HL Proteins and Enzymes

Describe proteome. Entire set of proteins expressed by the genome and allows organisms to express its phenotypes (characteristics)

State the monomer of a protein / polypeptide. Amino acids

State the 3 parts of an amino acid. Amino group, carboxyl group, & Variable side chain (R)

State the part of the amino acid that makes them structurally different from each other. R groups

Be able to draw and label a diagram of an amino acid

State the type of R group seen in polar amino acids / type of R group seen in nonpolar amino acids

hydrophilic R groups create polar amino acids

hydrophobic R groups create non polar amino acids

State the Number of different amino acids. 20

Outline the 3 types of dietary amino acids.

essential amino acids: body cannot make; must be present in diet

non-essential amino acids: produced by body; not required to be apart of diet

conditional amino acids: produced by body; sometimes not enough, depending on condition (pregnancy)

Describe what determines the sequence of amino acids in a polypeptide. Anabolic/ Condensation Reactions.

State the location of the creation of polypeptide chains / protein synthesis in a cell. Ribosomes

Be able to draw the condensation reaction between two amino acids showing the formation of a dipeptide (label the peptide bond)

Describe how monomers create dipeptide / polypeptides. Amino acids bond together creating dipeptides and polypeptides

Describe how a dipeptide / polypeptide is broken down into its monomers. 1 water used to break each peptide bond

State the function of Lysozyme. Enzyme in tears and saliva that breaks down cell walls of bacteria.

State the function of alpha neurotoxins. Found in snake venom, disrupts the nervous system.

State the function of glucagon. Hormone that raises blood sugar levels

State the function of myoglobin. Stores oxygen for muscles

Describe denaturation in a protein. Outside of the proteins optimal temperature and pH the protein will denature, hydrogen bonds break, biologically ineffective, tertiary and quaternary levels irreversibly changed

Protein AHL Material:

Outline the four levels of structure in a protein- make sure you know who is attracted to each other in the secondary, tertiary, and quaternary levels (ex: side chains, amino to carboxyl, etc)

Primary

Sequence of amino acids

Influences all remaining levels

Secondary

folding into alpha helix, beta-pleated sheet or random coil

hydrogen bonding between amino and carboxyl groups.

Tertiary

- folding into complex 3D shape

- interactions between R / side / variable groups

Quaternary

Multiple polypeptides interacting

Forms large single protein

Distinguish between conjugated and nonconjugated proteins

Conjugated Proteins:

Multiple polypeptide chains

Have a nonprotein component

metal, carbohydrate

Ex: Hemoglobin (has iron)

Non Conjugated proteins:

Just multiple polypeptide chains

Ex: collagen, insulin

Outline fibrous and globular proteins (know an example too)

Fibrous

thin and thread like

often play structural roles

Ex: collagen

main component of connective tissue in animals

Globular

- globe-like or spherical

- play active roles in metabolism

- Ex: Insulin

- lowers blood sugar levels

Enzyme Concepts to know and study

Describe enzymes.

“biological catalyst”

globular protein

tertiary or quaternary conformation

‘ase’ ending

increase rate of reaction

lower activation energy

Describe activation energy. amount of energy to run reaction

Describe substrate.

Molecule that interacts with enzyme

Connects to enzyme’s active site

chemical reaction changes it into products

State the name of an enzyme, its substrate, and products formed.

Enzyme: Lactase

Substrate: Lactose

Products: Glucose and Galactose

Be familiar with graph with activation energy shown (know where an enzyme is present and where one is not)

Describe active site. Specific location (sequence of amino acids) where the substrate binds, responsible for enzymes catalytic activity

Explain enzyme-substrate specificity (induced fit model).

Active site (of enzyme) and substrate mostly complement each other

Active site undergoes conformational change

shape now better fits substrate

Enzyme-substrate complex created

active site and substrate reacting

Enzyme catalyzes conversion of substrate into products

State if an enzyme is ever consumed in a reaction. In the reaction, enzyme is not consumed

State what happens to the substrate in a reaction catalyzed by an enzyme. After the reaction, substrate is gone and turned into products.

