AP Bio - Meiosis (Unit 11)

What are homologous chromosomes?

Paired chromosomes with the same size, same banding pattern, same type of genes but not necessarily the exact same forms of each genes (alleles). An example gene on one chromosome for brown eyes and gene on its homologue for blue eyes

What are sister chromatids

Halves of the same double chromosome and are exact copies if one another

Karyotype (definition and what process and phase is this best observed in)

Spread of human chromosomes (looking for chromosomal abnormalities) and must get the cell in mitosis, typically near metaphase so chromosomes are clear and present

Diploid (def and # of n)

cell with the normal # of chromosomes (2n)

Haploid (def and # of n)

cell with 1/2 the normal # of chromosomes (n)

Somatic cell (def an # of n)

Normal body cell (2n)

Sex cell, gamete (what type of cells, diploid/haploid)

sperm and egg haploid cells

Germ cell (def and what # of n)

2n cell that is the precursor to the gametes (becomes a gamete through meiosis)

Meiosis

cell division process that produces sperm and egg (n)

The purpose of _____ is to make ______ sex cells so that when they come together, the _____ has the normal amount of ___ (_n)

meiosis, haploid, zygote, DNA, 2

What else happens in prophase in meiosis that is different from prophase in mitosis

Synapsis (coming together and laying on top of each other) and crossing over between non-sister chromatids ain a homologous pair of chromosomes resulting in recombinant DNA

Chiasma

The place where the crossing over actually happens

In ______ _, _____ ____ line up down the ____, and in _____ _, the _____ ____ move to opposite ____ of the cell.

metaphase I, homologous chromosomes, center, anaphase I, homolgous chromosomes, poles

In ______ _, the ______ ____ (which are now _____) regather into nuclei, and the original ___ divides

telophase I, homologous chromosomes, separated, cell

Meiosis I is the _______ _____ because the cell went from __ chromosomes to __ chromosomes (in humans)

reduction division, 46, 23

After meiosis I, the daughter cells are now _____ but they don't yet have ___ of the ___ of the original ___ ___, so they must undergo _______ ___.

haploid, half, DNA, germ cell, meiosis II

What happens in between meiosis I and meiosis II briefly and what's special about it?

A brief interphase takes place where DNA does not replicate (already done in interphase before meiosis I)

In ____ II, the _____ recondense, reforming in the two ____ ___

prophase, chromosomes, daughter cells

In _____ II, each _______ ______ lines up down the ____ and _____ _____ split. Then, in _____ II, the ______ of the ______ finally separate by the ______, becoming their own _______, and move to opposite ___.

metaphase, individual chromosome, center, sister chromatids, anaphase II, chromatids, chromosomes, centromeres, chromosomes, poles

In _____ II, the ______ gather into nuclei, and the cells _____, each of the ____ cells has a _______ with a ______ # of chromsomes. Now that ______ _____ split, we have ____ _____ chromosomes in a human cell, the DNA of a normal cell.

telophase, chromosomes, divide, four, nucleus, haploid, sister chromatids, 23 single

If a skin cell has 60 chromosomes, how many chromosomes are in G1?

60 single

If a skin cell has 60 chromosomes, how many chromosomes are in Metaphase I?

60 double

If a skin cell has 60 chromosomes, how many chromosomes are in Metaphase II?

30 double

If a skin cell has 60 chromosomes, how many chromosomes are in Anaphase II?

60 single

If a skin cell has 60 chromosomes, how many chromosomes are in the gametes?

30 single

Happens in germ cells

Occurs in mitosis, meiosis, or both?

Both

happens in flowering plants

Occurs in mitosis, meiosis, or both?

Both

separation of homologous pairs

Occurs in mitosis, meiosis, or both?

Meiosis

separation of sister chromatids

Occurs in mitosis, meiosis, or both?

Both

happens in somatic cells

Occurs in mitosis, meiosis, or both?

Mitosis

creates n cells

Occurs in mitosis, meiosis, or both?

Meiosis

creates 2n cells

Occurs in mitosis, meiosis, or both?

Mitosis

homologs pair up

Occurs in mitosis, meiosis, or both?

Meiosis

Happens after puberty in males

Occurs in mitosis, meiosis, or both?

Both

creates genetically dissimilar daughter cells

Occurs in mitosis, meiosis, or both?

Meiosis

happens the same way in both male and female

Occurs in mitosis, meiosis, or both?

Mitosis

involves the lining up of autosomes on the metaphase plate

Occurs in mitosis, meiosis, or both?

Both

daughter cells have a sex chromosome

Occurs in mitosis, meiosis, or both?

Meiosis

For males:

Germ cell (undergo _______ and one _____ cell goes through _______) starting at _____ and continuing until _____.

The _____ cell divides evenly into _ sperm

______ then undergo changes to become ______ (spit out all of their ____ ____, ____ their _____, grow a _____).

mitosis, daughter, meiosis, puberty, death, germ, 4, gametes, sperm, cell parts, condense, DNA, flagella

For females:

Germ cell (undergo _______ and one _____ cell goes through _______)

____ cells start _____ in ________ development and at ____

all "eggs" are "_______" in ______ _

After puberty, 1 "egg" per month is ovulated and finishes ____ __ and "_____" in ______ __ again

The cell's _________ divides ______ to produce 1 _____cell which will be the ____ and 1 ____ ___

At ________, meiosis finishes to form 1 _____ ____ and 1 ____ ____

mitosis, daughter, meiosis, germ, meiosis, embryonic, birth, frozen, metaphase I, meiosis I, freezes, metaphase II, cytoplasm, unevenly, large, egg, polar body, fertilization, haploid egg, polar body

Independent assortment

the arrangement of each homologous chromosome pair in metaphase 1 and metaphase 2 of meiosis is independent of each other and results in genetic variation. Each chromosome is independent of any other chromosome which gametes it's going into.

What step determines the final assortment (the way chromosomes are arranged independently)?

Metaphase I (of meiosis)

Random fertilization

source of genetic variation caused by the unlimited number of possible sperm & egg combinations

Nondisjunction

Chromosomes failing to separate in meiosis - either in anaphase I or II. This can lead to trisomies or Monosomies like down syndrome.

Aneuploidy

Presence/state of an abnormal # of chromosomes in a cell

Translocations

Rearrangements of nonhomologous chromosomes due to the insertion of genetic material from one chromosome to another