Meiosis and Reproduction

What are the 3 parts of sexual reproduction?

meiosis, gamete production, fertilization

Does the process of sexual reproduction produce variation among offspring?

yes

what does sexual reproduction provide for?

Genetic diversity among offspring

what does sexual reproduction help to eliminate?

mutations

approximately how many genes are coded for in each human’s DNA?

About 20,000 to 25,000 genes.

How many genetic combinations does that mean are possible?

8 million

where does this variation occur in the process of meiosis?

occurs in crossing-over in prophase 1

What are the homologous chromosomes?

chromosomes pairs that are like in shape and genetic information

how many sets does each cell have?

2 sets of 23

Where do the chromosomes come from?

mom and dad

What are alleles?

different forms of the same trait that are found on homologous chromosomes

where are alleles found?

traits

how are alleles distributed?

meiosis randomly distributes

How many chromosomes are in each cell?

46

where did the 2 sets of chromosomes come from?

one set from each parent

what type of cells have 2 sets of chromosomes?

Somatic cells, or diploid cells.

How many divisions are there in the process of meiosis?

Meiosis consists of two divisions, meiosis I and meiosis II, which result in four haploid cells.

Is the DNA duplicated between 2 division?

No, DNA is only duplicated once before meiosis I. It does not undergo duplication before meiosis II.

For each cell that undergoes meiosis, how many cells result?

Four haploid gametes.

How do the chromosomes arrange themselves in prophase 1 of meiosis 1?

During prophase I of meiosis I, homologous chromosomes pair up and undergo crossing over, resulting in genetic recombination.

what happens to portions of the DNA strands of the homologous chromosomes?

They exchange segments through crossing over, leading to genetic diversity.

what is exchange?

The process where segments of DNA are transferred between homologous chromosomes during prophase I of meiosis, enhancing genetic variation.

what is the result of each chromosome?

The result is two genetically distinct sister chromatids for each chromosome, which are separated during meiosis II.

what is created in meiosis 1?

Two haploid daughter cells are created, each containing half the number of chromosomes.

What is separated in anaphase 1 of meiosis 1?

Homologous chromosomes are separated.

How many cells are there at the end of Meiosis 1?

There are two haploid cells at the end of Meiosis 1, each with half the original number of chromosomes.

what is separated at the end of anaphase 2 of meiosis 2?

Sister chromatids are separated.

how many cells are there is total at the end of meiosis 2?

There are a total of four haploid cells at the end of meiosis 2, each containing half the original number of chromosomes.

What are the parts of the male reproductive system?

testis, epididymis, vas deferens, glands, penis, urethra

testis:

produces sperm, secretes testostrone

epididymis:

area of sperm maturation

vas deferens:

carry mature sperm for release

glands:

produce fluids that transport and support sperm

penis:

deliver sperm

urethra:

dual purpose duct

what are the glands of the male reproductive system?

bulbourethral, prostate, seminal

bulbourethral:

secretes lubricating mucus

prostate:

secretes fluid and buffers

seminal:

produces fluid high in fructose that provides nutrients for sperm

what are the parts of the female reproductive system?

ovary, oviduct, uterus, cervix, vagina

ovary:

produces eggs and releases estrogen

oviduct:

carries mature egg towards uterus

myometrium:

muscles of the uterus

endometrium:

inner lining of the uterus

cervix:

opening of uterus

vagina:

muscular tube; birth canal

what is spermatogenesis?

the process by which sperm cells (spermatozoa) are produced in the male testes

where does it spermatogenesis occur?

testes

what is the first germ cell called?

spermatogonia

after a period of growth what is the cell called?

spermatocyte

how many are created?

four mature sperm cells

what is oogenesis?

is the process by which egg cells (ova) are produced in the ovaries of females. It involves the development and maturation of primary oocytes into mature egg cells, ready for fertilization.

in what part of the female reproductive system does it occur?

ovaries

what is the first cell called female?

oogonium

after growth what is the cell called female?

primary oocyte

how many cells result female?

one mature egg