3.33 -3.34

Antibiotics
• Resistance to antibiotics can increase bacteria population
• The resistant form of the bacteria becomes more common and the rate of its survival increases

Causes of Mutation
• Mutation can be caused by radiation (x-rays, gamma rays) and chemical Mutagens (chemicals in tobacco)
• Changes base sequence and forms new harmful alleles
• Cancer is also caused by Mutations

3.32

• Most mutations are harmful
• However some can be beneficial
• Mutation creates new alleles which could be: Beneficial (creates new enzymes), Neutral (no effect at the current time maybe affected by a change in the environment) and Harmful (non-functional enzyme)

3.31 Evolution

Occurs because of Natural Selection
Evolution:
• Change in the forms of Organism
• Change in frequency of alleles
Natural selection:
• Mechanism of evolution
• For example: a virus is susceptible to an antidote but it randomly mutates and can survive the antidote this form of the virus is called the resistant form
• All the versions of the virus which cannot survive the antidote die out and as a result only the mutated ones remain
• It is a Random Mutation But Non-random Selection

3.29 - 3.30

3.29 Variation

Variation = differences

Individual Phenotype = Genotype + Environment

Variation in the population = Variation in the Gene + Variation in the Environment

Their 3 classes of Variation:

·         Discontinuous – When the variation is caused only by gene

·         Continuous – When the variation is caused gene and the environment

·         Environmental variation- when the variation  is caused by only the environment

3.30 Mutation

·         Mutation is rare

·         It changes the base sequence in the gene

·         It can be inherited 

3.20

• Family pedigrees are shown like a tree diagrams with a symbol representing male and another symbol representing female. (For example square is male and circle is female)
• If these symbols are colored/filled in it shows that the person is affected by a disease that may or may not be passed on to the younger generations
• By using methods of trial and error we are able to eliminate and find out which gene caused the disease the recessive or the dominant.
• This is done by taking a sample from the family pedigree and testing the hypothesis for both dominant and recessive gene.