Biology Chapter 20 Prokaryotes Flashcards

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Questions and Answers

How are prokaryotes classified?

Prokaryotes are classified as Bacteria or Archaea.

What are prokaryotes?

The smallest and most abundant microorganisms; unicellular organisms that lack a nucleus.

What do bacteria have cell walls made up of?

Peptidoglycan.

Where can Archaea live?

In extremely harsh environments. Signup and view all the answers

How do prokaryotes vary in their structure and function?

They vary in size and shape, in the way they move, and in how they obtain and release energy. Signup and view all the answers

There are many types of prokaryotes like the (1)_ (rod-shaped), the (2) (spherical), and the (3)____ (spiral/corkscrew).

(1) Bacilli, (2) cocci, (3) spirilla. Signup and view all the answers

What is Binary Fission in prokaryotes?

When a prokaryote has grown so that the mass has doubled, and the DNA can duplicate and the cell divides. Signup and view all the answers

What is an endospore?

A thick internal wall that encloses the DNA and a portion of the cytoplasm. Signup and view all the answers

What needs to occur in prokaryotic DNA for evolution to happen?

Mutations and/or conjugations. Signup and view all the answers

What is conjugation?

A bridge forms between two bacterial cells, and genetic material moves from one cell to another. Signup and view all the answers

What roles do prokaryotes play in the living world?

They are essential in maintaining ecological balance and have specific uses in human industry. Signup and view all the answers

What are some examples of roles that prokaryotes have?

Decomposers, producers, nitrogen fixers. Signup and view all the answers

How do living things obtain raw materials for survival?

From prokaryotic decomposers that harvest materials from dead organisms. Signup and view all the answers

What is algae?

A photosynthetic prokaryote that is among the many producers on the planet. Signup and view all the answers

What are nitrogen fixers and what do they do for other organisms?

Nitrogen fixers convert nitrogen into ammonia and then into nitrates for plants. Signup and view all the answers

How do humans use prokaryotes?

For making yogurt, synthesizing drugs, and chemical genetic engineering. Signup and view all the answers

Study Notes

Classification of Prokaryotes

Prokaryotes belong to two domains: Bacteria and Archaea.
They are the smallest and most abundant microorganisms.

Structure and Composition

Prokaryotes are unicellular and lack a nucleus.
Bacterial cell walls are composed of peptidoglycan, a polymer made of sugars and amino acids.

Unique Characteristics of Archaea

Archaea thrive in extreme environments, such as high salt levels, extreme temperatures, and areas with little or no oxygen.

Diversity in Prokaryotes

Prokaryotes exhibit variation in size, shape, motility, and energy acquisition.
Different shapes include bacilli (rod-shaped), cocci (spherical), and spirilla (spiral/corkscrew).

Reproduction

Prokaryotes reproduce asexually through a process called binary fission, which involves duplication of DNA and cell division.

Endospores

Endospores are protective structures formed by some prokaryotes, containing DNA and cytoplasm, enabling survival in harsh conditions.

Evolutionary Processes

Prokaryotic evolution relies on mutations or conjugation, despite asexual reproduction limiting genetic variation.

Genetic Exchange: Conjugation

Conjugation involves the formation of a bridge between two bacterial cells for the transfer of genetic material, usually in the form of plasmids.

Ecological Roles

Prokaryotes play crucial roles in ecological balance, acting as decomposers, producers, and nitrogen fixers.

Decomposition and Nutrient Recycling

Prokaryotic decomposers break down dead organisms, recycling raw materials essential for the survival of living organisms.

Importance of Algae

Algae, a photosynthetic prokaryote, contribute significantly to food chains and are vital producers of food and biomass.

Nitrogen Fixation

Nitrogen fixers convert atmospheric nitrogen into ammonia, which is then transformed into nitrates for plant use or attached to amino acids for general utilization by various organisms.

Human Utilization of Prokaryotes

Prokaryotes have practical applications in human industry, including yogurt production and the synthesis of pharmaceuticals through genetic engineering.

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Description

Explore the classification and characteristics of prokaryotes through these informative flashcards. Learn about their classification into Bacteria and Archaea, their unique cellular structures, and more. Perfect for studying microbiology concepts effectively.