CR Biology B Module 2 Lesson 1

Questions and Answers

What are the two domains that consist of prokaryotes?

Bacteria and Archaea (correct)

Bacteria and Fungi

Bacteria and Eukarya

Archaea and Eukarya

Which of the following is a characteristic of prokaryotic organisms?

They lack membrane-bound organelles. (correct)

They are multicellular.

They have a nucleus.

They cannot reproduce.

What important role do bacteria play in the ecosystem?

They are harmful and have no benefits.

They dominate the food chain.

They are the only organisms that can survive extreme conditions.

They are essential for nutrient cycling. (correct)

Which domain includes all eukaryotes?

Eukarya Signup and view all the answers

How do Archaea differ from Bacteria?

They can survive in extreme environments. Signup and view all the answers

What is one hypothesis about the origin of Eukarya?

Eukarya arose from a fusion of a Bacterial cell and an Archaean cell. Signup and view all the answers

What distinguishes eukaryotes from prokaryotes?

Eukaryotes possess a nucleus. Signup and view all the answers

Why are prokaryotes considered the simplest organisms?

They are unicellular and lack a nucleus. Signup and view all the answers

What was once believed about the relationship between Archaea and Bacteria?

Archaea evolved from Bacteria. Signup and view all the answers

Which of the following statements about the domains of life is accurate?

Bacteria consist of prokaryotic organisms. Signup and view all the answers

Which is a characteristic unique to Archaea?

Presence of introns Signup and view all the answers

What role do cyanobacteria play in the environment?

They perform photosynthesis and release oxygen Signup and view all the answers

Which statement about Bacteria is correct?

They are the most abundant group of organisms on Earth Signup and view all the answers

How are bacteria classified in terms of their cell walls?

As gram-positive or gram-negative Signup and view all the answers

Which option describes a common trait of Eukarya?

Presence of introns in their genes Signup and view all the answers

What environment is not typically associated with Archaea?

High-temperature human habitats Signup and view all the answers

Which statement about Bacteria and Archaea is true?

Both are prokaryotes Signup and view all the answers

What distinguishes extremophile Archaea from other organisms?

Their specialization for extreme environments Signup and view all the answers

Why are Bacteria considered essential for the carbon and nitrogen cycles?

They are involved in decomposition and nutrient cycling Signup and view all the answers

What is a main characteristic of archaea cell membranes compared to bacteria and eukaryotes?

Their lipid structure is unique and different Signup and view all the answers

Study Notes

Prokaryotes Overview

Prokaryotes are single-celled organisms without a nucleus and membrane-bound organelles.
Two primary domains of prokaryotes: Bacteria and Archaea, with Eukarya as a third domain containing eukaryotic organisms.

Evolution of Prokaryotes

Prokaryotes are the simplest and earliest forms of life on Earth.
Evolution suggests Archaea may have given rise to Eukarya through fusion with a Bacterial cell.

Characteristics of the Three Domains

Bacteria: Unique flagella, cell membrane composition, absent introns, and peptidoglycan in cell walls.
Archaea: Unique flagella, similar cell membrane to Eukarya, present introns, and generally lack peptidoglycan.
Eukarya: Unique flagella, complex cell membranes, present introns, and lack peptidoglycan.

Prokaryotes in the Environment

Bacteria are the most abundant organisms, estimated at 5 × 10^30 in total, residing in diverse habitats like oceans, soils, and animal intestines.
Archaea thrive in extreme conditions (extremophiles) and are also found abundant in oceans.

Importance of Bacteria

Essential for ecological balance; they participate in nutrient cycling and oxygen production.
Cyanobacteria played a significant role in early Earth by releasing oxygen and believed to be ancestors of chloroplasts.

Bacterial Classification

Bacteria can be classified by traits such as shape, cell wall structure, and Gram staining characteristics.
Gram-positive and Gram-negative classifications are based on cell wall staining patterns.

Archaea Research Challenges

Limited laboratory growth of Archaea has led to gaps in understanding.
Known Archaea contribute to carbon and nitrogen cycles; some live in conditions resembling ancient Earth.

Urban Bacterial Studies

Bacterial presence in urban settings, such as subways, exemplifies human interaction with microbial ecosystems.
Innovative applications of bacteria in technology, such as powering micro-robots, highlight their multifaceted roles.

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Description

Test your knowledge on the evolution and significance of prokaryotes, including bacteria. This quiz will explore their roles, growth conditions, and importance to human survival. Challenge yourself to see how much you know about these fascinating microorganisms.