micro study exam 2

Describe the nutritional types of microorganisms based on carbon, electron, and energy sources?

carbon source: autotrophs= carbon dioxide, heterotrophs= organic carbon

energy source: phototrophs=light(ENERGY), chemotrophs=chemical(ENERGY)

electron source: organotrophs= organic molecules, lithotrophs= inorganic molecules

What are the 3 main mechanisms by which a molecule can cross the plasma membrane of a cell?

simple diffusion, facilitated diffusion, and active transport

At lower concentrations, would a substrate that uses facilitated diffusion enter the cell faster or slower than if it used passive diffusion?

facilitated is helped. it is most useful when things are scarce

Describe how the active transporters of the ABC superfamily can move a substrate into the bacterial cell.

the ABC acts like a power gate.

a helper brings the object to the gate→ ATP provides electricity→ gate open→package goes inside the gate

Describe how group transfer can concentrate a nutrient inside the bacteria cell

It’s like bringing people into a room and immediately giving them a disguise. The door only recognizes people without disguises, so once inside, they can’t leave. This lets you pack the room full

Label the parts of a bacterial growth curve

p1= lag phase

p2= log phase (growth)

p3= stationary phase

p4= death phase

What is diauxic growth?

a two-phase microbial growth pattern where a population consumes one carbon or energy source first, pauses in a temporary lag phase, and then resumes growth by metabolizing a second, alternative carbon source

define psychrophile

extremophilic microorganisms—mostly bacteria and archaea, alongside some fungi and algae—that are capable of growth, reproduction, and survival in permanently cold environments

define mesophile

a microorganism that grows best in moderate temperatures, typically between 20 °C and 45 °C (68 °F to 113 °F), with an optimal growth temperature around 37 °C (98.6 °F)

define thermophile

a microorganism that thrives and grows at relatively high temperatures, typically between 45°C and 80°C (113°F to 176°F)

define hyperthermophile

a microorganism—primarily belonging to the domain Archaea, with a few bacterial species—that thrives in extremely hot environments, growing best at temperatures of 80°C (176°F) or higher

define aerobe

requiring or occurring in the presence of molecular oxygen

define anaerobe

any microorganism that does not require molecular oxygen (O₂) for growth or energy metabolism, and may even be harmed by it

define facultative anaerobe

an organism—usually a bacterium—that makes adenosine triphosphate (ATP) by aerobic respiration when oxygen is present, but can switch to fermentation or anaerobic respiration when oxygen is absent

what are reactive oxygen species(ROS)?

very highly reactive oxygen containing molecules that are essential for life but damages when its uncontrolled

how do aerobes deal with the formation of ROS?

1. it converting superoxide→ hydrogen peroxide

2. converting hydrogen peroxide→ H20 + oxygen

3. preventing ROS Formation

4. repairing oxidative damages

Why can’t strict anaerobes survive in the presence of oxygen?

oxygen makes toxic chemicals and strict anaerobes don’t have tools to protect themselves along with oxygen kills them

what are some of the general reasons that bacteria develop/differentiate?

1. survive environment change

2. protecting themselves

3. coordinate the behaviors

what are the 3 primary strategies for bacterial development?

1. environment adaptation

2. division of labor

3. bet-hedging

Describe some specific examples of bacterial development.

chlamydia, myxobacteria, bacillus, anabaena-

What are some clinical implications of bacterial development?

1. adapt

2. share tasks

3. prepare for uncertainty

What are the 2 basic types of motility utilized by bacteria? How are they different?

1. swimming (flagellar motility)

2. twitching motion

Describe how a flagellum moves a bacterium

the bacterium spins its tail and the spinning pushes it the the water like substance

How does a complex, multi-subunit structure like a flagellum come to exist outside the bacterial cell?

the cell builds a base, pushes parts through a hollow tube, and parts nap together until a full flagellum exits outside of the cell

What is the primary purpose of bacterial motility?

B motility exists so b can go where life is good and leave the bad life behind

List and describe 3 types of bacterial behavior.

1. chemotaxis-sensing and moving

2. quorum sensing- communicating

3. biofilm formation

Explain how a bacterium moves towards a nutrient source along a concentration gradient

bacteria smells. if the smell is stronger it will keep going. smell is weaker it will keep trying

What proteins are responsible for the detection of nutrients and the subsequent decision to “run or tumble”? How are they regulated?

