What is mitosis?

The process in which a eukaryotic cell nucleus splits in two. (A parent cell to 2 daughter cells)

What does the word mitosis mean?

threads (because of its threadlike appearance)

What are the microtubules collectively known as?

the spindle

What are centrosomes?

they organize the microtubules and control cell division

What are the phases of mitosis?

Prophase, prometaphase, metaphase, anaphase, telophase, cytokinesis

What happens during prophase?

The first stage of mitosis. when the parent cells condense and become compacted. The miotic spindle also begin to form

Each duplicated chromosome consist of _______ joined at a point called the _______.

two sister chromosomes; centromere

What DNA-binding proteins catalyze the condensation process?

cohesin and condensin

What is cohesin?

It forms rings that hold the sister chromatids together

What is condensin?

Forms rings that coil the chromosomes into compact forms

What happens in prometaphase?

phosphorylation of nuclear lamins by M-CDK causes the nuclear membrane to break down into numerous small vesicles. The spindle microtubules now have access to DNA

What is the kinetochore?

a complex of proteins positioned at the centromere. Its kind of like a tug of war game that ensues as the chromosomes move back and forth toward the two poles

What happens during metaphase?

the chromosomes align along the cell equator and become balanced. The chromosomes no longer move back and forth. The spindle is also complete.

What does the kinetochore microtubules do during metaphase?

they attach the chromosomes to the spindle pole

What does the interpolar microtubules do during metaphase?

extend from the spindle pole across the equator, almost to the opposite spindle pole

What do the astral microtubules do during metaphase?

They extend from the spindle pole to the cell membrane

What happens during anaphase?

Each chromosome's sister chromatids separate and
move to opposite poles of the cell. Cohesin also breaks down, and every chromatid becomes an independent chromosome.

What happens specifically in anaphase A?

the kinetochore microtubules shorten and draw the chromosomes toward the spindle poles

What happens specifically in anaphase B?

the astral microtubules that are anchored to the cell membrane pull the poles further apart and the interpolar microtubules slide past each othe

What happens during telophase?

the chromosomes arrive at the cell poles, the mitotic spindle disassembles, and the vesicles that contain fragments of the original nuclear membrane assemble around the two sets of chromosomes

The dephosphorylation in telophase results in the formation of what?

new nuclear membrane around each group of chromosomes

What happens during cytokinesis?

the physical process that finally splits the parent cell into two identical daughter cells

What is the cleavage furrow? And what filaments cause this?

During cytokinesis, the cell membrane pinches in at the cell equator, forming a cleft. myosin and actin filaments

What is meiosis?

cell division that educes the number of chromosomes in the parent cell by half and produces four gamete cells. (It produces egg and sperm cell for sexual reproduction)

What are the steps of meiosis?

It starts with a diploid parent and the parent goes through DNA replication and are then separated in 2 cycles. The results are 4 haploid daughter cells which contain half the number of chromosomes.

What is meiosis I?

A type of cell division unique to germ cells

What are the steps of prohase I?

1. the complex of DNA and protein known as chromatin condenses to form chromosomes.

2. The pairs of replicated chromosomes are known as sister chromatids, and they remain joined at a central point called the
centromere

3. A large structure called the meiotic spindle also forms from long proteins called microtubules on each side, or pole, of the cell

What is a tetrad?

(Formed by homologous chromosomes between prophase I and metaphase I.) Within the tetrad, any pair of chromatid arms can overlap and fuse in a process called crossing-over or recombination.

What is recombination?

A process that breaks, recombines and rejoins sections of DNA to produce new combinations of genes.

What happens in metaphase I?

the homologous pairs of chromosomes align on either side of the equatorial plate

What happens in anaphase I?

the spindle fibers contract and pull the homologous pairs, each with two chromatids, away from each other and toward each pole of the cell.

What happens in telophase I?

The chromosomes are enclosed in nuclei

What happens in cytokinesis in meiosis I?

It divides the cytoplasm of the original cell into two daughter cells where each one has half the total number of chromosomes of the original cell

What is meiosis II?

It is very similar to mitosis and is the division of each haploid cell produced by the first stage

What happens during prophase II?

The chromosomes condense, and a new set of spindle fibers forms. The chromosomes begin moving toward the equator of the cell.

What happens during metaphase II?

the centromeres of the paired chromatids align along the equatorial plate in both cells.

What happens during anaphase II?

the chromosomes separate at the centromeres. The spindle fibers pull the separated chromosomes toward each pole of the cell.

What happens during telophase II?

The chromosomes are enclosed in nuclear membrane

What happens during cytokinesis in meiosis II?

dividing the cytoplasm of the two cells where there are 4 haploid daughter cells that develop into sperm or egg cells

What is sex linkage?

genes that are located on the sex chromosomes.

What are sex chromosomes?

They determine whether an individual is male or female. (females (eggs) have XX and males(sperm) have XY)

What are non-sex chromosomes called?

autosomes and they come in homologous pairs

What are homologous pairs?

They have the same gene arranged in the same order

True or false. X and Y chromosomes have different genes

true

How many genes do the X and Y chromosomes have?

X - more than 1000

Y - only a few

An egg and sperm join to make what?

a zygote which develop into an offspring

Which chromosomes passes from father to son?

Y chromosome

Genes code for what?

proteins and proteins make traits

What are alleles?

different versions of the same gene

Why are sex linked disorders more common males than female?

Because males have no back up copy of genes. These differences lead to specific inheritance patterns for sex linked genes

Recombination makes what?

new allele combinations, which can be passed to offsprings

In which sex chromosomes is no recombination?

the XY male animals

True or false. Genes that are genetically linked are inherited separately less than 50% of the time

true

What is sordaria?

A fungus that is convenient to use in labs for conducting tetrad analysis of segregation of color mutants. (Spends half of its life in a haploid vegetative state)

Finish reading about sordaria

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