Bio Q3 CSA Review

B=Brown fur

b=tan fur

What percent of the offspring would be tan when you cross BbxBb?

• 75%

• 25%

• 50%

• 100%

Answer explanation

In a Bb x Bb cross, the genotypes are BB, Bb, Bb, and bb. Only the bb genotype results in tan fur. Thus, 1 out of 4 offspring (25%) will have tan fur.

#6

• Ribose Sugar

• Deoxyribose sugar

• Monosaccharide

• Phosphate

Answer explanation

Deoxyribose sugar is the correct answer as it is the sugar component of DNA, while ribose sugar is found in RNA. Monosaccharides are simple sugars, and phosphate is a component of nucleotides, but not a sugar.

One allele is stronger and will be expressed over another.

• Law of Dominance

• Law of Independent Assortment

• Law of Conservation of Matter

• Law of Segregation

Answer explanation

The Law of Dominance states that in a pair of alleles, one can mask the expression of the other. This means the stronger allele is expressed over the weaker one, making it the correct choice.

Which of the following conclusions can be drawn from this graph?

• The optimum pH of the enzyme is 6.6.
  

• The optimum pH of the enzyme is 5.8
  

• The enzyme’s activity increases as pH increases 5.0 to 9.0
  

• The enzyme’s activity is greater around pH of 8.0 .
  

Answer explanation

The graph indicates that the enzyme's activity peaks at a pH of 6.6, making it the optimum pH. Other options either misstate the optimum pH or incorrectly describe the enzyme's activity across the pH range.

What stage of mitosis comes before this stage?

• Prophase

• Metaphase

• Anaphase

• Interphase

Answer explanation

Prophase is the first stage of mitosis, where chromatin condenses into visible chromosomes and the nuclear envelope begins to break down. Therefore, it is the stage that comes before the next stages of mitosis.

Which of the following would require the use of recombinant DNA?

• crossing apple trees to create better apples

• engineering bacteria to produce human insulin

• breeding a donkey and a horse to make a mule

• creating a polyploid tree

Answer explanation

Engineering bacteria to produce human insulin involves manipulating DNA to create a new organism with specific traits, which requires recombinant DNA technology. The other options do not involve genetic engineering.

#7

• Nucleic Acid

• Sugar

• Nitrogen Base

• Nucleotide

Answer explanation

A nucleotide is the basic building block of nucleic acids, consisting of a sugar, a phosphate group, and a nitrogen base. Therefore, the correct answer is 'Nucleotide'.

What proportion of the offspring in Figure 11-4 would be expected to have white, smooth hair?

• 9/16

• 3/16

• 4/16

• 1/16

Answer explanation

In a typical dihybrid cross, the ratio of phenotypes is 9:3:3:1. The white, smooth hair phenotype corresponds to the recessive traits, which occurs in 1 out of 16 offspring, making the expected proportion 1/16.

A farmer has bred his pineapple plants from the sweetest pineapples in his last harvest to get even sweeter pineapple plants next time. What is this an example of?

• Natural Selection

• Genetic Engineering

• Selective Breeding or artificial selection

• Extinction

Answer explanation

This is an example of selective breeding or artificial selection, where the farmer chooses the sweetest pineapples to breed, enhancing desirable traits in future generations.

Crossing over ensures that every gamete is _______.

• destroyed

• unique

• copied

• doubled

Answer explanation

Crossing over during meiosis mixes genetic material between homologous chromosomes, resulting in gametes that are unique. This genetic variation is crucial for evolution and diversity in offspring.