Download Honors Biology Chapter 6 CELLULAR RESPIRATION 2-27

CELLULAR RESPIRATION
Living organisms require energy
 What is the usable form of energy for cells?
ATP
 Used for mechanical, chemical and transport work.
What is the ultimate source of energy?
SUN *
Eukaryotic organisms (plants, protists, fungi and animals)
use the O2 and the stored potential energy in the organic
molecule (“Glucose”) during Cellular Respiration to
produce usable potential energy ATP.
 CO2, H2O and heat are waste products.
What organelle do eukaryotic cells use for Cellular
Respiration?
Mitochondria
Describe the relationship between Photosynthesis and
Cellular Respiration:
Cellular Respiration (Simplified)
*
40% of energy in glucose converted to ATP, 60% into heat
Identifying Oxidation and Reduction in Reactions
The oxidation number of an element indicates the number
of electrons lost, gained, or shared as a result of chemical
bonding.
Oxidation
Oxidation is an increase in the oxidation number of the
element which is associated with loss of electrons. From
this we get the abbreviation OIL: Oxidation is Loss (of
electrons).
Reduction
Reduction is the opposite of oxidation so it is no surprise
that reduction is defined as a decrease in the oxidation
number of the element which is associated with gain of
electrons. This gives us a second abbreviation RIG:
Reduction is Gain (of electrons).
OILRIG
OILRIG is a convenient and easy way to
remember the rules for electron loss and
gain in oxidation reduction reactions.
OIL: Oxidation is Loss (of electrons).
RIG: Reduction is Gain (of electrons).
LEO says GER
GERRRR
LEO – Losing Electrons is
Oxidation
GER – Gaining Electrons is
Reduction
SUBSTANCE X
-
LOSES e : OXIDIZED
X loses electrons
X is oxidized
X increases oxidation number
SUBSTANCE Y
-
GAIN e : REDUCED
Y gains electrons
Y is reduced
Y decreases oxidation number
The oxidation number of an element indicates the number of
electrons lost, gained, or shared as a result of chemical
bonding.
Cellular Respiration… keep your eyes on the electrons
(hydrogen).
Energy is contained in the arrangement of electrons in the
chemical bonds that hold organic molecules together.
 Electrons lose energy as they “fall”/are transferred to
oxygen. The energy released can be stored in ATP.
 NAD+ = Nicotinamide Adenine Dinucleotide (coenzyme)
Cellular Respiration Overview
Stage 1: Glycolysis
 Occurs in the cytoplasm
 Breaks glucose into 2 pyruvate
 Removes electrons (Hydrogen atoms)
 Generates ATP
Stage 2: Citric Acid Cycle (Krebs Cycle)
 Occurs in the mitochondrial matrix
 Carbons released as CO2
 Removes electrons
 Generates ATP
Stage 3: Oxidative Phosphorylation (ETC and Chemiosmosis)
 Occurs at the inner mitochondrial membrane (Cristae)
 Electrons and protons used to generate ATP
 Water produced
Glycolysis – “Splitting of Glucose”
 Located in the cytoplasm of the cell
 In a series of chemical reactions, a 6-carbon organic
molecule, Glucose, is split into 2, 3-carbon
molecules called pyruvate (pyruvic acid).
o First phase – energy invested – used to prepare
glucose and intermediate molecules for
breaking.
o Second phase – energy harvested – NADH and
ATP molecules are produced.
Important Numbers
 2 ATP are invested
 2 NAD+ are reduced to 2NADH + 2H+ (2NADH2)
 4 ATP are produced
 ATP Net Gain?
2ATP
Substrate-level Phosphorylation – an
enzyme transfers a phosphate group
from a substrate molecule directly to
ADP to form ATP.
https://www.youtube.com/watch?v=3GTjQTqUuOw
https://www.youtube.com/watch?v=iChb5hEDzqc
Glycolysis – might be an ancient metabolic (energyharvesting process) pathway.
 Found in all types of cells (bacteria humans)
 Does not require oxygen
 Does not require membrane bound organelles