(10) DNA: The Genetic Material (6.1) 176 Master 6.1b, 6.1a Cystic Fibrosis DNA, Mutations, and Cancer (6.2) Lifestyle and Cancer (6.3)

(10)

DNA: The Genetic Material (6.1) 176Master 6.1b, 6.1a

Cystic FibrosisDNA, Mutations, and Cancer (6.2)

Lifestyle and Cancer (6.3)

DNA: The Genetic MaterialThe chromosomes of all living organisms are

composed of DNADeoxyribonucleic acid.

What does it do? Guides the repair of damaged cells. Describes how cells will respond to changes

in their environment.How is this information sent? Sent from DNA to organelles through

chemical messengers.

DNA is made of phosphate, ribose, and nitrogen bases held in a long winding double helix.

The nitrogen bases: thymine (t), adenine (a), cytosine (c), and guanine (g) are the characters (letters) of the genetic alphabet. The order they appear in is a code.

A sequence of 3 nitrogen bases from a genetic code (word) that determines characteristics. (hair colour, skin colour…)

A sequence of codes form a gene (phrase) that can be read by the cell.

DNA Replication

The genetic code is stored in the 6 billion nitrogen bases of DNA, arranged in about 100 000genes on the 46 human chromosomes.

During interphase, DNA unzips in order to allow the cell to duplicate.

During cell division, the duplicates separate so each cell gets a complete set of genetic information.

Humans have 46 chromosomes in 23 pairs.

At conception, each parent provide one

chromosome of each type (23).Within each copy of the same gene, there

might be small differences in the code. This genetic diversity accounts for why each human is different.

Since DNA is unique for each person (except for identical twins), it is possible to identify a person through DNA fingerprinting. (6.1a)

Who committed the crime? (Scan)Who committed the crime? (Scan)

DNA, Mutations, and Cancer

Genes found on chromosomes can undergo changes called mutations that can cause diseases.

Cancer is uncontrolled cell division. The oncogenes can become mutated and defective and cells may quickly and repeatedly divide themselves.

The mutations of oncogenes is caused by substances or energy called carcinogens.

Lifestyle and Cancer (6.3)

Rapid uncontrolled division of cancerous cells can result in a mass of cells called a tumour.

Harmless tumours are called benign. Dangerous tumours spawn cells that

can break away and form tumours in other parts of the body… these tumours are called malignant.

% of Cancers Related to Risk Factors (Estimated)

Tobacco 32Diet (↑fat ↓fiber) 30Viruses 10STDs 7Unknown 5Environmental (chemical pollution) 10Alcohol 3Sunlight (radiation) 1Food additives 2

1994 - Statistics Canada - Cancer

Type New Cases Deaths Survival Rate

Lung 19 600 16 600 15%Breast17 000 5 400 68%Colon 16 300 6 300 61%Prostate 14 300 4 100 73%Bladder 4 800 1 350 72%Kidney 3 700 1 350 64%Leukemia 3 200 1 110 63%

Prevention of Cancer Do not smoke. Hygenic lifestyle. Abstinence/prevention of STDs Moderate or no Alcohol consumption. Use sun block from UV rays (SPF 30). Keep environment clean. Nutrition: (↓ fat ↑fiber)

Organic agriculture. Food without additives. Food high in fiber.