1. Introduction to genetics
Genes

2. What is DNA?
DNA stands for DeoxyriboNucleic Acid
It is the hereditary material in humans and almost all other organisms.
Most DNA is located in the cell nucleus.
“Blueprint of life”
The main role of DNA molecules is the long-term storage of information.

3. DNA Structure
DNA is a double-stranded molecule . The shape of the DNA molecule is a double-helix (think of a spiral staircase or like a twisted ladder). The sides of the ladder are composed of alternating sugars (deoxyribose) and phosphates. The rungs of the ladder are composed of nucleotides.

4. Base pairing rule Nucleotides (also called Bases)
Adenine, Thymine, , Guanine, Cytosine or A, T, G, C
Nucleotides pair in a specific way - called the Base-Pair Rule
Adenine pairs to Thymine
Guanine pairs to Cytosine
Memory helper - think "A T Granite City" - which is where you live.

5. The structure of DNA was established by James Watson and Francis Crick.

6. What is a gene?
Gene - a segment of DNA that codes for a protein, which in turn codes for a trait (skin tone, eye color.etc),
a gene is a stretch of DNA.
Every person has two copies of each gene, one inherited from each parent.

7. What is a chromosome?
Chromosomes are DNA molecule packaged into thread-like structures in the nucleus

8. How many chromosomes do people have?
In humans, each cell normally contains 23 pairs of chromosomes, for a total of 46. Twenty-two of these pairs, called autosomes, look the same in both males and females.
Diploid a cell that contains “two sets” of chromosome 2N
Haploid a cell that contains “one set” of chromosome

9. Sex Determination
Sex cell chromosomes determine the sex of an organism
Sex cells are the sperm and egg–gametes
Females have two X chromosomes, (XX)
while males have one X and one Y chromosome (XY)
Zygote is the union of the sperm and egg (46 chromosomes).

10. Heredity is the transmission of characteristics from parents to offspring.
The genes for many traits are passed down in families from parents to children.
Because you come from two parents, each parent will provide one half of your genes for any trait. That is called an "allele." So you have two alleles for each gene, one from each parent.

11. Gregor Mendel

12. Dominant and recessive
Dominant traits are the expressed characteristic. It is always represented with a capital letter
Recessive traits are the repressed alleles; the ones that are not expressed. It is always represented with a lower case

13. Homozygous organisms that have two identical alleles
Heterozygous organism with two different alleles.
Phenotype is the physical appearance
Genotype is the genetic make up