BSCI223: Metabolism, Energy Production & Storage, and Enzymes

UMD | Dr. Erin Tran

Metabolism

All biochemical reactions that take place in a living cell

Catabolism

The breakdown of nutrients to release energy

Anabolism

The building of macromolecules and cell components using energy

What is the outcome of metabolism?

Reproduction

1. What do cells acquire for metabolism?

Nutrients (building blocks and energy)

2. How does a cell gain energy?

From light or from the catabolism of acquired nutrients

3. In metabolism, where do cells store metabolic energy?

Chemical bonds of adenosine triphosphate (ATP)

4. What allows cells to anabolically link building blocks together to form macromolecules?

Enzymes and energy from ATP

5. Metabolism: Cells grow by assembling ________ into _________.

Macromolecules; cellular structures (ribosomes, membranes, cell walls, etc.)

Metabolism of a substrate is controlled by ______.

Enzymes (reactions will not happen without them)

What are the catalysts that increase the likelihood of a reaction occuring?

Enzymes

Transporters

Proteins that pass material into and out of the cell

Passive Transport

Movement across the membrane without energy (no ATP used)

Active Transport

Movement across the membrane using energy (ATP) through transmembrane permease proteins (gated channels/ports), move material against electrochemical gradient

What breaks down ATP into ADP during transport? What is released to move substance across membrane?

ATPase transport proteins; energy

What molecules cross the membrane by passive transport?

Small or lipid-soluble molecules (water, oxygen, CO2)

What molecules need active transport?

Larger molecules (proteins, amino acids, salts, glucose)

What powers active transport?

ATP or PMF (proton motive force)

What is this metabolic pathway?

Anabolic reaction

What is this metabolic pathway?

Catabolic reaction

What do catabolic pathways produce?

Useful forms of energy and lost heat

What do anabolic pathways do?

Use energy to build the molecules that form the cell

What are the three ways cells store energy?

ATP, Proton Motive Force (PMF), and NADH/FADH2

What is Proton Motive Force (PMF)?

The transfer of H+ through a proton pump generates electrochemical gradient of protons.

What drives conversion of ADP to ATP using ATP synthase (membrane proton channels that phosphorylate ADP)?

Proton Motive Force (PMF)

Proton gradients can also help what?

Bacterial flagellar motion (no ATP produced)

What are the two electron carriers that store high energy electrons?

NADH and FADH2

When two hydrogen atoms (with two electrons) are released from another molecule, they are added to NAD+ to form _________

NADH + H⁺

Electrons pass from good electron _____ to good electron _____.

donors; acceptors

When donor is oxidized, acceptor is ______.

Reduced

What can the metabolic capabilities of a microbial species tell us? How?

Where/when a microbe grows and can be used to identify/characterize microbes (e.g., for clinical diagnosis).

It can help determine what nutrients bacterial cells can metabolize and determine what products are created as a result of metabolism