Essential Idea
Proteins have a very wide range of functions in living organisms.
Understandings
Amino acids are linked together by condensation to form polypeptides.
There are 20 different amino acids in polypeptides synthesized on ribosomes.
Amino acids can be linked together in any sequence giving a huge range of possible polypeptides.
The amino acid sequence of polypeptides is coded for by genes.
A protein may consist of a single polypeptide or more than one polypeptide linked together.
The amino acid sequence determines the three-dimensional conformation of a protein.
Living organisms synthesize many different proteins with a wide range of functions.
Every individual has a unique proteome.
Applications
Rubisco, insulin, immunoglobulins, rhodopsin, collagen and spider silk as examples of the range of protein functions.
Denaturation of proteins by heat or by deviation of pH from the optimum.
Skills
Drawing molecular diagrams to show the formation of a peptide bond.
Guidance
The detailed structure of the six proteins selected to illustrate the functions of proteins is not needed.
Egg white or albumin solutions can be used in denaturation experiments.
Students should know that most organisms use the same 20 amino acids in the same genetic code although there are some exceptions. Specific examples could be used for illustration.
Key Vocabulary
Amino acid
Base chain
Side chain
Condensation reaction (or Dehydration synthesis)
Polypeptide
Primary structure
Secondary structure
Alpha helix (twisting)
Beta pleated sheet (folding)
Tertiary structure
Quaternary structure
Hydrogen bonding
Denaturation
Proteome
Textbook Reading and/or Activities
Click HERE for a pdf of chapter 2.
Pages XYZ-XYZ
Nature of Science (p. XYZ)
Challenge Yourself (p. XYZ)
Worked Example (p. XYZ)
Notes
A detailed set of notes, prepared by Bob Smullen, examining all of the IB learning expectations.
i-Biology Notes (Not available)
A detailed set of notes, prepared by Stephen Taylor, examining U1 - U8 and A1 - A4.
A series of questions, prepared by Stephen Taylor, to help check your understanding of the IB learning expectations. This is VERY GOOD practice.
A detailed set of notes, created by Chris Paine, examining all of the IB learning expectations.
A series of questions, created by Chris Paine, to help check your understanding of the IB learning expectations. This is VERY GOOD practice.
A detailed set of notes, prepared by Jacob Cedarbaum, examining all of the IB learning expectations (slides 1-30).
2.4 Study Questions (NEW Syllabus)
A series of questions, prepared by Jacob Cedarbaum, to help check your understanding of the IB learning expectations. This is VERY GOOD practice but it also includes some HL material so please mind the SL Understandings and Applications at left. Answers (OLD).
Learning Activities
Molecular Workbench - Proteins & DNA
An interactive online module enabling you to explore the structure and function of proteins. Only review the protein section (p.1-6) of the module. Trouble using the module? Use these screen shots to see what you're missing.
Amino Acids and Proteins Animations and Notes
This simple animation, produced by John Kyrk, illustrates the building blocks of proteins as well as the process by which they twist and fold to become functional proteins.
Supplemental Reading
Title
Description
This video outlines the process by which proteins are formed and by which they are made useless by denaturation.
Must Watch Videos
This video outlines the structure of proteins and identifies a
variety of different proteins and their function within the body.
Should Watch Videos
This video outlines the general structure of an amino acid as well as the complex structure of polypeptides.
This video examines research into the understanding of how proteins fold into their three-dimensional (functional) shape.