Cell Division

Asters in prophase of mitosis and meiosis

Asters form around the centrioles which move apart to opposite poles of the cell.

Meiosis Definition

Form of nuclear division that produces daughter nuclei containing half the number of chromosomes as the parent nucleus.

Chromatin threads in prophase

Chromatin threads condense, coil and shorten to become chromosomes.

cytokinesis in plants

Cleavage of cytoplasm does not occur during cytokinesis, instead, a cell plate is formed between two daughter nuclei, dividing the cell into two.

Centrioles during interphase

centrioles divide in an animal cell at interphase.

Chromatin threads during interphase

Chromatin threads replicate producing two identical sister chromatids attached to the centromere that is not visible under the microscope.

Homologous chromosomes in the anaphase of meiosis

Homologous chromosomes separate and are pulled to opposite poles of the cell as the spindle fibres shorten.

nuclear envelope during telophase

A(n) nuclear envelope forms around the chromosomes at each pole, followed by the division of the cytoplasm.

Chromosomes during metaphase

Chromosomes arrange themselves on the equatorial plane of the spindle.

sister chromatids in anaphase of mitosis

The centromeres divide and sister chromatids separate and become daughter chromosomes, which are pulled towards opposite poles of the cells.

Cytokinesis of meiosis I

The cytoplasm cleaves into two, producing two daughter cells, each with a(n)] haploid number of chromosomes, the centrioles divide.

Gametes definition

Reproductive cells that contain half the number of chromosomes as normal body cells, sex organs go through meiosis.

Interphase of mitosis

Cells are resting /non-dividing, carrying out activities such as absorbing nutrients and building up protoplasm.

Cytokinesis of mitosis

The nucleolus reforms in each nucleus and the chromosomes uncoil and lengthen to become thin chromatin threads.

what is chiasma

Chromatids of homologous chromosomes may cross and twist around one another which is called a chiasma.

What happens during Late prophase

The nucleolus and nuclear envelope disintegrate and breakdowns.

multicellular organism

For a(n) ________ to grow, new cells must be produced by mitosis.

What is a cell plate

The cell plate is formed by the fusion of small fluid-filled vesicles produced by the Golgi apparatus.

asexual reproduction

Allows ________ to occur.

What happens during Early Prophase

Chromatin threads condense, coil and shorten to become chromosomes and chromosomes are now visible under a microscope as x- shaped structures.

What is DNA replication

DNA replication copies all the information stored within the chromosomes.

What is Fertilisation

Fertilisation is when two gametes fuse to form a zygote, which is a fertilised egg.

Why is variation important

Variation increases the chances of survival of species during changes in the environment.

What are Chromosomes

Chromosomes are made up of deoxyribonucleic acid (DNA) that stores all the information that a cell needs in order to grow and carry out vital activities by a section called genes.

chromosomes

Once the chromatids are separated, they are called daughter ________.

Meiosis

Form of nuclear division that produces daughter nuclei containing half the number of chromosomes as the parent nucleus

Why is meiosis important?

1. Meiosis produces haploid gametes
2. Meiosis results in variations in the gametes produced

Why is mitosis important?

1. Mitosis enables the growth of an organism
2. Mitosis is needed for the repair of worn-out parts of the body
3. Allows asexual reproduction to occur