Transcript Lorem Ipsum - Tri-County Technical College

Chapter 6
Biology 100
Tri-County Technical College
Pendleton, SC
What is respiration?
 process
by which living organisms take
glucose and other nutrients and make ATP
 Aerobic respiration
– utilizes oxygen in the process
 Anaerobic
respiration
– is done without oxygen
 C6H12O6
+ 6O2 6CO2 + 6H2O + ATP
The first step is glycolysis
 Glycolysis
is a pathway of reactions that
takes glucose (6C) and splits it into two
pyruvate molecules (3C).
 Raw material for glycolysis -- glucose
 Products-– pyruvate
– 2 molecules of ATP
– reduced NAD (NADH)
What happens to products of
glycolysis?
 pyruvate
– converted to acetyl-CoA and carbon dioxide
2
molecules of ATP
– used by the cell for energy
 NADH
and FADH2
– is used by electron transport system to make
ATP
– the NAD+ is reused
Kreb’s Cycle
 same
as citric acid cycle
 acetyl-CoA enters the cycle (raw material)
 the cycle is a series of oxidation-reduction
reactions
 Products
– 2 ATP’s
– reduced NAD (NADH) and FAD (FADH2)
– carbon dioxide
So far not much energy
 2 ATP’s
from glycolysis
 2 ATP’s from Kreb’s cycle
 not enough to cuss a cat with
 most of the energy comes from the Electron
Transport System
Electron Transport System
 Raw
materials
– NADH and FADH2 from the other pathways
– oxygen
 What
is it? A series of oxidation-reduction
reactions involving cytochromes.
 Products
– A lot of ATP (32 molecule/original glucose)
– water (water of metabolism)
The Overall Scheme
Glucose
Citric
Acid
Cycle
Glycolysis
2 Pyruvates, NADH, 2ATP
Acetyl-CoA
Carbon
dioxide
Electron
Transport
System
NADH
2 ATP
FADH2
32 ATP, water, NAD+, FAD+
Oxygen and Carbon Dioxide
 Oxygen
is needed
– final acceptor of electrons and hydrogen ions to
produce water
 Carbon
dioxide is a waste product
– generated at the entrance to the Citric Acid
Cycle and during the cycle itself
Where Do These Take Place?
 Glycolysis
(Universal pathway)
– in the cytoplasm - eukaryotic cells
– in the cytoplasm - prokaryotic cells
 Citric Acid
(Kreb’s) cycle
– in the inner membranes of the mitochondria eukaryotic cells
– inner surface of cell membrane - prokayotic
cells
Where, ctd?
 Electron
transport system
– inner surface of cell membrane - prokaryotic
cells
– Inner membranes of mitochondria -- eukaryotic
cells
 Eukaryotic
cells are more specialized in
their specific functions.
Aerobic vs. Anaerobic
 Aerobic
respiration is what we have been
discussing.
 Anaerobic respiration=inorganic atom/molecule
other than OXYGEN as FEA
 Some prokaryotes utilize anaerobic respiration
 Without oxygen ETS for aerobic respiration WILL
NOT WORK
Aerobic vs. Anaerobic
 Considerably
less ATP is produced by
anaerobic respiration
– aerobic respiration -- 36 ATP/glucose
– anaerobic respiration – equivalent ATP/glucose
– Fermentation yields only 2 ATP per glucose
 In
muscle tissue, pyruvic acid is converted
to lactic acid
– muscle fatigue
Fermentation
 A special
kind of anaerobic respiration
carried out by yeasts and some bacteria.
 Instead of going into the Kreb’s cycle,
pyruvic acid is converted to ethyl alcohol
and carbon dioxide
 Basis of multi-billion dollar fermentation
industry
Synthesizing Information
 Obligate
aerobe is organism that requires
oxygen for cellular respiration and CAN”T
live without it
 Obligate anaerobe is organism that cannot
use oxygen and is poisoned by it
 Facultative anaerobe is organism that uses
oxygen if available (in fact, prefers it) but
can switch to alternate pathway if oxygen is
unavailable
How are fats metabolized?
 Glycerol
and fatty acids
 Glycerol is converted to one of the
intermediates of Glycolysis.
 Fatty acids are broken down into two
carbon pieces and each piece is converted to
acetyl-CoA which enters the Kreb’s cycle
 Energy is produced as with glucose.
Protein metabolism
 Amino
group is removed from amino acids
 The result is a keto acid
 Keto acids enter the respiratory cycle as
pyruvic acid or as one of the other types of
molecules found in the Kreb’s cycle.
 The amino group is converted to ammonia
What to do with ammonia?
 Ammonia
is very toxic
 some organisms eliminate ammonia
 others, such as us, convert ammonia into
urea and uric acid which are much less toxic
– both are eliminated by the kidneys in urine