Microbiology: Prokaryotes and Viruses Flashcards

Questions and Answers

What is a prokaryote?

Prokaryotes do not have a nucleus or membrane-bound organelles.

What is a domain of prokaryotes that usually has a cell wall and reproduces by cell division?

Bacteria.

What is Archaea?

A domain of prokaryotes that are genetically very different from bacteria and have unique chemicals in their cell walls.

What are some characteristics of Archaea?

Archaea have unique molecular traits; their cell walls differ from bacteria, and some molecules are similar to eukaryotes. Signup and view all the answers

Where do Archaea often live?

In extreme environments such as hot springs, acidic or salty habitats, and near deep-sea vents. Signup and view all the answers

What characterizes bacteria?

Most known prokaryotes are bacteria, and the domain Bacteria contains more individuals than all other domains combined. Signup and view all the answers

How do many bacteria obtain nutrients?

Many bacteria are consumers that feed on other organisms. Some are decomposers, while others produce their own food. Signup and view all the answers

What is the structure of bacteria?

Bacteria are small, single-celled organisms, often forming strands or films. Signup and view all the answers

How do bacteria reproduce?

By binary fission, where a single-celled organism splits into two. Signup and view all the answers

What is the first step in bacterial reproduction?

Copying the cell's genetic material, which is in the form of a long circular strand of DNA. Signup and view all the answers

What happens after the DNA is copied in bacterial reproduction?

The two chromosomes separate, with one on each side of the cell. Signup and view all the answers

What is a virus?

A microscopic particle that cannot replicate on its own and requires a host cell. Signup and view all the answers

Viruses are considered living organisms.

False Signup and view all the answers

What significant event was caused by the 1918 flu virus?

It killed more than 50 million people and infected more than 500 million. Signup and view all the answers

How do viruses replicate?

Viruses can replicate only inside a living cell that serves as a host. Signup and view all the answers

What happens after new viruses are created?

They search for new host cells to continue the lytic cycle. Signup and view all the answers

Study Notes

Prokaryotes Overview

Prokaryotes lack a nucleus and membrane-bound organelles.
Two main domains of prokaryotes are Bacteria and Archaea.

Bacteria

Bacteria possess cell walls and usually reproduce via cell division.
They encompass the majority of known prokaryotic organisms.
The bacterial domain contains more individuals than all other domains combined.

Characteristics of Bacteria

Many bacteria function as consumers; they obtain nutrients by feeding on other organisms.
Some bacteria are decomposers, feeding on dead organisms, while others are producers, using sunlight for energy.
Bacteria are typically small, single-celled organisms, though they may form films or strands.
Spiral-shaped bacteria can move in a corkscrew manner.

Reproduction in Bacteria

Both archaea and bacteria reproduce through binary fission, where one cell splits into two.
The process begins with copying the genetic material, which is structured as a long circular strand of DNA called a chromosome.
After copying, the chromosomes separate to opposite sides of the cell before division.

Archaea

Archaea are genetically distinct from bacteria and have unique cell wall chemicals.
Many archaea thrive in extreme environments, such as hot springs or highly acidic habitats.
Some archaea can utilize sulfur to generate energy near deep-sea vents.

Viruses

Viruses are microscopic particles that cannot replicate independently.
They must enter a host cell or inject their DNA to reproduce, often leading to cell destruction.
Common viral illnesses include the common cold, flu, and AIDS.

Characteristics of Viruses

Composed of genetic material and proteins, viruses do not perform metabolic functions.
They can only replicate inside living cells, making them non-living entities.

Historical Impact of Viruses

The 1918 influenza pandemic was caused by a deadly virus, resulting in over 50 million deaths and infecting more than 500 million people worldwide.

Viral Replication

Viruses replicate exclusively within host cells, which provide essential resources for survival and proliferation.
After replication, new viruses seek additional host cells, continuing the cycle of infection.

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Description

This quiz focuses on key concepts related to prokaryotes, including bacteria, archaea, as well as an overview of viruses and other microorganisms. Each card defines important terms and differences, aiming to enhance understanding of microbial life forms. Perfect for students studying microbiology or related fields.