Mitosis and meiosis

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Mitosis

Growth and repair

Produces diploid cells identical to each other and the parent cell

Meiosis

Sexual reproduction

Produces haploid cells different to each other and the parent cell

Growth

Humans are made up of millions of cells, benefits:

Can be specialized to do particular tasks

Groups of cells can function as organs making a more efficient organism

Organism can grow very large

Cell division

New cells needed throughout life

For growth; replace damaged cells and worn down tissues

Normal human body cells are diploid that have two of each chromosome

When new cells are made the 46 chromosomes are copied exactly by mitosis

Mitosis

Type of cell division used for growth, repair and asexual reproduction

Occurs whenever new cells are created

Produces two cells the exact same and the parent cells

In mitosis each chromosome is copied then new chromosomes moved to opposite side of the cell before the cell divides, leaving on set of 46 chromosomes in two new cells

Mitosis

Formation of Sex Cells

All human reproduction is sexual

Joining together haploid gamete cells from each parent half the normal number of chromosomes

This makes a new cell with both the parents genetic material

This is called a diploid zygote

Male gamete is sperm and females is the egg

When the sperm and egg join they create a zygote cell

Sperm contains 23 chromosomes and egg contains 23, when together they make a human zygote with 46 chromosomes containing genetic material from both parents

This is called meiosis that's used to produce cells for repair and asexual reproduction

Gametes contain different genetic material to each other and to the parent cell

Meiosis responsible for genetic variation

Process of fertilisation

Helpful terms:

Gamete – cell with half the normal number of chromosomes, and only used for sexual reproduction

Zygote – cell formed when two gametes combine

Fertilisation – term to describe the joining of two gametes

Haploid – having half the normal number of chromosomes

Diploid – having the normal number of chromosomes

Gametes

Are all haploid

Other adaptions to increase chances of fertilization and development in the embryo

Sperm cells have a tail to propel them to the egg; more mitochondria to provide more energy and enzymes at the front to digest the eggs membrane

Egg cells contain large food stores to support the zygote before it can feed from the placenta

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