Lecture 5/6 Metabolism

Question 1

Microbial metabolism

Answer 1

the sum of all chemical reactions in a cell - separated into two components which are catabolism and anabolism

Question 2

catabolism

Answer 2

set of chemical reactions that degrade compounds and release energy that cells capture to make ATP
the processes also produce precursor metabolites used in biosynthesis (anabolic processes)

Question 3

Anabolism/biosynthesis

Answer 3

set of chemical reactions that cells use to synthesize and assemble the subunits of macromolecules using ATP for energy

Question 4

what are the subunits of macromolecules

Answer 4

amino acids, nucleotides, monosaccharides, fatty acids

Question 5

what is the relationship between catabolism and anabolism?

Answer 5

precursor metabolites are compounds produced during catabolism that can either be further degraded or be used in anabolism to make subunits of macromolecules

Question 6

precursor metabolites

Answer 6

chemicals that can either be further broken down to generate energy (via catabolism) or used to make certain subunits of of macromolecules (via anabolism)

Question 7

photosynthetic organisms

Answer 7

harvest energy of sun and use it to power the synthesis of organic compounds from CO2

Question 8

chemoorganotrophs

Answer 8

obtain energy by degrading organic compounds; they then use some of that energy to make other organic compounds - they take the potential energy of certain chemical bonds and use it to create other ones

Question 9

describe the three types of metabolic pathways (figure 6.4)

Answer 9

linear
branched
cyclical

Question 10

how do cells regulate certain processes and ensure that certain molecules are produced in precise quantities

Answer 10

if a metabolic step is blocked, certain products downstream of that block will not be made
starting compound - intermediate -end product

Question 11

what are the essential components of a metabolic pathway

Answer 11

enzymes, ATP, chemical energy source, terminal electron acceptor, electron carriers

Question 12

what is an enzyme

Answer 12

usually a protein that functions as a biological catalyst which speeds up the conversion of one substance to another - a specific enzyme facilitates each step of a metabolic pathway

Question 13

how does an enzyme catalyze a chemical reaction?

Answer 13

by lowering the activation energy of the reaction

Question 14

how do chemoorganotrophs make ATP

Answer 14

they use two different processes to make ATP

substrate-level phosphorylation

oxidative phosphoryaltion

Question 15

substrate-level phosphorylation

Answer 15

energy released in a n exergonic reaction is used to power the addition of Pi to ADP

Question 16

oxidative phosphorylation

Answer 16

the energy of a proton motive force drives the reaction

Question 17

proton motive force

Answer 17

form of energy generated as an electron transport chain moves protons across a membrane to create a chemiosmotic gradient

Question 18

proton motive force

Answer 18

form of energy generated as an electron transport chain moves protons across a membrane to create a chemiosmotic gradient

energy that results from the electrochemical gradient established by the electron transport chain

Question 19

photophosphorylation

Answer 19

how photosynthetic organisms can generate ATP - uses sun’s radiant energy and an electron transport chain to create a proton motive force

Question 20

when do cells produce and use ATP or ADP

Answer 20

cells produce ATP by adding a phosphate during exergonic reactions of catabolism and then use it to power endergonic reactions of anabolism

Question 21

how do cells obtain the energy used to make ATP

Answer 21

they remove electrons from glucose or another low electron affinity chemical and donate them to a molecule such as O2 that has a higher electron affinity - energy is released in this process

Question 22

what is the source of energy in the process of making ATP

Answer 22

the chemical that serves as the electron donor

Question 23

terminal electron acceptor

Answer 23

chemical that is ultimately reduced as a consequence of fermentation or respiration - it accepts the electrons that are donated by the energy source. in this exergonic reaction energy is released to make ATP

Question 24

Name 3 examples of chemoorganotrophic metabolism

Answer 24

glucose as energy source and pyruvate as electron acceptor

glucose as energy source and O2 as electron acceptor

glucose as energy source and NO3- as acceptor

Question 25

give 3 examples of chemolithotrophic metabolism

Answer 25

H2 energy source
CO2 terminal electron acceptor
H2S energy source O2 as terminal electron acceptor
Fe2+ as energy source O2 as electron acceptor

Question 26

oxidation-reduction reactions

Answer 26

substance that loses electrons is oxidized

substance that gains electrons is reduced

Question 27

dehydrogenation vs. hydrogenation

Answer 27

when electrons are moved normally a proton follows - thus dehydrogenation (removal of hydrogen) is oxidation
hydrogenation (addition of hydrogen is reduction)

Question 28

What are the general rules of redox reactions (oil rig)

Answer 28

if a compound gains oxygen or loses hydrogen, the reaction is an oxidation
if a compound loses oxygen or gains hydrogen the reaction is a reduction

Question 29

Name the electron carries (“reducing powers”)

Answer 29

NAD+/NADH: two electrons and one proton used to transfer electrons to electron transport chain to be used in oxidative phosphorylation
FAD/FADH2: carries two electrons and two protons used to make proton motive force through electron transport chain
NADP+/ NADPH: carries two electrons and one proton and is used during biosynthetic reactions