Lecture 21

Question 1

_______ and _________ allows microbes to colonize every aspect of every niche in our world.

Answer 1

metabolic potential and versatility

Question 2

The three energy classes of microbes?

Answer 2

Use Chemotrophy: chemoorganotrophs, chemolithotrophs

Use Phototrophy: phototrophs

Question 3

If microbes conserve energy from chemicals we call them what?

Answer 3

chemotrophs

Question 4

If microbes are able to convert light energy into chemical energy, they are called?

Answer 4

phototrophs

Question 5

Use organic chemicals for energy metabolism

Answer 5

Chemoorganotrophs (heterotrophs)

-most microbes brought into the lab

Question 6

Chemoorganotrophs can use _____, _____, etc., but in almost all cases, energy is conserved from the _______ of the ________ . The conserved energy is what?

Answer 6

• glucose, acetate
• oxidation of the compound
• trapped in the cell as ATP

Question 7

Microbes that tap into the oxidation of inorganic chemicals

H2, H2S, Fe, etc.

Answer 7

chemolithotrophs

Question 8

How do chemolithotrophs and chemoorganotrophs often live?

Answer 8

Near each other. Chemoorganotrophs oxidize organic compounds that produce waste products, such as H2 and H2S, which are then used by chemolithotrophs as an energy source. Living close means less competition for energy.

Question 9

Microbes that have special pigments that allow them to convert light energy into chemical energy. A significant metabolic advantage because they are not competing for energy from the chemotrophs

Answer 9

phototrophs

Question 10

Two major forms of phototrophy

Answer 10

oxygenic photosynthesis, and anoxygenic photosynthesis

Question 11

oxygen is produced via photosynthesis, what prokaryote is an example, and what eukaryote?

Answer 11

oxygenic photosynthesis, and cyanobacteria prok, and algae euk

Question 12

does not yield oxygen during photosynthesis, and found in what types of bacteria?

Answer 12

anoxygenic photosynthesis

purple and green bacteria, and heliobacteria

Question 13

Refers to the sum of all chemical reactions within an organism (catabolic and anabolic rxns)

Answer 13

metabolism

Question 14

Catabolic rxns

Generates what?

Answer 14

when a microorganism consumes large complex molecules for energy, such as carbohydrates (sugars, starches), proteins, or nucleic acids even, they need to break it down to release energy.

Generates smaller molecules (carbs to glucose units, proteins to individual amino acids)

Question 15

catabolic reactions are generally what?

Answer 15

oxidative. Meaning that there is a removal of electrons from an atom or molecule, a rxn that often produces energy.

Question 16

The oxidation of large molecules results in what? Some what is released during these reactions?

Answer 16

energy conserved and stored as ATP

-some heat b/c rxn is not 100% efficient

Question 17

After the breakdown of molecules (catabolic rxn), the cell is now able to go through _____ ?

Answer 17

anabolic reactions

Question 18

Anabolic reactions

-These rxns require what?

Answer 18

Simple building blocks of Carbon, Hydrogen, and oxygen from the breakdown of carbs, amino acids, nucleotides, lipids, etc. are used to generate larger molecules for the cell, such as using nucleotides to build new cellular DNA and RNA in preparation for cell division, using glycerol and fatty acids to make the phospholipids for a new cell membrane

-input of energy such as ATP to do this work for the cell

Question 19

Anabolic reactions are primarily _______ (think type of rxn)

Answer 19

reduction, meaning a molecule has gained one or more electrons

Question 20

Oxidation and reduction rxns are always ______.

Answer 20

Coupled. As one molecule is oxidized, another is simultaneously reduced

Question 21

ATP is produced when you _______ large complex molecules, and this ATP is then used to ________ new complex molecules.

Answer 21

breakdown, build

Question 22

Most biological oxidation reactions involve the loss of what? So they are also called what type of reactions?

