Chapter 9: Cellular Respiration and Fermentation Flashcards
fermentation
a catabolic process that makes a limited amount of ATP from glucose, without an electron transport chain and produces a characteristic end product, like ethyl alcohol or lactic acid
aerobic respiration
a catabolic pathway for organic molecules, using oxygen as the final electron acceptor in an electron transport chain and ultimately producing ATP. most efficient catabolic pathway and its carried out in most eukaryotic cells and many prokaryotic organisms
anaerobic respiration
a catabolic pathway in which inorganic molecules other than oxygen accept electrons at the downhill end of the electron transport chains
cellular respiration
the catabolic pathways of aerobic and anaerobic respiration, which break down organic molecules and use an electron transport chain for the production of ATP
cellular respiration
?
redox reactions
a chemical reaction involving the complete or partial transfer of one or more electrons from one reactant to another. Short for reduction-oxidation reaction
oxidation
complete or partial loss of electrons from a substance involved in a redox reaction
reduction
the complete or partial addition of electrons to a substance involved in the redox reaction
reduction agent
the electron donor in a redox reaction
oxidizing agent
the electron acceptor in a redox reaction
electron transport chain
a sequence of electron carrier molecules (membrane proteins) that carry an electron down a series of redox reactions that release energy used to make ATP
citric acid cycle
a chemical cycle involving eight steps that completes the metabolic breakdown of glucose molecules
- begun in glycolysis
- oxidizing the acetyl CoA (which is derived from pyruvate–which is the product of glycolysis) to carbon dioxide
- —occurs within the mitochondrion in eukaryotic cells and in the cytosol of prokaryotes; together with pyruvate oxidation, the second major stage in cellular respiration
krebs cycle
the second stage of cellular respiration, aka the citric acid cycle
oxidative phosphorylation
3rd major stage of cellular respiration, production of ATP using energy derived from the redox reaction of an electron transport chain
substrate-level phosphorylation
the enzyme-catalyzed formation of ATP from a phosphate group directly transferring to ADP from an intermediate substrate in catabolism
(ATP comes from ADP being phosphorylized in an enzymatic reaction)
glucose
a six carbon sugar, the molecule energy is harvested from for cellular respiration
pyruvate
ionized form of pyruvic acid, formed when the products of glycolysis (2 3-carbon sugars) are oxidized
acetyl coenzyme A
the entry compound for the citric acid cycle in cellular respiration, formed from a 2 carbon fragment of pyruvate attached to a coenzyme
chemiosmosis
an energy-coupling mechanism
- uses energy stored in the form of a hydrogen ion gradient across a membrane
- drive cellular works, such as the synthesis of ATP.
Under aerobic conditions most ATP synthesis in cells occurs by chemiosmosis.
Catabolic pathways and electron transfer play a major role in yielding energy from organic molecules. explain why this is so.
Yielding energy from organic molecules is done by cellular respiration, photosynthesis, and fermentation. All of these processes require molecules to be broken (catabolized/oxidized)
to create new bonds and molecules, and require the transfer of electrons to do so. Glycolysis breaks glucose into and 2 pyruvates, which are fixed into Acetyl CoA. This is catabolic. In the electron transport chain, the transfer of electrons by NADH and FADH2 units allows the protein in the chain to release protons, which are then used to power ATP synthase. Which is what yields energy for the cell
Define the areas within the cell that the three steps of cellular respiration occur and dictate the number of ATP produced for each step
Glycolysis: net 2. Happens in the Cytoplasm
Krebs Cycle: net 2. Happens in the Inner membrane of the Mitochondria
ETC: net 34. Happens in the Mitochondria
Explain how ATP is called the “energy currency of the cell”
It is the high yield energy molecule all living cells use for energy.
It produces high amounts of energy on its hydrolysis.
Compare and contrast obligate anaerobes and facultative anaerobes.
Obligate anaerobes cannot grow in the presence of oxygen.
**They depend on fermentation and anaerobic respiration using a final electron acceptor other than oxygen.
Facultative anaerobes show better growth in the presence of oxygen but will also grow without it.
