3.24c Mitosis 3

understand that the division of a diploid cell by mitosis produces two cells which contains identical sets of chromosomes.

mitosis consists of 6 stages:

1. interphase - dna replication
2. prophase - nucleus membranes break down
3. late prophase - chromatids move towards protein spindles
4. metaphase - centramere joins ups with spindles
5. anaphase - seperation of chromatids
6. telophase - end of mitosis

3.24b Mitosis 2

understand that the division of a diploid cell by mitosis produces two cells which contains identical sets of chromosomes.

cells which undergo the process of mitosis will divide into two cells with the same sets of chromosomes as the original.

replicated DNA are held together by a centromere

3.24a Mitosis 1

understand that the division of a diploid cell by mitosis produces which contain identical sets of chromosomes.

Mitosis describes the process of cell division, this causes a growth in the increase of cells.

3.16 DNA and Genetic Information

describe DNA molecule as two strands coiled to form a double helix. the strands being linked with a series of paired bases. adenine A with thymine T and cytosine C with guanine G

3.15 Genes

understand that a gene is a section of DNA.

each gene carries the information which defines the characteristics of the organism.

genes are located in the nucleus which are then transferred to the cytoplasm which converts the information into protein.

3.14 Chromosomes

recall that the nucleus of a cell contains chromosomes on which genes are located.

Chromosomes are composed of smaller molecules called DNA which forms the shape of a double helix.

each section of the DNA is called a gene

a single chromosome may contain thousands of genes

these genes hold the information used to produce protein

proteins give us the characteristic associated with the gene, such as blood group

different organisms have different number of chromosomes
Cat= 38
Chicken = 78
Chimpanzee = 42
Human = 46

chromosomes operate in pairs known as homologous pairs.
the nature of each pair depends on the length of the chromosome
the position of a gene is called the gene loci
if we go to the same position on the other chromosome in the same homologous, we will find another version of the same gene.

3.1 Sexual and Asexual Reproduction

describe the differences between sexual and asexual reproduction.

Sexual Reproduction -
1. Sex- male/female
2. Gametes
-male = sperm cell
-female = egg cell
3. Meiosis - half chromosomes
4. Fertilisation
5. Variation - broad

Asexual Reproduction -
1. no sex
2. no gametes
3. mitosis/binary fission
4. no fertilisation
5. variation - small

Question: What is a chromosome?