Biology - Topic 2

Genotype

The instructions provided by DNA to code for proteins that give the phenotype (A, C, T, G)

Phenotype

Term used to describe the traits that are expressed by the individual. It is physical. Inside features and outside features.

Asexual reproduction

Does not involve the fusion of sex cells. Uses mitosis to create more cells.

Sexual Reproduction

Involves the fusion of male and female gametes. Created by meiosis.

Mitosis - Interphase

During interphase DNA replicates; cell organelles replicates and the cytoplasm increases in size.

Mitosis - Prophase

Plumping of DNA to become chromosome structures. Nuclear membrane disappears. Spindle fibres start to form.

Mitosis - Metaphase

Chromosomes line up in the middle of the cell. They do this via the spindle fibres.

Mitosis - Anaphase

The sister chromatids go at each end of the cell. The sister chromatids have separated. This happens because the spindle fibres contract.

Mitosis - Telophase

Two nuclear membranes are formed around the chromatids.

Mitosis - Cytokinesis

The cytoplasm divides and two new cells form.

Order of mitosis

Interphase, prophase, metaphase, anaphase, telophase. cytokinesis.

Meiosis - Interphase

Cell prepares, DNA replication, chromatin replicates

Meiosis - Prophase (1)

DNA (replicated) plumps up/condenses into chromosome structure. Nuclear membrane disapears. Homologous pairs find each other in the cell. Sister chromatids between homologous pairs can exchange DNA.

Meiosis - Metaphase (1)

Homologous pairs next to each other in the middle of the becell. This uses spindle fibres. Which of the pairs go on the left or right side in middle is random.

Meiosis - Anaphase (1)

Spindle fibres contract, and homologous pairs move away from each other and go to the end of the cell.

Meiosis - Telophase (1)

Two nuclear membranes are formed around the replicated chromosomes.

Meiosis - Cytokinesis (1)

Cytoplasm divides, and two cells are formed. These cells contain replicated chromosomes.

Meiosis - Prophase (2)

Chromosome structure appears as DNA condenses + plumps up. Nuclear membrane disaperas.

Meiosis - Metaphase (2)

The replicated chromosmomes line up in the middle of the cell along the spindle fibres.

Meiosis - Anapahase (2)

Spindle fibres contract and the sister chromatids separate and go at each end of the cell.

Meiosis - Telophase (2)

Two nucleur membranes form around the chromotids

Meiosis - Cytokinesis (2)

Cytoplasm divides and 4 new cells are created with half the number of chromosomes compared to what you started with.

Genotype

The instructions provided by DNA to code for proteins that give the phenotype (A, C, T, G)

Phenotype

Term used to describe the traits that are expressed by the individual. It is physical. Inside features and outside features.

Asexual reproduction

Does not involve the fusion of sex cells. Uses mitosis to create more cells.

Sexual Reproduction

Involves the fusion of male and female gametes. Created by meiosis.