Prokaryotes: Bacteria vs Archaea

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Questions and Answers

What is the primary function of endospores in bacteria?

To assist in the fermentation process

To help bacteria form conjugation bridges

To protect DNA and cytoplasm during unfavorable conditions (correct)

To produce toxins for defense

What type of toxin is released by bacteria when they multiply, often leading to severe symptoms?

Endotoxin

Cytotoxin

Exotoxin (correct)

Neurotoxin

Which bacteria are known for their ability to convert nitrogen from the air into nitrates for plant use?

Lactic acid bacteria

Endospore-forming bacteria

Pathogenic bacteria

Nitrogen-fixing bacteria (correct)

In sewage treatment, bacteria are utilized for what primary purpose?

To break down organic matter Signup and view all the answers

What process do lactic acid bacteria assist with in dairy food production?

Fermentation of sugars Signup and view all the answers

Which characteristic distinguishes Archaebacteria from Eubacteria?

Different genetic makeup with over 50% differing genes Signup and view all the answers

What environment would you typically find a halophile?

Salty lakes Signup and view all the answers

What is the primary mode of reproduction for bacteria?

Binary fission Signup and view all the answers

Where is the DNA located in prokaryotic cells?

Floating freely in the cytoplasm Signup and view all the answers

Which of the following is true about the size comparison between prokaryotes and eukaryotes?

Eukaryotes are approximately 10 times larger than prokaryotes. Signup and view all the answers

What is the function of the flagella in bacteria?

Facilitates movement Signup and view all the answers

Which group of Archaebacteria is known to produce methane gas?

Anaerobic methanogens Signup and view all the answers

What is a key feature of Eubacteria cell structure compared to Archaebacteria?

Different types of cell walls and membranes Signup and view all the answers

What are cyanobacteria commonly known as?

Blue-green bacteria Signup and view all the answers

What is a primary indicator of water pollution related to cyanobacteria?

Increased nitrates and phosphates Signup and view all the answers

Where do bacteria primarily carry out cellular respiration?

On the inner surface of the cell membrane Signup and view all the answers

Which type of bacteria absolutely require oxygen for survival?

Obligate aerobes Signup and view all the answers

What is the process by which bacteria reproduce asexually?

Binary fission Signup and view all the answers

What happens during the process of binary fission?

Two identical offspring cells are produced Signup and view all the answers

Which type of reproduction allows bacteria to adapt to difficult conditions?

Conjugation Signup and view all the answers

What is a characteristic of facultative anaerobes?

They can survive with or without oxygen Signup and view all the answers

What is the shape of bacteria classified as 'Coccus'?

Sphere-shaped Signup and view all the answers

Which arrangement refers to bacteria that are in clusters?

Staphylo Signup and view all the answers

What color do Gram-positive bacteria appear after staining?

Purple Signup and view all the answers

Which type of bacteria make their own organic compounds from carbon dioxide?

Chemoautotrophs Signup and view all the answers

What distinguishes Gram-negative bacteria from Gram-positive bacteria?

Color of the stain Signup and view all the answers

What form of nutrition do photoheterotrophs utilize?

Organic compounds as a carbon source and light Signup and view all the answers

If a bacterium is described as 'Streptobacillus', what does this indicate about its morphology and arrangement?

Chain of rod-shaped bacteria Signup and view all the answers

Which of the following is NOT a classification factor for bacteria?

Color of the stain Signup and view all the answers

Study Notes

Prokaryotes: Comparing Bacteria and Archaea

Bacteria are organisms belonging to Kingdom Archaebacteria and Eubacteria. The singular form is bacterium.
Archaebacteria are the oldest organisms on Earth, living in harsh environments like extremely salty, acidic, and hot areas.
Examples of Archaebacteria include:
- Anaerobic methanogens: found in oxygen-free places like the digestive systems of herbivores, producing methane gas.
- Halophiles: salt-loving organisms found in salty lakes.
- Thermophiles: heat-loving organisms found in acidic environments like hot springs.
Eubacteria contain the majority of the prokaryotes on Earth.
Eubacteria are also known as "true bacteria".
Eubacteria have cell walls and cell membranes that are different from Archaebacteria, and are also genetically different, with over 50% of their genes being different.
Examples of Eubacteria include Gram-positive bacteria and cyanobacteria.

Structure of Bacteria

Bacteria have a single, circular chromosome containing genetic information.
Plasmids are smaller rings of DNA containing fewer genes than the chromosome.
A cell wall provides structure and protection.
Flagella are whip-like structures for movement, extending from the cell wall and cell membrane.

Prokaryotes vs. Eukaryotes

Prokaryotes: DNA floats freely in the cytoplasm, lack a nucleus and membrane-bound organelles.
Eukaryotes: DNA enclosed in a nucleus, with membrane-bound organelles such as chloroplasts and mitochondria, and are larger than prokaryotes.

