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Review Game #3
 

LAMC
BIOLOGY

LAMC Bio 3 Lecture Notes: Chapter 6 - How Cells Harvest Chemical Energy

Reading Assignment: Chapter 6

Learning Outcomes:
By the end of today’s lecture, you should be able to:
- explain the steps involved in cellular respiration.
- write the general equation for cellular respiration.
- explain the differences and similarities between respiration and fermentation
- identify the different products formed by fermentation.

I. Cellular Respiration

Breathing supplies O₂ to cells & removes CO₂.  Cellular respiration produces ATP.  The human body uses energy from ATP for all its activities.
A pair of redox (oxidation/reduction) reactions occurs simultaneously in cellular respiration. 
Oxidation: the loss of electrons from a substance.
Reduction: the gain of electrons by a substance.
Electrons “fall down” an energy staircase and reduce O2.
Cellular respiration: C₆H₁₂O₆ + 6O₂ à 6CO₂ + 6H₂O + Energy (ATP + heat)

The steps in cellular respiration:

i) Glycolysis harvests chemical energy by oxidizing glucose to pyruvate. 
Substrate-level phosphorylation produces a small amount of ATP.

ii) Pyruvate is converted to acteyl coenzyme A.

ii) The citric acid cycle completes the oxidation of organic fuel, generating many NADH & FADH₂ molecules.

iii) Oxidative phosphorylation (electron transport chain and chemiosmosis) produces the most amount of ATP in cellular respiration.

Certain poisons interrupt critical events in cellular respiration.

Each molecule of glucose yields many molecules of ATP.  Cells use many kinds of organic molecules as fuel for cellular respiration.  The fuel for cellular respiration ultimately comes from photosynthesis.

II. Fermentation

Fermentation enables cells to produce ATP without oxygen; it is an extension of glycolysis.

There are many different types of fermentation (they vary in the final product produced):
i) alcohol fermentation (final product is ethanol, used in fermenting alcoholic drinks and baking)
ii) lactic acid fermentation (final product is lactate, occurs in the muscle cells when there is not enough oxygen)

Plant Predators Video Questions:

1. How has the sloth adapted to the low nutrient content of its leaf diet?

2. a) Can mammals digest cellulose? 

2. b) How can herbivorous mammals survive on plants as their only food source?

3. List the ways in which a tapir avoids being poisoned by the toxins contained in the plants it feeds on.

4. How do pikas use plant poisons to their advantage?

5. a) What are some of mineral deficiencies that plant predators face? 

5. b) List the ways in which they supplement their diet with minerals.

6. a) What are the various defenses that plants have against their predators?

6. b) What are the various adaptations that plant predators have to deal with these plant defenses?

7. What are the adaptations that the following animals have for feeding on acacia?

a) dik dik:

b) impala:

c) gerenuk:

d) giraffe:

e) elephant:

©2003-2004 Dilek Sanver-Wang, MS
Los Angeles, CA USA.  All Rights Reserved.