proteins
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Proteins
Recap (Nutrients and Water)
Biological Molecules
Nutrients
Energy Raw materials
Carbohydrates
Proteins Fats
Repair/Growth
Water
Functions
Carbohydrates
maltose
monosaccharides
disaccharides
polysaccharides
glucose
galactose
lactose
fructose sucrose
starch
Straight and branched chains of glucose molecules
Condensation reaction
Hydrolysis
+ glucoseEnergy store
+ glucose
+ glucose
are grouped into
examples examples
examples
function
structure
Notes
Some notes are in the PPT, some are not. Do listen out for the clues
in my lesson!
“Proteins Proteins Proteins”
Why study proteins?
See it for yourself
African child Singapore child
Kwashiorkor
• In poor countries, when children do not have sufficient intake of proteins, they developed “big tummy”, which is the accumulation of water outside the blood capillaries.
Active research area
HIV researchPakinson’s disease
Elements in Proteins
Carbohydrates• Carbohydrates are a
group of organic biomolecules made up of the elements carbon, hydrogen and oxygen.
Proteins• Proteins are a group of
organic biomolecules made up of the elements carbon, hydrogen and oxygen and …
• Nitrogen and some sulphur.
Other differences?
Structural Differences!
General chemical structure for the Basic unit of carbohydrates
maltose
C6H12O6 + C6H12O6 C12H22O11 + H20
glucose + glucose maltose + water
OH
+ +
glycosidic bondCondensationreaction
OH O
General chemical structure for the Basic unit of proteins
—N—H
HC—OH
||O
R
|—C— |
H
Basic unit of protein is called Amino Acid (aa)
Basic unit comparison
Carbohydrates Proteins
Amino acidsStructure:central carbon amino groupacidic group (Carboxyl) R group (side chain)
variable group gives unique
chemical properties to the amino acid
—N—H
HC—OH
||O
R
|—C— |
H
What is the “R” group?1. It is the variable
groups that give rise to different Amino Acids in our body
2. There are 20 natural occurring AAs
With different “R” groups, you can come out with different AAs
—N—H
HC—OH
||O
R
|—C— |
H
Alanine
Joining different AAs together[Condensation]
Hydrolysis
Condensation and Hydrolysis Game !
2 groups • 1&2 vs 3&4
Objectives •Form the given polypeptides and hydrolyse it in the time given•Time limit is 5 mins
Instructions •Move the tables to the side, with the pail at the center•Paste the AAs sticker on your shirt
Example
Gly – Arg – Val
1st Polypeptide
Gly – Arg – Val- Ala- Ser – Thr – Cys- Met - His
2nd Polypeptide
Ser– Met- His- Gly– Thr - Ala– Cys- Arg -Val
What are the functions of proteins?
Other functions of food? Other than providing energy?
Growth
Regeneration By providing the necessary raw
material
“Proteins Proteins Proteins”
How does the lobster protein got transformed
into your muscle protein?
Eat the lobster
Digestion
Proteins
Polypeptide
Amino Acids
Digestion is a series of hydrolytic process
Proteins are first hydrolysed into short polypeptides which are in turn hydrolysed to amino acids.
Amino Acids
Polypeptide
Proteins
To different kinds of tissues and cells
Muscles
EnzymesAntibodies
Main functions of proteins
• Synthesis of new protoplasm, for growth and repair of worn-out body cells.• Synthesis of enzymes, hormones,
antibodies and other biological molecules.
Going a bit further
• What if the sequence in a protein is arranged wrongly?
•Gly – Arg – Val changed to Val– Arg –Gly
• What will happen?• Let’s watch a video
Mad Cow Disease
Q1. What is the basic unit of protein?
A. GlucoseB. MaltoseC. Amino AcidsD. Water
Q2. How many natural occuring amino acids are there?
A. 19B. 20C. 21D. 22
Q3. Proteins are only found in the cells of animals
A. TrueB. False
Q4. Condensation only happens in protein synthesis
A. TrueB. False
Q5. What is the name of the bond between two adjacent Amino acids?
A. Ionic BondB. Hydrogen BondC. Covalent BondD. Peptide Bond
HW• Find out the test for proteins. • Biuret test. • Write down the exact steps in conducting the
biuret test and find pictures on the internet that describe the test.
• Put it in a word document.• Send to Canberra3E1@gmail.com by
Wednesday. Go through on thurs!
Construct a protein mind map
• Construct a protein mind map based on today’s lesson.
• Take reference from the mind maps constructed by the teachers in water and carbohydrates
• Hand in by this thurs, 12th March.
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