Answer 22

H atoms (one proton and one electron)

-dehydrogenation reactions

Question 23

NAD+ accepts ______ and _____.

Answer 23

2 electrons, and 1 proton.

One H+ is left over and is released into the surrounding medium

Question 24

NAD+ reduced becomes what?

And it contains ______ energy than NAD+.

Answer 24

NADH - can be used to generate ATP

-MORE

Question 25

Much of the energy released during oxidation-reduction rxns is trapped within the cell by the formation of _______ .

Answer 25

ATP

Question 26

Specifically, an ________ is added to _______ with the input of energy to from ________ .

Answer 26

inorganic phosphate group is added to ADP to form ATP

Question 27

The addition of phosphate to a chemical is called

Answer 27

Phosphorylation

Question 28

Microbes use _____ mechanisms of phosphorylation to generate ATP from ADP. What are they?

Answer 28

three mechanisms:

• substrate-level phosphorylation
• oxidative phosphorylation
• photophosphorylation

Question 29

~

Answer 29

high energy bond that when broken releases usable energy

Question 30

ATP is made when a high energy phosphate is directly transferred from a phosphorylated compound (a substrate) to ADP.
How has the phosphate acquired energy here?

Answer 30

substrate-level phosphorylation

-generally, the phosphate has acquired energy during an earlier rxn in which the substrate itself was oxidized
NOTE: the phosphate group does not have to come directly from the substrate

Question 31

PEP

Answer 31

a substrate that can offer a phosphate group to form ATP. It is a three carbon compound called phosphoenolpyruvate, one of the breakdown products of glycolysis

Question 32

Oxidative phosphorylation

where does it occur in prokaryotes?

Answer 32

Electrons are transferred from organic compounds to one group of e- carriers (usually to NAD+ and FAD). Then the electrons are passed through a series of different e- carriers to molecules of oxygen or other oxidized inorganic and organic molecules. This sequence of e- carriers used in oxid phosph is called an e- transport chain/system (ETC).

This occurs in the plasma membrane of prokaryotes.

Question 33

The transfer of e-s from one e-carrier to the next releases energy, some of which is used to make ATP from ADP through a process called _______

Answer 33

chemiosmosis

Question 34

Photophosphorylation

converts _____ energy to _____ energy of _____ and ______.

Answer 34

occurs only in photosynthetic cells with light trapping pigments like chlorophylls. Organic molecules, especially glucose, are synthesized with the energy of light, CO2 and H2O.

light energy to chemical energy of ATP and NADPH, which in turn are used to make organic molecules.

Question 35

Light causes chlorophyll to ________ . The energy released from the _________ of chlorophyll through a system of carrier molecules is used to generate ATP.

Answer 35

• to give up electrons

- transfer of electrons (oxidation) of chlorophyll through a system of carrier molecules is used to generate ATP

Question 36

Metabolism Big Picture

Answer 36

Go back to this

Question 37

carbohydrates broken down through what pathway? lipids broken down through what pathway?

What eventually enters glycolytic pathway? Process of ________ ?

Answer 37

glycolytic pathways break down carbohydrates, others must be oxidized in separate pathways( beta oxidation pathways break down lipids),

but all of these large biopolymers (protein, nucleic acids, polysaccharides, etc) enter the glycolytic pathway at some point during the process of catabolism.

Question 38

glucose 6-phosphate made during the first step of glycolysis is metabolized by both the ________ and the _______ pathways.

What does the latter pathway create?

Answer 38

glycolytic pathway, and the pentose phosphate pathway.

-pentose phosphate pathway creates precursors for the synthesis of nucleotides ATGC

Question 39

Citrate made in the Krebs cycle can go into precursors for _______ _______ synthesis, important for ___________

Answer 39

fatty acid synthesis, important for phospholipids in cell membranes

Question 40

oxidation and reduction rxns involve

Answer 40

transfer that involves 2 coupled reactions, oxidation and reduction