Occurs mostly in Fungi and Protists

They can join together to form diploid cells

Seen in animals

Parents make haploid gametes and are stored in reproductive organs.

They reunite through sex and the DNA combines forming another organism.

These are sex cells (male-sperm/female-egg)

They are haploid

Egg and Sperm fertilize to form a diploid cell called a zygote.

A lot like MITOSIS.

There are 2 sets of division leaving you with 4 exact cells.

Occurs in the gonads.

The S phase doubles the # of chromosomes.

Males produce 4 sperm and females produce 1 egg.

3 Major differences between 

MITOSIS AND MEIOSIS

Crossover

Chromosome PAIRS seperate in Anaphase I

Sister chromatids seperate in Anaphase II

Genetic swapping between homologous chromosomes.

This occurs to create variation

SYNAPSIS- Chromosomes intertwine together

Tetrad-4 chromosomes twist together

Chiasmata- Chromosomes physically overlap

Requires 2 allels (one from each parent)

Variation of character

Different version of a gene

2 allels are needed for 1 trait

Dominant allels have capital letters

Recessive allels have lower letters

Only have one type of allels for a certain trait (BB or bb)

Otherwise known as Homozygous allels.

Creates an organism with 2 types of allels. (Bb)

Otherwise known as Heterozygous allels.

Phenotype

Pheno=PHYSICAL

Refers to a physical trait that can be seen.

(Blood Type or eye color)

Organisms genetic makeup for a certain trait.

(BB, Bb, bb)

If genotype is unknown, perform a testcross to find it.

Test cross must be done with a homologous recessive allel so that the unknown will not have genetic makeup covered.

A chart that shows the possible genotypic outcome based on the parents genotypes.

MONOhybrid=1 trait=4 squares=4^1

DIhybrid=2 traits=16 squares=4^2

TRIhybrid=3 traits=64 squares=4^3

The genes on chromosomes can move independently of one another.

This is supported by what is happening in crossover during Anaphase I of Meiosis.

This states that the chromosomes move independantly of one another.

Occurs in Anaphase 1 and 2

And in Mitosis 

Chance that certain outcome will actually happen.

Probability ranges from 0 and 1.00 (0%-100%)

Both allels are seen, but they ARE NOT BLENDED.

They are equally present in terms of phenotype.

There are MULTIPLE versions of the same basic allel.

Variations of Blood Types for ex.

A gene at 1 LOCUS affects a gene at a 2nd LOCUS

Hair is a good example. color, texture, thickness

MANY different degrees of phenotypic outcomes.

This is due to Quantitative Characters (How many allels you recieved from your parents)

Skin Color for ex.

Family history of trait occurance in chart form. Affected individuals are SHADED in the chart.

These help tell the past occurance and can be helpful when trying to predict the future occurance through mating.

NO INFORMATION inherited on both chromosomes.

EXTREMELY HARMFUL

ONLY OCCUR in the homologous recessive state.

Nothing is there to dominate the disorder.

Heterozygous in genotype

They have a 50% chance of passing the trait along ( If the sperm and egg both are homozygous recessive then the trait will pass on to the opffspring)

Most common lethal disease

1 in 2500 births

In caucasions, 1 in 25 is a carrier.

Creates faulty Chloride ion (Cl-) protein carrier on cell membranes in the lungs.

This causes fluid to build up in the lung tissues.

People drown in their own fluid

There is NO CURE

Creates a non-functional lysosome in brain cells.

Brain cells need a lot of energy to function properly. Therefore the feed off on lipids primarily.

Lysosomes break down lipids, but the lysosomes in this disorder are missing an enzyme that helps do this, so the lysosomes fill of with lipids then die.

Affects Jews a lot bc of marrying within the culture

Children affected die a painful death usually by the age of 5

Most common within Black population.

Affects 1 in 400 births

The 6th amino acid is changed (Glutein-->Valine) in the PRIMARY  sequence of one of the proteins needed to make red blood cells.(666 is BAD; changing the 6th amino acid is BAD)

Are resistant to Malaria bc of the 1 recessive allel but they mostly have normal red blood cells for carrying O.

