bio - 3a. reproduction in humans (not done)

3 facts about asexual reproduction

• only 1 parent cell required, allows for rapid reproduction - normal cell division by mitosis only

• parent will divide in 2 to make 2 genetically identical offspring, clones

• works well in stable environments

3 facts about sexual reproduction

• 2 parent cells required, slower - involves the production of gametes via meiosis, each parent passes down half theur genetic info in their gametes (haploid cells) - offspring are genetically varied

• allow species to adapt to changing environments e.g. humans

how do bacteria reproduce

binary fission

how do fungi reproduce

budding - asexual

what are the 4 stages of sexual reproduction

• The gametes are produced

• the male gamete is transferred to the female gamete

• fertilisation must occur

• the zygote formed then develops into a new individual

how are gametes produced

via meiosis, produces cells that aren’t genetically identical and are haploid

what is a gene

a section DNA that determines a particular characteristic or feature. Genes are found on the chromosomes within a nucleus

what is fertilisation

the fusion of the nuclei of the male and female gametes in sexual reproduction to result in a zygote.

asexual v sexual reproduction

• 1 parent cell vs 2 parent cells

• genetically identical vs genetic variation

• asexual - no gametes are formed while in sexual r. they are

• asexual - no fertilisation to form a zygote sexual r. there is

what is the cervix

the strong circular muscle that holds the baby in place

what is the oviduct

where fertilisation takes place if a sperm is present to form a zygote

what is an ovary

produces eggs and secretes oestrogen the female sex hormone that causes secondary sexual characteristics

what is the uterus

where implantation of the embryo occurs, part of it that implants into the uterine wall will become the placenta that will provide nutrients

what makes up an egg cell

nucleus

cytoplasm - contains a food store to provide energy for the zygote

cell surface membrane

jelly coat - ensures only one sperm cell can enter

what is the acrosome in the sperm

sac of enzymes that digests the outer membrane of the egg cell allowing the sperm to penetrate

what is the nucleus in a sperm

it contains genetic information, 23 chromosomes as a haploid

role of mitochondria in a sperm cell

many mitochondria for aerobic respiration to release energy, to allow the tail to move so the sperm can swim

what is the function of the penis

inserts into the vagina during sexual intercourse so semen can be ejaculated by the cervix

what is the function of the testes

hangs outside the body to produce sperm at their optimum temp.

what is the function of the sperm duct

where the fluids are added from the seminal vesical to make semen

what is the max. number of X chromosomes found in the nucleus of a sperm cell

1

chromosomes of a female cell

XX

chromsomes in a male cell

XY

what is the route of implantation

fertilised cell/ zygote

embryo - zygote divides via mitosis to become a ball of cells

foetus - an embryo with a full set of organs

the placenta allows the embryo to…

• anchor the embryo in uterus

• obtain oxygen, nutrients (glucose, amino acids, fatty acids) and antibodies from the mothers blood

• get rid of waste products e.g. urea and CO2

what does the placenta do in terms of hormones

secretes the female hormone progesterone which maintains the pregnancy and causes primary sexual characteristics

what is the membrane amnion

• it encloses the developing embryo

• the amnion secretes fluid called the amniotic fluid which protects the embryo from

sudden movements

changes in temp.

bumps

effects of testosterone

secondary sexual characteristics

• sperm production begins

• growth of armpit, pubic and facial hair

• increase in body mass

• voice breaks

• sexual drive develops

effects of oestrogen

secondary sexual characteristics

• menstrual cycle begins

• growth of armpit and pubic hair

• increase in body mass, hips

• voice deepens

• sexual drive develops

• breasts develop

what does the pituitary gland have to do with reproduction

FSH and LH are produved here, oestrogen and progesterone inhibits their production

functions of FSH

• it stimulates egg maturation

• stimulates follicles in the ovaries to secret oestrogen

functions of LH

• it stimulates ovulation

• results in formation of a corpus luteum (which secretes progesterone)

functions of oestrogen

• causes the lining of the uterus to thicken and develop AFTER MENSTRUATION

• stimulates secretion of LH

• slows down production of FSH

functions of progestrone

• maintains the lining of the uterus

• inhibits LH and FSH production

label each sex hormone

pink - FSH

red - LH

orange - oestrogen

yellow - progesterone