Loren bio 2
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- the division and distribution of the cell's DNA to its two daughter cells
- each cell gets a complete copy of the original genome
What is Karyokinesis?
the division of the nucleus
What is cytokinesis?
the division of the cell
- 90% of cells life is interphase
- Chromosomes are duplicated
- chromosomes are loose (chromatin)
What's the centromere?
the "waist" spot where the chromatids are held together.
- the chromosomes condense
- the centriole separate and move to opposite ends
- the spindle forms
- spindle attaches to a chromatid
- they align at the metaphase plate
The chromatid sister's separate to opposite ends
- Spindles disappear
- nuclear membrane forms around each chromosomes
- chromosomes uncoil
I Plan Marriage At The Church
Do plants have centrioles?
No, they form a cell plate
- the process by which sex cells are produced
- it halves the number of chromosomes
- the gametes are produced in the gonads
- specialized organs
Female gonads are called....
contain functional male and female gonads (hydra and earthworm)
- the sperm production
- occurs in the seminiferous tubules
- the production of female gametes (eggs)
- occurs in the ovaries
the union of the egg and sperm nuclei to form a zygote (diploid number of chromosomes)
The pathway of Sperm....
- SEVEn UP
- (seminiferous tubules)
- (Vas deferens)
- (Ejaculatory duct)
The testes produce what two things?
- 1. testosterone (for secondary male characteristics)
- 2. Sperm
What cell produces estrogen?
What two things do follicle cells do?
- 1. produce estrogen
- 2. contains, nourishes the ovum (egg cell)
Where does the fetus develop?
in the uterus
All the eggs that a female will ovulate during her lifetime are already present in the ovaries
What regulates secretion of estrogens and progesterone?
LH and FSH
What do estrogens do?
- they are the steroid necessary for normal female maturation. female sexual characteristics
- thicken the endometrium (uterine wall)
What does progesterone do?
progesterone stimulates the development and maintenance of the endometrial wall in preparation for the fetus
Four phases of the menstrual cycle
- 1. follicular phase
- 2. Ovulation
- 3. Luteal phase
- 4. menstruation
FSH (follicle stimulating hormone) promotes development of the follicle. It grows and begins secreting estrogen
- midway through the cycle
- mature ovarian follicles burst and release ovum
- caused by a surge in LH
LH (luteinizing hormone) induces the ruptured follicle to develop into the corpus luteum (it secretes estrogen and progesterone)
if ovum isn't fertilized the corpus luteum dies (the drop in estrogen/progesterone causes the endometrium (membrane with lots of blood) to slough off
- no fertilization takes place.
- genetic carbon copies
- asexual reproduction
- used in prokaryotes
- the cell just divides down the center.
- the replication of the nucleus followed by unequal cytokinesis
- yeast and hydra
- like starfish growing an arm, or a salamander growing a tail
- needs the central disk in the limb
- occurs by mitosis
- the development of an unfertilized egg innto an adult
- male bees develop this way. not fertilized
Sexual reproduction in plants
- alternate between diploid sporophyte to haploid gametophyte
- evolution trends toward dominance of the sporophyte generation
- haploid gametophyte produces gamets (1n) by mitosis.
- they join and fertilize together (sexual reproduction)
Sporophyte generation (2n)
- diploid (2n)
- meiosis goes to 1n, and then to gametophyte (1n)
- reproduces asexually
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