Q: Which of the following is a correct representation of the central dogma of molecular biology?

$$DNA \rightarrow RNA \rightarrow \text{Protein}$$

Question 1

Which of the following best describes the structural difference between DNA and RNA sugars?

Accepted Answer

DNA contains deoxyribose, which lacks an oxygen atom at the 2' carbon, while RNA contains ribose, which has an -OH group at the 2' carbon.

Question 2

Which of the following base pairs is found in DNA but NOT in RNA?

Accepted Answer

Adenine–Thymine

Question 3

During the formation of a polynucleotide, which type of bond is formed between the 3' hydroxyl group of one nucleotide and the 5' phosphate group of the next?

Accepted Answer

Phosphodiester bond

Question 4

Which of the following statements about hydrogen bonding in nucleic acids is correct?

Accepted Answer

Hydrogen bonds form between complementary nitrogenous bases on opposite strands, stabilizing the double helix structure.

Question 5

A scientist isolates a nucleic acid and finds that it contains uracil, ribose, and is single-stranded. Which type of molecule is this most likely to be?

Accepted Answer

RNA

Question 6

Which of the following best explains why cellulose and starch, both composed of glucose monomers, have different properties?

Accepted Answer

They differ in the type of glycosidic linkages between glucose monomers, resulting in different three-dimensional structures.

Question 7

Which of the following is a correct representation of the central dogma of molecular biology?

Accepted Answer

$$DNA ightarrow RNA ightarrow 	ext{Protein}$$

Question 8

Which of the following is a function of carbohydrates in living organisms?

Accepted Answer

Energy storage and structural support

Question 9

Which of the following best describes a dehydration synthesis reaction in the context of nucleic acids?

Accepted Answer

A reaction in which a water molecule is removed to form a phosphodiester bond between nucleotides

Question 10

A mutation causes a cell to produce a nucleotide with a ribose sugar and thymine as its nitrogenous base. Which of the following best describes the result?

Accepted Answer

This nucleotide does not normally occur in nature, as thymine is not found in RNA.

Question 11

Which of the following statements about polysaccharides is correct?

Accepted Answer

Glycogen is a highly branched polysaccharide used for energy storage in animals.

Question 12

Which of the following best explains why chitin and peptidoglycan are both strong structural molecules?

Accepted Answer

They have parallel strands joined by hydrogen or peptide bonds, providing rigidity.

Question 13

Which of the following is a pyrimidine found only in RNA?

Accepted Answer

Uracil

Question 14

A sample of DNA is found to contain 30% adenine. According to base-pairing rules, what percentage of guanine would you expect to find?

Accepted Answer

20%

Question 15

Which of the following best describes the backbone of a nucleic acid strand?

Accepted Answer

It is composed of alternating sugar and phosphate groups linked by phosphodiester bonds.

Question 16

Which of the following is a correct statement about the difference between purines and pyrimidines?

Accepted Answer

Purines have a double-ring structure, while pyrimidines have a single-ring structure.

Question 17

Which of the following best explains why glycogen is more suitable for rapid energy release in animals compared to cellulose?

Accepted Answer

Glycogen is highly branched, allowing enzymes to access glucose units quickly, while cellulose has a linear structure with hydrogen bonds that make it rigid and indigestible to most animals.

Question 18

Which of the following is a correct description of a disaccharide?

Accepted Answer

A molecule formed by two monosaccharides joined by a glycosidic bond through dehydration synthesis.

Question 19

A patient is diagnosed with a genetic disorder that affects the formation of phosphodiester bonds. Which process would be most directly impaired?

Accepted Answer

Synthesis of nucleic acids such as DNA and RNA

Question 20

Which of the following best describes the role of oligosaccharides in biological systems?

Accepted Answer

They are often involved in cell recognition and signaling on cell surfaces.

Nucleic Acids and Carbohydrates: Structure and Function

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