1. Genetics

2. Vocabulary Allele – a pair of chromosomes
Dominant – a gene that is always expressed (seen)
Gene – a part of a chromosome made up of DNA
Hybrid – Having two different types of genes for a particular trait

3. Vocabulary
Offspring – new individuals produced as a result of reproduction
Purebred – Having two identical genes for a trait
Recessive – Genes that are hidden by dominant genes, there must be two of them for the trait to be expressed (seen)
Traits – characteristics of an organism

4. Chromosomes:
Made up of several ___________ (unit of _______________ for a particular trait)
All human cells have ______ pairs (46) except sex cells have _____ total
A pair (______________) determines the trait expressed
Genes
Hereditary 23 23
Allele

5. DNA: Structure: _______________ helix (twisted ladder)
Makes up __________
Double
Genes

6. Genetics:
Mendel
A. Studied ______ plants height, seed color, and seed shape
Pea

7. Genetics: Hides Capital 1 gene Hidden Dominant Two B. Dominant Genes
1. __________ or mask another trait
2. Written as a _________ letter Ex. Tall = T
3. Only ______ needs to be present for the trait to be expressed Ex. Tall = TT or Tt
C. Recessive Genes
1. ____________ by dominant genes
2. Written as the lower case letter of the _________ trait Ex. Short = t
3. ______ are needed for the trait to be expressed
Ex. Short = tt
Hides
Capital
1 gene
Hidden
Dominant
Two

8. Genetics: Homozygous Same Heterozygous Different Alleles separate
D. Purebred
1. Also known as _______________________
2. Having the __________ genes for a trait
E. Hybrid
2. Having __________________ genes for a trait
F. Principle of segregation
1. States ____________ (gene pairs) separate during
meiosis (formation of gametes)
2. Nondisjunction - occurs when part or all of a
chromosome does not _____________ during meiosis resulting in too many or too few chromosomes in an egg or sperm cell ex. Trisomy 21 (Downs Syndrome)
Homozygous
Same
Heterozygous
Different
Alleles
separate

10. Punnett Squares: Grid used to determine gene pairs of ________________
Example: Tt x Tt
1. Draw the square
2. Place one parent at the top of the square (one gene above each box) and the other parent to the left of the square (one gene next to each box).
3. Write in the top genes in each box below them.
4. Write in the side genes in each box to the right of them. Be sure that the capital letter is written first in each box.
Offspring

11. Punnett Squares:
5. Determine the genotypes and express as a ratio or percent.
Dominant : Hybrid : Recessive 1 : 2 : 1
Purebred Purebred
25% Purebred Tall, 50% Hybrid Tall, and 25% Short
6. Determine the phenotypes and express as a ratio or percent.
Dominant : Recessive 3 : 1
75% Tall and 25% Short

12. Genetics: Incomplete Dominance A. ____________ of two traits
B. Example: Four o’clock flowers
Blending

13. Variation:
Causes:
A. Sexual Reproduction - offspring appear different from parents due to inheriting _________ from both parents
B. Nondisjunction - Part or all of a chromosome doesn’t separate during ____________
C. Mutation - a change in DNA causing a change in a ______
Genes
Meiosis
Trait

14. Sex Determination Sex chromosomes are the 23rd pair
Females have two x chromosomes
Males have an x and a y chromosome

15. Sex Linked Traits
Traits located on the upper portion of the x chromosome
Ex. Colorblindness, baldness, hemophilia
They are recessive traits, so they won’t be expressed (seen) if there is a dominant gene without the trait present

16. Females and Sex Linked Traits
Inherit 2 dominant x’s without the trait (don’t exhibit the triat)
Hybrid – inherit 1 dominant x without the trait and 1 recessive x with the trait (called a carrier – does not exhibit the trait but can pass it to their offspring)
Inherit 2 recessive x’s with the trait (exhibits the trait)
Rare for females to have sex-linked traits because they need to inherit 2 recessive x’s

17. Males and Sex Linked Traits
Inherit 1 dominant x without the trait (don’t exhibit the trait)
Inherit 1 recessive x with the trait (exhibits the trait)
Males can not be carriers because they only have 1 x gene (y doesn’t have genes for these traits)
Higher percentage of males with sex linked traits because they only need to inherit 1 recessive x to exhibit the trait

18. Pedigree Chart: Shows inheritance of ___________ through generations
Traits

19. Genetic Engineering:
Altering an organisms genetic material to affect its ____________
________________ breeding - breeding organisms with specific traits
Cloning - creating new organisms from cells of _______ organism
Uses - food production and _______________
Traits
Selective
One
Medical Purpose

20. A gene is inserted into a fertilized egg so that the organism that develops will have that trait
Example: Inserting the gene that allows fish to survive in icy waters into tomato seeds so that the tomatoes can survive a frost

21. Remove the nucleus from a skin cell (full set of chromosomes)
Remove the nucleus from an egg cell
Insert the skin cell nucleus into the empty egg so it has a full set of chromosomes
Egg will divide to produce an identical copy of the organism that the skin cell came from
Cloning is a type of asexual reproduction

22. Review - Heat
Conduction – heat transfer by direct contact ex. Frying an egg
Convection – heat transfer within fluids (liquids and gases) ex. Boiling water
Radiation – heat transfer through empty space ex. Warming hands by a campfire

23. Review – Phase Changes Melting – solid to a liquid, heat absorbed
Freezing – liquid to a solid, heat released
Condensation – gas to a liquid, heat released
Evaporation or Vaporization (Boiling) – liquid to a gas, heat absorbed
Sublimation – solid to a gas (no liquid phase), heat absorbed
Deposition – gas to a solid (no liquid phase), heat released