Questions and Answers
• 1.
The nitrogen bases which pair with two hydrogen bonds are
o A.
Adenine and thymine
o B.
Adenine and cytosine
o C.
Cytosine and guanine
o D.
Cytosine and adenine
Correct Answer
A. Adenine and thymine
Explanation
Adenine and thymine pair with two hydrogen bonds because they have
complementary shapes and sizes that allow them to fit together. Adenine has a
flat structure with two hydrogen bond donor sites, while thymine has a
complementary shape with two hydrogen bond acceptor sites. This allows
adenine and thymine to form a stable base pair in DNA. The other options,
adenine and cytosine, and cytosine and guanine, form three hydrogen bonds,
making them incorrect answers.
• 2.
DNA differs from RNA in
o A.
Presence of deoxyribose sugar
, o B.
Presence of thymine base
o C.
Property of replication
o D.
All of the above
Correct Answer
D. All of the above
Explanation
DNA differs from RNA in all of the above mentioned ways. DNA contains
deoxyribose sugar instead of ribose sugar found in RNA. Additionally, DNA
contains thymine base while RNA contains uracil base. Finally, DNA has the
property of replication, meaning it can make copies of itself, while RNA does
not have this ability. Therefore, the correct answer is all of the above.
:
• 3.
Extranuclear genetic material is found in
o A.
Plastid and nucleus
o B.
Mitochondria and plastids
o C.
Nucleus and cytoplasm
o D.
• 1.
The nitrogen bases which pair with two hydrogen bonds are
o A.
Adenine and thymine
o B.
Adenine and cytosine
o C.
Cytosine and guanine
o D.
Cytosine and adenine
Correct Answer
A. Adenine and thymine
Explanation
Adenine and thymine pair with two hydrogen bonds because they have
complementary shapes and sizes that allow them to fit together. Adenine has a
flat structure with two hydrogen bond donor sites, while thymine has a
complementary shape with two hydrogen bond acceptor sites. This allows
adenine and thymine to form a stable base pair in DNA. The other options,
adenine and cytosine, and cytosine and guanine, form three hydrogen bonds,
making them incorrect answers.
• 2.
DNA differs from RNA in
o A.
Presence of deoxyribose sugar
, o B.
Presence of thymine base
o C.
Property of replication
o D.
All of the above
Correct Answer
D. All of the above
Explanation
DNA differs from RNA in all of the above mentioned ways. DNA contains
deoxyribose sugar instead of ribose sugar found in RNA. Additionally, DNA
contains thymine base while RNA contains uracil base. Finally, DNA has the
property of replication, meaning it can make copies of itself, while RNA does
not have this ability. Therefore, the correct answer is all of the above.
:
• 3.
Extranuclear genetic material is found in
o A.
Plastid and nucleus
o B.
Mitochondria and plastids
o C.
Nucleus and cytoplasm
o D.
