Lecture 5 Flashcards
An organism gains energy using sugars as an electron donor and Fe+3 as an electron acceptor. This type of metabolism is an example of:
A) aerobic organotrophy
B) anaerobic lithotrophy
C) aerobic lithotrophy
D) anaerobic organotrophy
D) anaerobic organotrophy
When organic molecules, such as sugars, are the electron donor in energy-yielding reactions, the process is known as ?
organotrophy
Which reaction pairs both have positive free energy changes?
A) ATP hydrolysis and reduction of NAD+
B) ATP hydrolysis and oxidation of NADH
C) ATP production and oxidation of NADH
D) ATP production and reduction of NAD+
D) ATP production and reduction of NAD+
Since ATP hydrolysis and NADH oxidation liberate energy, ATP production and NAD+ reduction to form NADH require energy. Energy-requiring reactions have positive ΔG values.
What is it called when inorganic food molecules serve as electron donors in energy-yielding metabolic reactions?
A) lithotrophy
B) organotrophy
C) phototrophy
D) fermentation
lithotrophy
Organisms can obtain energy from light (phototrophy) or from the chemical bonds of molecules (chemotrophy).
Chemotrophy is divided into ____ (organic molecules serve as the energy source) and ____ (inorganic molecules serve as the energy source).
Organotrophy; Lithotrophy
What role do enzymes perform in allowing for chemical reactions to occur at a quicker rate?
They decrease activation energies
Which of the following molecules can donate electrons in metabolic reactions?
A) ADP
B) ATP
C) NAD+
D) NADH
NADH
ATP production and hydrolysis are not redox reactions. NADH is the reduced form of NAD+ and can donate electrons to other molecules in redox reactions.
Before feeding into the TCA cycle, pyruvate is first converted to ?
A) FADH2
B) citrate
C) acetyl-CoA
D) NADH
C) acetyl-CoA
After glycolysis, pyruvate has two potential fates. If no electron acceptor is available to perform respiration, pyruvate enters the fermentation pathway. If respiration can occur, pyruvate is first acted on by the pyruvate dehydrogenase complex; one product is acetyl-CoA.
As electrons are passed down an electron transport system…
A) NADH is produced
B) Oxygen is produced
C) The electrons are also pumped across a membrane
D) Protons are pumped across a membrane, which creates a proton gradient
Protons are pumped across a membrane, which creates a proton gradient
As electrons pass down an ETS, the energy released is used to pump protons across a membrane, generating a proton gradient. NADH often serves as the initial electron donor. It is not produced. Water is only produced when oxygen is the final electron acceptor; in anaerobic respiration, water is not a product.
Which type of metabolism is considered the most efficient?
A) Anaerobic
B) Fermentation
C) Aerobic
Aerobic
Aerobic respiration is the most efficient with the ability to produce up to 38 ATP. Anaerobic respiration produces variable amounts of ATP (5-36) depending on the final electron acceptor used. Fermentation produces a net of 2 ATP, which makes it the least efficient pathway.
In both fermentation and respiration:
A) NAD+ is regenerated from NADH
B) Pyruvate is further oxidized to CO2
C) Protons are pumped across a membrane
D) NADH is produced
A) NAD+ is regenerated from NADH
____ ____ involves reactions wherein organic molecules donate electrons to oxygen to form water
Aerobic organotrophy
In ____ ____, the organic molecule donates electrons to non-oxygen electron donors such as nitrate, sulphates etc
anaerobic organotrophy
In ____ ____, inorganic molecules donate electrons to oxygen
aerobic lithotrophy
In respiration, glycolysis produces two ATP, two NADH2 and two pyruvate from one molecule of glucose. The pyruvate is then converted to ?
acetyl-CoA