Meioses/Mitosis

Interphase - Mitosis

cells that are about to divide replicate DNA

During mitosis, the chromosomes move because

chromosomes attach to a dynamic, precisely regulated mitotic spindle

What must happen before a cell can begin mitosis?

chromosomes must be duplicated

Cytokinesis

cytoplasm of eukaryotic cell divides to produce two cells

What is Variation?

result of independent assortment & crossing over

Recombination

segments of non sister chromatids trade places

What happens in Meiosis II

sister chromatids are separated

Which of the following is a key difference between meiosis and mitosis?

synapsis occurs during prophase I of meiosis

S phase stands for

synthesis of DNA

Asexual Reproduction

the creation of genetically identical offspring by a single parent, without the participation of sperm and egg

The first step of bacterial replication is?

DNA Replication

Where do sister chromatids come from?

DNA Replication

What is result of crossing over?

Genetic Recombination

Independent Assortment

Independent segregation of genes during the formation of gametes

Stages of Mitosis

Interphase Prophase Metaphase Anaphase Telophase (Cytokinesis)

Variation occurs when chromosomes are shuffled in?

Meiosis

After fertilization, the resulting zygote begins to divide by

Mitosis (gametes divide by Meiosis)

Meiosis 2

Pro - nucleus envelope breaks, new spindles form Meta - spindle fibers bind to both sides of centromeres Ana - spindle fibers contract , sisters move to opposite poles Tele - nucleus envelope reforms around SETS of daughters (4 sets)

Meiosis 1

Pro- recombination, synapsis Metaphase -nucleus membrane disappears, microtubules form, homo chromo lineup Anaphase - chromosomes pull toward poles taking sisters Tele/Cyto- nucleus membrane reforms around daughters

Crossing over occurs during?

Prophase 1 - Meiosis

What is Synapsis and where does it occur?

Prophase 1 of meiosis and it is the pairing of homologous chromosomes

Chromatids form during

S phase - Interphase

Where is DNA synthesized?

S phase of interphase

Production of S phase - Interphase

Single chromosomes enter the synthesis or S phase of interphase. At the end of this phase, after DNA replication, the chromosomes are double, each consisting of TWO SISTER CHROMATIDS.

During which phase of mitosis does the nuclear envelope re-form?

Telophase - Mitosis

Within one chromosome, what is the relationship between the sequence of bases in DNA of one sister chromatid compared to the other?

The sequences are identical

What kind of cell does Meiosis start with?

a single diploid cell

What does Meiosis produce?

4 haploid cells

# of chromosomes of human zygote

46

Autosomes

Any chromosome that is not a sex chromosome

What occurs during Mitosis?

Chromatids separate (during anaphase)

Meiosis occurs in

ovaries & testes

Method bacteria divide by?

binary fission

Telophase - Mitosis

- chromosomes arrive at poles -nuclear envelope forms

Prophase 1 - Meiosis

- homologous chromosomes stick together in pairs -recombination

Anaphase - Mitosis

- sister chromatids separate & become chromosomes - move to opposite poles

Homologous Chromosomes

-identical in arrangement of genes -genes may differ between chromosomes

Metaphase - Mitosis

-spindle fully forms - chromosomes line up

Prophase - Mitosis

1) centrosomes move away from each other& nuclear envelope breaks 2) mitotic spindle begins to form

What is different concerning the DNA in bacterial cells as opposed to eukaryotic cells?

1) whether DNA is linear or circular 2) the amount of DNA present 3) whether the DNA is housed in a nucleus or not

How many pairs of autosomes & sex chromosomes do humans have?

22 & 1 pair of sex chromosomes

Order of Meiosis

interphase prophase 1 metaphase 1 anaphase 1 telophase 1 cytokinesis -> meiosis 2

All sexual life cycles involve

an alteration of diploid and haploid stages

The function of mitosis is to produce daughter cells that?

are genetically identical to the parent cell (assuming no mutation has occurred)

As a patch of scraped skin heals, the cells fill in the injured area but do not grow beyond that. This is an example of

density- dependent inhibition

Cell Division involves

distribution of identical DNA to two daughter chromosomes.

Interphase - Meiosis

duplicates chromosomes

What is a feature of plant cell division that distinguishes it from animal cell division?

formation of a cell plate

At the conclusion of meiosis I, the daughter cells are

haploid and the sister chromatids are joined