BIOL 251 Microbiology Week 6 Lecture Notes

Microbiology: An Introduction 13th Edition - Chapter 5

Metabolism

Sum of chemical reactions in an organisms

Catabolism

released

Breakdown of larger molecules to smaller molecules

Energy is generally _____

Mediated by enzymes

Anabolism

used

Synthesis of larger molecules from smaller molecules

Energy is generally _____

Mediated by enzymes

Exergonic

Describes reactions that release energy

Endergonic

Describes reactions that absorb energy

ATP

The universal energy carrier

A modified nucleotide - adenine linked to 5C sugar ribose and 3 phosphate groups

Metabolic pathway

Sequences of enzymatically catalyzed chemical reactions in a cell

Enzymes

Activation energy

Substrate specific biological catalysts for reactions

Made of proteins or RNA molecules

_____ _____: The energy needed to begin reactions

Activation energy

The minimum amount of energy required for a chemical reaction to occur within a cell

-ase

The suffix usually indicating a substance in an enzyme

Apoenzyme

Cofactor

Coenzyme

Holoenzyme

Enzyme Components

1. _____: Protein

2. _____: Nonprotein component - inorganic

3. _____: Nonprotein component - organic

4. _____: Apoenzyme + cofactor/coenzyme

NAD+

NADP+

FAD

Coenzyme A

Name some important coenzymes

Temperature

pH

Substrate concentration

Inhibitors

What factors influence enzyme activity?

1. _____: Enzyme activity increases with temp to an optimal point, but excessive heat can denature the enzyme

2. _____: Deviations from the very narrow, optimal range can alter the enzyme’s shape and function, reducing its activity.

3. _____: Increasing concentration generally increases enzyme activity until the active sites are saturated, after which the rate plateaus.

4. _____: interfere with enzyme function by either blocking the active site (competitive inhibition) or altering the enzyme’s shape (non-competitive inhibition), reducing its activity.

Allosteric site

A location on an enzyme that's separate from the active site. Regulatory molecules bind to this part, which can activate or inhibit the enzyme's activity.

Oxidation

Reduction

_____: Removal of electrons

_____: Gain of electrons

Redox

An oxidation reaction paired with a reduction reaction

Dehydrogenation

A reaction with the removal of hydrogen

ATP generation

Results from the phosphorylation of ADP with the input of energy

Fermentation, glycolysis, Krebs cycle

Photophosphorylation

Mechanisms of Phosphorylation In microorganisms

Subtrate level phosphorylation (examples?)

Oxidative phosphorylation/cellular respiration

What is it called in chlorophyll containing bacteria and plants?

Oxidative phosphorylation

Energy released from transfer of electrons from one compound to another to generate ATP

Electron Transport Chain

Refers specifically to the series of protein complexes that transfer electrons

Photophosphorylation

Occurs only in photosynthetic cells

ATP is generated by transfer of electrons from chlorophyll to a system of carrier molecules

Cellular respiration, fermentation

Name two examples of carbohydrate catabolism (breakdown of glucose)

Glycolysis, Kreb’s cycle, ETC system

What are the 3 types of cellular respiration?

lipid and protein catabolism

What are two other types of catabolism?

Glycolysis

Krebs Cycle

Chemiosmosis

Stages of Cellular Respiration (Oxidation of Glucose)

1. _____

   Substrate level phosphorylation

2. Pyruvate oxidation and _____ _____

   Substrate level phosphorylation

3. ETC And _____

   Oxidative phosphorylation

cytoplasm

pyruvate

Stage 1: Glycolysis

Occurs in the _____

Product: _____

4

2

2

Products from glycolysis per glucose molecule

_____ ATP

• 2 ATP invested

• Net gain 2 ATP

____ Pyruvate

____ NADH molecules

Pentose

2

1

Alternative Pathways to Glycolysis

1. _____ Phosphate Pathway

   • Produces pentose sugars and ___ NADPH

   • Net gain: ___ ATP

   • E coli, E faecalis, B subtilis

Entner Doudoroff

1, 2

Alternative Pathways to Glycolysis

2. _____ _____ Pathway

   • Net gain: ___ ATP and ___ NADPH

   • Some gram negative bacteria

   • Does not involve glycolysis

Intermediate

Acetyl Co-A

Glycolysis: _____ Step

Pyruvic acid (from glycolysis) is converted to what?

Via decarboxylation

1

3

1

2

cytoplasm

2, 6, 2, 4

Stage 2: Krebs Cycle

_____ ATP

_____ NADH

_____ FADH2

_____ CO2

Occurs in _____

Products: _____ ATP, _____ NADH, _____ FADH2, _____ CO2

most

oxidative

Stage 3: ETC and Chemiosmosis

• Plasma membrane of prokaryotes

• Involves electrons carried by NADH and FAD2

• Carrier molecules

• Produces the _____ ATP

• _____ phosphorylation

Flavoproteins

Cytochromes

Uniquinone

_____: A group of enzymes that play a role in many biological processes, including metabolism, DNA repair, and photosynthesis. They are found in many microorganisms, including cyanobacteria and Helicobacter pylori.

