1. Amino Acids and Proteins
Biology
Amino Acids and Proteins

2. Amino Acids and Proteins
Biology
Amino Acids and Proteins

3. The Big Picture Large whiteboard in groups:
Each person in your group has to write one key point for each of water, ions, carbohydrates and lipids
Find amino acids / proteins on your ‘biological molecules’ mindmap

4. The Big Picture Structure and role of amino acids and proteins.
The peptide link between the amino acid monomers to make a protein polymer
The structure of different types of proteins

5. Protein

7. Get an envelope of amino acid cards
Get an envelope of amino acid cards. Make a table to show the ways that the amino acids are the same or different (see next slides for hints)
Ways they are the same
Ways they are different

8. Amino Acids
Ways they are the same
Ways they are different
Timer

9. Amino Acids

10. Amino Acids

11. Amino Acids

12. Amino Acid (simple version)

13. Look at this interactive amino acid structure now!
More help: Interactive animation showing the basics and then all of the ‘R’ groups (first 2 slides only!)

14. Candidates are not expected to recall names of amino acids
but can be expected to identify them, given a structural formula and a suitable table showing -R groups

15. Make and draw the following amino acids:
Glycine
Alanine
Aspartic acid
Cysteine

17. Watch this reaction

18. Joining 2 amino acids together to make a dipeptide in a condensation reaction. They make a peptide bond

19. This is the primary structure of a protein
Make a dipeptide from two of your amino acid models.
Find another group and join both of your dipeptides together into a polypeptide (protein)
Put 5 yellow cards in a line. Draw the polypeptide that would be made. Name the reaction. Identify and name the bonds formed
This is the primary structure of a protein

20. Break up this polypeptide (protein primary structure)
Break up this polypeptide (protein primary structure). Name the reaction, the other molecules that would be needed, and the general name for the products formed. (Or can you name the actual products?)

21. Primary structure
Number, type and sequence of amino acids (determined by DNA triplet sequence)

22. Answer the practice questions below (1,2,3) as a team.
Then copy out and complete the exam question (Q2, 8 marks)
Ask the teacher or another student to mark your work and answer any queries

26. Well done! You now know about the primary structure of proteins!

27. Next part…building a full protein

28. Use sellotape/staples/glue to make a spiral with the paper
Make a very long strip of paper. Write the names of many amino acids along the length
Use sellotape/staples/glue to make a spiral with the paper
Use sellotape/staples/glue to show extra folds of the whole spiral structure
Use sellotape/staples/glue to attach your shape to another group’s
Use the theory slides /books/notes to identify the different levels of protein structure, and the types of bonds that could be present at each level
STAPLES = peptide bonds
SELLOTAPE = Hydrogen, ionic, disulfide bonds

29. A protein is one or more polypeptide chains folded into a complex 3D shape
It has a…..
Primary structure
Secondary structure
Tertiary structure
Quaternary structure

31. Primary structure
Number, type and sequence of amino acids determined by DNA triplet sequence

32. Secondary structure
Coiling of primary structure: Alpha Helix (α): Left handed spiral stabilized by hydrogen bonds between amino acids between –NH and -CO

33. Tertiary structure
Projecting R groups of amino acids determine bonding/folding
3D Shape which eg. forms active site in enzymes
(more) Hydrogen bonding
Ionic bonding
Disulfide bonding
Hydrophobic interactions

34. Hydrogen bonding

35. Ionic bonding

36. Disulfide bonding

37. Hydrophobic interactions

38. Tertiary structure

39. Quaternary structure
More than one polypeptide chain

40. This is insulin, a hormone
This is insulin, a hormone. Identify the different levels of protein structure, and the types of bonds be present at each level

41. Proteins have a function linked to their structure
Globular proteins are enzymes, antibodies, hormones and plasma proteins. They are folded or spherical, and soluble in water
Fibrous proteins have structural functions and are strong and tough. They are made up of long chains with many crosslinks

42. Use the next slides and your notes to make simple models to show the general shapes of a globular protein (eg. Haemoglobin) and a fibrous protein (eg. Collagen) Show your models to the teacher and link the structures to the functions

43. Haemoglobin (Globular Protein) (detailed structure of haemoglobin not required).

44. Haemoglobin (Globular Protein)
4 x Polypeptide chains (2 x α, 2 x β) in the quaternary structure each with an iron group
Folded spherical tertiary structure important for bonding
Carries oxygen in the blood

45. Other globular proteins
Enzymes
Antibodies
Hormones

46. Fibrous proteins Have alpha helices linked into strands
Eg Collagen, Keratin

47. Collagen (Fibrous Protein)
3 polypeptide chains (each an α-helix)
In a long rope-like structure with ends of molecules staggered so no weak points in the fibre
Held together by hydrogen bonds between R groups keeping the chains tightly bound
High tensile strength so used for structural tissues eg. tendons

48. Make a group spider diagram to plan out where you think the 15 marks are for this question.
Reveal the mark scheme (next slide) and score yourself

50. Well done! Next step….do the task book and Moodle questions!
Want a recap? Watch a video summary of protein structure