Domain 2 - Pre-Review Practice

Which statement describes the function of nucleic acids during the synthesis of proteins? (SB2a)

• Complementary codons on mRNA and anticodons on DNA bind together.

• Complementary bases on tRNA and on rRNA bind together.

• Complementary bases on rRNA and DNA bind together.

• Complementary codons on mRNA and anticodons on tRNA bind together.

Answer explanation

This answer is correct. The codons or series of three nucleotides on mRNA bind to the complementary anticodons on tRNA during protein synthesis.

The diagram shows the process of crossing over. Which claim about crossing over in chromosomes is best supported by the diagram? (SB2b)

• Crossing over increases genetic diversity through deletion.

• Crossing over decreases genetic diversity through mutation.

• Crossing over increases genetic diversity by creating new combinations of genes.

• Crossing over decreases genetic diversity by inserting nucleotides into gene sequences.

What beneficial impact could genetically engineered crops have on society? (SB2c)

• They could create a more stable food supply, as crops could be altered to resist droughts.

• They could create more efficient production, as crops could be altered to need no light.

• They increase genetic variation in crops.

• They decrease food allergies from crops.

A scientist is studying genes with complete dominance in flowers. If one parent is homozygous for the dominant gene, what principle is true no matter what genes the other parent carries? (SB3a)

• All offspring will be affected by the dominant trait. 

• Crossing over can affect the genes that the offspring carry. 

• Multiple alleles always affect traits in offspring. 

• Some offspring will show the recessive form of the trait. 

Answer explanation

This is correct. All offspring will be affected by the trait if the parent is homozygous. 

Leia is crossing sunflowers that have different genotypes for height. She crosses a tall sunflower plant with a genotype of TT with a short sunflower plant with a genotype of tt. Which ratio shows the probability that the two sunflower plants will produce a sunflower plant with a genotype of Tt? (SB3b)

• 1/4

• 2/4

• 3/4

• 4/4

Answer explanation

Each sunflower will contribute one of their alleles, and in this case each sunflower will contribute either T or t. All offspring are expected to have a genotype of Tt.

Which of the following is an advantage of sexual reproduction? (SB3c)

• It does not require organisms to use energy to find a mate.

• It results in genetic variation in a species.

• It allows a large number of identical organisms to rapidly reproduce.

• It increases the number of chromosomes in each generation.