Explain enzyme substrate specificity (4 marks) According to the induced fit model, active site of enzyme is almost always complementary to the substrate. When they interact, the active site undergoes a conformational change, allowing substrate to bond. This creates enzyme substrate complex and reaction takes place. Substrate turns into products and enzyme is ready to catalyze another substrate

Describe the effects of temperature on enzyme activity / rate of reaction.

Low temperatures: low activity

(insufficient energy for movement)

Increasing temperature: increased enzyme activity

(molecule speed causes more collisions)

optimal temperature: activity peaks

Higher than optimal: enzyme denatures

Describe the effects of pH on enzyme activity / rate of reaction

Too acidic: enzyme denatures

optimum pH: activity peaks

Too basic: enzyme denatures

“Optimal” pH range depends on enzyme

Describe the effects of substrate concentration on enzyme activity / rate of reaction

Increasing substrate concentration: increases activity

Point of saturation (Vmax): Maximum activity

environment saturated with substrate, all enzymes are reacting

rate of activity plateaus after Vmax

Recognize the graphs for effects of temp, pH, or substrate concentration on enzyme activity / rate of reaction

State the formula for rate of reaction. rate: Amount of product formed / Time

Be able to complete a rate of reaction problem. Example:

Ex: Lactase underwent a reaction with lactose. 250 glucose and galactose molecules were formed over 250 seconds. What was the rate of reaction?

1 molecule produced per second

Describe denaturation in enzymes.

structural change in a protein / enzyme resulting in loss of biological properties

breaking hydrogen bonds

Caused by heat and pH extremes

State why immobilized enzymes are used in industry.

enzyme attached to material restricting movement

Provides Fastest rate of reaction

Common Uses:

Detergent industry (cleaning products)

Biotech industry (gene cutting / splicing)

Food industry (juice extraction, lactose free milk)

Outline the method for creating lactose free milk / Use of biotechnology in the production of lactose free milk

Enzyme: Lactase

extract lactase from yeast or bacteria

bind it to beads to immobilize it

Substrate: Lactose

Milk (containing lactose) is passed over beads

Lactose: disaccharide made of glucose + galactose

Products: Glucose and galactose

Disaccharide lactose is broken into its monomers

Milk contains glucose and galactose (not lactose)

“Lactose free”

Enzymes AHL Material:

Describe metabolism. All the enzyme catalyzed reactions in cell

State the two locations of enzyme pathways. Intracellular, takes place inside the cell, extracellular, takes place outside the cell.

State the two shapes of enzyme pathways. chains and cycles

State the type of energy lost by metabolic reactions. Heat

State the type of correlation between metabolic rate and heat. More metabolic reactions, more heat

Describe the significance of metabolic heat in the regulation of body temperature in living organisms. Metabolic heat is significant for regulating body temperature as it maintains warmth and supports enzyme activity.

State the two main ways to inhibit the activity of enzymes. Competitive inhibition and noncompetitive inhibition.

Outline Competitive inhibition.

Uses inhibitor molecules

Competes with substrates to bind to active site of enzyme

Inhibitors effect are reduced by increasing substrate concentration

State where a competitive inhibitor would dock on an enzyme. Active site

Outline noncompetitive inhibition.

molecule binds to allosteric site

not similar to substrate

causes conformational change in active site

substrate can no longer bind

Reversible if inhibitor removed

Compare competitive and noncompetitive inhibition. Competitive inhibition involves an inhibitor competing with the substrate for the active site, while noncompetitive inhibition occurs when an inhibition binds to a different site, affecting the enzyme function regardless of substrate concentration.

State where a noncompetitive inhibitor would dock on an enzyme. Allosteric site

Be able to identify the parts of the enzyme graph showing competitive inhibition, noncompetitive inhibition, and uninhibited

Explain how metabolic pathways are controlled (end product inhibition). Metabolic pathways are controlled by end product inhibition, where the final product inhibits an earlier enzyme to prevent overproduction.

Describe mechanism inhibition, providing an example. Mechanism inhibition occurs when an inhibitor prevents an enzyme's catalytic activity.