5.2

Differences or variation in DNA are what makes us different from each other!

Each human cell contains 46 chromosomes Each cell has 3 billion base pairs of DNA (wow!)

Our DNA is 99.99% similar

Of the 6 billion base pairs of DNA, only 5% are in the genes that code for RNA and proteins.

Errors can occur when DNA is copied UV light, X-rays, chemicals, etc. affect DNA

Substitution – Exchanges one base for another. CTGGAG---- CTGGGG

Insertion – Extra base pairs are inserted.CTGGAG---- CTGGTGGAG

Deletion- Section is lost, or deleted. CTGGAG -----CTAG

Frameshift- Message is no longer read correctly.THE FAT CAT SAT --- HEF ATC ATS

AT

Cells have different ways to repair mistakes

Certain enzymes can proofread DNA such as correcting mismatched base pairs

1. The mutation causes no effect.1. Amino acids have more than 1 code2. Enough protein may be produced already

2. The effect of a mutation is minor.1. Could affect skin/eye/hair pigmentation

3. The effect of a mutation is great.1. Genetic disorder/disease

Sometimes passed from parents to offspring Sickle Cell AnemiaCystic Fibrosis (CF)HemophiliaTay- Sachs Disease Huntington’s Disease (HD)HypercholesterolemiaCancer

People can carry a tendency for a disease.Alzheimer'sEmphysemaDiabetesCancer

Their behavior can prevent it:Not smoking can prevent emphysema and many

types of cancer

Most genetic disorders cannot be cured, although progress is being made.

Families who have a history of genetic disorders are recommended to undergo counseling before having a child. They can find out how it could affect their offspring.

Some genetic disorders can be treated if diagnosed early enough, such as PKU (lacking a certain enzyme). If known, that child can be put on a certain diet

and medicine routine.

Mutation occurs on gene that codes for hemoglobin

Hemoglobin – a protein that carries oxygen in red blood cells

Mutation causes 1 amino acid to be replaced with another

Need 2 recessive genes to be affected (ss)

Can be a carrier (Ss)

5.3

Random changes in DNA can introduce new traits in an organism

Humans can breed animals to get the certain traits they want.Ex: a cow that gives

more quantities of milk

The process of selecting and

breeding parent organisms to pass on particular traits to the offspring.

Bloodhound – strong sense of smell

A sequence of DNA from an organism is first isolated, then inserted into the DNA of another organism.

The DNA inserted usually codes for a particular trait of interest

GMO – Genetically modified organism

Can make plants more insect resistant.

Create crops suitable for areas with poor soil conditions

PROS CONS

Food can be resistant to certain bacteria and pests.

Reduces chemical pesticides

Increases food production

Add nutrients

Possibly harmful to the human body but still unknown

Could risk wild population like salmon

Can be used to produce new and better drugs for treating disease

Determine the side effects of a drug on an individual

Can be used to screen for and treat genetic disorders

May soon allow scientists to correct certain recessive genetic disorders by replacing defective genes with copies of a healthy one.

First step of gene therapy is to isolate a copy of the gene.

Scientists are trying to input that gene into the cell by attaching it to a cold virus. Attempts in humans have not been successful.

However, the outlook is promising.

Crime scenes – skin, hair, blood

DNA profile – a DNA fingerprint

Everyone different except identical twins!

All the genetic material in an organism.

The human genome project wanted to sequence all of the human genome (that’s a lot)

We can then compare DNA across speciesWe have similar genes to fruit flies and

mice

A technique that uses technology to make copies.

Can be applied to a segment of DNA or a whole organism

Dolly

Place gene that codes for producing insulin

That bacteria then replicates in large numbers

Treats people with diabetes