Enzymes

Energy is defined as the ability to do …

work

The 1st law of thermodynamics

energy cannot be destroyed or created

The 2nd law of thermodynamics

Energy cannot be fully converted into another useable form

Metabolism in a cell is

The sum of all chemical reactions occurring inside the living cell.

What hormone is related to metabolism

thyroxin

thyroxin function, and applies to …

increases the metabolic rate; all cells in of the body

thyroxin is produced where?

thyroid gland

Where is the thyroid gland?

In front of the neck, attached to the trachea just below the larynx

Hyperthyroidism is …, and causes …

excessive thyroxin secretion; increased metabolism

Symptoms of hyperthyroidism

weight loss, extreme nervousness, and raised body temperature

Hyperthyroidism is caused by …

stress, genetics, and diet

Hypothyroidism is …, and causes …

not enough thyroxin secretion; slowed metabolism

Hypothyroidism symptoms

weight gain, loss of hair, and lowered body temperature

Hypothyroidism is caused by …

Stress, cancer of thyroid gland, autoimmune diseases

Most reactions … spontaneously unless they are …

do not; activated in some way

The rate of chemical reaction depends on … because …

temperature; more kinetic energy → more collisions

Activation Energy definition

The kinetic energy required to cause molecules to react with one another and start a chemical reaction

Catalysts definition

chemicals that control the speed of chemical reactions

The catalysts … after a chemical reaction, meaning it …

is unchanged; used over and over again

Protein catalysts that control chemical reactions in living cells are …

enzymes

Enzymes definition

protein molecules that functions as an organic catalyst allowing biological reactions to occur faster and at the low temperature of cells.

Enzymes does it function by …

lowering activation energy

Four feature that enzymes have in common.

1. Enzymes will not make anything happen that could not happen on it own.

2. Does not change the product of the reactions

3. Does not undergo change after reaction

4. Highly specific

Enzyme lower activation energy by …, so the reaction …

forming an enzyme-substrate complex; occurs more readily

substrate definition

compounds which enzymes act upon

products definition

compounds produced

enzyme also lower activation energy by …

placing substrates in the precise collision course.

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Enzyme naming convention & example

“ase” is change for the substrate’s final sound; lipid's enzyme is lipase and lactose is lactase, etc.

Active site definition

A small region of an enzyme where the substrate(s) bind in a specific orientation to react.

Most’s enzymes only have … active sites

one

Active sites are polar such that it will …

Attract substrates

Induced-fit model of enzyme activity … after it …

Enzyme undergoes a slight change in shape to accommodate the substrate perfectly; returns to its shape

Synthetic reaction

enzymes holds two substrates to react to form one larger molecules.

Degradation reaction

twisting a chemical bond so that is weakened breaking down the substrate into smaller molecules.

Cofactors or coenzymes

essential part of the active site.

Without coenzyme or cofactor …

the substrate does not bind to the enzyme, or if it does then the reaction does not proceed at a significant rate.

Body is … coenzymes without … because …

synthesizing; vitamins; it is a vital component

Vitamins are needed in …, and why?

small amounts only

Because lipid soluble vitamins can build up and become toxic.

A lack of vitamins causes …

lack of coenzymes and lack of certain enzymatic actions.

What are the factors that affect enzyme activity

1. Enzyme Concentration

2. Substrate Concentration

3. Temperature

4. pH

5. Heavy Metals

Explanation Enzyme Concentration

Increasing the amount of enzyme present will increase the rate of reaction because more collisions between enzymes and substrate more filled active sites more products.

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A cell can increase amount of enzyme by …

increasing protein synthesis of that enzyme

A cell can decrease enzymes available …

by deactivating the enzyme using enzyme inhibitors.

Two kinds of enzyme inhibitors

Competitive and Non-competitive

Competitive enzyme inhibitors are …, and will

close in shape to the enzyme’s normal substrate; prevent substrates from binding either permanently or temporarily.

Non-competitive enzyme inhibitors also called … will …

allosteric; bind to the enzyme and change the shape of the active site so substrates cannot bind.

Substrate concentration explained

enzyme activity increases as substrate concentration increases because more collisions more filled active sites, and more products.

With fixed enzyme concentration …

at one point enzyme active site saturated and rate of activity plateau

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denaturation is the …, and for the case of enzyme’s this mean …

permanent loss of normal shape of enzyme; loses its ability to form an enzyme-substrate complex.

Temperature explained

A rise in temperature results in an increase in enzyme activity because more kinetic energy more collisions, more active site filled.

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Beyond optimum temperature

the reaction rate levels off because the enzyme is denaturing by disrupting hydrogen bonds.

pH explained

Each enzyme has an optimum pH to maintain tertiary structure.

A change from the optimum pH can …

alter the enzyme structure and denaturation follows

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Heavy metals explained

Can bond with proteins and inactivate enzymes.