REVIEW – Back of books

1. Name 3 differences between sexual and asexual reproduction.

2. Give 2 examples of asexual reproduction.

3. What is a variation?4. What is the difference between

continuous and discontinuous variation?

5. Give an example of each type of variation.

GeneticsLO: Describe the basic process by which genetic information is passed from one generation to the next.

https://www.youtube.com/watch?v=ubq4eu_TDFc

4.25

Inheritance and Genes

Why are we like our parents?

It’s all to do with the genes we have inherited.

Living Things

All living things are made of cells

All cells contain a central nucleus

The nucleus is the control centre for the cell.

Cells

More Cells

Lets take a closer lookThis cell has a

number of ribosomes, mitochondria and other un-named objects (5 yellow ones)

It has only one nucleus.

The nucleus has a number of

chromosomes

Chromosomes

What are chromosomes?

Chromosomes are made up of DNA molecules.

The DNA molecules have genes coded on them

Highlight the organism cellchromosome DNA sequence in your book IMPORTANT

What are genes?Genes are sections

of DNA molecules which contain coded information.

Genes determine how we will develop.

Genes control factors such as eye colour, facial features, hair type, height.

Human GeneticsHumans are diploid. That is our

chromosomes come in pairs, each with the same sequences of genes, except the sex-pair – called XY.

Each feature is therefore controlled by a gene on each chromosome in the pair.

DNAhttps://www.youtube.com/watch?

v=-1ZvsYDTxc8

https://www.youtube.com/watch?v=S8DMoDJ8FWA

6.31/2.29

DNAThe structure of DNA is the same

in all living thingsIt looks like a twisted ladder,

known as a double helix.DNA is made of repeating units

called nucleotides.A nucleotide is made of 3 parts, a

sugar, a phosphate and a base.

Highlight the red text from above in your SciPad page 129

DNAIn your books page 129 on the

diagram of a nucleotide…..◦Colour the phosphates one colour◦Colour the sugars another colour◦Colour the ‘A’s and the word adenine

below a different colour◦Colour the ‘T’s and the word thymine◦Colour the ‘G’s and the word guanine◦Colour the ‘C’s and the word

cytosine

DNA StructureThe side of the helix are made up

of the sugar and the phosphate. These are linked together by the nucleotide bases.

There are four nucleotide bases.◦Adenine (A)◦Thymine (T)◦Cytosine (C)◦Guanine (G)

The chemical make-up of the bases means that adenine always bonds with thymine and cytosine always bonds with guanine.

This is called the “complementary base-pairing rule”

(A) adenine = thymine (T)(C) cytosine = guanine (G)

Complementary base-pairing rule

Hint: straight lettersgo together (A-T), curvedletters go together (C-G)

SciPad pg 129Complete the questions and the

base-pairing sequence.

Next LessonCell reproduction and karyotypes