HL Bio Enzymes, Respiration, and Photosynthesis Flashcards
What is an Enzyme
A globular protein which acts as a catalyst by speeding up the rate of a reaction.
The active site
Is the region of the enzyme which binds to the substrate molecule.
A substrate is the molecule that the enzyme reacts with.
In order for catalysis to occur,
the substrate and enzyme must bump into each other, in the correct orientation. This means the substrate must be in, or make contact with, the active site.
Enzyme activity is affected by
Temperature
Low temperatures restrict the enzyme’s
pH
Affects protein conformation, and the active sites ability to perform catalysis.
Substrate Concentration
Increasing substrate concentration will increase the activity of the corresponding enzyme.
What is protein function determined by?
Protein function is determined by its 3-D structure. Proteins are synthesized as a linear collection of AA (primary structure) proteins, which are then continuously folded to create higher order proteins. They hold this 3-D structure through hydrophobic interactions, hydrogen bonds (backbone), salt bridges, and cysteines (disulfide bonds).
Denaturation
the unfolding of a protein, which destroys its 3-D Structure. The structure of the protein directly correlates with its function. No structure = No function.
Denaturizing by Temperature
Enough kinetic energy to break up hydrogen bonds and London Dispersion Forces.
Denaturing by pH
Alters the charges of ionic R-groups (acidic/basic) that form the salt bridges.
Denaturing by Detergents and High Salt
Detergents - Disrupts London Dispersion Forces within hydrophobic interactions.
High Salt - Breaks salt bridges and disrupts hydrogen bonds in the protein backbone.
Immobilized Enzymes
Enzymes that have been fixed to a static surface in order to improve the efficiency of a catalyzed reaction, as opposed to using chemical catalysts. They:
*can be reused
*are more stable/less likely to denature when binded to a surface
*don’t need to be purified as there are no residual enzymes left in the product
*can be used in many food products, ex:
-Making lactose free milk
*can be used in biosensors since each enzyme is specific to a substrate for example…
Glucose test strips
Lactase
(enzyme in our bodies) breaks down lactose into glucose and galactose.
Immobilized lactase can be used to produce lactose free milk:
Normal milk is poured down a column lined with immobilized lactase enzymes, which breaks down the lactose in the milk.
After the milk passes through this system, only the products (glucose and galactose) are left, allowing lactose intolerant people to drink it.
Cellular Respiration
The controlled release of energy from organic compounds to produce ATP. There are two forms of cellular respiration…
Aerobic Respiration
Anaerobic Respiration
Aerobic Respiration
(with oxygen) Utilizes oxygen to completely breakdown glucose in the mitochondria for a larger yield of ATP.
Anaerobic Respiration
(without oxygen) Involves the partial breakdown of glucose in the cytosol for a small yield of ATP.
Glycolysis
The breakdown of glucose into pyruvate in the cytoplasm outside of the mitochondria; in this reaction, 2 ATP are produced, along with 2 molecules of pyruvate. It involves glucose.
