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.

Reproductive organs

3.9a - Male reproductive organ
Structure and uses:

• Bladder - Store Urine 
• Tesis - Meisosis Germinate sperm cells 
• Epididymis - Store Sperm cells 
• Vas deferens - Sends Sperm cells to the penis 
• Prostate - 30% semen 
• Seminal Vesicles - 70% semen 
• Uretha - Common tube, takes semen ou of the penis 
• Penis - Carry sperm cells into the vagina 

3.9b Female reproductive organ 

Structure and uses: 

• Ovary - Meiosis/ produces eggs
• Oviducts - Carries eggs 
• Uterus - wall of uterus made of muscle (stretch for pregenancy)
• Lining of the Uterus - development of embryo/egg
• Uterus Space - Embryo developes here 
•  Cervix - Where sperm cells enter
• Vagina -allows sperm cells to come in  

3.24c Stages of Mitosis

First the cell starts of in the inter phase where the chrmosones begin to replicate thier DNA.
This causes a pair of Chromosomes that are held together by a centremere this is called a Chromatids.

At this point their are 46 pairs of Chromatids in all, which means 92 individual Chromosomes
Then Begins the Prophase where the Nucleus starts to deteriorate revealing the Chromosomes
The late Prophase is when strands of protien start to from, these are called swindle cords
The Chromatids then get attached to the swindle cords through the centermere and they start to shift towards the equator of the cell, this is the Metaphase
The the Anaphase begins and the cells begin to expand and the swindle cords slowly pull the chromatids apart.
After this is the Telaphase where nucleus start to from around the different sets of chromosones and creates two nucleus

Then there is Cyto-Kinesis which is when the two nucleus split out of the cell and create to identical cells