1.1 Biological molecules Flashcards
What is a macromolecule?
A complex molecule with a large molecular mass
What is a polymer?
A large, complex molecule made of repeating monomers joined together in chains
What is a monomer?
A small repeating subunit that can join together in chains to form polymers
What monomers join together to form carbohydrates?
Monosaccharides
What monomers join together to form proteins?
Amino acids
What monomers join together to form DNA?
Nucleotides
What is a condensation reaction?
A reaction that releases water
What is a hydrolysis reaction?
A reaction that uses water to split up molecules
What is metabolism?
All the chemical reactions that take place in a living organism
What is an isomer?
Molecules with the same molecular formula but with the atoms connected in a different way
What bond is formed between monosaccharides?
Glycosidic bond
What is a disaccharide?
Two monosaccharides joined together by a glycosidic bond
What is a polysaccharide?
Two or more monosaccharides joined together
What is amylose?
Long, unbranched chain of alpha glucose
what is amylopectin?
long, heavily branched chain of alpha glucose
What is the function of starch?
To store glucose for energy
What is starch made up of?
Polysaccharides of alpha glucose: amylose and amylopectin
How is starch suited for its function? (2 reasons)
It is insoluble in water so doesn’t affect water potential or cause osmosis. It is very compact so can store lots in a small space.
What is glycogen?
An alpha glucose polysaccharide made with excess glucose
How is glycogen suited for its function? (2 reasons)
Lots of branches allow glucose to be released quickly. Very compact so lots of glucose can be stored in a small space.
What is cellulose made up of?
Long, unbranched chains of beta-glucose
What are microfibrils?
Strong fibres made of cellulose chains linked by hydrogen bonds.
How is cellulose suited for its function? (1 reason)
Strong fibres enable good structural support in the cell wall
Glucose + glucose = ?
Maltose
Glucose + fructose = ?
Sucrose
Glucose + galactose = ?
Lactose
What type of bonds hold together beta-glucose chains that form cellulose?
Hydrogen bonds
Are lipids polymers?
No
Which elements make up lipids?
Carbon, oxygen and hydrogen
Are lipids soluble in water?
No
How can we test for lipids?
Emulsion tests
Are lipids soluble in alcohol and acetone?
Yes
What roles do lipids play in cell membranes? [2]
Phospholipid bilayer transports lipid soluble molecules through the membrane, cell membrane is kept flexible
What roles do lipids play in protection?
Layers of fat surround and protect internal organs in animals and humans from damage
Why is it useful that lipids are insoluble in water? [2]
Their presence doesn’t affect water potential, they act as a waterproofing layer in both plant and animal cells
How do lipids act as insulation?
They are poor conductors of heat, so help prevent heat from escaping to maintain our normal body temperature
Why are lipids a good store of energy?
They can release large amounts of energy at a time
Name two types of lipids
Phospholipids and triglycerides
What is a dipeptide?
Two amino acids bonded together
What is a polypeptide?
More than two amino acids bonded together
What is a protein?
One or more folded polypeptides
How is a peptide bond formed?
Condensation reaction between the carboxyl group group one amino acid and the amino group of another
What two substances are formed when two amino acid molecules join together?
- dipeptide
- water
What type of bond forms between amino acid molecules?
Peptide bond
How can we test for protein?
Add buret solution, shake, presence of protein causes colour to change from blue to purple
What is the primary structure of protein?
The order of amino acid sequence in the polypeptide chain
What does the primary structure of protein determine?
The way the chain will fold
What are the secondary structures of protein?
alpha helices and beta pleated sheets
How do the secondary structures of protein form?
Hydrogen bonds form between non-adjacent amine and carboxyl groups in the amino acid chain
How many different amino acids make up all living things?
20
How is the shape of an enzyme’s active site determined?
The enzyme’s tertiary structure
What is an intracellular enzyme?
An enzyme that is used by the cell it was made in
What is an extracellular enzyme?
An enzyme that works outside the cell it was made in
How is activation energy reduced?
Enzyme-substrate complexes bend the bonds of the substrate
What is the induced fit model?
The idea that the active site of an enzyme is not perfectly complimentary, and instead changes shape as the enzyme-substrate complex forms, bending the bonds in the substrate.
What are the two types of enzyme inhibitor?
- competitive inhibitors
-non-competitive inhibitors
Name four factors that affect enzyme activity
Temperature, pH, substrate concentration, enzyme concentration
How does a competitive inhibitor work?
Inhibitor with a similar shape to the substrate binds to the enzyme’s active site, preventing the substrate from binding
How does a non-competitive inhibitor work?
Inhibitor binds to allosteric site of the enzyme, causing active site to change shape, preventing the substrate from binding
Which type of inhibitor can be overcome by increasing the substrate concentration?
competitive inhibitors
What does pH stand for?
Potential for Hydrogen
What ion can be increased to make a solution more acidic?
H+ ions
What ion can be increased to make a solution more alkaline?
OH- ions
What is an R group?
The variable group that differentiates different amino acids
