Biology Module 2

What do we call a small circular section of DNA that confers one or more traits to a bacteria?

• filament

• flagellum

• basal body

• plasmid

What is letter "b"?

• flagellum

• capsule

• cytoplasm

• fimbria

What is letter "d"?

• cytoplasm

• DNA

• ribosome

• fimbria

What is letter "h"?

• cell wall

• DNA

• flagellum

• ribosome

There are two alleles for claw length in a certain mammal population.  Some members of the population have long claws that enable them to climb trees, while most do not.  When a new predator that feeds on these animals is introduced into this environment, some long-clawed animals climb up trees to escape. Which statement describes the most likely impact of natural selection on the population over the coming generations?

• The alleles for long claws will increase in the population.
• The alleles for long claws will decrease in the population.
• The alleles for short claws will increase in the population.
• The alleles for short claws will disappear from the population.

Which statement best describes how chromosomes are related to genes?

• Chromosomes are sequences of DNA within a gene.
• Chromosomes are copies of the genes of an organism.
• Chromosomes are all the different forms a gene can take.
• Chromosomes are structures that contain the genes of an organism.

A section of a gene has the following sequence of nitrogenous bases:  TGACAT.  If a frame-shift mutation occurs in this section, which of the following could be the mRNA strand coded from it?

• ACTGTA
• ACUGUA
• ACTGTTA
• ACUGUUA

Which statement correctly describes how a cell's DNA is replicated after the strands unwind?

• The double helix consists of two copies of the same strand, so copying one strand twice produces identical DNA.
• When the nitrogenous base "rungs" separate from the double helix "ladder", new complementary pairs take their place.
• The original strands are complementary, so each new strand built using complementary base pairs will match an original strand.
• The hydrogen bonds between complementary bases are too strong to be broken, so the sugar and phosphate groups are replaced with identical molecules.

A trait for petal color in snapdragons has two alleles, white and red, that demonstrates incomplete dominance.  If one white homozygous and one red homozygous individual are crossed, what percentage of their offspring is likely to have pink petals?

• 0%
• 25%
• 50%
• 100%

Pea plants have two alleles for seed shape.  Round seeds are the dominant trait, while wrinkled seeds are recessive.  Which of the following crosses is guaranteed to produce offspring with wrinkled seeds?

• heterozygous with heterozygous
• heterozygous with homozygous dominant
• homozygous recessive with homozygous recessive
• homozygous dominant with homozygous dominant