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Sexual & Asexual Reproduction

The document outlines the differences between sexual and asexual reproduction, highlighting the processes of meiosis and mitosis. It explains that meiosis produces genetically diverse gametes for sexual reproduction, while mitosis creates identical cells for growth and repair. Additionally, it discusses various reproductive strategies in organisms, including examples from mammals, plants, and bacteria.

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9 views13 pages

Sexual & Asexual Reproduction

The document outlines the differences between sexual and asexual reproduction, highlighting the processes of meiosis and mitosis. It explains that meiosis produces genetically diverse gametes for sexual reproduction, while mitosis creates identical cells for growth and repair. Additionally, it discusses various reproductive strategies in organisms, including examples from mammals, plants, and bacteria.

Uploaded by

layane.marketing05
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Sexual & Asexual reproduction

Lesson Objectives

1. Understand the role of Meiosis and how it is different from Mitosis.


2. Explain what a gamete is and that there are different types.
3. Explain sexual reproduction involves the fusion of gametes at
fertilisation.
4. Explain how asexual reproduction is different from sexual
reproduction.
5. Evaluate sexual and asexual reproduction as reproductive
strategies.
Meiosis v Mitosis.
Mitosis.
Mitosis produces two genetically identical cells.

In mammals, body cells are diploid. The chromosomes need to be


copied exactly so that new cells can be produced for

➔ growth
➔ repair to damaged tissue
➔ replacement of worn-out cells

Mitosis is a form of asexual reproduction because the daughter cells


produced are genetically identical.
Meiosis
Meiosis

Meiosis produces four genetically


different haploid gametes.

Unlike mitosis, meiosis is a reduction


division – the chromosome number is
halved from diploid (46 chromosomes
in 23 pairs in humans) to haploid (23
chromosomes in humans).
How do we have 46 chromosomes?

Due to a special kind of cell division the chromosome number is halved from 46 to
23 to make gametes or sex cells which we know as sperm and egg cells
Sexual reproduction

The sperm with its 23 chromosomes has fertilised the egg cell with its 23 chromosomes and created
a new individual with 46 chromosomes.
Gonads - Reproductive organs

Male gametes - sperm are


produced by the testis Female gametes - ova are
produced by the ovary.
Gonads - Reproductive organs

In flowering plants the male gametes - pollen are produced by the anthers

The female gametes - ovules are produced by the ovary.


These E.Coli reproduce through Asexual reproduction.

This means they do However each new


not need to invest daughter bacteria
energy in finding a cell will be an exact
mate. genetic copy or clone
of the parent.

This means no
variation in the
population of
bacteria
Bacteria reproduce by asexual reproduction or binary fission.
One bacteria copies it genetic material and splits in two to produce two genetically
identical daughter cells.
It takes 29 minutes for 1 bacteria to divide – think how many bacteria there could be in 24
hours!

This means that every bacterial cell is genetically identical – there is no variation in the
population.
This means that the population is vulnerable – if an antibiotic can kill one it will kill them
all.
Yeast reproduce through asexual reproduction. In yeast it is referred to as
Budding

New Bud
Forming
Mitosis is also a type of asexual reproduction

The cells in our bodies are constantly undergoing new divisions for growth and repair.
This spider plant reproduces Asexually.

These small growths are called


runners – they are genetically
identical clones of the parent
plant

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