Genes and chromosomes

1.

Genes and chromosomes

2.

Lesson objectives
⚫ To explain role of genes in determining
traits
⚫ To explain role of genetic material DNA
in chromosomes.

3.

⚫Did you know that there is a place
in your body that stores
information about your body?

4.

⚫In the cell
nucleus there are
structures called
chromosomes
that store
information
about whole
organism.

5.

Chromosomes are
made up of tightly
coiled molecule called
DNA (deoxyribonucleic
acid).

6.

⚫A gene is specific part of the
DNA that is responsible for the
specific trait.

7.

8.

When cells divide the DNA is
copied and passed to the new
cells.

9.

alleles
⚫ In humans and most of organisms there
are two genes that are responsible for
one trait.
⚫ A pair of genes that are responsible for
one trait is called alleles.

10.

Dominant and recessive alleles
⚫ Some alleles are dominant and some are recessive.
⚫ It means if you get two different alleles from your
parents the one will dominate over the another one.
⚫ The one which dominates is expressed and called as
dominant allele (gene).
⚫ The one which is not expressed in this condition is
called recessive allele (gene).

11.

Let’s do activity on p.179

12.

Homework
⚫Read p. 178-179
⚫Answer to literacy questions on p 179
⚫New words