Diversity of Microbes and Protists

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Questions and Answers

What is the primary function of the plasma membrane in prokaryotic cells?

Barrier separating the cell from its environment. (correct)

Storage of genetic material.

Structure providing locomotion.

Site for protein synthesis.

Which of the following shapes do prokaryotes commonly exhibit?

Flat

Cuboidal

Branched

Cocci (correct)

What unique feature is characteristic of prokaryotic cells compared to eukaryotic cells?

Multiple linear chromosomes.

Lack of membrane-bound organelles. (correct)

Complex genetic structures.

Presence of a nucleus.

What is located in the nucleoid of a prokaryotic cell?

Circular DNA chromosome. Signup and view all the answers

Which structure in some prokaryotic species helps in attachment and preventing dehydration?

Capsule. Signup and view all the answers

What distinguishes the cell walls of Bacteria and Archaea?

Significant differences in composition. Signup and view all the answers

What role does flagella play in certain prokaryotic species?

Facilitates locomotion. Signup and view all the answers

Which of the following statements is true regarding plasmids in prokaryotic cells?

They consist of small pieces of circular DNA. Signup and view all the answers

What is a primary concern related to antibiotic usage as mentioned in the content?

A potential return to high mortality from bacterial infections. Signup and view all the answers

Which statement best characterizes foodborne diseases?

They can also result from viruses and parasites. Signup and view all the answers

What source of energy do phototrophs utilize?

Sunlight Signup and view all the answers

What pathogen was responsible for the raw spinach outbreak in the United States in 2006?

E. coli O157:H7 Signup and view all the answers

Which of the following statements about pathogenic prokaryotes is true?

All pathogenic prokaryotes are Bacteria. Signup and view all the answers

What factor contributed to a decrease in botulism cases?

Improved sterilization and canning procedures. Signup and view all the answers

How many Americans are reported to die each year from foodborne illnesses?

5,000 Signup and view all the answers

What historical misconception did cultures have regarding the cause of diseases?

Diseases were seen as punishments from deities. Signup and view all the answers

Which method is typically ineffective against foodborne bacterial infections?

Consuming food without proper storage. Signup and view all the answers

What disease transmission pattern is indicated by zoonoses?

Diseases that transfer from animals to humans. Signup and view all the answers

What role did public sanitation play in reducing deaths from bacterial infections?

It helped by ensuring access to clean drinking water and proper sewage disposal. Signup and view all the answers

What has been reported about the safety of the food supply in the United States?

The United States has one of the safest food supplies in the world. Signup and view all the answers

What is a common source of most foodborne illnesses currently?

Produce contaminated by animal waste. Signup and view all the answers

What impact did the development of antibiotics have on mortality rates from bacterial infections?

Mortality rates decreased significantly but not universally. Signup and view all the answers

Which pandemic significantly weakened Athens during the Great Peloponnesian War?

The plague of Athens Signup and view all the answers

How far back do records of infectious diseases date?

3,000 B.C. Signup and view all the answers

What is a significant chemical difference between archaeal and bacterial plasma membranes?

Archaeal membranes can be lipid monolayers. Signup and view all the answers

What is the primary function of the cell wall in prokaryotic cells?

To provide shape and prevent osmotic lysis. Signup and view all the answers

Which of the following is true regarding the structure of Gram-positive and Gram-negative bacteria?

Gram-positive bacteria have a thick layer of peptidoglycan. Signup and view all the answers

Which type of chemical component is NOT found in archaeal cell walls?

Peptidoglycan. Signup and view all the answers

How do bacteria reproduce primarily?

By binary fission. Signup and view all the answers

What characterizes Gram-negative bacteria in terms of their cell wall structure?

Thin peptidoglycan layer with an outer membrane. Signup and view all the answers

Which statement best describes the differences in cell walls across different bacterial species?

The chemical composition of cell walls varies between bacterial species. Signup and view all the answers

Which type of archaeal cell wall component provides structural support similar to peptidoglycan?

Pseudopeptidoglycan. Signup and view all the answers

What significant characteristic do Bacteroides bacteria possess?

They can become resistant to antibiotics. Signup and view all the answers

Why did older anaerobic prokaryotes struggle during the rise of aerobic conditions on Earth?

They could not function in the new oxygen-rich environment. Signup and view all the answers

How did photosynthetic prokaryotes influence the Earth's atmosphere?

By releasing oxygen as a byproduct. Signup and view all the answers

What role does the Human Microbiome Project serve in research?

To investigate the relationship between diseases and microbial flora. Signup and view all the answers

What does the endosymbiotic theory explain?

