Chapter 6: Metabolism

Question 1

assimilation

Answer 1

Process by which cells import a molecule and incorporate it into cellular constituents

Question 2

phototroph

Answer 2

Organism that captures light energy, or photons, through the process of photosynthesis to generate chemical energy, such as ATP

Question 3

lithotroph

Answer 3

Organism that removes electrons from inorganic reduced molecules, such as H2S, H2, or elemental sulfur (S0)

Question 4

organic VS inorganic

Answer 4

Molecule containing carbon-hydrogen bonds vs one that does not

Question 5

heterotroph

Answer 5

Organism that obtains carbon from organic molecules, such as sugars, obtained from the environment

Question 6

autotroph

Answer 6

Organism that can build complex organic molecules used as nutrients from an inorganic carbon source

Question 7

carbon fixation

Answer 7

Conversion of inorganic carbon, usually CO2, from the environment into organic molecules for growth; common in autotrophs

Question 8

catabolism

Answer 8

Breakdown of larger molecules into smaller ones for energy production

Question 9

anabolism

Answer 9

Biosynthesis of macromolecular cell components from smaller molecular units

Question 10

cofactor

Answer 10

Small ion or organic molecule essential for enzyme catalytic activity by assisting in the transfer of functional groups

Question 11

coenzyme

Answer 11

An organic cofactor

Question 12

allosteric regulation

Answer 12

Regulation of enzyme action by an effector molecule that binds reversibly to the enzyme allosteric site and is not changed in the reaction; regulation can be positive (activation) or negative (inhibition)

Question 13

tricarboxylic acid (TCA) cycle

Answer 13

Series of metabolic reactions used in the oxidation of carbon compounds, producing CO2, NADH, and ATP; also called the citric acid cycle or Krebs cycle

Question 14

chemiosmosis

Answer 14

Synthesis of ATP from free ADP and Pi using energy and electrons to create a proton gradient across a membrane; the flow of protons back across the membrane releases energy that is harnessed by ATP synthase to produce ATP

Question 15

photophosphorylation

Answer 15

Chemiosmotic process used by phototrophs to generate ATP using light energy; used by phototrophs

Question 16

oxidative phosphorylation

Answer 16

Chemiosmotic process used by chemotrophs to generate ATP using the energy captured from oxidation of a chemical substrate; used by chemotrophs

Question 17

nicotinamide adenine dinucleotide (NAD)

Answer 17

Cytoplasmic electron carrier molecule serving as a coenzyme

Question 18

electron transport system

Answer 18

Chain of membrane-associated proteins that transfers electrons in a series of steps, yielding energy to move protons across the membrane

Question 19

ATP synthase

Answer 19

Membrane enzyme complex that uses the kinetic energy of flowing protons to synthesize ATP from free ADP and Pi

Question 20

redox reactions

Answer 20

Reduction and oxidation reactions involving the transfer of electrons from one molecule to another

Question 21

Oxidized

Answer 21

Loss of Electrons (LEO the lion says GER)

Question 22

Reduced

Answer 22

Gain of Electrons (LEO the lion says GER)

Question 23

reduction potential

Answer 23

Tendency of a molecule to accept electrons; represented by the electrode potential, E, which is measured in units of volts (V); also called redox potential

Question 24

Embden–Meyerhof–Parnas (EMP) pathway

Answer 24

Glycolytic pathway where glucose is converted into two molecules of pyruvate, producing a total of two molecules of ATP from each glucose molecule

Question 25

anaplerotic reaction

Answer 25

Replenishing reaction that generates a critical metabolic intermediate in order to sustain another metabolic pathway

Question 26

Entner–Doudoroff pathway (ED)

Answer 26

Glycolytic pathway interacting with the EMP pathway in which glucose is converted to two molecules of pyruvate, producing one molecule of ATP from each glucose molecule; commonly used for glucose catabolism but is often used for catabolism of other carbohydrates containing aldehyde groups, such as gluconate, which cannot be readily processed by the EMP pathway.

Question 27

pentose phosphate pathway

Answer 27

Glycolytic pathway interacting with the EMP pathway where glucose is converted to a number of 3- to 7-carbon compounds, many of which are used for biosynthesis, and producing NADPH and ATP; The pathway is of significant importance since it generates NADPH for biosynthetic reactions. The pentose phosphate pathway works with the EMP pathway rather than replacing it. Its primary use is in generating the electron donor NADPH and essential precursors for biosynthesis.

Question 28

fermentation

Answer 28

electrons are passed directly to an organic terminal electron acceptor and the TCA cycle and the electron transport system is not utilized

Question 29

Cellular respiration

Answer 29

where the electrons are passed through an electron transport system and on to an inorganic or sometimes an organic terminal electron acceptor

Question 30

primary difference between fermentation and respiration

Answer 30

fermentation does not use ETS and respiration does