MCQs EXAMINATION SET 2026 SOLVED
QUESTIONS GRADED A+
● Figure 1 represents a segment of DNA. Radiation can damage the
nucleotides in a DNA molecule. To repair some types of damage, a
single nucleotide can be removed from a DNA molecule and replaced
with an undamaged nucleotide. Which of the four labeled bonds in
Figure 1 could be broken to remove and replace the cytosine nucleotide
without affecting the biological information coded in the DNA
molecule? Answer: C. Bonds YY and ZZ at the same time
By breaking bonds Y and Z at the same time, the cytosine nucleotide
could be removed from the DNA molecule and replaced with an
undamaged cytosine without changing the biological information stored
in the DNA.
● A student wants to modify model 1 so that it represents an RNA
double helix instead of a DNA double helix. Of the following possible
changes, which would be most effective in making model 1 look more
like RNA than DNA? Answer: B. Changing the deoxyriboses to riboses
by adding −OH groups
RNA contains ribose, whereas DNA contains deoxyribose. A ribose
sugar has an −OH group linked to the 2′ carbon that a deoxyribose sugar
does not have.
, ● Different polysaccharides are used by plants for energy storage and
structural support. The molecular structures for two common
polysaccharides are shown in Figure 1. Starch is used by plants for
energy storage, and cellulose provides structural support for cell walls.
The monomer used to construct both molecules is glucose.
A study determined the effect of two different digestive enzymes, A and
B, on these two polysaccharides. Table 1 presents the data from the
study.
Mammals do not produce digestive enzyme B. However, sheep and
cattle are two types of mammals that contain microorganisms in their
digestive tract that produce enzyme B.
Based on Figure 1, which of the following best compares the atomic
structures of starch and cellulose? Answer: B. Starch and cellulose are
composed of repeating glucose monomers; however, in cellulose every
other glucose monomer is rotated 180 degrees.
Both starch and cellulose are both composed of repeating glucose
molecules; however, the orientation of every other glucose in cellulose is
upside down compared with the ones on either side.
● Different polysaccharides are used by plants for energy storage and
structural support. The molecular structures for two common
polysaccharides are shown in Figure 1. Starch is used by plants for
energy storage, and cellulose provides structural support for cell walls.
The monomer used to construct both molecules is glucose.
QUESTIONS GRADED A+
● Figure 1 represents a segment of DNA. Radiation can damage the
nucleotides in a DNA molecule. To repair some types of damage, a
single nucleotide can be removed from a DNA molecule and replaced
with an undamaged nucleotide. Which of the four labeled bonds in
Figure 1 could be broken to remove and replace the cytosine nucleotide
without affecting the biological information coded in the DNA
molecule? Answer: C. Bonds YY and ZZ at the same time
By breaking bonds Y and Z at the same time, the cytosine nucleotide
could be removed from the DNA molecule and replaced with an
undamaged cytosine without changing the biological information stored
in the DNA.
● A student wants to modify model 1 so that it represents an RNA
double helix instead of a DNA double helix. Of the following possible
changes, which would be most effective in making model 1 look more
like RNA than DNA? Answer: B. Changing the deoxyriboses to riboses
by adding −OH groups
RNA contains ribose, whereas DNA contains deoxyribose. A ribose
sugar has an −OH group linked to the 2′ carbon that a deoxyribose sugar
does not have.
, ● Different polysaccharides are used by plants for energy storage and
structural support. The molecular structures for two common
polysaccharides are shown in Figure 1. Starch is used by plants for
energy storage, and cellulose provides structural support for cell walls.
The monomer used to construct both molecules is glucose.
A study determined the effect of two different digestive enzymes, A and
B, on these two polysaccharides. Table 1 presents the data from the
study.
Mammals do not produce digestive enzyme B. However, sheep and
cattle are two types of mammals that contain microorganisms in their
digestive tract that produce enzyme B.
Based on Figure 1, which of the following best compares the atomic
structures of starch and cellulose? Answer: B. Starch and cellulose are
composed of repeating glucose monomers; however, in cellulose every
other glucose monomer is rotated 180 degrees.
Both starch and cellulose are both composed of repeating glucose
molecules; however, the orientation of every other glucose in cellulose is
upside down compared with the ones on either side.
● Different polysaccharides are used by plants for energy storage and
structural support. The molecular structures for two common
polysaccharides are shown in Figure 1. Starch is used by plants for
energy storage, and cellulose provides structural support for cell walls.
The monomer used to construct both molecules is glucose.
