Macromolecules Flashcards
What is a macromolecule?
A very large molecule important to biological processes, such as proteins, lipids, carbohydrates and amino acids. They are composed of thousands of bonded atoms.
What is a protein?
A protein is a polymer, meaning it is a larger molecule made of smaller ones. These smaller molecule being amino acids.
What are the roles of proteins?
- They provide structural support through keratin in the hair and nails and collagen in connective tissue.
- They facilitate transport through protein channels and ion pumps.
- They provide immune support through antibodies, as they are proteins.
- They help with hormone regulation.
- Enzymes are proteins which speed up and slow down reactions, as they are biological catalysts.
Explain the structure of an amino acid.
H H O - H
\ l /
N - C - C
/ I \
H R O
- ‘H’ is the ‘H group’.
- H
\
N is the ‘amino group’.
/
H - O - H is the ‘carboxyl group’.
/
C
O - ‘R’ is the ‘variable group’. This is always different as it indicates what amino acid it is.
What elements are proteins made of?
Carbon, hydrogen, nitrogen and oxygen.
How many types of amino acids are there and what are their roles?
There are 20 types of amino acids in the body and they build proteins as they are monomers of proteins.
What is a primary protein structure?
This is a chain of amino acids.
What is a secondary protein structure?
The hydrogen bonding of the peptide backbone causes the amino acid chain to fold into a repeating pattern.
Hydrogen bonds then form on the chain, causing it to coil into an alpha helix or a beta pleated sheet.
This is very strong.
What is a tertiary protein structure?
A three dimensional folding pattern of proteins due to side chain interactions.
This coils further and ionic bonds, hydrogen bonds and disulphide bridges form.
What is a quaternary protein structure?
More than one amino acid chain.
What is a polypeptide formation?
This is a chain of amino acids, joined by peptide bonds. Polypeptides link in a condensation reaction.
What is a condensation reaction?
A condensation reaction is a type of chemical reaction in which two molecules are combined to form a single molecule, usually with the loss of a small molecule such as water.
There is 1 less water for every sugar.
Join these two molecules in a condensation reaction.
H R
\ |
N - C - COOH
/ |
H H
H R
\ |
N - C - COOH
/ |
H H
H R
\ |
N - C - CO [OH]
/ |
H H
[OH]+[H]= [H2O]
H R
\ |
N - C - COOH
/ |
[H] H
After the condensation reaction, a peptide bond is formed joining the two molecules.
H R O H R
\ | || | |
N - C - C ——— N - C - COOH
/ | | |
H H Peptide H
bond
What is a lipid?
broad group of organic compounds which include fats, triglycerides and phospholipids. They’re insoluble in water and soluble in non-polar solvents.
What is meant by soluble and insoluble?
Soluble means it easily dissolves in water and breaks down. Insoluble means it does not dissolve in water and does not break down in digestion.
What is a triglyceride?
This is composed of 3 fatty acids and 1 glycerol. Each fatty acid forms an ester bond with the glycerol in a condensation reaction. This ester bond can be broken down with lipase.
[GLYCEROL]
| | | —— ESTER BOND
F F F
A A A
How do you break down a triglyceride?
Using lipase.
What is a phospholipid?
These are composed of 2 fatty acids and 1 phosphate group. The phosphate self assembles above the glycerol on a triglyceride, and 1 of the fatty acids of the triglyceride is substituted by the phosphate group, to make a phospholipid. They can be found in the cell membrane.
[PHOSPHATE]
[GLYCEROL]
F F
A A
What are the roles of lipids?
- They’re a source of energy as when oxidised they provide more than twice the amount of energy as a carbohydrate.
- Plants and insects have waxy lipid cuticles that conserve water, water proofing them.
- They provide electrical insulation in the myelin sheath around the nerve cells.
- Fat is stored around delicate organs to protect them.
What is an emulsion test?
This tests for the presence of lipids.
You put your sample and ethanol in a test tube together, shake it and then add water. A milky colour indicates the presence of a lipid.
What is a saturated fat and its features?
This is a type of fat where its fatty acid chains have single bonds.
Its key features are:
- A straight and solid structure.
- Its carbon atoms are bonded to hydrogen atoms.
- They’re solid at room temperature.
- They raise your bad LDL cholesterol, causing fatty deposits in your arteries.
- They’re full of hydrogen.
What is an unsaturated fat and what are its features?
This is a type of fat where there is at least one double bond within a fatty acid chain.
Its key features are:
- Some carbon atoms bonded to hydrogen atoms.
- Lower your LDL cholesterol level, so they wont clog your arteries.
- Not full of hydrogen
- Less solid at room temperature.
- Healthier than saturated fats.
What are the two forms of unsaturated fats?
- Mono-unsaturated fats have a kink and are soft solids.
- Poly-unsaturated fats have more than one kink and are liquids.
What is a carbohydrate?
They’re a bio molecule and a source of energy for all living things. They’re found in sugars, starches and fibres.
