Biology- Meiosis and Reproduction

meiosis

• reduces chromosome # by half

• creates reproductive cells known as gametes

• DNA replicates once and divides twice

• creates 4, genetically unique, haploid gametes

haploid

Refers to cells that contain a single set of chromosomes, representing half the genetic material of the organism.

diploid

Refers to cells or organisms having two sets of chromosomes, one set inherited from each parent.

gametes

reproductive cells with half the number of chromosomes, produced by meiosis

reduction division

a type of cell division that occurs during meiosis, where the chromosome number is halved to produce gametes with half the number of chromosomes.

crossing over

Process during meiosis where homologous chromosomes exchange genetic material, leading to genetic variation in offspring.

oogenesis

the process of egg cell formation in females through meiosis, resulting in the production of mature eggs for fertilization.

spermatogenesis

Process of sperm production that occurs in the seminiferous tubules of the testes, involving mitosis, meiosis, and spermiogenesis to produce mature sperm cells.

nondisjunction

abnormal cell division during meiosis that can lead to genetic disorders

monosomy

a genetic condition where a cell is missing one chromosome in a pair

trisomy

a genetic disorder where an individual has an extra chromosome in their cells

karyotype

A visual representation of an individual's chromosomes arranged in a systematic manner to analyze genetic abnormalities or variations.

testis

male gonads, produce sperm and testosterone

scrotum

sack of skin and tissue that contains and supports the testis

epididymis

sperm storage and where sperm mature

vas deferens

pair of ducts carrying sperm from testis to the outside through the urethra

urethra

duct leading from urinary bladder to exterior, joined by vase deferens in males, conducting both semen and urine

penis

terminal part of urethra, made up of spongy, erectile tissue

prostate gland

secretes nourishing “seminal fluid”, nourishes and helps transfers sperm

ovaries

female gonads, produces eggs

fallopian tube

tube that joins ovaries to the uterus, location of fertilization and first rounds of cell division of zygote into embryo

uterus

site of embryo implantation,

cervix

narrow neckline of the uterus, holds baby in, gatekeeper- protects internal

vagina

birth canal, tube leading from the uterus to the outside, sperm are deposited here

testosterone

produced by testes, responsible for primary and secondary sex characteristics

estrogen

produced by ovaries, stimulates growth of the eggs and secondary sexual characteristics

LSH

stimulates ovulation

FSH

produced by pituitary gland, stimulates follicle production

progesterone

produced by the corpes lutheum, high levels prevent endometrium from shedding, preparing for implantation

oxytocin

a hormone released during childbirth and breastfeeding, promoting bonding and social behavior, reducing stress and anxiety.

negative feedback

how the body maintains homeostasis- high levels of one hormones leads to a decrease in level of another

positive feedback

the effects of one reaction speed up or increase the affect of another