Biology  by Bradford
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1.7 Proteins: revision map

The subtopic in the middle and five tasks round it: label two diagrams, complete a table, put a process in order and fill 13 gaps. Every box rests on a learning objective of the topic in the AP Biology course and exam description. Type into the blanks and check them, or print it on A4, Letter or A3 with an answer key.

Unit 1 practice questionsThe whole Unit 1 map

Topic 1.7

Proteins

AP Biology · Unit 1 Chemistry of LifeName

1.7.AFrom sequence to function

Number the steps in order.

  1. Where there is more than one polypeptide, they associate into a quaternary structure.
  2. Amino acids are joined by peptide bonds in a specific sequence: the primary structure.
  3. Interactions between R groups fold the whole chain into a three-dimensional shape.
  4. The final shape determines which molecules the protein can bind, so it sets its function.
  5. Hydrogen bonds between backbone atoms fold the chain locally into alpha helices and beta sheets.

1.7.AR groups decide the fold

An amino acid's R group is , hydrophilic or ionic. In water a protein usually folds with nonpolar R groups buried in the core and hydrophilic ones on the outside. Because shape decides function, changing one amino acid can change the fold: in sickle cell disease, a single substitution replaces a hydrophilic amino acid with a nonpolar one and makes hemoglobin stick together. A change in temperature or pH can break the weak bonds that hold the shape, so the protein is and loses its function.

1.7.AFour levels of structure

1234
  1. 1
  2. 2
  3. 3
  4. 4
Topic 1.7Proteins

1.7.AAn amino acid

NH₂COOHHR1234
  1. 1
  2. 2
  3. 3
  4. 4

1.7.AWhat holds each level together

LevelHeld bySet by
Primary bonds between amino acidsthe order of amino acids
Secondary bonds along the backbonelocal folding into helices and sheets
TertiaryR group interactions: nonpolar clustering, ionic bonds, polar attractions and disulfide bridgesthe overall 3D shape
Quaternaryinteractions between separate how many chains join and how
Word bank alpha carbonamino groupcarboxyl groupdenaturedhydrogenhydrophobicpeptidepolypeptidesprimary structurequaternary structureR groupsecondary structuretertiary structure

Answer key

Every box on the sheet with its gaps filled in, as the subtopic reads in full.

  1. LabelAn amino acid

    1. amino group
    2. carboxyl group
    3. R group
    4. alpha carbon

  2. LabelFour levels of structure

    1. primary structure
    2. secondary structure
    3. tertiary structure
    4. quaternary structure

  3. OrderFrom sequence to function

    1. Amino acids are joined by peptide bonds in a specific sequence: the primary structure.
    2. Hydrogen bonds between backbone atoms fold the chain locally into alpha helices and beta sheets.
    3. Interactions between R groups fold the whole chain into a three-dimensional shape.
    4. Where there is more than one polypeptide, they associate into a quaternary structure.
    5. The final shape determines which molecules the protein can bind, so it sets its function.

  4. TableWhat holds each level together

    LevelHeld bySet by
    Primarypeptide bonds between amino acidsthe order of amino acids
    Secondaryhydrogen bonds along the backbonelocal folding into helices and sheets
    TertiaryR group interactions: nonpolar clustering, ionic bonds, polar attractions and disulfide bridgesthe overall 3D shape
    Quaternaryinteractions between separate polypeptideshow many chains join and how

  5. GapsR groups decide the fold

    An amino acid's R group is hydrophobic, hydrophilic or ionic. In water a protein usually folds with nonpolar R groups buried in the core and hydrophilic ones on the outside. Because shape decides function, changing one amino acid can change the fold: in sickle cell disease, a single substitution replaces a hydrophilic amino acid with a nonpolar one and makes hemoglobin stick together. A change in temperature or pH can break the weak bonds that hold the shape, so the protein is denatured and loses its function.