Chapter 7 (Bacterial Metabolism)

Cell structures and organic material built by living organisms

Biomass

If energy stops flowing through an organism, the organism

Dies

The measure of disorder or randomness in the universe

Entropy

As a cell builds complex molecules, local entropy (inside the cell) [Increases/Decreases]

Decreases

As a cell releases heat/waste, global entropy (outside the cell) [Increases/Decreases]

Increases

Ultimate source of energy to overcome entropy on Earth

Sun

As energy passes through successive consumer levels, most is lost as

Heat

Biochemical reactions that capture energy from light

Phototrophy

Process where light-excited electrons pass to CO2, building sugar and releasing O2

Oxygenic photosynthesis

Organisms that form their own organic molecules from minerals (like CO2)

Autotrophs

Organisms that require preformed organic compounds for carbon

Heterotrophs

Reactions that yield energy stored in the chemical bonds of food

Chemotrophy

Chemotrophy where electron donors are organic molecules

Organotrophy

Chemotrophy where electron donors are inorganic molecules (minerals)

Lithotrophy

Metabolism combining light energy + organic food molecules

Photoorganotrophy

Organic molecule donates electrons to O2, forming H2O

Aerobic respiration

Anaerobic organotrophy using an alternative electron acceptor (like nitrate)

Anaerobic respiration

Anaerobic organotrophy that partially breaks down food to ethanol/lactic acid

Fermentation

Example of Aerobic Lithotrophy: Oxidation of ________.

Ammonia

Example of Anaerobic Lithotrophy: Archaea producing methane

Methanogenesis

Predicts whether a reaction goes forward or in revers

Free energy change

For a reaction to yield energy, Delta G be [Positive/Negative]

Negative

Free energy formula

Delta G = Delta H - T Delta S

In the free energy formula, Delta H represents a change in

Chemical energy

In the free energy formula, Delta S represents a change in

Entropy

Primary driver making Delta G negative in Aerobic Respiration

Chemical stability

Primary driver making Delta G negative in Fermentation

Entropy

Catalyst that increases reaction rate without being consumed

Enzyme

Location on an enzyme that binds a specific substrate

Active site

Input energy needed to reach the high-energy transition state

Activation energy

Enzymes speed up reactions by lowering the _______.

Activation energy

Uncontrolled oxidation where all energy is lost quickly as hea

Combustion

Metabolism best for food production because it yields nutrient-rich waste

Fermentation

Does CO2 require energy to build?

No

Chemical reaction that does NOT require an enzyme

Combustion

The process of breaking down complex organic food molecules

Catabolism

Catabolism can break down any environmental substance that is

Organic

A species can only catabolize substances for which its DNA makes the right ________.

Enzymes

The human body makes enzymes to digest starches, lipids, and ________.

Proteins

Plant carbohydrate that humans cannot digest but some soil bacteria can

Cellulose

Structural substance in woody plants that humans cannot digest, but soil bacteria can

Lignin

Bacterium that causes acne by catabolizing skin molecules

Cutibacterium acnes

Specific skin cell molecules catabolized by Cutibacterium acnes include matrix proteins, lipids, and

Sialic acids

Polysaccharides are first broken down into this two-sugar unit before becoming monosaccharides

Disaccharides

Monosaccharides such as glucose contain this many carbon atom

6

Glucose and sugar acids are both ultimately converted to this 3-carbon molecul

Pyruvate

Pyruvate releases these groups to feed into the TCA cycle

Acetyl groups

Breakdown products of fatty acids, amino acids, and complex aromatic plant materials

Acetyl groups and acetate

Starch is a polymer composed of units of this sugar

Glucose

Smaller molecules resulting from the enzymatic breakdown of large food molecules

Catabolites

After breakdown, catabolites feed into these shared routes within an organism

Central pathways

Pathway of step-by-step catabolism where glucose is broken down

Glycolysis

During glycolysis, energy is transferred to these two specific energy carriers

ATP and NADH

The specific enzyme required to break down cellulose

Cellulase

Lipids are broken down into fatty acids and _______.

Glycerol

Lipid breakdown products enter glycolysis and the ________.

TCA cycle

Alternative names for the TCA cycle: Krebs cycle or the ________.

Citric acid cycle

Peptides are hydrolyzed into ________.

Amino acids

Amino acids are broken down and converted to intermediates of the ________

TCA cycle

Many metabolic intermediates, such as acetic and pyruvic acid, belong to this chemical group

Carboxylic acids

Interchangeable cell forms of acetic acid: Acetic acid, Acetate, and _____.

Acetyl-CoA

In the acetate form of acetic acid, it is missing a proton, meaning it is

Deprotonated

In Acetyl-CoA, coenzyme A reversibly replaces this chemical group from acetic acid

-OH

Organisms capable of digesting petroleum compounds and complex plant materials

Bacteria or fungi

Percentage of human caloric intake provided by intestinal bacteria

15%

Genus of gut bacteria that catabolizes complex plant fibers

Bacteroides

In the oceans, petroleum from damaged wellheads is broken down by

Oil-eating bacteria

Petroleum and complex plant fibers are eventually converted by bacteria into ________.

Acetyl-CoA

Enzymes regulate energy-yielding reactions and transfer the energy into

Biosynthesis

Common molecules (like ATP) used to harvest energy from many different substrates

Energy carriers

Using common energy carriers enables a smaller genome to direct many kinds of ________

If a cell directly coupled every 100 energy substrates to 100 products without common carriers, it would need this many enzymes

10,000

By using a common energy carrier like ATP, coupling 100 substrates to 100 products requires only this many enzymes

200

An important function of energy carriers is to gain and release energy in what size amounts?

Small

Releasing all energy from food in one step (combustion) dissipates energy as ________.

Heat

The "small change" energy carriers used by all organisms include ATP and

NADH

The nitrogenous base molecule inside ATP

Adenine

The sugar molecule inside ATP

Ribose

Number of phosphoryl groups in ATP

3

The adenine-ribose-phosphate molecule is equivalent to a monomer of RNA called a ________

Ribonucleotide

In early Earth origin-of-life experiments, this ATP base forms spontaneously

Adenine

ATP is formed by the condensation of inorganic phosphate with ________

ADP

The process of adding an inorganic phosphate to ADP to form ATP is called

Phosphorylation

Forming ATP requires energy because the negatively charged oxygens of the phosphates do what?

Repel

Because ATP formation requires energy input, its free energy change Delta G is

Positive

ATP breaks down to yield energy via cleavage while incorporating H2O, a process called

Hydrolysis

Energy carrier that holds about three times as much energy as ATP

NADH

Besides carrying energy, NADH carries two of these particles from a food molecule

Electrons

Reactions involving the transfer of electrons between two molecules

Redox reactions

The loss of an electron from a molecul

Oxidation

A molecule that loses an electron is oxidized. Oxygen has a strong ability to do what to electrons?

Take them

The gain of an electron by a molecule

Reduction

When a molecule gains an electron and is reduced, its charge becomes slightly more

Negative

Complete step-wise breakdown of the sugar glucose ultimately produces

Carbon dioxide

An atom of hydrogen removed from a C-H bond consists of an electron and a ________

Proton

The oxidized form of the energy carrier NADH is called

NAD+

Number of electrons transferred to NAD+ to make one NADH

Two

Number of protons (H+) consumed to make one NADH

Two

When NAD+ is reduced to NADH, the second proton (H+) from glucose enters the

Water solution

The reduction of NAD+ to NADH requires an energy input of how many kJ/mol?

62