Ch. 6 How Cells Harvest Chemical Energy Flashcards
Aerobic
Containing/requiring molecular oxygen
Anaerobic
Lacking/not requiring molecular oxygen
Cellular Respiration
Aerobic harvesting of energy from food molecules
- energy releasing chemical breakdown of food molecules, such as glucose, and the storage of potential energy in a form that called can use to perform work
What are the three phases of cellular respiration?
1) Glycolysis
2) Krebs Cycle
3) Electron Transport Chain & Chemiosmosis
Why can’t the cell harvest all of the energy in a useable form?
40% of glucose is turned into ATP and the rest is converted to heat.
Redox Reaction
Oxidation reduction
- describes movement of electrons from donor molecules to an acceptor molecule
Oxidation
Loss of electrons from a substance involved in a redox reaction
Reduction
Gain of electrons by a substance involved in a redox reaction
What does oxidation and reduction accompany each other?
Always together because electron transfer needs both donor and acceptor.
Dehydrogenase
An enzyme that catalyzes a chemical reaction during which one or more hydrogen atoms are removed from a molecules
What is NAD+?
Nicotinamide adenine dinucleotide
- a coenzyme that assists enzymes by converting electrons (from hydrogen atoms) during the redox reactions of cellular metabolism
- oxidized molecule, ready to pick up electrons
Electron Carrier
A molecule that conveys electrons within a cell
- make up the electron transport chain
- shuttles electrons during redox reactions that release energy for ATP synthesis
What keeps electrons of the carrier molecules moving?
Affinity for electrons.
Electron Transport Chain
Synthesizes ATP by the process of chemiosmosis.
- inner membrane of mitochondria, thylakoid of chloroplast, plasma membrane of prokaryotes
Chemiosmosis
The production of ATP using the energy of H+ gradients across membranes to phosphorylate ADP
- powers most of the ATP synthase
ATP Synthase
Series of protein complexes embedded in the inner membrane of mitochondria loaded with enzymes for phosphoration of ADP to ATP
- provides the port through which H+ diffuse (uses PE of concentration gradient)
Substrate-level Phosphorylation
The formation of ATP occurring when an enzyme transfers a phosphate group from an organic molecule to ADP
- occurring because bond holding phosphate group in substrate molecule is less stable than ATP bond
Glycolysis
"splitting of sugar" Multistep chemical breakdown of a molecule of a glucose into two molecules of pyretic acid. - first step of of cellular respiration - occurs in cytoplasmic fluid - exergonic
Krebs Cycle
Metabolic cycle fueled by acetyl CoA formed after glycolysis in cellular respiration
- chemical reactions complete the metabolic breakdown of glucose molecules to carbon dioxide
- occurs in matrix of mitochondria and supplies most of the NADH molecules that carry energy to electron transport carriers
- exergonic
What are the three steps of cellular respiration?
1) Glycolsysis
2) Krebs Cycle
3) Electron Transport
What are the two carriers of electron transport chain?
NADH (NAD+) and FAD (FADH2)
Intermediate
A compound formed between initial reactant in metabolic pathway and the final product
How many steps are there in glycolysis?
9 steps
1 - 4) Preparatory & Consumer Energy Phase [consumes 2 ATP]
5 - 9) Energy Payoff Phase [Yields 4 ATP]
What is the net gain of glycolysis?
2 ATP molecules
