5.1.5 Life Science Practice

5.1.5 Life Science Practice

- Why some traits cannot be inherited and how inherited traits are passed from one generation to the next by genes.

- Sexual vs. asexual reproduction

- Basic patterns of inheritance.

- Punnett squares and pedigree diagrams to predict the probabilities of certain genotypes and phenotypes.

Traits

• A characteristic or quality of a living thing

• Inherited - genetically passed down

• Acquired - influenced by experience or the environment

Inherited Traits

Multiple Select

Which traits are INHERITED?

• Eye color

• Knowing how to ride a bike

• Zebra stripes

• Scar on you knee

• Hair color

Multiple Select

Which traits are ACQUIRED?

• Hair color

• Short hair

• Ear lobes attached

• Tree is short due to lack of water

• Freckled skin

Traits can be both inherited and acquired

How tall a plant grows is genetic trait, but it is also affected by the environmental conditions

Open Ended

How can skin color be BOTH an inherited and acquired trait?

Two Types of Reproduction

• Asexual - one parent, identical genes (plants, bacteria)

• Sexual - two parents, different genes (humans, animals, insects)

Sexual Reproduction

• The parent cells have TWO of each chromosome. 

• The four cells from meiosis have only ONE of each chromosome

• One cell from each parent combine to produce the offspring

• Offspring gets half its chromosomes from each parent = TWO chromosomes

Multiple Choice

If two organisms reproduce sexually, then their offspring will exhibit a genetic makeup that is -

• identical to only one parent
• identical to all of its siblings
• a unique combination of traits
• the recessive traits of each parent

Multiple Choice

What is an advantage of sexual reproduction?

• Higher chance of adapting or evolving over time
• Only needs one parent
• Happens very quickly and easily 
• Produces many offspring

Multiple Choice

What is one disadvantage for asexual reproduction?

• Happens very quickly
• Only needs one parent
• Lack of genetic diversity
• All offspring are exact copies of parent

Multiple Choice

In asexual reproduction, all of the offspring are:

• Physically Identical

• Genetically Identical

• The same age

• Not Identical

Alleles

• The factors are now called GENES

• Two forms of genes are called ALLELES

• Offspring get one allele from each parent

Multiple Choice

One version of a gene for a certain characteristic

• Gene

• Chromosome

• Allele

Multiple Choice

Recessive genotypes are written with:

• Upper case always

• Lower case always

Multiple Choice

Dominant genotypes are written with:

• Upper case always

• Lower case always

Multiple Choice

Which trait is dominant?

• Smooth

• Constricted

Multiple Choice

dd is

• Dominant

• Recessive

• Both

• None

Multiple Choice

Dd is

• Dominant

• Recessive

• Both

• None

Gregory Mendell Pea Experiment

• Different traits appear in different generations

• Dominant allele - capital letter

• Recessive allele - lower case letter

Pea Experiment

• Mendel crossed two plants that were pure for different traits for a certain characteristic

• First generation - only one trait observed (dominant)

• Second generation - both traits observed - told him offspring must inherit TWO factors (one from each parent)

Multiple Choice

How many factors did Mendel conclude an offspring receives for a single characteristic?

• 2

• 1

• 0

• 3

Multiple Choice

What did Mendel conclude from the results of this cross?

• Yellow seed color is codominant with green seed color

• Yellow seed color is dominant and green seed color is recessive.

• Green seed color is dominant and yellow seed color is recessive

• Seed color is determined by multiple genes.

Multiple Choice

Which trait is dominant?

• Purple

• White

Genes vs. Appearance

• Phenotype - traits that can be observed (color, height, etc.)

• Genotype - specific gene or combination of alleles

Multiple Choice

Hair colour is an example of

• genotype
• phenotype

Multiple Choice

"G" is dominant, "g" is recessive. If an organism has the genes "gg."

Which will trait will result?

• "G" dominant

• "g" recessive

Multiple Choice

What type of Genotype is this: aa?

• Homozygous

• Heterozygous

Multiple Choice

What type of Genotype is this: Aa?

• Homozygous

• Heterozygous

Multiple Choice

"T" is dominant, "t" is recessive. If an organism has the genes "Tt."

Which will trait will result?

• "T" dominant

• "t" recessive

Multiple Choice

Which of the following is heterozygous

• FF

• tt

• Gg

• RR

Multiple Choice

What type of Genotype is this: AA?

• Homozygous

• Heterozygous

Multiple Choice

Which of the following is homozygous recessive?

• rr

• AA

• TT

• Ff

Other Patterns of Inheritance

Incomplete Dominance

• One allele does not totally hide the other

Codominance

• Genes have alleles that are both dominant

Multiple Genes

• Traits or characteristics are affected by more than one gene

Multiple Choice

A plant that is heterozygous for a characteristic has two different alleles for that characteristic.

Which trait did heterozygous individuals show in Mendel's experiments on pea plants?

• The recessive trait

• The acquired trait

• The dominant trait

• The codominant trait

Multiple Choice

The photo shows a cross between a cow that is pure red with a cow that is pure white. The offspring is a cow that has both colors.

Which pattern of inheritance is shown?

• Multiple genes

• Recessive

• Incomplete dominance

• Codominance

Multiple Choice

Which pattern of inheritance is shown?

• Recessiveness

• Codominance

• Incomplete dominance

• Multiple genes

Punnett Square

• Used to show likelihood (% chance) of each phenotype (i.e. flower color)

• Genotypes of each parent are placed on the top and side of the box

• Dominant alleles have capital letters

Multiple Choice

What should you write in the blank square?

• RR

• Rr

• rr

Multiple Choice

What should you write in the blank square?

• RR

• Rr

• rr

Multiple Choice

What fraction of the crosses will exhibit the DOMINANT TRAIT?

• 1/4

• 1/2

• 3/4

Multiple Choice

What can you conclude about the genotypes of the people in the diagram?

• The person with the disease is heterozygous.

• The parents are heterozygous for the disease.

• Both children without the disease are homozygous.

• One parent is homozygous for the recessive allele.