D515: Lecture 5

Cell growth is the result of coupling ____ and ____ reactions.

Catabolic

Anabolic

What is cell metabolism?

The total activity of cells, divided into catabolism and anabolism

In what common molecule is free energy trapped so more thermodynamically unfavorable reactions can occur?

ATP

Catabolism ____ energy (ATP), while anabolism ____ energy (ATP).

Releases

Requires

In eukaryotes, most catabolic processes are ____. The exception to this is the process of ____.

Aerobic

Fermentation

In what eukaryotic cells does fermentation typically occur?

Yeast (yes, this is a eukaryote)

Muscle cells

T/F: In general, eukaryotes seem to possess a greater diversity of catabolic pathways, creating free energy.

False, prokaryotes have far more aerobic and anaerobic processes.

Does the process of glycolysis require oxygen.

No, it is anaerobic in both eukaryotes and prokaryotes

Chemoheterotrophs usually use what type of molecule to kickstart catabolic reactions (what molecule is the substrate)?

Sugar (glucose)

Catabolism is divided into two different parts that have to do with losing and gaining electrons. These processes are called ____ and ____

Oxidation

Reduction

What is oxidation?

The process of an organic substrate transferring its electrons (losing them) to a coenzyme (also called a redox carrier)

What is reduction?

The process of reduced coenzymes releasing their electrons to final electron acceptors or organic molecules so they can be reutilized (reduced).

At the start of glycolysis, coenzymes need to be in their ____ state.

Oxidized

What are redox carriers (coenzymes)

Small organic molecules that act as a shuttle for electrons and can oscillate between reduced and oxidized forms.

LEO GER

Lose electrons = Oxidation

Gain electrons = Reduction

A reducing agent will ____ electrons

release (so another molecule can become reduced)

An oxidizing agent will ____ electrons

accept (so another molecule can become oxidized)

NAD/NADP

NADH/NADPH

accepts 2 electrons and 1 H+

FAD

FADH2 (flavoprotein)

Accepts 2 electrons and 2 H+

Ubiquinone

CoQ

Accepts 2 electrons and 2 H+

What other redox carriers accept electrons?

Heme groups in cytochromes

FeS

What are saccharolytic bacteria?

Bacteria that use carbs/sugars as their primary energy source

What are asaccharolytic bacteria?

Bacteria that use substances other than carbs/sugars as their primary energy source

Proteolytic - proteins from Gingival crevicular fluid

Lipolytic - Fatsa

What is the net result of glucose catabolism and the TCA cycle?

Glucose carbons are oxidized to become CO2

ATP made

Redox rxns occur

Intermediates are recycled

T/F: Fermentation produces ATP independently

False, it only allows for the recycling or redox carriers so glycolysis can repeat itself and product ATP

T/F: Some bacteria and eukaryotes can undergo anaerobic respiration (with the TCA cycle), in which the final electron acceptor is oxygen.

False, although they can undergo anaerobic respiration, the final electron acceptor is not oxygen

T/F: Fermentation requires a large amount of sugars to be utilized?

True

What are the products of homolactic acid fermentation?

Lactate

What are the products of heterolactic acid fermentation?

Lactate, acetate, ethanol, CO2

What can dietary carbohydrates also be used for when catabolized?

Extracellular polysaccharides, be put in storage granules, etc

Fermentative end products of one bacterial species often serve as a carbon and energy source for other species. This is called ____.

Metabolic interdependence or cross feeding

Glycolysis is an example of what type of phosphorylation?

Substrate level phosphorylation

What products result in bad breath?

Fermentative