3 Define Heredity.The passing on of traits from one generation to the next.
4 Where is genetic information stored? DNASpecifically, in each individual’s DNA on chromosomes that contain many genes.
5 What did Mendel study to understand inheritance? Common garden pea plantsWhy did he choose pea plants?1--Fast growing with many offspring = quick results2—Sexually Reproduce and male as well as female reproductive organs in each plant3—Traits come in a dichotomy—only two forms.Like tall and short or green and yellow
6 What did Mendel call true breeding? Plants that come from a long line of plants that show the same traitWhen he crossed two true-breeding plants with opposite traits, he called this what?The “P” cross for Parental generation
7 What two individuals did Mendel cross in the P generation? True-breeding Tall and Short pea plantsGenotypes?Tall = TTShort = tt
8 What resulted in the F1 generation? Pea plants that were…Phenotypes?All TALLGenotype?All “Tt”
9 What was Mendel’s next step? He crossed two F1 plants.What results did he get?The F2 generationWhat interesting ratio did he find?They were 3:1 (dominant to recessive)
10 What is the Law of Segregation? 1--Individuals must have two copies of genetic information for every trait– one from each parent2—each copy is passed randomly3—One of these copies (alleles) can mask the expression of the other, ie. Dominant alleles can mask recessive alleles when both are present
11 What is the Law of Independent Assortment? Alleles of different genes separate independently of one another during gamete formationWhat does that mean?The allele a parent gives for one trait does not affect what he/she gives for another trait so you can have many different combinations of traits given to the egg or sperm
12 What are alleles? Different forms of the same gene for a trait When an individual has two of the same allele, the genotype is called…HomozygousWhen there are two different alleles, it is…Heterozygous
13 What is the difference between genotype and phenotype? Genotype isthe type of genes or allelesPhenotype isWhat is looks like--The physical appearance of the organism
14 Monohybrid vs. Dihybrid Mono hybrid: a cross when there is just one trait involved, ex.Height: Tt X ttDi hybrid: Two traits are involved, ex.The horse’s coat and gait are crossedFFGg X Ffgg
15 Sex-linked Inheritance Autosomes are chromosomes not on the.. X or y chromosomesSex-linked characteristics are always on…The X-chromosomeGive an example of a sex-linked conditionHemophiliaWhy does it occur more in males?Males only inherit 1 X-chromosome so there is a better chance they would express (whether its dominant or recessive) the condition.
16 Contrast a Punnett Square and a Pedigree A Punnett Square is…a grid that predicts the types of possible offspring from a crossA Pedigree is..A diagram that shows a family tree and how traits pass from generation to generation
19 Modes of Dominance: 1--Complete dominance… One allele is completely dominant over the recessive and the recessive is masked in a heterozygous individual2--Incomplete dominance..The dominant does not completely mask the recessive and the heterozygous phenotype is a blend of the two- an intermediate variation.There are three possible phenotypes.
20 More modes of inheritance 3-- Co dominance..More than one genotype is dominant and when two of these are together, they form another phenotype4– Multiple alleles..These traits have 3 or more allelesExample of both codominance and multiple alleles..blood types. How many blood types are possible?Four-- They are..A, B, AB, and O
21 Modes of Inheritance cont. 5-- Polygenic Inheritance: traits that are..controlled by multiple genes pairs.This makes many variations of color and trait possibleWhat are characteristics controlled by multiple pairs of alleles?Human hair and eye color