BIOL 120 - Metabolism and Photosynthesis

Chapters 6, 7, and 8

What is energetics?

The study of energy flow through living systems

What is a catabolic pathway?

A pathway that BREAKS down a complex.

What is an anabolic pathway?

A pathway that BUILDS a complex.

What is energy?

The ability to do work or cause change

What is activation energy?

The energy REQUIRED for a reaction to proceed. This can be lowered if the reaction is catalyzed…

What are the 4 types of energy?

• Kinetic

• Heat

• Potential

• Chemical

What is kinetic energy?

The energy of motion by an object that is moving

What is potential energy?

The energy an object has due to its position in space.

The object has the POTENTIAL to do WORK

What is heat/thermal energy?

A transfer of energy from one system to another system that is NOT doing work

What is chemical energy?

Energy that exists in the form of bonds

What is free energy?

The amount of a system’s energy that is available to do useful work

What is enthalpy?

Characterized by ΔH, and represents the total energy in a system

What is an exergonic reaction?

A reaction that releases energy. 

This reaction is often spontaneous

The resulting value will be a negative number (ΔH = -XYZ)

What is an endergonic reaction?

A reaction that absorbs energy

This reaction is often non-spontaneous

The resulting value will be a positive number (ΔH = XYZ)

How does an enzyme affect reactions?

Lowers activation energy

What are the two PHYSICAL properties of an enzyme?

• A substrate (usually a ligand)

• An active site

What is the function of a substrate?

A molecule that an enzyme binds to and converts into a product

What is the function of an active site?

Where the substrate binds to, and where the reaction takes place.

What is an enzyme?

A catalytic (rate-increasing) protein

What are the functional properties of an enzyme?

• Not used up in chemical reactions

• Converts things and makes things easier to do

What causes an enzyme to denature?

High temperatures cause their natural properties to change

What is oxidation in a redox reaction?

The loss of electrons

What is reduction in a redox reaction?

The gain of electrons

What is a cofactor?

Inorganic ions (non-proteins) that are essential for the proper functioning of enzymes

What is a coenzyme?

A subgroup of cofactors that are organic helper molecules with basic atomic structures, and are required for enzyme action.

What is respiration?

The process of releasing energy from food within a cell, and requires oxygen. (aerobic pahtway)

What is fermentation?

Converting sugars into a new product in the absence of oxygen. (anaerobic pathway)

What is an aerobic pathway?

Metabolic processes that require oxygen to generate energy (ATP)

What is anaerobic pathway?

Metabolic processes that do NOT require oxygen to generate energy (ATP)

What is thermodynamics?

The study of energy transformations

What is the first law of thermodynamics?

Energy can NOT be created NOR destroyed

What is the second law of thermodynamics?

Every energy transfer or transformation INCREASES the entropy (disorder)

What is entropy?

Disorder within a system

What are the five components being put in the electron transport chain?

NADH, FADH2, Oxygen, and ADP + P

What are the four outputs of the electron transport chain?

ATP, Water, NAD+ and FAD

How many ATP molecules are produced at the end of all the cycles? (Glycolysis, krebs, electron transport chain)

32-34 ATP molecules

Where does glycolysis take place, and where does the product move to?

Cytoplasm; into the mitochondria and into the krebs cycle pathway.

Where does the Krebs/Citric Acid cycle take place, and where do its products move to?

Mitochondrion; Electron transport chain

Where does the electron transport chain take place, and where do its products move to?

Mitochondrion; out of the mitochondrion

What are the products of Glycolysis?

2 pyruvate, 2 ATP, and 2 NADH.

What are the products of the Krebs/Citric Acid Cycle? (per cycle)

3 NADH, 1 FADH2, 1 ATP, 2 CO2.

Which process (glycolysis, krebs, electron transport chain) produces the most ATP?

Electron Transport Chain

What is the chemical equation for cellular respiration?

C6H12O6 + 6O2 —> 6CO2 + 6H2O + ATP

OR (divide by six)

CH2O + O2 —> CO2 + H2O + ATP