IB Biology 2.4 Proteins

1. 2.4 Proteins

2. Guidance
-Thedetailedstructureof6proteinsselectedtoillustratethefunctionsofproteinsisnotneeded
-Eggwhiteoralbuminsolutionscanbeusedindenaturationexperiments.
- Studentsshouldknowthatmostorganismsusethesame20aminoacidsinthesamegenetic
code,althoughtherearesomeexceptions.Specificexamplescouldbeusedforillustration.
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.
Living organisms synthesize many different
proteins with a wide range of functions.
Every individual has a unique proteome.
APPLICATIONS/SKILLS
A: Rubisco, insulin, immunoglobulins,
rhodopsin, collagen, and spider silk as
examples of a range of protein
functions.
A: Denaturation of proteins by heat or
by deviation of pH from the optimum.
S: Drawing molecular diagrams to
show the formation of a peptide bond.

3. Formation of
polypeptides
Polypeptide sequence controlled by
genes
Composed of amino acids
Sequence determines shape which
determines function
http://38.media.tumblr.com/2d8c9ab82999391b5a69869e350a3992/tumblr_inline_n88bc46Rfg1qg4nwx.jpg

4. http://www.nutrientsreview.com/wp-content/uploads/2014/10/Amino-Acid-Structure.jpg
In an Aqueous Solution
http://classconnection.s3.amazonaws.com/986/flashcards/2980986/png/screen_shot_2013-09-21_at_33353_pm-1414271A7D034E3B11C.png

6. pleated sheet pleated sheet
http://eng.thesaurus.rusnano.com/upload/iblock/94a/belky1.jpg

7. Denaturing proteins: temperature
Increase in molecular motion puts stress on bonds
Protein loses its shape which causes it to lose its function
Could return to normal shape if returned to optimal temperature
http://classes.midlandstech.edu/carterp/Courses/bio225/chap05/05-06_Denaturation_1.jpg

8. Denaturing proteins: pH
Presence of extra charges interferes with hydrogen
bonding
Prevents protein from taking on functional shape

9. Homework
VOCAB OTHER
Challenge yourself #7
Exercises 9-11
gene
polypeptide
R-group
n-terminal end
c-terminal end
primary protein structure
secondary protein structure
tertiary protein structure
quaternary protein structure
protein
polypeptide
genome
proteome