Question 1

Which of the following statements best explains why cellulose is insoluble fiber in the human diet, while starch is digestible?

Accepted Answer

Cellulose is composed of glucose monomers joined by $$\beta$$ glycosidic linkages, which human enzymes cannot hydrolyze.

Question 2

A patient is diagnosed with a genetic disorder that results in the substitution of valine for glutamic acid in the primary structure of hemoglobin. What is the most likely consequence of this mutation?

Accepted Answer

The hemoglobin will form abnormal shapes, leading to sickle-shaped red blood cells.

Question 3

Which of the following best describes the structural difference between saturated and unsaturated fatty acids, and its effect on their physical state at room temperature?

Accepted Answer

Saturated fatty acids have no double bonds, allowing them to pack tightly and be solid at room temperature.

Question 4

During digestion, the breakdown of starch into glucose monomers is an example of which chemical reaction?

Accepted Answer

Hydrolysis

Question 5

Which of the following best explains why phospholipids form bilayers in aqueous environments?

Accepted Answer

Their fatty acid tails are hydrophobic and avoid water, while their phosphate heads are hydrophilic and interact with water.

Question 6

A scientist is comparing the amino acid sequences of hemoglobin in humans and several other vertebrates. She finds that humans and gorillas differ by only one amino acid, while humans and frogs differ by 67 amino acids. What does this suggest about their evolutionary relationships?

Accepted Answer

Humans and gorillas share a more recent common ancestor than humans and frogs.

Question 7

Which of the following is a correct description of the flow of genetic information in a eukaryotic cell?

Accepted Answer

DNA $$\rightarrow$$ RNA $$\rightarrow$$ Protein

Question 8

Which of the following statements about the structure of DNA is correct?

Accepted Answer

The two strands of DNA are held together by hydrogen bonds between complementary bases.

Question 9

Which of the following best explains why trans fats are considered more harmful than saturated fats in the human diet?

Accepted Answer

Trans fats increase the risk of atherosclerosis more than saturated fats by affecting cholesterol levels.

Question 10

Which of the following is NOT a function of proteins in living organisms?

Accepted Answer

Storing genetic information

Question 11

A researcher isolates a macromolecule that contains nitrogen, phosphorus, and a pentose sugar. Which class of biological molecule does it most likely belong to?

Accepted Answer

Nucleic acid

Question 12

Which of the following best describes the role of chaperonins in protein folding?

Accepted Answer

They provide a protected environment for polypeptides to fold spontaneously.

Question 13

Which of the following statements about the formation of a peptide bond is correct?

Accepted Answer

A peptide bond forms by dehydration between the carboxyl group of one amino acid and the amino group of another.

Question 14

Which of the following is a correct pairing of a nitrogenous base with its complement in DNA?

Accepted Answer

Cytosine pairs with guanine

Question 15

Which of the following best explains why a gram of fat stores more energy than a gram of starch?

Accepted Answer

Fats have more nonpolar C—H bonds, which store more energy.

Question 16

Which of the following is a unique feature of chitin compared to cellulose?

Accepted Answer

Chitin contains a nitrogen-containing appendage on each glucose monomer.

Question 17

Which of the following best describes the difference between a nucleoside and a nucleotide?

Accepted Answer

A nucleotide contains a nitrogenous base, a pentose sugar, and a phosphate group.

Question 18

Which of the following is a real-life example of the importance of protein structure for function?

Accepted Answer

The ability of morphine to bind to endorphin receptors due to its similar shape.

Question 19

Which of the following statements about the antiparallel nature of DNA is correct?

Accepted Answer

One DNA strand runs from 5' to 3', and the other runs from 3' to 5'.

Question 20

Which of the following best describes the role of hydrogen bonds in the secondary structure of proteins?

Accepted Answer

Hydrogen bonds form between the repeating constituents of the polypeptide backbone, stabilizing $$\alpha$$ helices and $$\beta$$ sheets.

The Structure and Function of Large Biological Molecules

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