Biology Students’ Companion Resources SB025 1 | KMPk CHAPTER 5: CELLULAR RESPIRATION AND FERMENTATION SUBTOPIC : 5.1 Aerobic respiration LEARNING OUTCOMES: (a) State the needs for energy and the role of respiration in living organisms. (b) Outline the complete oxidation of glucose which involves glycolysis, Krebs cycle and oxidative phosphorylation. MAIN IDEAS /KEY POINT EXPLANATION NOTES Cellular Respiration • The catabolic pathway of aerobic and anaerobic respiration, which break down organic molecules and use an electron transport chain for the production of ATP. Aerobic respiration • A catabolic pathway for organic molecules (glucose) • Using oxygen as the final electron acceptor in an electron transport chain and producing ATP. Needs for energy and the role of respiration in living organisms • Most of the processes taking place in cells need energy to make them happen. • Examples of energy consuming processes in living organisms are: a) The contraction of muscle cells – to create movement of the organism, or peristalsis. b) Building up proteins from amino acids c) The process of cell division to create more cells, or replace damaged or worn out cells, or to make reproductive cells d) The process of active transport, involving the movement of molecules across a cell membrane against a concentration gradient e) The conduction of electrical impulses by nerve cells
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Biology Students’ Companion Resources SB025
1 | KMPk
CHAPTER 5: CELLULAR RESPIRATION AND
FERMENTATION
SUBTOPIC : 5.1 Aerobic respiration
LEARNING OUTCOMES: (a) State the needs for energy and the role of respiration in living organisms.
(b) Outline the complete oxidation of glucose which involves glycolysis, Krebs
cycle and oxidative phosphorylation.
MAIN IDEAS
/KEY POINT EXPLANATION NOTES
Cellular
Respiration
• The catabolic pathway of aerobic and anaerobic respiration,
which break down organic molecules and use an electron
transport chain for the production of ATP.
Aerobic
respiration
• A catabolic pathway for organic molecules (glucose)
• Using oxygen as the final electron acceptor in an electron
transport chain and producing ATP.
Needs for energy
and the role of
respiration in
living organisms
• Most of the processes taking place in cells need energy to
make them happen.
• Examples of energy consuming processes in living
organisms are:
a) The contraction of muscle cells – to create movement
of the organism, or peristalsis.
b) Building up proteins from amino acids
c) The process of cell division to create more cells, or
replace damaged or worn out cells, or to make
reproductive cells
d) The process of active transport, involving the
movement of molecules across a cell membrane against
a concentration gradient
e) The conduction of electrical impulses by nerve cells
Biology Students’ Companion Resources SB025
2 | KMPk
MAIN IDEAS
/KEY POINT EXPLANATION NOTES
• The Adenosine triphosphate (ATP) molecule is the "molecular
currency" of intracellular energy transfer.
• ATP is produced by:
a) Substrate-level phosphorylation
b) Oxidative phosphorylation
Substrate-level phosphorylation
• The enzyme-catalyzed formation of ATP
• By direct transfer of a phosphate group to ADP from an
intermediate substrate in catabolism
Oxidative phosphorylation
• The production of ATP using energy derived from the redox
reactions of electron transport chain.
• Generates most of ATP (90%).
Complete oxidation of glucose involves:
1. Glycolysis (in cytoplasm)
2. Krebs Cycle (in the matrix of mitochondrion)
3. Oxidative Phosphorylation : electron transport chain and
chemiosmosis (at cristae/inner membrane of
mitochondrion)
Complete
oxidation of
glucose
Complete oxidation of glucose
Complete oxidation of glucose
Link
reaction Kreb
cycle
Biology Students’ Companion Resources SB025
3 | KMPk
SUBTOPIC : 5.1.1 Glycolysis
LEARNING OUTCOMES: (a) Ilustrate to explain glycolysis pathway: (from glucose to pyruvate).
(b) Describe link reaction: (conversion of pyruvate to acetyl coenzyme A).
MAIN IDEAS
/KEY POINT EXPLANATION NOTES
Glycolysis
• In the cytoplasm
• Glycolysis means “sugar splitting”. Break down glucose
(6C) into TWO molecules of pyruvate (3C).
• Occurs with or without O2 .
• Has two major phases:
a) Energy investment phase
o 2 ATP used
o Phosphorylate Sugar
b) Energy payoff phase
o 4 ATP yielded
• Net ATP yield : 2 ATP
• Produces : 2 NADH + 2H+
• No carbon is released as CO2
Glycolysis
pathway
Energy investment phase
- 2 ATP used
- involves 5 steps which are:
1. Glucose undergoes phosphorylation to become glucose-
6-phosphate • Catalysed by Hexokinase. • ATP is used.
2. Glucose 6-phosphate is converted to its isomer, fructose
6-phosphate
3. Fructose 6-phosphate undergoes phosphorylation to
become fructose 1,6-bisphosphate.
• Catalysed by Phosphofructokinase.
• ATP is used.
4. Fructose 1,6-bisphosphate split into dihydroxyacetone