Biological Molecules- Carbs, Lipids, Proteins, Enzymes Flashcards
(51 cards)
What is an enzyme?
A biological catalyst
Speeds up the rate of reaction without being used up, by lowering the activation energy
What makes an enzyme specific?
It has a specific active site shape.
Only complementary substrates can bind to the active site to form ES complexes.
What is the lock and key model?
Active site shape rigid
Only exactly complementary substrates can bind and form ES complexes
What is the induced fit model?
Active site changes shape
Substrate binds to active site
AS changes shape
so substrate fits exactly forming an ES complex
How does substrate concentration increase RofR?
^substrate concentration
^chance of successful collisions
^chance of forming ES complexes
^RofR
Continues till all ACTIVE SITES FULL= max RofR
How does enzyme concentration affect RofR?
^enzyme conc
^chance if successful collisions
^chance of forming ES complexes
^RofR
Continues till all SUBSTRATE used up= max RofR
How does pH affect RofR?
Tertiary
If you change pH away from optimum Causes bonds in tertiary structure to break Active site shape lost Can’t form ES complex Enzyme denatured Lowers RofR
How does pH affect RofR?
Amino Acids
Change in pH
Alters charges on the A.As that make up active site
(Hydrogen+ionic bonds between -NH2 and -COOH groups of the polypeptides)
Substrate can no longer be attached to active site
No ES complexes can be formed
How does temperature affect RofR?
As temp ^ Kinetic energy ^ Molecules move faster ^ chance of successful collisions ^ chance of forming ES complexes ^ RofR
What happens when temp exceeds optimum for max RofR?
After optimum, bonds in tertiary break
AS shape is lost
Substrate no longer complementary to AS
Can’t form ES complexes as the enzyme is denatured.
What is a competitive inhibitor?
Molecules that have a similar shape to the normal substrate and a complementary shape to the AS
Bonds to AS, blocking it
Prevents ES complexes forming
What is a non competitive inhibitor?
A substrate that binds to ANOTHER AS on the enzyme- allosteric site
Causes AS to change shape, and so less ES complexes can form
What is a biological molecule?
A molecule made and used by living organisms
What are the 3 main functions of carbohydrates?
Energy store
Energy source
Provide structure
What are the building blocks of carbohydrates?
Monosaccharides
Glucose fructose galactose
Glucose is a heroes sugar. What does this mean?
It is a monosaccharide with 6 carbon atoms in each molecule
What are the two types of glucose and what can they be describes as?
Alpha and Beta.
Isomers- they have the same formula but different structures.
What is the difference between A & B glucose ?
On carbon 1, A glucose has an OH group on the BOTTOM
B glucose has an OH group on the TOP
How are monosaccharides joined together?
Condensation reaction
Removes a water molecule between 2 OH groups
Forming a glycosidic bond
How is maltose made?
Glucose + glucose
How is lactose made?
Glucose + galactose
What is a polysaccharide?
Many monosaccharides joined together with a condensation reaction. Has glycosidic bonds
What is starch a mixture of?
2 polysaccharides of alpha glucose:
Amylose - unbranched
Amylopectin - branched
How is the structure of starch suited to its function?
Insoluble - doesn’t affect WP as water not drawn into cells by osmosis.
Compact - angles of glycosidic bonds give it a coiled structure. This is good for storage in a small space.
Easily broken down - amylopectin branches allow the enzymes to act on the glycosidic bonds easily, breaking them down and therefore releasing the glucose quickly.
