The <strongprimary</strong structure of a protein refers to

Answer: Its sequence of amino acids Primary = sequence; secondary = local folds (helices/sheets); tertiary = overall 3D shape; quaternary = multi-chain assembly.

Triglycerides serve as long-term energy storage primarily because

Answer: Their highly reduced C-H bonds release more ATP per gram than carbohydrates Lipids are more reduced (more C-H bonds) than carbs/proteins, so full oxidation releases 9 kcal/g vs 4 kcal/g for carbohydrates.

A peptide bond forms between

Answer: An amino group and a carboxyl group The amino (-NH₂) of one amino acid joins the carboxyl (-COOH) of another via dehydration synthesis.

AP Biology · Topic 1.5

Structure and Function of Biological Macromolecules Practice

Q: The <strongprimary</strong structure of a protein refers to

Answer: Its sequence of amino acids Primary = sequence; secondary = local folds (helices/sheets); tertiary = overall 3D shape; quaternary = multi-chain assembly.

Q: Triglycerides serve as long-term energy storage primarily because

Answer: Their highly reduced C-H bonds release more ATP per gram than carbohydrates Lipids are more reduced (more C-H bonds) than carbs/proteins, so full oxidation releases 9 kcal/g vs 4 kcal/g for carbohydrates.

Q: A peptide bond forms between

Answer: An amino group and a carboxyl group The amino (-NH₂) of one amino acid joins the carboxyl (-COOH) of another via dehydration synthesis.

Part of Chemistry of Life.(SYI-1.E)

Practice questions

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Sample questions

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Sample 1difficulty 2/5
$The <strong> primary </strong> structure of a protein refers to$
- A
  $Its alpha helices and beta sheets$
- B
  $Its three-dimensional folded shape$
- C
  $Its sequence of amino acids$
  check_circle
- D
  $Multi-subunit assemblies$
Why
$Primary = sequence; secondary = local folds (helices/sheets); tertiary = overall 3D shape; quaternary = multi-chain assembly.$
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Sample 2difficulty 2/5
$Triglycerides serve as long-term energy storage primarily because$
- A
  $Their nitrogen-rich tails store energy more densely than sugars$
- B
  $Their highly oxidized C-O bonds release ATP faster than glycogen$
- C
  $Their polar ester linkages dissolve readily in cytosolic water$
- D
  $Their highly reduced C-H bonds release more ATP per gram than carbohydrates$
  check_circle
Why
$Lipids are more reduced (more C-H bonds) than carbs/proteins, so full oxidation releases ~9 kcal/g vs ~4 kcal/g for carbohydrates.$
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Sample 3difficulty 2/5
$A peptide bond forms between$
- A
  $Two carboxyl groups of adjacent residues$
- B
  $A sulfhydryl group and an amino group$
- C
  $A hydroxyl group and a phosphate group$
- D
  $An amino group and a carboxyl group$
  check_circle
Why
$The amino (-NH₂) of one amino acid joins the carboxyl (-COOH) of another via dehydration synthesis.$
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Sample 4difficulty 2/5
$A triglyceride consists of$
- A
  $Glycerol + three fatty acids$
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- B
  $Three nucleotides$
- C
  $Three glucose molecules$
- D
  $A glycerol + phosphate + two fatty acids$
Why
$Glycerol provides three -OH groups to which three fatty acids are esterified.$
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Sample 5difficulty 2/5
$All steroids share what structural feature?$
- A
  $A phosphate-sugar repeating backbone$
- B
  $A long fatty-acid hydrocarbon tail$
- C
  $A four-fused-ring carbon skeleton$
  check_circle
- D
  $A polypeptide chain of amino acids$
Why
$The four-ring (three 6-carbon, one 5-carbon) sterol skeleton, with different side groups giving cholesterol, testosterone, etc.$
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