Inheritance Study Guide

Heredity and Inheritance- What are traits and how are they passed from parent to offspring?

Structure of DNA- What does DNA look like and how does it copy itself?

Protein Synthesis- What role does DNA play in constructing proteins in our cells?

Mutations- What happens when there is a change in the structure of DNA?

Study of Genetics- starting with the outside (physical appearance) and moving inside (genes)

Genetics- study of genes

Heredity- how traits are passed from parent to offspring

Inheritance- receiving alleles from both parents

Lab Investigation: What are traits?

1. PTC paper test (taster or not taster)2. Hairline (widows peak or straight)3. eye shape ( almond or round)4. eyelash length ( long or short)5. tongue rolling ( roll or not)6. thumb ( hitchhiker's or straight)7. lip thickness ( thick or thin)8. hair texture ( curly, straight, wavy)9. inter-eye distance (close- set, far-set or medium-set)10. lip protusion ( protruding, slightly protruding, or nonprotuding)

Traits

Outside (physical apperance) = phenotype ex: long eyelashes

Inside (genes) = genotype ex: EE or Ee

The "E" is known as an allele. So, two alleles come together to form a genotype, and how this is expressed (what it looks like) is called a phenotype.

The genotype determines the phenotype because of the rule of dominance and recessive.

For example: Plant height (tall or short)

Dominance is represented by a capital allele, such as T.

Recessive is represented by a lower case allele, such as t.

Two alleles make up a genotype, such as Tt. This genotype would be expressed as a tall plant because the capital T is present and it takes over and hides the lower case t, the recessive allele.

Mendel looked at several different traits of pea plants: stem length, seed shape, seed color, pod shape, pod color, flower position, seed coat color, flower color

Mendel and his Pea Plants

This is what Mendel observed in stem height:

Pure-bred tall plant

Pure-bred short plant

P generation

Both offspring are tall plants

Next generation of offspring is 3 tall plants and 1 short plant

This is what he observed in flower color:

Crossed a purely purple flower with a purely white flower

All offspring had purple flowers

Next generation of offspring had 3 purple and 1 white

Punnett Squares: What is the probability of getting offspring with a particular genotype?

Flower Color P= dominant p = recessive

P P

p

p

Complete Dominance- What Mendel observed. If you have a genotype that is heterozygous/hybrid, the dominant allele will hide the recessive allele and the dominant trait will be expressed (phenotype).

Example: Flower ColorPp is a heterozygous

genotype, but the dominant allele (P) is purple and it will hide the recessive allele, therefore the phenotype (physical appearance) of the plant will have purple flowers.

Complete Dominance

Co-Dominance- If you have a genotype that is heterozygous/hybrid, both traits will be expressed (phenotype).

Example: Flower ColorFP FW is a heterozygous

genotype, with both a dominant purple allele and dominant white allele present, therefore the phenotype of the plant would be purple with white marks or white with purple marks.

C0-Dominance for Fur Color (Red + White)

Incomplete Dominance- If you have a genotype that is heterozygous/hybrid, both traits will be expressed (phenotype) as a blend of the two alleles.

Example: Flower ColorFPFW is a heterozygous

genotype, with both a dominant purple allele and dominant white allele present, therefore the phenotype of the plant would be a blend/mix of the two colors; lavender flower color.

Co- Dominance for Skin Color (green + pink)

Incomplete Dominance for Body Type (Medium)

Example: Two parents have 3 children. One child has a chronic disease, one child is a carrier, and the other is normal. The gene for this particular disease is found on recessive alleles.

Child #1 Genotype = ggChild #2 Genotype = GgChild #3 Genotype = GG

Child #1 Phenotype = afflicted with diseaseChild #2 Phenotype = carrier of diseaseChild #3 Phenotype = normal

What is a carrier?

Blood Typing: A, B, AB, and O

Both A and B are dominant and O is recessive.

How are blood types different?Physical structure of the blood cell

Rh factor- positive or negative blooddue to the proteins that make up the blood cells

Sex-Linked Traits

All chromosomes are numbered except sex chromosomes. They are called X and Y.

XX = female

XY = male

Traits can be carried on these sex chromsomes and be passed from parent to offspring.

Hemophilia and Red-Green Colorblindness are sex-linked traits

XHXh = female carrier XHY= male normalXHXH = female normal XhY = male hemoXhXh = female hemo

XCXC = female normal XCY = male normalXCXc = female carrier XcY = male colorblindXcXc = female colorblind