Question 1

Which of the following best describes the stabilization of a protein's tertiary structure?

Accepted Answer

Disulfide bridges, hydrophobic interactions, ionic bonds, and hydrogen bonds among side chains

Question 2

A protein is found to have multiple identical subunits that interact to form a functional complex. Which level of protein structure does this describe?

Accepted Answer

Quaternary structure

Question 3

Which of the following is an example of a protein motif?

Accepted Answer

Helix-turn-helix

Question 4

Which physicochemical property of proteins is most responsible for their ability to act as buffers in biological systems?

Accepted Answer

Amphoteric nature due to ionizable side chains

Question 5

A protein is denatured by heating. Which thermodynamic force is most disrupted during this process?

Accepted Answer

Hydrophobic interactions among nonpolar side chains

Question 6

Which post-translational modification is essential for the activation of many enzymes and involves the addition of a phosphate group?

Accepted Answer

Phosphorylation

Question 7

A scientist uses size-exclusion chromatography to purify a protein. What property of the protein is primarily being exploited in this technique?

Accepted Answer

Molecular size

Question 8

Which of the following statements about enantiomers of monosaccharides is correct?

Accepted Answer

They are mirror images and differ at all chiral centers

Question 9

In the Haworth projection of maltose, which glycosidic bond connects the two glucose units?

Accepted Answer

$$\alpha-1$$,4

Question 10

Which of the following disaccharides is a reducing sugar?

Accepted Answer

Lactose

Question 11

Why is glycogen water soluble while cellulose is not?

Accepted Answer

Glycogen is highly branched with $$\alpha-1$$,6 linkages, preventing tight packing

Question 12

Which structural feature is characteristic of glycosaminoglycans?

Accepted Answer

Repeating disaccharide units containing an amino sugar and a uronic acid

Question 13

Proteoglycans are important in the extracellular matrix because they:

Accepted Answer

Facilitate cell-cell recognition and contribute to matrix hydration

Question 14

Which of the following is NOT a function of lipids in biological systems?

Accepted Answer

Catalysis of biochemical reactions

Question 15

Which of the following best describes the structure of cholesterol?

Accepted Answer

A four-ring steroid nucleus with a hydrocarbon tail

Question 16

Which class of lipoprotein is primarily responsible for transporting dietary triglycerides from the intestine to peripheral tissues?

Accepted Answer

Chylomicrons

Question 17

Which type of phospholipid contains a sphingosine backbone?

Accepted Answer

Sphingomyelin

Question 18

Cholesterol serves as a precursor for which of the following molecules?

Accepted Answer

Steroid hormones

Question 19

Which of the following is a function of prostaglandins?

Accepted Answer

Regulation of inflammation and pain

Question 20

Which of the following best describes facilitated diffusion across a biological membrane?

Accepted Answer

Passive transport of molecules down their concentration gradient via a specific protein

Biochemistry Exam 2 Study Guide: Proteins, Carbohydrates, Lipids, Membranes, and Transport

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