Mendel's Laws

Mendel's Laws

SB3a. Use Mendel’s laws (segregation and independent assortment) to ask questions and define problems that explain the role of meiosis in reproductive variability.

Open Ended

How is meiosis involved in the transfer of genes?

Multiple Choice

The variety of genes and alleles that exist in organisms

• independent assortment

• chromosomal abnormalities

• genetic diversity

• mutations

Gregor Mendel

• In the mid-1800s, an Austrian monk had questions about genetics.

• He specifically wanted to know how traits were passed down from one generation to the next. He conducted his research on pea plants.

• He is often referred to as the “father of genetics”

Multiple Choice

Who is Gregor Mendel

• an Austrian Monk from the mid 1800s who contributed to the study of Genetics

• The scientist who discovered the structure of DNA

• a British scientist who discovered penicillin

• The scientist who used X-Ray Crystallography to shed light on the structure of DNA

Multiple Choice

What did Gregor Mendel study?

• Mold Spores

• Pea Plants

• Sun Flowers

• Rats

Genetics Vocabulary

• Trait-a specific characteristic of an organism

• Allele- alternative versions of the gene

• Genotype-the alleles an organism inherits from its parents.

• Phenotype-The physical trait that is expressed

Genetics Vocabulary

• Dominant-A dominant allele is an allele whose trait always shows up in the organism when the allele is present. (Always represented by a Capital letter- A)

• Recessive-A recessive allele is an allele that is masked when a dominant allele is present. (Always represented by a lower case letter- a)

Genetics Vocabulary

• Heterozygous-Alleles are different (hybrid)

• Homozygous-Alleles are the same (pure)

Multiple Choice

Which best describes an inherited trait?

• a characteristic one chooses to express
• a characteristic one receives from the food one eats
• a characteristic that is passed on from one's parents
• a characteristic that is influenced by one's surroundings

Multiple Choice

An allele is

• another word for a gene
• a homozygous genotype
• a heterozygous genotype
• one of several possible forms of a gene

Multiple Choice

Genotype

• the allele combination of an organism

• different forms of genes

• alleles for traits are the same

• factors that determine traits

Multiple Choice

Phenotype refers to the ______________________ of an individual.

• genetic makeup
• actual physical appearance
• recessive alleles

Multiple Choice

What does heterozygous mean?

• An organism that has the same alleles for a trait (TT or tt)

• An organism that has different alleles for a trait (Tt)

• When neither allele is fully dominant; offspring is a mixture of both

• the different forms of a trait (hair color--> brown, blonde, red

Multiple Choice

Which of the following genotypes is homozygous recessive?

• Tt

• tt

• TT

• T

Law of Dominance

States that the dominant allele will prevent the recessive allele from being expressed. The recessive allele will only appear when it is paired with another recessive allele in the offspring.

Multiple Choice

If a person has a dominant gene and a recessive gene for a certain trait, which will be expressed?

• the dominant gene

• the recessive gene

• both genes

• neither gene

Multiple Choice

If P represents purple color, and p represents white color, what combination(s) of factors represents white color?

• PP and Pp

• pp only

• Pp only

• PP only

Remember:

We have two copies of all of our chromosomes

Why?

Because you get one from each parent

Diploid cells= 2n

Multiple Choice

How many alleles (letters) do each person carry for a trait?

• 1
• 2
• 3
• 4

Law of Segregation

When traits are inherited, individual alleles assort independently during gamete production giving different traits an equal opportunity of being passed down. 

Law of Independent Assortment

When two or more characteristics are inherited, individual hereditary factors assort independently during gamete production, giving different traits an equal opportunity of occurring together. 

Caused by gene shuffling/random assortment of chromosomes during meiosis

Multiple Choice

Which of Mendel's laws states that alleles are separated during meiosis?

• Law of Dominance

• Law of Segregation

• Law of Independent Assortment

Multiple Choice

If your genotype is Bb, then you can only pass a B or b to your child but you can't pass both.

• Law of Dominance

• Law of Segregation

• Law of Independent Assortment

Multiple Choice

One gene for the type of earlobes a person will have will be in each gamete.

• Law of Dominance

• Law of Independent Assortment

• Law of Segregation

Multiple Choice

This law describes how each homologous pair separates independently of any other pairs during Anaphase I of meiosis

• Law of Segregation

• Law of Independent Assortment

• Law of Gravity

• Law of Mathematical Order

Multiple Choice

This law describes how each member of a homologous pair is pulled randomly to one side or another in anaphase I

• Law of Segregation

• Law of Independent Assortment

• Law of Gravity

• Law of Mathematical Order

Fill in the Blank

A _____ is a characteristic an individual receives from its parents.

Fill in the Blank

_____ carry the instructions responsible for the expression of traits.

Fill in the Blank

Alternative versions of genes are known as _______.

Multiple Choice

The Italian monk/scientist who first showed

the principles of genetics

• Watson and Crick

• Linnaeus

• Darwin

• Mendel

Multiple Choice

During meiosis, the homologous pairs of chromosomes and the matching alleles are lined up independently.

Offspring are a mix of maternal genes and paternal genes.

This increases genetic variation.

• Homozygous Dominant

• Law of Segregation

• Crossing Over

• Independent Assortment

Multiple Choice

During meiosis and gamete formation, homologous (paired up) alleles split up

• Phenotype

• Law of Segregation

• Genotype

• Dihybrid Cross

Multiple Choice

The letter symbols for both homologous alleles.

BB Bb bb AA Aa aa

• Genotype

• Phenotype

• Recessive

• Dominant

Multiple Choice

The instruction of one allele covers up the instruction

of the other allele in a homologous pair. Symbolized by a capital letter.

• Recessive Allele

• Dominant Allele

• Heredity

• Trait

Multiple Choice

A feature regulated by a set of genes (allele) passed on

from parents to offspring. Also called inherited traits.

• Heterozygous

• Mendel

• Chromosome

• Traits