This is also refered to as Heterozygous Advantage

ONLY NEED 1 ALLEL FOR THE DISEASE TO BE EXPRESSED

If the individual in homozygous dominant, then the disease in normally fatal

Genetic Dwarfism

Affects 1 in 10000 births

Huntingtons Disease

Affects 1 in 10000 births

Not apparent until the 40s and 50s

The dominant gene has a locus on tip of autosome 4

Family history is important in the diagnosis of this disorder.

Almost always fatal

Heart Disease

Diabetes

Cancer

Alchoholism

Individuals who run PEDIGREES using family history data to look at potential outcomes and to give advice on whether the parent should attempt at concieving a child.

They can use Amniocentesis, Chorionic Villus Sampling, Ultrasound, Fetoscopy, and Newborn Screening for conformation that the offspring does/doesnt have disorders.

Can occur at crossover in Prophase 1 or when chromosomes seperate.

Parental types look like their parents

Recombinant types look like a combination of both parents.

Genes found on the sex chromosomes. 95% refers to the X (seX linked)

Sex chromosomes undergo very little crossover in Prophase 1 of Meiosis.

Sex of organism will be determined at conception.

Everyone is female at first

COLOR BLINDNESS

MUSCULAR DYSTROPHY

HEMOPHILIA

Due to males having X and Y, if they get a recessive gene with a disease, they will not have a dominant gene to cover it up, resulting in more males with Inheritance/SexLinked Diseases

Chromosomal Number: failure to seperate during anaphase.

Individual Chromosome Structure: occur bc of faulty crossover.

refers to an organism possessing the traits of a particular genetic disorder.

Downs: Extra 21 autosome

Klinefelters: XXY both penis and vagina

Turners: XO underdeveloped vagina

Cri du Chat: part of 5 is deleted. windpipe 

Leukemia: translocation between 9 and 22. cancerous white blood cells.

Fragile X: heavy methylation on X. mental

Erasing your parents DNA and creating your own.

Too much methylation=doesnt look like parents

not a lot= similar

The process of making a complete copy of an entire length of DNA.

Occurs during the S phase. of the cell cycle.

It is easy to do for cells, bc both sides are complementary.

A=T  G=C

EXTREMELY quick

Specific nucleotide sequences in the DNA strands that act as staring points.

The enzyme helicase unwinds the DNA double helix to create a Replication Bubble.

The ends of the bubbles are called replication forks.

Work is happening on both sides of the forks and bubbles.

Many bubbles can be on the same DNA strand.

brought to the enzyme from the cytoplasm of a cell.

A nucleoside has 3 phosphates to supply the bonding process with energy.

The Nucleoside will lose 2 phosphates in the bonding process.Loss of phosphates make it a nucleotide.

This saves ATP for other cellular processes.

The 5' carbon of the sugar has a phosphate attached to it

The 1' carbon of the sugar has the nitrogen base attached to it.

The 3' carbon of the sugar has an open bond

The strand runs in a 5' to 3' direction as it opens.

In order to start adding nucleosides, attach RNA PRIMER using PRIMASE  AND GO!

Lead strands on both sides of the replication bubble are located diagonally from each other. This is bc the 2 DNA strands are anti parallel.

THIS SIDE IS NOT RUNNING 5'TO3' therefore it laggs.

This fork has to wait for a long segment of DNA before adding a primer.

Once helicase opens and the RNA primer attaches and then DNA Polymerase III works backwars forming Okazaki fragment.

The O fragments are stiched together using Ligase.

They are located diagonally also.

used when the wrong nucleotide is added to the sequence. DNA Polymerace will reverse a spot, removing the wrong nucleotide.

NUCLEOTIDE ESISION REPAIR

1.Nuclease cuts around so they can be removed

2. DNA replaces

3. Ligase stiches together.

Are repeated nucleotide sequences found at the end of each chromosomes used for RNA primers to attach and start replication w/o bubble.

Number of telomeres depends on cell type.

Having telomeres protects from erosion.

APOPTOSIS is programmed cell death

This is the enzyme that replaces telomeres during fatal developement. After the fetus is developed this enzyme shuts off.The DNA segment that is responsible for providing the blueprint will become heavily methylated.

Tumors can be formed when the enzyme is turned back on.