B3 REVISION

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  • Created by: jojboj
  • Created on: 03-04-16 20:06

B3 REVISION

Chromosomes are inside the nucleus.

Chromosome = 1000s of coils of genes.

Genes have DNA - DNA decides our charcteristics.

Each gene acts as a code for a particular characteristic.

A human egg cell and sperm cell contains 23 chromosomes

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B3 REVISION

An Animal Cell contains-

- Nucleus (controls the cells function)

- Cytoplasm (Chemical reactions take place here)

- Cell membrane (allows things to enter and leave the cell)

- Mitochondria (Energy is released here by respiration)

A Plant Cell contains the same but also includes-

- Cell wall (cell support)

- Large vacuole (filled with a solution of sugars and salts)

- Chloroplasts (Photosynethesis happens here)

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B3 REVISION

Cell Division

Mitosis and Meiosis are the two types of cell division.

Mitosis enables growth and repair to occur.

Meiosis is for the production of sex cells.

Mitosis is used in asexual reproduction.

Meiosis is used to produce gametes for sexual reproduction

Mitosis prodcues cells with identical number of chromosomes and genetic information are produced (46 in humans).

Meiosis produces daughter cells with half the number of chromosomes of the parent (23 in humans)

Mitosis (Asexual)

Mitosis is a process of cell division which results in the production of two daughter cells from a single parent cell.

The daughter cells are identical to one another and to the original parent cell.

Each chromosome replicates.

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B3 REVISION

The right side of the heart pumps de-oxygenated blood to the lungs to pick up oxygen.

The left side of the heart pumps the oxygenated blood from the lungs around the rest of the body.

1. Deoxygenated blood enters through the vena cava into the right atrium

2. It’s then pumped through a valve into the right ventricle chamber

3. And then up through the pulmonary valve into the pulmonary artery towards the lungs

4. Oxygenated blood enters through the pulmonary veins into the left atrium

5. It’s then pumped through a valve into the left ventricle

6. And then through the aortic valve and out of the aorta to the rest of the body

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