Download CELLULAR RESPIRATION

Describe the relationship between Photosynthesis and
Cellular Respiration:
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 O2 and the stored energy in an organic molecule
(“Glucose”) during Cellular Respiration to produce usable
potential energy ATP.
 CO2 and H2O are waste products.
What organelle do eukaryotic cells use for Cellular
Respiration?
Mitochondria
Heterotrophs – organisms that must eat other organisms for
food.
Food molecules store chemical energy.
We measure the energy in food using the calorie. A calorie
is the amount of energy needed to raise 1 gram of water 1
degree Celsius. The Calories you see on food labels are
kilocalories (C). 1 Calorie = 1000 calories.
Cellular Respiration (Simplified)
ATP – Adenosine Triphosphate – usable energy in a cell
Adenine
Ribose
Phosphate Groups (3)
High Energy Bond
High Energy Molecule
Hydrolysis of ATP into ADP and P
Lower Energy Molecule
ATP – ADP + P Cycle
Three Types of Cellular Work:
1. Chemical Work – Energy is
needed for chemical reactions.
2. Mechanical Work – Energy
is needed to contract muscles.
3. Transport Work – Energy is
needed for protein pumps and
to change the plasma
membrane
Cellular Respiration… keep your eyes on the electrons
(hydrogen).
Cellular Respiration Overview
 NAD+ = Nicotinamide Adenine Dinucleotide
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).
Important Numbers
 2 ATP are invested
 2 NAD+ become 2NADH + 2H+ (2NADH2)
 Glucose broken into 2 pyruvate
 4 ATP are produced
 ATP Net Gain?
2ATP
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
Stage 2 – Krebs Cycle
 Occurs in the mitochondrial matrix
 Carbons released as CO2
 Removes electrons (hydrogen)
 Generates ATP
Pyruvate to Acetyl Coenzyme A (Acetyl CoA)
Pyruvate is first transported to the mitochondria.
 One carbon atom is released as CO2.
 NAD+ becomes NADH + H+.
 Coenzyme A is attached to the remaining 2-carbon
molecule to form acetyl coenzyme A.
How many molecules of Acetyl CoA are produced from
one molecule of glucose?
2
Stage 2: Krebs Cycle
Takes place in the Matrix of the Mitochondria
For 1 Acetyl CoA molecule:
 The 2-carbon chain (not CoA) enters the Kreb’s
Cycle.
 The carbons are released as 2 CO2.
 Electrons (Hydrogen) are removed.
o 3 NAD+ become 3 NADH + 3H+
o FAD (another electron carrier) becomes FADH2.
 1 ATP molecule is produced.
Since 2 molecules of Acetyl CoA enter the Kreb’s Cycle,
what are the total products for one molecule of glucose?
 Carbons released: 4 CO2.
 Electrons (Hydrogen)
https://www.youtube.com/watch?v=ubzw64PQPqM
carriers:
o 6 NADH + 6H+
o 2 FADH2.
 ATP produced: 2 ATP (Net Gain)
Stage 3 – Electron Transport Chain and Chemiosmosis
 Occurs at the inner mitochondrial membrane (Cristae)
 Electrons and protons used to generate ATP
 Water produced
Mitochondria use chemical energy to produce an H+
gradient and then use the energy stored in that gradient to
drive ATP synthesis.
https://www.youtube.com/watch?v=00jbG_cfGuQ
http://vcell.ndsu.edu/animations/atpgradient/movie-flash.htm
Song: http://www.youtube.com/watch?v=3aZrkdzrd04
Major Events:
 Electron/hydrogen carriers (NADH and FADH2) drop
off their electrons and protons at the Electron
Transport Chain.
o Energy is released as electrons are passed from
protein molecule to protein molecule down to
Oxygen.
 The energy is used to pump H+ across the
innermembrane into the intermembrane
space.
 Concentration gradient is potential
energy.
o Protons (H+) flow through ATP Synthase from
the intermembrane space into the matrix.
 The flow of electrons releases enough
energy to attach phosphate groups to ADP to
generate ATP.
 Net Gain: 32 ATP
o 2 electrons and 2 protons (H+) attach to ½ O2 to
form water.
Organic Molecules as Fuel and Materials for
Biosynthesis
Glucose is not the only organic molecule used as fuel for
cellular respiration.
Polysaccharides, Proteins and Lipids are also used, but
must be broken into their monomer building blocks first.
Food is also used to build needed molecules for repair and
growth.
o Cells use ATP and Cellular Respiration intermediates
to build macromolecules.
Fermentation
Fermentation – Anaerobic Respiration – Energy production
in the absence of oxygen.
Tweak Glycolysis
Location: Cytoplasm
Net Gain: 2 ATP
Two Types of Fermentation:
1. Lactic Acid Fermentation – Animal muscle cells,
fungi, bacteria and others
o NADH is oxidized, pyruvate is reduced to
lactate/lactic acid.
o Lactic acid is transported to the liver and
converted back to pyruvate.
2. Alcohol Fermentation – Plants and Some
microorganisms (Ex. fungi (yeast) and some bacteria)
o NADH is oxidized, ethyl alcohol and CO2 released.
o Used for baking and brewing.
https://www.youtube.com/watch?v=XREALVgxBEI
Review Stages of Cellular Respiration
http://www.sumanasinc.com/webcontent/animations/content/cellularrespiratio
n.html