Meiosis 111 Flashcards
(29 cards)
What are gametes?
Sex cells (sperm or egg)
What is a diploid cell?
2 sets of chromosomes, 1 from each parent (full # of chromosomes)
What’s a homologous chromosome?
2 chromosomes of same length with same sets of genes
What’s crossing over?
Recombination, pieces of homologous chromosomes are swapped . Increases genetic diversity in next generation(new gene combos)
What’s a haploid cell?
Cell with half normal chromosome number
What is the result of Meiosis?
Cell division happens twice,
Ends with 4 haploid cells with single stranded chromosomes. (Unique gene combinations in each)
What’s nondisjunction?
Chromosomes don’t separate
normally during meiosis anaphase
Results in extra or missing chromosomes in gametes
May lead to chromosomal disorders like down syndrome
When/How Long does the menstrual cycle last for?
Begins at puberty, ends at menopause (ex 13-53)
Lasts 28 days or so.
What hormones are released by pituitary gland?
FSH = follicle stimulating hormone
LH = luteinizing hormone
What hormones are released by ovaries?
Estrogen - female hormone
Progesterone - Pregnancy hormone
What happens during the Follicle Stage of Menstrual Cycle
estrogen and progesterone are low, FSH is released - > increases
Follicles (chambers with eggs) starts to mature
Follicles release estrogen
Uterine lining thickens
What happens during the Ovulation Stage of Menstrual Cycle
Day 14,
Estrogen stops
FSH release
Increases LH
Follicles bursts open to release egg
What happens during the Corpus Luteum Stage of Menstrual Cycle
Broken follicle fills with cells -> becomes corpus luteum
Secretes progesterone to maintain uterine lining
What happens during the Menstruation Stage of Menstrual Cycle
No fertilization
Corpus luteum will disintegrate
decreases progesterone
Uterine lining + egg are shed.
What’s the order of the Menstrual Cycle?
Follicles stage -> Ovulation -> Corpus Luteum Stage -> Menstruation
What happens in the female reproduction system and what are the parts of it?
Produces eggs, Site of internal development + internal fertilization
Uterus - Where the fetus develops
Vagina - Birth canal
Ovaries - Female reproductive organ and stores eggs
What are the parts male reproductive system and where is sperm produced
Sperm is produced in testes
Sperm is released from the vas deferens
Penis - reproductive/urinary organ
Testosterone - male hormone
Semen - fluid sperm swims in
Pathway:
testis - epididymis -> vas deferens - > urethra
What’s internal and external fertilization
Internal: occurs inside female, protects eggs
External: must occur in water, many egg cells.
What’s internal and external development
Internal: inside female
External: inside eggs
What happens during internal development in humans.
Zygote begins mitotic division and forms a embryo.
Embryo grows via Mitosis while oviduct transports it to the uterus
Embryo implants into uterine lining where it receives nourishment and cells differentiate
Development of placenta: organ that nourishes fetus
Embryo is considered a fetus by week 9
Fetus develops further
Birth by week 40
What are some things that help the fetus develop in the uterus?
Placenta: Temporary organ made of embryonic and uterine cells
Delivers nutrients and oxygen, removes wastes from fetal blood
Maternal and fetal blood don’t mix
Umbilical cord: connects fetus to placenta
Amniotic sac and amniotic fluid:
Protects fetus from shock
What’s Morula, Gastrula, Blastula? (When a Zygote develops into a fetus)
Morula - solid ball of cells
Blastula - hollow ball of cells
Gastrula - 3 layers of cells are present
(In order)
What is the separation of homologous pairs of chromosomes in meiosis?
Disjunction
What are some changes to the mother’s body
Uterus enlarges and breast tissue enlarges and begins milk production
