Mendelian Genetics & Meiosis

Mendel was a careful researcher who studied the inheritance of certain traits in garden peas. Which research practices did Mendel use? Choose all that apply.

• He crossed true-breeding pea plants.

• He allowed eggs to be fertilized only by self-pollination.

• He analyzed his data mathematically.

• He controlled variables by studying one or two traits at a time.

Answer explanation

Mendel crossed true-breeding pea plants to ensure consistent traits. He analyzed data mathematically to identify patterns and controlled variables by studying one or two traits at a time for clarity.

The expression of a trait (what you see) in an organism is called​ (a)  

• phenotype.
• genotype.
• homozygous.
• heterozygous.

Tags

NGSS.HS-LS4-4

Match each genotype to its description

• RR

• HOMOZYGOUS DOMINANT

• Rr

• HETEROZYGOUS

• rr

• HOMOZYGOUS

  RECESSIVE

Match the following genotypes and allelles.

• Dominant Allele

• RR

• Homozygous Recessive

• g

• Recessive Allele

• Bb

• Homozygous Dominant

• dd

• Heterozygous

• G

Tags

112.34.c.6.F

Match the following terms with their correct descriptions:

• Plants that produce offspring of the same variety when they self-pollinate.

• F1 Generation

• Offspring of the P generation

• F2 Generation

• Offspring of the F1 generation

• True-breeding

What were the genotypes of the parents that produced the offspring in the Punnett square?

• Tt for both parents

• TT for one parent, tt for the other parent

• TT for one parent, Tt for the other parent

• TtTt for both parents

Answer explanation

The genotypes of the parents can be Tt for both, TT and tt, or TT and Tt, as these combinations can produce the offspring shown in the Punnett square. Thus, all provided options are correct.

Tags

NGSS.HS-LS3-1

What phenotypes will be shown by the offspring?

• All offspring will show the recessive phenotype for this trait.

• All offspring will show the dominant phenotype for this trait.

• Half of the offspring will show the dominant phenotype and half will show the recessive phenotype.

• Three fourths of the offspring will show the dominant phenotype and one fourth will show the recessive phenotype.

Answer explanation

In a typical monohybrid cross, if one parent is homozygous dominant and the other is homozygous recessive, the offspring will be heterozygous, showing the dominant phenotype. Thus, half will show the dominant phenotype and half the recessive.

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

Which two genes are most likely to be affected by a crossing-over event?

• a. a pair of genes located adjacent to each other on a chromosome

• b. a pair of genes separated by a third gene on a chromosome

• c. a pair of genes located at opposite ends of a chromosome

• d. a pair of genes located on different chromosomes

Answer explanation

Crossing-over is more likely to occur between genes that are close together on the same chromosome. Therefore, genes that are adjacent (choice a) or separated by a third gene (choice b) are more likely to be affected.

Tags

NGSS.HS-LS3-2

In Drosophila, the wild type allele for body color is (a)   .

• Gray

• Black

• Red

• Brown

Answer explanation

In Drosophila, the wild type allele for body color is gray. This is the standard color observed in the species, while other colors like black, red, and brown are considered mutations.

Tags

NGSS.HS-LS3-1

Match the following terms with their correct descriptions:

• A variant form of a gene

• Allele

• A unit of heredity

• Haploid

• A cell with a double set of chromosomes

• Gene

• A cell with a single set of chromosomes

• Diploid