biological molecules Flashcards
what is a monomer?
repeating subunits that make up a polymer
What is a polymer?
a chain of monomers
What is a condensation reaction?
Forming bonds between between monomers, water is produced
What is a hydrolysis reaction?
Breaking bonds between polymers, water used
Give two examples of biological polymers
Proteins
Polysaccharides
Give three examples of biological monomers
Monosaccarides
Amino acids
Nucleotides
What is the general formula for carbohydrates?
(CH2O)n
What are monosaccarides?
. Sweet tasting soluble substances
. Glucose, fructose, galactose
where is starch found and what is it made of?
. plants
. amylose and amyloplecin
what is the structure of starch?
. compact (due to coiled and branched chains)
. insoluble so does not effect osmotic properties of cell
what is the function of starch?
. storage of energy in plants
. lots of glucose can be fit in a small space due to coils
where is glycogen found and what is it made of?
. animals
. alpha glucose
what is the structure of glycogen?
. even more coiled and branched than amylopecin
. insoluble so does not effect osmotic properties of cell
what is the function of glycogen?
. main energy store in animals
. lots of glucose so can fit in small space due to coils
where is cellulose found and what is it made of?
. cell walls of plants
. beta glucose and hydrogen bonds
what is the structure of cellulose?
. long and unbranched
. held together by hydrogen bonds
. large numbers of beta glucose chains
. layers on top of eachother
what is the function of cellulose?
. structure
. many chains together in layers to form microfibril and fibril to keep cell wall strong
what is the structure of lipids?
. contains C,H,O
. O:C:H smaller than carbohydrates
. insoluble in water
. soluble in organic solvents (acetone and alcohol)
. tryglycerides and phospholipids
how are lipids used in cell membranes?
. cell surface membrane and around organelles
. phospholipids contribute to flexibility of membranes and transfer of lipid-soluble substances
how are lipids a source of energy?
. when oxidised, provide more than 2x energy of carbs and release valuable water
how are lipids waterproof?
. insoluble in water, waxy lipid cuticles that conserve water
. mammals have oily sector
how do lipids provide protection?
. stored in delicate organs such as kidney
how do lipids provide insulation?
. slow conductors of heat, can help retain body heat
. act as electrical insulators around mylen sheath in nerve cells
what are properties of tryglycerides?
. glycerol and 3x fatty acids
. condensation reaction for fatty acid bond
. ester bond with glycerol
. glycerol is the same in fats and oils
. variations in fatty acids
. over 70 different fatty acids
. all have -COOH group with hydrocarbon
. saturated= c-c
. unsaturated= c=c
what is the structure of phospholipids?
. 2 fatty acids and glycerol
. inorganic phosphate group in place of 3rd fatty acid
how can phospholipids be described as polar?
in an aqueous environment, phospholipid molecules from a bilayer within cell surface membranes
how do they have hydrophyllic heads?
faces water and helps to hold at cell surface membrane
What can be made of proteins?
. Hair and skin contain a protein called keratin
. They make haemoglobin (o2 carrying RBC)
. Bones contain a protein called collagen
. Hormones such as insulin are often proteins
. Found in cell membranes
How many different amino acids are there?
20
What are primary structure proteins?
The sequence of amino acids in a polypeptide or protein
What are secondary structure proteins?
The regular folding or coiling of the polypeptide chain due to the formation of hydrogen bonds
What are tertiary structure proteins?
The unique 3D folding of the polypeptide chain
What are quaternary structure proteins?
The 3D arrangement of 2 or more polypeptide chains, often involving a prosthetic group
What are the qualities of enzymes?
Increased temperature makes molecules move faster
Biological systems are very sensitive to temperature changes
Increase RoR without increasing temp
Create a new reaction pathway “short cut”
What is free energy?
Energy available the enzymes need to perform work
What is the structure of enzymes?
Have a specific 3d shape
Specific region of enzyme is functional- active site
Small depression in enzyme molecule
Substrate fits into depression to form enzyme-substrate complex
Substrate is held by temporary bonds that form between certain amino acids of active sites and groups of substrate molecules
How does the lock and key model explain denaturation?
Breaking of peptide bonds within the structure
What is the induced fit model?
Substrate and active site not entirely complimentary
Can change shape - conformation
When Substrate bonds with enzyme, induces change in enzymes conformation
Active site moulded into precise conformation
Bonds stretched to make reaction easier
Chemical reaction is suitable
What factors effect enzymes?
Substrate concentration
Ph
Temperature
Inhibitors
What are competitive inhibitors?
Structurally similar to substrate
Blocks active site
Cannot react with enzyme
What are non competitive inhibitors?
No structural similarity to substrate
Binds to site other than active site
Binding changes shape of active site
How does substrate concentration effect enzymes?
. Faster reaction until it reaches saturation point when enzyme molecules are occupied
. If you alter concentration of enzyme then Vmax will change too
How does pH effect enzymes?
Extreme pH can produce denaturation
Structure of enzyme changed
Active site distorted
Is pH values are slightly different from optimum small changes to enzyme and substrate occur
Change in ionisation effects binding
How does temperature effect enzymes?
Enzymes are not denatured at cold temperatures
As temperatures increase, substrate and enzyme have more kinetic energy
High temperatures cause denaturation
Changed due to excessive movement within the enzyme and the ionic and hydrogen bonds break
Substrate will no longer fit