The origin of mitochondria and chloroplasts. Signup and view all the answers

Approximately how long ago did prokaryotic cells first originate on Earth?

3.5 billion years ago. Signup and view all the answers

What was the primary byproduct of photosynthesis conducted by early prokaryotes?

Molecular oxygen. Signup and view all the answers

What mechanism did some early prokaryotes evolve to adapt to an oxygenated atmosphere?

Aerobic respiration. Signup and view all the answers

What feature of mitochondria resembles certain bacteria?

The infoldings of their inner membrane Signup and view all the answers

What process do mitochondria use to divide?

Binary fission Signup and view all the answers

Which of the following components do mitochondria contain that support their similarity to prokaryotes?

Specialized ribosomes and transfer RNAs Signup and view all the answers

What evolutionary theory explains the origin of plastids?

Endosymbiosis of a photosynthetic cyanobacterium Signup and view all the answers

Which statement is true about chloroplasts in plants?

They are involved in photosynthesis and contain green pigment chlorophyll. Signup and view all the answers

Why are mitochondria considered to have evolved before plastids?

All eukaryotes have mitochondria or mitochondria-like organelles. Signup and view all the answers

What do red and green algae have in common regarding their chloroplasts?

They exhibit DNA sequences closely related to photosynthetic cyanobacteria. Signup and view all the answers

Which of the following best describes the membranes of plastids?

Plastids have two or more membranes. Signup and view all the answers

Study Notes

Diversity of Microbes, Fungi, and Protists

Living things are incredibly diverse, ranging from simple single-celled organisms to complex multicellular ones
Prokaryotes lack a nucleus and membrane-bound organelles
Three domains of life: Bacteria, Archaea, and Eukarya
Prokaryotes are ubiquitous, found in extreme environments like boiling hot springs and in more benign environments
Prokaryotes perform essential roles, like nutrient cycling and driving ecosystem evolution
Prokaryotes existed before multicellular life
DNA sequencing provided critical insight into prokaryotic relationships and origins, leading to a reclassification of life
Early life on Earth consisted of prokaryotes, estimated at 3.9 billion years ago
Early Earth's atmosphere was anoxic (no oxygen) , supporting only anaerobic organisms
Phototrophic organisms appeared after approximately 1 billion years
Cyanobacteria were important in oxygenating the atmosphere
Microbial mats are multi-layered sheets of prokaryotes, found in various colors reflecting their diverse metabolic functions
Extremophiles thrive in extreme conditions, such as high temperatures, high radiation, and highly acidic environments
Biofilms are communal microbial communities, often robust and difficult to destroy
Prokaryotes exhibit three main shapes: cocci (spherical), bacilli (rod-shaped), and spirilla (spiral-shaped)
Prokaryotes reproduce asexually via binary fission, altering their genetic makeup through transformation, transduction, and conjugation
Cell walls of prokaryotes differ, some contain peptidoglycan (bacteria)
Gram-positive bacteria have thick cell walls with peptidoglycan
Gram-negative bacteria have thin cell walls with peptidoglycan surrounded by an outer membrane
Prokaryotes obtain energy from sunlight (phototrophs) or chemical compounds (chemotrophs)
Prokaryotes cause diseases ("pathogenic bacteria")
Foodborne illnesses exist
Bacteria, such as Clostridium botulinum, can produce foodborne toxins
Escherichia coli strain 0157:H7 has been implicated in outbreaks associated with raw produce
Antibiotic resistance is a growing concern
Staphylococcus aureus (staph) includes resistant strains like MRSA (methicillin-resistant Staphylococcus aureus)
Historical outbreaks and pandemics
Bubonic plague was caused by Yersinia pestis
Prokaryotes are crucial for bioremediation to remove pollutants.

Eukaryotic Origins

Eukaryotes emerged 2.1 billion years ago
Endosymbiotic theory proposes that mitochondria and chloroplasts originated from engulfed prokaryotic cells
Mitochondria have their own circular DNA and resemble bacteria
Chloroplasts are derived from photosynthetic cyanobacteria, resembling their structure and function
Eukaryotic cells evolved increasingly complex structures like the nucleus, endoplasmic reticulum, and a sophisticated infrastructure

Protists

Protists are diverse eukaryotic organisms
Protists exhibit a wide range of characteristics, from microscopic single-celled forms to large, multicellular organisms
Some protists play important ecological roles as food sources and decomposers
Several types of protists can cause human disease

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Description

Explore the fascinating world of microbes, fungi, and protists through this quiz. Learn about the three domains of life, the roles of prokaryotes in ecosystems, and the evolutionary history that shaped our planet. Test your knowledge on early life forms and their impact on Earth's atmosphere.