MCPs detect nutrients. CheA decides if conditions are improving. CheY‑P tells the motor to run or tumble. CheR and CheB regulate receptor sensitivity so the system never gets stuck.

define metabolism

the sum of all chemical reactions that occur inside a microorganism to sustain life, grow, reproduce, and interact with its environment

define catabolism

the set of enzyme-catalyzed metabolic pathways that breaks down large, complex molecules (such as carbohydrates, lipids, and proteins) into smaller, simpler units (such as monosaccharides, fatty acids, and amino acids).

define anabolism

the set of constructive, enzyme-catalyzed metabolic pathways that build complex cellular macromolecules from simpler precursor molecules

how does ATP energize other chemical reaction?

ATP powers reactions by transferring a phosphate group to another molecule, which raises that molecule’s energy and makes it react

Is ATP used for anything other than a chemical reaction coupling?

ATP doesn’t just power reactions — it powers movement, transport, signaling, biosynthesis, protein folding, DNA replication, and the entire internal stability of the cell.

Describe 2 reasons why the hydrolysis of ATP to ADP + Pi releases energy.

1. breaking the high-energy phosphate bonds and relieves strong repulsion

2. the products are more stable and lower in energy

What is the chemical formula for the core process of aerobic respiration?

C6H12O6+6O2→6CO2+6H2O+energy (ATP)

What are the products of glycolysis and the Krebs cycle?

• Glycolysis gives the cell a little ATP and prepares fuel (pyruvate) for the Krebs cycle.

• The Krebs cycle produces lots of electron carriers (NADH, FADH₂) that power oxidative phosphorylation, plus CO₂ as waste.

What is the role of the electron carriers

1. temporarily stores energy

2. the deliver electrons to ETC

3. regenerates so metabolism can continue

Explain how ATP is made through work during the electron transport chain

• The electron transport chain pumps protons out.
  The proton gradient pushes protons back in.
  ATP synthase uses that flow to spin and make ATP.

• It’s a microscopic hydroelectric dam.

Summary of the products during glycolysis, krebs cycle, and the electron transport chain

What are some major differences between aerobic and anaerobic respiration?

Aerobic respiration

• Uses oxygen (O₂) as the final electron acceptor.

• Oxygen is extremely efficient because it has a high affinity for electrons

Anaerobic respiration

• Uses something other than oxygen, such as:

  • nitrate (NO₃⁻)

  • sulfate (SO₄²⁻)

  • carbon dioxide (CO₂)

  • ferric iron (Fe³⁺)

What is fermentation?

is the way many bacteria make ATP when no oxygen is available

what molecule serves as the “hub” of fermentative processes?

1. Latic acid

2. alcohol fermentation

3. mixed-acid fermentation

4. other specialized fermentation

give some examples of products of fermentation?

• lactic acid

• ethanol

• carbon dioxide

• acetic acid

• hydrogen gas

• formic acid

What are chemolithotrophs?

are microorganisms that get their energy by oxidizing inorganic molecules rather than organic carbon sources like glucose

how are they able to survive on such poor energy sources?

Chemolithotrophs survive on poor energy sources because they have highly efficient electron transport chains, slow growth rates, abundant inorganic substrates, and specialized pathways that let them extract and conserve tiny amounts of energy

identify/describe basic characteristics of the various groups of archaea

methanogens, halophiles, thermophiles and hyperthermophiles

identify/describe basic characteristics of the various groups of gram-negative

Gram‑negative bacteria share a thin peptidoglycan layer and an outer membrane with LPS, but they fall into major groups like Proteobacteria, Spirochetes, Cyanobacteria, Bacteroidetes, Chlamydiae, and others—each with distinct shapes, lifestyles, and ecological roles

identify/describe basic characteristics of the various groups of gram-positive

Gram‑positive bacteria include Firmicutes (cocci, spore‑formers, lactic acid bacteria) and Actinobacteria (acid‑fast bacteria, filamentous forms). They share a thick peptidoglycan wall but differ widely in shape, metabolism, and ecological roles

Describe 3 molecular techniques used to determine the relatedness of different bacteria. What are the possibilities and limitations of each?

1. 16S rRNA Gene Sequencing

2. DNA & DNA hybridization

3. multilogues sequence typing

What is the endosymbiotic hypothesis?

The endosymbiotic hypothesis says mitochondria and chloroplasts were once free‑living bacteria that got swallowed by another cell and eventually became permanent parts of it

What is the evidence supporting this hypothesis?

Mitochondria and chloroplasts look, act, and replicate like bacteria. Their DNA, membranes, ribosomes, division, and antibiotic sensitivity all point to a bacterial origin