Bacterial Metabolism: Overview

Question 1

series of biochemical reactions in which the cell breaks down or biosynthesizes various metabolites for growth, repair, and cell division

Answer 1

metabolism

Question 2

how do prokaryotic cells transfer nutrients?

3

Answer 2

they need to employ various active transport mechanisms such as:
- simple transport
- group translocation
- ABC transport systems (ATP-Binding Cassettes)

Question 3

process by which cells accumulate solutes against the concentration gradient

Answer 3

active transport

Question 4

cellular transport can be classified into two main categories:

Answer 4

passive and active

Question 5

molecules always move from an area of high to low concentration until they are equally spread out on an area

Answer 5

brownian movement

Question 6

process by which cells accumulate solutes against the concentration gradient

Answer 6

active transport

Question 7

in prokaryotes, active transport makes use of

Answer 7

transmembrane proteins

Question 8

transmembrane proteins have

Answer 8

• 12 domains
• that weave back and forth through membrane
• to form a channel
• (where the solute can pass through)

Question 9

true or false. simple transport is classified as active transport.

Answer 9

true

Question 10

uses proton motive force (or PMF)

Answer 10

simple transport

Question 11

a solute and a proton are co-transported in one direction

Answer 11

symport

Question 12

the solute and proton are transported in opposite directions

Answer 12

antiport

Question 13

example of symport

Answer 13

lac permease in Escherichia coli.

Question 14

employs a series of proteins, and not just one transmembrane protein, in the transport event

Answer 14

group translocation

Question 15

In group translocation,

transported substance is ____ or modified as it is transported
across via ____ events triggered by a ____

Answer 15

chemically altered
phosphorylation
phosphotransferase system

Question 16

example of group translocation

Answer 16

monosaccharide transport in E. coli, which includes

1. glucose
2. fructose
3. mannose

Question 17

3 requirements of ABC transport system

Answer 17

• substrate-binding protein
• transmembrane transporter
• ATP-hydrolyzing protein

Question 18

ABC stands for

Answer 18

ATP-binding cassettes which are parts of a protein that can
bind ATP

Question 19

n Gram-negative bacteria, ABC transport systems make use of

Answer 19

uses

• periplasmic-binding proteins (aka transport proteins found in the periplasm of the cell)
• Recall: periplasm: region between OM and CM

Question 20

those that obtain their energy from chemicals undergo a process called

Answer 20

chemotrophy

Question 21

those that break down organic chemicals to release ATP or
related energy-rich compounds are referred to as

Answer 21

chemoorganotrophs

Question 22

energy-rich compounds are often derived from other living microorganisms,
which classifies them as

Answer 22

heterotrophs (ex. most microorganisms culturable in the laboratory, like E. coli.)

Question 23

those that use inorganic compounds such as gaseous
hydrogen, hydrogen sulfide, ammonia, and ferrous iron, are called

Answer 23

chemolithotrophs (they are autotrophs) [ex. nitrifying bacteria, like Nitrosomonas spp. and Thiobacillus thiooxidans]

Question 24

they do not obtain their nutrient sources from other microorganisms

Answer 24

autotrophic

Question 25

hose that use light as a source of energy for metabolism undergo a process referred to as

Answer 25

phototrophy

Question 26

these microorganisms often have photosynthetic pigments that can convert light energy to ATP

Answer 26

phototrophs

Question 27

example of organisms that undergo oxygenic photosynthesis

Answer 27

cyanobacteria

Question 28

example of organisms that can perform anoxygenic photosynthesis

Answer 28

purple bacteria (Rhodobacter capsulatus)

Question 29

energy available to do work

Answer 29

Gibbs free energy

Question 30

For a specific chemical reaction to be spontaneous, that is, not needing any energy input, the value of ΔG0 should be

Answer 30

negative (means that the reactants of the chemical reaction have higher energy than that of the product, which, instead of needing energy to push the reaction to occur)

Question 31

energy released during a reaction

Answer 31

Gibbs free energy

Question 32

if gibbs is positive

Answer 32

the particular reaction requires energy to proceed

Question 33

unfavorable, non-spontaneous, endergonic

Answer 33

positive G

Question 34

favorable, spontaneous, exergonic

Answer 34

negative G

Question 35

reactions that involve breaking down of molecules into smaller molecules tend to release energy and is referred to as

Answer 35

catabolic and exergonic reactions

Question 36

reactions that involve the building of larger molecules from smaller molecules require energy are called

Answer 36

anabolic and endergonic reactions

Question 37

for any reaction to occur, it needs a minimum amount of energy for it to occur

Answer 37

activation energy

Question 38

protein catalysts, or substances that facilitate a reaction but are not consumed by it

Answer 38

enzymes

Question 39

how do enzymes function

Answer 39

lowers the activation energy (less energy is needed for the reaction to proceed, thus increasing the reaction rate)

Question 40

enzymes are also highly specific in the reactions that they catalyze, which can be attributed to their

Answer 40

3D conformation or shape

Question 41

true or false. enzymes are not reversible in activity.

Answer 41

false. they are.

Question 42

highly (blank) reactions typically work in one direction

Answer 42

endergonic or exergonic

Question 43

for a reverse reaction to occur in those responsible for highly endergonic or exergonic reactions,

Answer 43

another enzyme usually catalyzes it

Question 44

tightly bound, and are usually permanently bound to the enzyme (e.g. heme groups)

Answer 44

rosthetic groups or co-factors

Question 45

loosely and transiently bound (and may be derivatives of vitamins)

Answer 45

co-enzymes

Question 46

an enzyme combines with a reactant or reactants (or substrate), forming an

Answer 46

enzyme-substrate complex

Question 47

substrates attach to a region in the enzyme called the

Answer 47

active site

Question 48

the common name of an enzyme usually indicates the

Answer 48

substrate and the nature of the reaction catalyzed

Question 49

aside from lowering the activation energy, enzymes also

Answer 49

make sure that the substrates can interact properly for reaction to take place

Question 50

how do enzymes make sure that substrates can interact properly

Answer 50

- changing the substrate orientation - changing the reactivity by stabilizing the transition state (or the state in which the reaction attains the highest potential energy, leading to the formation of products) - straining the bonds of the substrate.

Question 51

a cell’s ATP pool is replaced every (blanks) as (blank) molecules of ATP are produced per second

Answer 51

1-2 minutes 10^7

Question 52

involves the adding of a phosphate group

Answer 52

phosphorylation