Bacteria Characteristics

Bacteria live everywhere, from microscopic to 1-10µm.
They are single-celled organisms.
All bacteria are prokaryotes and lack membrane-bound organelles.
Their DNA is a single chromosome in a ring shape.
Bacteria reproduce asexually through binary fission.

Bacteria Diversity

Bacteria are diverse and grouped according to morphology, aggregation, reaction to Gram stain, habitat, nutrition and respiration.

Morphology (Cell Shape)

Coccus (pl. cocci): sphere-shaped
Bacillus (pl. bacilli): rod-shaped
Spirillum (pl. spirilla): spiral-shaped

Aggregation (Arrangement/Grouping)

Diplo: arranged in pairs
Strepto: arranged in chains
Staphylo: arranged in clusters

Reaction to Gram Staining

Gram stain uses crystal violet and iodine to classify bacteria.
Gram-positive bacteria retain crystal violet, appearing purple.
Gram-negative bacteria do not retain crystal violet, appearing light pink.
Gram stain significantly differs between bacteria due to different cell wall compositions.

Comparing Nutrition

Nutrition is acquiring or creating organic compounds to fuel cellular metabolism.
Autotrophs: organisms that create organic compounds, such as glucose from carbon dioxide. Examples include photoautotrophs (like cyanobacteria) who use light and chemoautotrophs who use inorganic chemicals.
Heterotrophs: organisms that obtain carbon from their environment.

Comparing Nutritional Patterns of Bacteria (Autotrophs vs. Heterotrophs)

Summary of bacterial nutrition based on energy and carbon sources, distinguishing photoautotrophs, chemoautotrophs, photoheterotrophs, and chemoheterotrophs.

Photoautotroph (ex. Cyanobacteria)

Cyanobacteria, also known as "blue-green" bacteria, use CO2 and sunlight to produce organic compounds.
Cyanobacteria blooms are rapid increases in population, often indicating water pollution due to high nitrate and phosphate levels.
Cyanobacteria can live symbiotically with fungi in a composite organism called lichen.

Characteristics of Heterotrophs

Heterotrophs get carbon from other living things or decaying matter.
Parasites: absorb nutrients from living host organisms.
Saprobes: absorb nutrients from decomposing organic matter.

Respiration (Aerobic)

Cellular respiration is breaking down organic compounds to create energy.
Bacteria can carry out respiration on the inner surface of their cell membranes.
Aerobes use oxygen in respiration.
Obligate aerobes need oxygen to survive.

Respiration (Anaerobic)

Anaerobes respire in oxygen-free environments.
Obligate anaerobes are killed by oxygen.
Facultative anaerobes can survive with or without oxygen.

Comparing Reproduction (Asexual)

Bacteria reproduce asexually by binary fission, where a parent cell divides into two identical offspring cells.
Binary fission is rapid and exponential, depending on the availability of resources.

Binary Fission (Asexual Reproduction)

Steps of binary fission, from chromosome duplication, attachment to the plasma membrane, to the final division into two identical daughter cells.

Conjugation (Sexual Reproduction)

Conjugation is a type of sexual reproduction in which bacteria connect with a protein bridge to transfer plasmids to another bacterium.
This alters the genetic material of the recipient bacteria.

What are Plasmids?

Plasmids are small, circular DNA molecules separate from the bacterial chromosome, often used to transmit genetic material in conjugation.
Plasmids contain genes that might give bacteria an advantage in their environment.

What are Endospores?

Bacteria form endospores when conditions are unfavorable, creating protective structures that surround the DNA and cytoplasm.
Endospores are dormant and remain this way until environmental conditions are favorable for growth again.

Bacteria & Disease

Pathogens: bacteria that cause disease via toxins.
Toxins: harmful substances released by bacteria, causing symptoms in the host.
Endotoxins: released during gram-negative bacteria's disintegration, causing fever, vomiting, and diarrhea.
Exotoxins: highly toxic substances produced by multiplying bacteria.

How are various bacteria used in helpful ways?

Nitrogen-fixing bacteria: convert nitrogen gas (in the air) into nitrates, usable by plants.
Bacteria for Sewage Treatment: break down organic matter in sewage.
Bacteria to clean Oil Spills: eliminate or neutralize toxic compounds in oil spills.
Lactic acid bacteria: is used in dairy products like yogurt to ferment sugars into acids that give the yogurt a specific taste.

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Description

Explore the fascinating differences between Bacteria and Archaea in this quiz. Learn about their unique characteristics, habitats, and examples that highlight their diversity. Test your knowledge on these fundamental prokaryotic organisms!