_____: Proteins that help transport electrons and are involved in respiration and photosynthesis

_____: A lipid-soluble molecule that plays a key role in electron transfer chains in both prokaryotes and eukaryotes (AKA Cytochrome Q)

proton motive

periplasmic, cytoplasm

synthase

Stage 3: ETC and Chemiosmosis

Chemiosmosis:

• Energy released from ETC is used

• This H+ gradient, or _____-_____ force, is created

• H+ ions high - _____ space and low _____

• ATP _____ will let the H+ ions through

Chemiosmotic Generation of ATP

The process where ATP (adenosine triphosphate), the cell's energy currency, is produced by the movement of protons (hydrogen ions) across a membrane through a protein complex called ATP synthase, creating an electrochemical gradient that drives the synthesis of ATP

Oxygen

Allows for the continuous flow of electrons through the chain, enabling the production of ATP

_____ is the final electron acceptor in the ETC.

Why is this important?

nitrate, sulfate, and carbonate

less

What is the final electron acceptor in inorganic substances

ATP yield is _____ than aerobic respiration

Fermentation

electron

_____

Scientific Definition:

• Releases energy from oxidation of organic molecules

• Does not require oxygen

• Does not use Krebs Cycle or ETC

• Uses an organic molecule as the final _____ acceptor

Hydrolytic

Lipases

Proteases, peptidases

Lipid & Protein Catabolism

• _____ enzymes: Lipases, proteases, peptidases

  • _____ break down fats to fatty acids & glycerol

  • _____ & _____ break down large proteins into amino acids

Biosynthesis

polysaccharides

lipids

proteins

Nucleic acids

ATP synthesized by microorganisms is used for:

• _____: process by which living things use chemical reactions to create products useful for cellular metabolism

  • Synthesis of

    • _____

    • _____

    • _____

    • _____

dependent

photophosphorylation

independent

Calvin

Plasma membrane

Photosynthesis has 2 stages

• Light _____ reaction

  • Products: O2, ATP, NADPH

  • NADP+ → NADPH

  • ATP → _____

• Light _____ reaction

  • Product: Sugar

  • _____ Cycle

Occurs in _____ _____ of prokaryotes

Chlorophyll A

Bacteriochlorophylls

700

680

Photosynthetic pigment

Green plants, algae, cyanobacteria - _____

Other bacteria - _____

Photosystem 1 - P___

Photosystem 2 - P___

Phototrophs

These organisms use energy for light

Chemotrophs

These organisms use energy from redox reactions

Autotrophs

These organisms use carbon dioxide

Lithotrophs

Heterotrophs

These organisms use organic carbon

Organotrophs

substrate and active site

To which of the following does a competitive inhibitor most structurally resemble?

The active site

The allosteric site

The substrate

A coenzyme

Crucial electron carriers (playing a vital role in redox reactions and energy production during cellular respiration)

What is the function of molecules like NAD/NADH and FAD/FADH2 in cells (other than being coenzymes)?

Thylakoid membranes

Where do you find photophosphorylation?

NADPH

Which of the following molecules is reduced?

NAD+

FAD

O2

NADPH

Pyruvate

Which of the following products is made during glycolysis?

NAD+

Pyruvate

CO2

Two-carbon acetyl

FADH2

During the catabolism of glucose, which of the following is produced only in the Krebs cycle?

ATP

NADH

NADPH

FADH2

Without CoA the krebs cycle cannot proceed

(Severe metabolic disruptions, leading to decreased energy production, impaired amino acid synthesis, and potential buildup of toxic metabolites, ultimately threatening cell survival)

What would be the consequences to a cell of having a mutation that knocks out coenzyme A synthesis?

The proton motive force

Which is the source of the energy used to make ATP by oxidative phosphorylation?

Oxygen

High-energy phosphate bonds

The proton motive force

Pi

Periplasmic space

In prokaryotes, where does H+ go after being pumped out of the cell during ETS?

To make NAD+

Which of the following is the purpose of fermentation?

To make ATP

To make carbon molecule intermediates for anabolism

To make NADH

To make NAD+

Glucose

Which of the following molecules is NOT produced during the breakdown of phospholipids?

Glucose

Glycerol

Acetyl groups

Fatty acids

Removal of fatty acids

Which of the following is the first step in triglyceride degradation?

Removal of fatty acids

β-oxidation

Breakage of fused rings

Formation of smaller peptides

Pigment molecule

During the light-dependent reactions, which molecule loses an electron?

Pigment molecule

NADPH

3-phosphoglycerate

ATP

NADPH formation

Which of the following does NOT occur during cyclic photophosphorylation in bacteria?

Electron transport through an ETS

Photosystem I use

ATP synthesis

NADPH formation

Chemoautotroph

Which of the following is an organism that obtains its energy from the transfer of electrons originating from chemical compounds and its carbon from an inorganic source?

Chemoautotroph

Chemoheterotroph

Photoheterotroph

Photoautotroph