Meiosis, Development and Aging Flashcards
Complex multi-step process that is complete in 24 hours
Fertilization
- The sperm from a male meets an ovum from a female and forms a zygote
- The first cell that a lead to development of a new individual is a fetilized ovum
Zygote
It forms when a _________ form a male and an _________ (also called an egg cell) from a female joint.
sperm
oocyte
The point in which pregnancy begins and leads to a ___day journey for a female
280 day
Sperm and oocyte are ________, or sex cells
Gametes
Paired structures, called _________, where the sperm and oocyte are manufactured:
Gonads
Male Gametes:
The _____________ are packed into paired, oval organs called testes.
Seminiferous Tubules
Also passes through the epididymis and ductus deferentia, where they mature before exiting the body through the urethra during sexual intercourse.
Male Gametes
Originates in the ovaries
Female Gametes
The female sex cells develop in paired organs in the abdomen
Ovaries
The uterine tube carries the oocyte into a muscular, saclike organ
Uterus or Womb
Oocytes are ____________
Female gametes
Female Gametes: Each month after puberty, one vary releases an oocyte into a uterine tube.
The oocyte then moves to the uterus for implantation or __________
Expulsion
- Packed, paired, oval organs of seminiferous tubules
- Male Gonads
Testes
- Lie outside the abdomen within a sac
- This location keeps the testes cooler than the rest of the body for the development of sperm.
Scrotum
A tightly coiled tube in which sperm cells mature and are stored.
Epididymis
Epididymis continues to another tube
ductus deferens
Tube that carries sperm and urine out of body through the penis
Urethra
a pleasable sensation. Accompanied by rhythmic muscular contractions that eject the sperm from each ductus deferens
Organsm
Discharge of sperm from the penis (delivers 200 to 600 million sperm cells)
Ejaculation
3 glands that add secretions along the sperm’s path
Prostate Gland
Seminal Vesicles
Bulbourethral Gland
■ The ductus deferentia/deferens pass through this.
■ Produces a thin, milky, acidic fluid that activates the sperm to swim.
Prostate Gland
- Opening into the ductus deferens; a duct
- Secrete fructose (an energy-rich sugar) and hormone like
prostaglandins (stimulates contractions in the female that help sperm and oocytes meet)
Seminal Vesicles
■ Each about the size of a pea.
■ For alkalinity of pH mucus.
■ Join the urethra where it passes through the body wall.
■ Secrete an alkaline mucus that coats the urethra before sperm are released.
Bulbourethral Gland
○ Female sex cells develop in paired organs in the abdomen.
○ Female gonads
○ Houses oocytes in different stages of development.
Ovaries
○ Muscular, saclike organ.
○ The uterine tube carries the oocyte in this organ.
○ Its lower end narrows and leads to the cervix.
Uterus or Womb
- Opens into a tubelike vagina
Cervix
Where the oocyte (released from the ovary) may encounter the sperm
Uternine Tube
Fertilized Ovum
- After a day, the first cell divides while moving through the uterine tube.
- Settles into a lining of the uterus to continue dividing and developing into an _______.
- If not fertilized, it will be expelled through ________.
embryo
menstruation
Contains one copy of the genome from each parent (haploid)
Germ Cell
Contains two copies of the genome (diploid)
Somatic Cells (Body cells)
Chromosomes pairs are called
Homologous Pairs
A genetically overloaded cell, with more than two sets of chromosomes
Polyploid
Meiosis is actually 2 divisions of the genetic material.
Reduction Meiosis
Equational Meiosis
- Mixes up trait combinations
- Occurs after Interphase (replication of DNA)
Meiosis
Where games form special cells called
Germline
Sculpts the distinctive characteristics of sperm and oocyte
Maturation
Contribute 23 different chromosomes constituting one copy of the genome, to a fertilized ovum
Gametes
Contain 23 pairs of chromosomes = 46 in total.
Somatic Cells
- First division of the genetic material in Meiosis
Reduction Division
- Random alignment of chromosomes during metaphase I
- Fate of a gene on one chromosome is not influenced by a gene on a different chromosome.
Independent Assortment
Interphase II