The Physiology of the Cell




BIO190: The Class: Cell Physiology: Lesson 5

The Physiology of the Cell

Energy/Laws of Thermodynamics

Two states of energy
1. kinetic-energy of motion
2. potential-stored energy
First law of thermodynamics
Energy cannot be created or destroyed.
Second law of thermodynamics
A closed system moves towards increasing disorder (entrophy). Bear in mind that living organisms are open systems, not closed systems.
free energy
reactions in cells
1. exergonic- release free energy (pg. 63 - diagram)
2. endergonic-require addition of free energy (pg. 63 - diagram)

The role of enzymes

Enzymes are chemical substances that accelerate reaction rates.

Enzyme Biochemistry Review
energy of activation (fig. 5-2)
catalysts-accelerate reactions
enzymes-catalysts of the living world

The nature of enzymes

cofactors-nonprotein groups that work with enzymes to do their work
coenzymes-organic cofactors

Action of enzymes

substrate-the molecule whose action the enzyme catalizes
ES complex (fig. 5-3C)

Specificity of enzymes

Enzymes are highly specific. In other words, there must be a precise molecular fit between the enzyme and substrate. Also, one enzyme usually catalizes only one reaction.

catabolic reaction-degrades proteins into amino acids
anabolic reaction-rebuilds amino acids into proteins

Chemical energy (ATP; fig. 5-5 & 5-6)

coupled reaction-reaction that requires a combination of an energy-requiring reaction with an energy-yielding reaction (fig. 5-7).

Cell respiration (fig. 5-9)

electron transport
redox reaction (fig. 5-8)
aerobic vs anaerobic metabolism
glycolysis (fig. 5-10)
1. DYI Glycolysis
2. pyruvic acid = pyruvate (fig. 5-15)
acetyl Co A (fig. 5-11)
Kreb cycle: (also called TCA and citric acid cycle) degradation 2 carbon acetyl group of acetyl coenzyme A.
electron transport chain; cytoplasm (mitochondria) (mitochondria)
(oxidative phosphorylation (fig. 5-13)
amount of ATP/glucose molecule (tab. 5-1)
anaerobic glycolysis (fig. 5-15)
1. alcoholic fermentation
oxygen debt

Lipid metabolism

How fatty acids are broken down? See fig. 5-16.

Protein metabolism

How amino acids are metabolized? Amino acid metabolism is complex. See fig. 5-17.

Once you have completed the lesson, you should go to Assignment 5-1.

E-mail Sylvester Allred at Syl.Allred@nau.edu