1. DNA, Chromosomes & Genes

2. GENOME
The nucleus of a human cell contains between 20,000 and 25,000 genes. This complete set of genes is called the GENOME.

3. Describe the structure of the genome

4. Describe the structure of the genome
Tightly coiled threads of deoxyribonucleic acid (DNA) and associated protein molecules
Organized into structures called chromosomes

5. What are CHROMOSOMES?

6. What are CHROMOSOMES? A packet of coiled up DNA
Humans have 23 pairs of chromosomes
They are in the nucleus of cells

7. What are CHROMOSOMES? Chromosomes contain a single, long piece of DNA
A chromosome is about mm long
The DNA is about 4 cm long
This is about 10 000 times longer than the chromosome
So it has to twist and coil to fit inside

8. What are CHROMOSOMES?
There are 23 pairs of chromosomes in the nucleus of any one of your cells
Each chromosome has a single strand of DNA (deoxyribonucleic acid) which carries the code for a couple of thousand genes

9. What is a GENE?

10. What is a GENE?
A code made up of pairs of bases carried on the DNA molecule.
Each DNA molecule contains many genes
The basic physical and functional units of heredity

11. What is a GENE? A specific sequence of bases or a section of DNA
Sequences carry the information needed for constructing proteins
Proteins provide the structural components of cells and tissues as well as enzymes for essential biochemical reactions.
The human genome is estimated to be made of 20,000 – 25,000 genes.

12. What is a GENE? Each chromosome carries a couple of thousand genes
Many of these are common to all human beings.
So, 99.9% of your DNA is identical to everyone else's

13. What is a GENE?
The remaining 0.1% influences the differences between us
height, hair color and susceptibility to a particular disease
Environmental factors, such as lifestyle (for example, smoking and nutrition) also influence the way we look and our susceptibility to disease

14. What is DNA?

15. The links between each strand are called bases.
What is DNA?
The DNA molecule is made from two strands, twisted together in a double helix.
The links between each strand are called bases.

16. What is DNA? Deoxyribonucleic acid
The molecule that contains the genetic code
It coils up tightly inside chromosomes
DNA is a double helix made from two strands which are joined together by a pair of bases

19. Gregor Mendel Father of genetics Austrian monk in mid 1800’s
Studied pea plants
Figured out that plants passed on traits such as height, flower color, type of seed
Figured out dominance & recessive