Energy and Metabolism (Biology)

Energy

The capacity to do work

Kinetic energy

The energy of motion

Potential energy

Stored energy

What are some forms of energy?

Heat, mechanical, electric current, and light

What bonds store a lot of potential energy?

Covalent bonds

What can most forms of energy be converted to?

Heat energy

What are kilocalories and what do they measure?

1000 calories, measures heat energy

How can potential energy be transferred?

Stored in chemical bonds then transferred by electrons.

What is oxidation and reduction?

Oxidation - loss of electrons

Reduction - gain of electrons

What are redox reductions?

Takes electrons and move somewhere else. Redox reductions are coupled to each other. Oxidation must happen first then reduction.

First Law of Thermodynamics

Energy can't be created or destroyed, can only be converted from one form to another

Second Law of Thermodynamics

Entropy is always increasing. Disorder more likely than order.

Endergonic reaction

A reaction requiring an input of energy

Exergonic reaction

A reaction that releases free energy

Activation energy

extra energy needed to get a reaction started

it destabilizes existing chemical bonds and is required for exergonic reactions

catalysts

substances that lower activation energy

ATP

adenine triphosphate.

energy currency of cells because we use it to do every day things

What is the structure of ATP?

Ribose (5 carbon sugar), adenine, three phosphates

Where does ATP store energy?

In the bonds of the phosphates

How is energy released from ATP?

Phosphates are highly negative so it takes a lot of energy to keep them together. When broken it releases a lot of energy. ATP becames ADP and Pi. Reaction is reversible.

Energy from ATP to ADP and Pi

Fuels endergonic reactions

Energy from exergonic reaction

Fuels production of ATP from ADP and Pi

Enzymes

Molecules that catalyze reactions in living cells

Proteins

Lowers activation energy

Not changed or consumed by reaction

Substrates

Molecules that will undergo a reaction.

Active site

where enzyme binds to substrate

What happens when an enzyme binds to a substrate?

The enzyme changes shape to produce a better induced fit

Advantages offered by multienzyme complexes

Product of one reaction can be directly delivered to the next enzyme

Possibility of unwanted side reactions eliminated

All reactions controlled as a unit

What is optimum temperature?

Temperature that an enzyme may be increased to, to increase enzyme activity. Any past that results in denaturation.

Inhibitors

Molecules that bind to an enzyme to decrease activity

Competitive inhibitors

Compete with substrate for binding to the same active site

Noncompetitive inhibitors

Bind to sites other than enzyme's active site

Allosteric enzymes

Exist in either active or inactive state

Allosteric site

Possessed by allosteric enzymes. Where molecules other than substrate binds.

Allosteric inhibitors

Binds to allosteric site to inactivate the enzyme

Allosteric activators

Bind to allosteric site to activate the enzyme

Metabolism

all chemical reactions occurring in an organism

Anabolism

chemical reactions that expend energy to make new chemical bonds

Catabolism

chemical reactions that harvest energy when bonds are broken

Cofactors

usually metal ions, found in active site participating in catalysis

coenzymes

nonprotein organic molecules, often used as an electron donor or acceptor in a redox reaction

biochemical pathways

series of reactions, product of one reaction becomes substrate for next reaction