Chapter 7 Flashcards
Catabolism
Energy released by breakdown reactions. It functions in regenerating ATP and it can also harvest energy stored in fats obtained from either food or from storage cells in the body.
Oxidative phosphorylation
Oxidative phosphorylation is the production of ATP using energy derived from the redox reactions of an electron transport chain.
Substrate-level phosphorylation
Substrate-level phosphorylation is the enzyme catalyzed formation of ATP by direct transfer of a phosphate group to ADP from an intermediate substrate in catabolism. ATP is made by this.
Citrate
The ionized form of citric acid, for which the cycle is named. In step 1 of the citric acid cycle, citrate is formed. The next 7 steps decompose the citrate back to oxoloacetate.
Proton concentration gradient
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Aerobic
A catabolic pathway for organic molecules, using oxygen (O2) as the final electron acceptor in an electron transport chain and ultimately producing ATP. This is the most efficient catabolic pathway and is carried out in most eukaryotic cells and many prokaryotic organisms.
Electron transport
Is embedded in the inner mitochondrial membrane, made of 3 hydrogen pumps and 2 carrier molecules. It is the primary ATP generating pathway, and it produces ATP through chemiosmosis. It’s powered by electrons that are on glucose. Electrons travel down the chain from less electronegative to higher electronegative molecule. Every time they move down the chain, some energy is peeled off making it more stable. This lost energy powers the protons pumps. KEY: at the end of the transport chain, electrons combine with 2 protons and OXYGEN. Without oxygen the whole system gets backed up and aerobic respiration turns off. The electron transport chain is necessary to cell respiration because it breaks the fall of electrons to oxygen into several energy-releasing steps.
What is the 1st step of cellular respiration?
Glycolysis. A glucose molecule is split into 2 3-carbon molecules called pyruvate
Electronegative
Electronegative is the attraction to an electron. In the electron transport chain each down hill carrier is more electronegative than its uphill carrier, thus capable of oxidizing with oxygen at the bottom of the chain.
Pyruvate
The ionized form of pyruvic acid. In glycolysis, when a 6 carbon sugar is broken into two 3-carbon sugars. These smaller sugars are then oxidized and their remaining atoms are rearranged to form two molecules of pyruvate.
Chemiosmosis
Couples the electron transport chain to ATP synthesis. Chemiosmosis is ATP synthesis is powered by the flow of H+ back across the membrane. In general terms, chemiosmosis is an energy-coupling mechanism that uses energy stored in the form of an H+ gradient across a membrane to drive cellular work.
ATP yield from different parts of cellular respiration and the net total
ATP yield from glycolysis is 2, citric acid cycle is 2, and oxidative phosphorylation is about 26 or 28 ATP. Maximum per glucose is about 36 - 38 ATP
NAD+
NAD+ acts as an electron carrier for hydrogen. It carries hydrogen sulfide electrons and transfers them to oxygen. Very little potential energy of the electrons are lost
FAD+
A coenzyme that temporarily gains energy. FAD is reduced every time is loses electrons.
ATP synthase
The enzyme that actually makes ATP from ADP and inborn aid phosphate. A complex of several membrane proteins that functions in chemiosmosis with adjacent electron transport chains, using the energy of a hydrogen ion (proton) concentration gradient to make ATP. ATP synthases are found in the inner mitochondrial membranes of eukaryotic cells and in the plasma membranes of prokaryotes.
Fermentation
Fermentation is a catabolic process that makes a limited amount of ATP from glucose (or other organic molecules) without an electron transport chain and that produces a characteristic end product, such as ethyl alcohol or lactic acid.
Anaerobic
Found in all living things. No oxygen present. Fermentation is an example of anaerobic.
Acetyl CoA
Acetyl coenzyme A; the entry compound for the citric acid cycle in cellular respiration, formed from a two-carbon fragment of pyruvate attached to a coenzyme. It is highly reactive. In Karen’s cycle, Acetyl CoA is oxidized to CO2. Each turn of the Krebs cycle requires one Acetyl CoA. So how many turns for one molecule of glucose? 2 turns.
Glycolysis
6 carbon sugar broken into two 3 carbon sugars
“To split sugar”
Net gain from this reaction: 2
Occurs in cytosol. Occurs in both prokaryotes and eukaryotes. It doesn’t need organelles to take place. Know the formula for this.
Oxidized: 6 carbon sugar
Starting reactants: the phosphate group bonded to ADP
