Unit 3

All of the chemical reactions in an organims:

Metabolism

Series of chemical reactions that either build complex molecules or break down complex molecules:

Metabolic pathways

What does metabolic pathways start with and end with?

Substrate → intermediate → product

What turns substrate into intermediate and intermediate into product?

Enzymes

Types of metabolic pathways:

Catabolic and anabolic

Pathways that release energy by breaking down complex molecules into simpler compounds:

Catabolic pathways

Pathways that consume energy to build complicated molecules from simpler compounds:

Anabolic pathways

The ability to do work:

Energy

What do organisms need energy to do?

Survive and function

What does a loss in energy flow result in?

Death

Energy associated with motion:

Kinetic energy

Energy associated with the movement of atoms or molecules:

Thermal energy

Stored energy:

Potential energy

Potential energy available for release in a chemical reaction:

Chemical energy

Example of chemical energy:

ATP

The study of energy transformations in matter:

Thermodynamics

What do thermodynamics laws apply to?

Whole universe

1st law of thermodynamics:

Energy cannot be created or destroyed, but can be transferred or transformed

What energy is transformed into what energy when nut gives energy for squirrel to climb tree?

Chemical (potential) energy to kinetic energy

2nd law of thermodynamics:

Energy transformation increases the entropy of the universe

Entropy:

Disorder

During energy transfers or transformations, is all energy usable?

No

During energy transfers or transformations, what happens to unusable energy?

Lost as heat

Example of 2nd law of thermodynamics:

As squirrel climbs tree, some energy released as heat

What does free energy determine?

Likelihood of reactions in organisms or if reactions are energetically favorable

What does the free energy change of reactions determine?

Whether or not reaction occurs spontaneously

What do spontaneous reactions not require?

Outside input energy

Based on free energy changes, what can chemical reactions be classified as?

Exergonic and endergonic

Reactions that release energy:

Exergonic reactions

Example of exergonic reaction:

Cellular respiration

Reactions that absorb energy:

Endergonic reactions

Example of endergonic reaction:

Photosynthesis

Diagram of exergonic reaction:

Diagram of endergonic reaction:

Are exergonic reactions spontaneous?

Yes

Are endergonic reactions spontaneous?

No

Why are endergonic reactions not spontaneous?

Absorb free energy

What do living cells have a constant flow of?

Materials in and out of membrane

Are cells at equilibrium?

No

What kinds of work do cells perform?

Mechanical, transport, chemical

Mechanical work:

Movement

Examples of mechanical work that cells perform:

Beating cilia, movement of chromosomes, contraction of muscles cells

What transport work do cells perform?

Pumping substances across membranes against spontaneous movement

What chemical work do cells perform?

Synthesizing molecules

Example of synthesizing molecules in cells:

Building polymers from monomers

Molecule that organisms use as a source of energy to perform work:

ATP

What does ATP stand for?

Adenosine triphosphate

What does ATP couple to power cellular work?

Exergonic reactions and endergonic reactions

When ATP powers cellular work, what drives the endergonic process?

Exergonic process

How do organisms obtain energy from ATP?

By breaking bond between 2nd and 3rd phosphate

What reaction breaks bond between 2nd and 3rd phosphate of ATP?

Hydrolysis reaction

What does hydrolysis reaction turn ATP into?

ADP

The released phosphate from ATP moves to another molecule to give energy:

Phosphorylation

Diagram of ATP:

What can ADP be regenerated to?

ATP

What can ADP be regenerated to ATP via?

ATP cycle

What is required to turn ADP into ATP?

Energy from another exergonic process

Do laws of thermodynamics describe rate of reaction?

No

Do some spontaneous reactions move quickly or slowly?

Slowly

What do spontaneous reactions moving slowly mean for cells utilizing them?

Cannot utilize them efficiently

How long does the hydrolysis of sucrose to glucose take to happen spontaneously?

1000 years

Macromolecules that catalyze reactions by lowering the activation energy:

Enzymes

What does catalyze mean?

Speed up

Are enzymes consumed by reaction?

No

What are enzymes a type of?

Protein

What do enzyme names end in?

-ase

What does enzyme act on?

Substrate

Areas for substrates to bind to on enzymes:

Active site

Process of enzymes catalyzing reactions:

Substrates held in active site, converted to products, released

What are substrates held in active site by?

Weak interactions

What do enzymes hold substrates to form?

Enzyme-substrate complex

How do enzymes allow substrate to bind better?

By changing shape of their active site

Enzymes changing shape of their active site to allow substrate to bind better:

Induced fit

Diagram of induced fit:

What does enzyme catabolism mean?

Enzymes help to break down complex molecules

What does enzyme anabolism mean?

Enzymes help to build complex molecules

What can the 3D shape of enzymes be affected by?

Temperature, pH, chemicals

What does changing the shape of enzymes affect?

Efficiency of enzymes

What does a change in shape mean?

Change in function

The conditions (temp and pH) that allow enzymes to function optimally:

Optimal conditions

How does the rate of enzyme activity change with temperature?

Increases up to a certain point

Why does rate of enzyme activity increase with temperature?

Due to collisions

Enzymes function best at a ______ pH

Specific

What happens when enzyme is outside normal pH range?

Hydrogen bonds in enzyme break

What happens when hydrogen bonds in enzyme break?

Shape of enzyme changes

Graph of enzyme activity rate vs pH:

Graph of enzyme activity rate vs temperature:

Graph of enzyme activity rate vs substrate concentration:

Non-protein molecules that assist enzyme function:

Cofactors

What do inorganic cofactors consist of?

Metals

How can enzyme cofactors be bound?

Loosely or tightly

An enzyme with the cofactor attached:

Holoenzyme

Organic cofactors:

Coenzymes

Example of coenzyme:

Vitamins

Diagram of holoenzymes:

What do enzyme inhibitors do?

Reduce activity of specific enzymes

Are inhibition from enzyme inhibitors permanent or reversible?

Can be either permanent or reversible

What does enzyme inhibitor bind with to produce permanent inhibition?

Covalent bonds

What does enzyme inhibitor bind with to produce reversible inhibition?

Weak interactions

Example of permanent inhibition:

Toxins and poisons