Archea and Bactera Quiz Prep - Prokaryote

Prokaryote

A single-celled organism that lacks a nucleus and membrane-bound organelles.

Characteristics of Prokaryotes

Single-celled, no nucleus, no membrane-bound organelles, reproduce by binary fission.

Archaea (Archaebacteria)

Prokaryotes that often live in extreme environments and do not contain peptidoglycan in their cell walls.

Eubacteria (Bacteria)

Prokaryotes with peptidoglycan in their cell walls that are found in almost every environment.

Peptidoglycan

A molecule that gives bacterial cell walls strength and rigidity.

Difference between Archaea and Eubacteria

Archaea lack peptidoglycan; Eubacteria contain peptidoglycan.

Pathogenic Archaea

None are currently known.

Extremeophile

An organism that lives in extreme environmental conditions.

Methanogens

Archaea that produce methane gas from hydrogen and carbon dioxide.

Where are Methanogens found?

wamps, sewage, sediments, and the digestive systems of animals.

Halophiles

Archaea that live in very salty environments.

Where are Halophiles found?

Salt lakes, salt ponds, and highly salty soils.

Thermoacidophiles

Archaea that live in hot, acidic environments.

Psychrophiles

Archaea that live in very cold environments.

Examples of energy sources used by Archaea

Hydrogen, ammonia, sulfur compounds, and metals.

Autotroph

An organism that makes its own food.

Photoautotroph

Uses sunlight to make food.

Chemoautotroph

Uses chemical energy to make food.

Heterotroph

An organism that obtains food from other organisms.

Phototroph

Gets energy from sunlight.

Chemotroph

Gets energy from chemicals.

Capsule

A protective outer layer that helps bacteria avoid drying out and resist immune defenses.

Cell Wall

Provides shape and protection to the cell.

Cell Membrane

Controls what enters and leaves the cell.

Order of Bacterial Structures (outside to inside)

→ Capsule → Cell Wall → Cell Membrane.

Flagellum

A whip-like structure used for movement.

Function of Flagellum

Allows bacteria to move.

Endospore

A dormant, highly resistant structure formed by some bacteria during harsh conditions.

Purpose of Endospores

To survive extreme conditions and preserve genetic material.

Do Archaea form Endospores?

no

Do some Bacteria form Endospores?

yes

Coccus

Spherical bacterium.

Bacillus

Rod-shaped bacterium.

Spirillum

Spiral-shaped bacterium.

Diplo

Pairs of bacteria

Strepto

Chains of bacteria

Staphylo

Clusters of bacteria

Obligate Aerobe

Requires oxygen to survive.

Obligate Anaerobe

Is killed by oxygen.

Facultative Anaerobe

Uses oxygen when available but can survive without it.

Gram Stain

A method used to classify bacteria based on their cell wall structure.

Gram-Positive Bacteria

Have a thick peptidoglycan layer and stain purple.

Gram-Positive Cell Wall

Thick peptidoglycan, no outer lipid membrane.

Gram-Negative Bacteria

Have a thin peptidoglycan layer and stain pink.

Gram-Negative Cell Wall

Thin peptidoglycan and an outer lipid membrane.

Why is Gram Staining Useful?

Helps identify bacteria and determine appropriate treatments.

Binary Fission

Asexual reproduction where one bacterial cell divides into two identical cells.

Steps of Binary Fission

Step 1 of Binary Fission → DNA replication.

Step 2 of Binary Fission → Cell elongation.

Step 3 of Binary Fission → Septum formation.

Step 4 of Binary Fission → Cytokinesis.

Result of Binary Fission → Two genetically identical daughter cells.

Asexual Reproduction

Reproduction involving only one parent and producing genetically identical offspring.

Conjugation

Transfer of DNA between bacteria through a pilus.

Pilus

A structure that connects two bacterial cells during conjugation.

Transformation

Uptake of free DNA from the environment.

Horizontal Gene Transfer

Movement of genetic material between organisms without reproduction.

Antibiotic Resistance

The ability of bacteria to survive exposure to antibiotics.

Why is Antibiotic Resistance Concerning?

→ Resistant bacteria survive, reproduce, and become harder to treat.

How Can Resistance Spread?

Through conjugation, transformation, and reproduction.

Which kingdom contains peptidoglycan in its cell walls?

Eubacteria.

Which kingdom often lives in extreme environments?

Archaea.

What are the three common bacterial shapes?

Coccus, bacillus, spirillum.

What structure helps bacteria move?

Flagellum.

What structure allows bacteria to survive harsh conditions?

Endospore.

What stain color indicates Gram-positive bacteria?

Purple.

What stain color indicates Gram-negative bacteria?

Pink.

How do prokaryotes reproduce?

Binary fission.

Which type of bacteria needs oxygen to survive?

Obligate aerobes.

Which type of bacteria is killed by oxygen?

Obligate anaerobes.

What is the main cell wall difference between Archaea and Eubacteria?

Eubacteria have peptidoglycan; Archaea do not.

What are the differences between gram negative and gram positive bacteria?

Gram-positive bacteria have a thick peptidoglycan layer and no outer lipid membrane, staining purple. Gram-negative bacteria have a thin peptidoglycan layer and an outer lipid membrane, staining pink.

Distinguish the 3 different oxygen requirements bacteria can have.

Obligate aerobes need oxygen to survive. Facultative anaerobes use oxygen when available but can survive without it. Obligate anaerobes are killed by oxygen.

Why do bacteria make endospores?

The formation of endospores is initiated by nutrient deprivation. It allows the bacterium to become dormant and highly resistant, preserving genetic material in extreme conditions.