina

birth canal; during labor and delivery, the baby passes through the cervix and into the vagina

22

Cervix

mouth of the uterus

23

Endometrium

lining of the uterus

24

Menstrual Cycle

  1. Follicular Stage
  2. Ovulation
  3. Corpus Luteum Stage
  4. Menstruation

key hormones - GnRH, FSH, LH, estrogen, progesterone

cycle that repeats every 28 days

25

Follicular Phase

• 1st stage of Menstrual Cycle
• Follicles(tiny cavities) grow/mature in the ovaries and secrete increasing amounts of estrogen in response to follicle-stimulating hormone(FSH) from the anterior pituitary
• Estrogen promotes thickening of the uterine lining to support an embryo if fertilization occurs
• 9-10 days

26

Ovulation

• 2nd stage of Menstrual Cycle
• Secondary oocyte ruptures out of the ovaries in response to a rapid surge in luteinizing hormone(LH) from the anterior pituitary
• 14th day
• Constant high levels of estrogen usually block the LH surge and block ovulation(birth control pills)

 

27

Luteal Phase

• 3rd stage of Menstrual Cycle
• After ovulation, the remains of the follicle create the corpus luteum
• LH from the pituitary stimulates it to secrete estrogen and progesterone that thicken the endometrium of the uterus; triggers vascularization(growth of blood vessels)
• Lasts 12-15 days

28

Menstruation

• 4th and last stage of Menstrual Cycle
• If no fertilization, the increased estrogen and progesterone block LH production
• Without LH, the corpus luteum wastes away and progesterone levels fall
• Without progesterone, the buildup of the uterus lining breaks down and is shed
• Lasts 4 days

29

What happens if fertilization occurs?

• The developing placenta produces HCG(human chorionic gonadotrophic hormone), which maintains the corpus luteum
• It continues to make progesterone and estrogen
• Progesterone prevents menstruation and ensures uterus lining is thickened to continue pregnancy
• The placenta develops and takes over estrogen and progesterone production during pregnancy

 

30

Hormonal Control of the Menstrual 

Hypothalamus
Releases
.
.
Gonadotropic-Releasing Hormone(GnRH)
.
.
Stimulates
 

Anterior Pituitary

Releases
 

Follicle-Stimulating Hormone(FSH)         

Luteinizing Hormone(LH)

Stimulates
.
.
Ovary

Releases
   

Estrogen         Progesterone

Stimulates
 

Thickens the lining of the uterus