DNA & Heredity

Vocabulary Fertilization-male and female reproductive cells join Dominant trait- the gene that shows Recessive trait- the gene that doesn’t show Co-dominant trait- when both genes are expressed Incomplete dominance- when neither gene is expressed they make an intermediate Phenotype- the physical characteristics Genotype- the actual genetic makeup

Homozygous- has 2 identical alleles for a particular trait (TT or tt) (true breeding) Heterozygous-has 2 different alleles for the same trait (Tt) (hybrid) Genetic engineering/gene splicing- direct changing of the genes Gene- the chemical factors that determine traits Alleles-the different forms of a gene Cloning-making an exact genetic copy of something Pedigree- is your family line Mutation- change in the DNA Inheritance- passing on of something from parent to offspring

Gregor Mendel Austrian Monk Did experiments on pea plants He cross pollinated pea plants. To see what would happen. He wanted to know why you have different kinds of pea’s

Medel based his experiments on these traits When you mix these different trait you get hybrids After his first pollination he noticed that one of the parents characteristic (traits or genes) were not present

Segregation- This is the suggestion that the alleles (dominant and recessive) separate from each other. Punnett Squares- this is a way to estimate the probability of what will be the result from the cross of the alleles

Independent assortment- states that genes for different traits can segregate independently during gamete formation –T–T–T–This help to account for the many genetic variations observed in plants and animals Probability- can predict average outcomes of a large number of events. However it can not predict the precise outcome of an individual event Multiple Alleles- have more than 2 allele possibilities in the population. Doesn’t mean that a person can have more than 2 alleles. Ex. (blood type) Polygenic traits- traits controlled by two or more genes. Ex. ( human skin color)

Why should we care? About Mendel? About DNA?

Disorders Nondisjunction- when the chromosomes don’t split from each other giving one cell more than the other. Autosomal- these are all of your chromosomes except for your sex chromosomes. You have 44 autosomal chromosomes. Down syndrome- produces mild to severe mental retardation. (nondisjunction)

Sex – linked traits Colorblindness- more common in males Hemophilia- blood clotting also more common in males Duchenne Muscular Dystrophy- progressive weakening and loss of skeletal muscle also more common in males Turners- happens in females only get one X they are sterile (nondisjunction) Klinefelter’s- happens in males they have an extra X that interferes with meiosis prevents these individuals from reproducing (nondisjunction)

Karyotypes / Pedigree Karyotype- is a way to look at the actual chromosomes. Pedigree- show’s my families traits for several generations

Vocabulary Nucleotide- A sugar, base and a phosphate Base pair- A-T, C-G Codon- 3 bases in a row on the mRNA strand Anticodon- the 3 bases that are on the tRNA

The finding of DNA Fredrick Griffith- in 1928 found out that a heat killed bacteria can transform a harmless strain into one that can cause disease Oswald Avery in 1944 figured out that genes are made of DNA Erwin Chargaff- figured out that Adenine paired Thymine, and Cytosine paired with Guanine (Chargaff’s Rule) Rosalind Franklin – in 1952 took x-ray photographs of DNA. Watson and Crick – in 1953 were credited with the discovery of the structure of DNA Sydney Brenner- in 1960 found the existence of RNA Walter Gilbert and Team- in 1977 found a way to read the DNA sequence 2000 the human genome project- sequence all human DNA

DNA (Deoxyribonucleic Acids)- it is a double helix shape –Adenine, Thymine, Guanine, Cytosine -the 4 bases nucleic acids –Adenine pairs with Thymine –Guanine pairs with Cytosine RNA (Ribonucleic Acids)- single stranded –Instead of Thymine, it has Uracil DNA

DNA replication DNA molecule separates into two strands, then produces two strands, then produces two new complimentary strands following the rule of base pairing. Each strand of the double helix of DNA serves as a template, or model, for the new strand.

Transcription DNA is separated to be used as a template to make an mRNA strand. Enzymes are used to split the DNA

mRNA- messenger RNA. RNA molecule that carries copies of base pairs. To help with making protein. tRNA- transfer RNA. Helps transfer amino acids to the mRNA. rRNA- ribose RNA it is inside the ribosome. mRNA tRNA Amino Acid

Protein synthesis/Translation mRNA- is grabbed onto by a ribosome. So that the ribosome can hold it in place for the tRNA. The tRNA then comes and hooks onto the mRNA and bring the amino acid. When a bunch of amino acids are hooked together it makes something called a polypeptide chain (protein).

Mutations Mutation- are changes in the genetic material. Frameshift- These may change every amino acid that follows the point of mutation. –these are additions or deletions of a base nucleic acid. Point mutations- this is when 1 to 2 base nucleic acids are substituted so they change which base it is.