gametogenesis

Question 1

what is gametogenesis ?

Answer 1

formation and development of gametes

Question 2

what are the two types of gametogenesis?

Answer 2

spermatogenesis and oogenesis

Question 3

what is spermatogenesis?

Answer 3

formation of spermatozoa (sperm) in the testis

Question 4

what is oogenesis?

Answer 4

formation of ova (eggs) in the ovary

Question 5

describe spermatogenesis

Answer 5

• commence at puberty and continues through life
• millions of sperm (haploid) produced continuously with uninterrupted meiotic division
• 4 sperm per spermatogonia
• occurs in seminiferous tubules (from outside in)
• spermatozoa then transported and stored in epidiymis
• testosterone produced by interstitial cells
• sertoli cells provide nourishment

Question 6

what is oogenesis?

Answer 6

production of ova in ovaries

Question 7

what happens in oogenesis before and at birth?

Answer 7

before birth = oogonia undergo mitosis to make more oogonia
at birth = hundreds of oogonia which have developed into primary oocytes , within a single layer of cells - primary follicle

Question 8

what happens at the commencment of each cycle during Oogenesis?

Answer 8

several primary follicles develop into secondary follicles

Question 9

what happens at the 1st meiotic division during Oogenesis?

Answer 9

• produces secondary oocytes
• uneven division
• also produced a polar body which may divide again to produce two

Question 10

what is a polar body?

Answer 10

non viable
haploid cells
disintegrate

Question 11

is the second last step of Oogenesis?

Answer 11

• Secondary oocyte is released at ovulation

- if fertilized by sperm, undergo another meiotic division to become and ootid

Question 12

waht is the last step in oogenesis?

Answer 12

Ootid becomes an ovum prior to the pronucleus of each gamete fusing to become a zygote

Question 13

what are some similarities between spermatogensesis and oogenesis?

Answer 13

• start with germ cells
• start with mitosis to produce multiple cells
• involve cell growth before mitosis
• involve create haploid cells

Question 14

what are some differences between spermatogensesis and oogenesis?

Answer 14

• testes vs ovaries
• millions produced daily vs one per month
• ejaculation vs ovulation
• puberty vs before birth
• doesnt stop vs stop at menopause
• four sperm per meiosis vs 1 eggs per meiosis

Question 15

what are the differences between sperm and eggs

Answer 15

• Sperm has a tail, ovum doesn’t
• Ovum has more cytoplasm than sperm
• Sperm has an acrosome, ovum doesn’t
• Ovum is larger, sperm are smaller
• Sperm are produced in greater number than ovum