Prokaryotes and Their Significance

These flashcards cover key concepts about prokaryotes, including their biology, genetics, and the impact they have on health and ecology.

What is the approximate age of the Earth?

About 4.6 billion years old (BYA).

When did the first life appear on Earth?

Approximately 3.7 billion years ago (BYA).

What do microfossils represent?

Fossilized forms of microscopic life that resemble present-day prokaryotes.

What are stromatolites?

Layered structures formed by the activity of prokaryotes, particularly cyanobacteria.

How many domains do prokaryotes fall into?

Two domains: Bacteria and Archaea.

What percentage of bacteria in the human body are unknown and undescribed?

Between 90 and 99%.

What is a defining trait of prokaryotic cells regarding the nucleus?

Prokaryotic cells do not have a nucleus; they contain circular DNA instead.

What is the difference in cell wall composition between Bacteria and Archaea?

Archaea do not have peptidoglycan in their cell wall.

What are the three basic shapes of prokaryotic cells?

Bacillus (rod-shaped), Coccus (spherical), and Spirillum (helical-shaped).

What are flagella and pili in prokaryotic cells?

Flagella are tail-like structures for movement, while pili are hair-like structures that aid in attachment and gene transfer.

What are endospores and their function?

Endospores are thick-walled structures that increase survival under environmental stress and germinate when conditions improve.

What are the three types of horizontal gene transfer in prokaryotes?

Conjugation, transduction, and transformation.

How does conjugation work in prokaryotes?

Conjugation involves the exchange of plasmids between cells through a conjugation bridge.

What is transformation in prokaryotic genetics?

The uptake of DNA fragments from the environment by a live cell, usually after the death of another bacterium.

What is an autotroph?

An organism that fixes carbon, can be photoautotrophic or chemoautotrophic.

What roles do beneficial prokaryotes play in ecology?

Nitrogen fixation and decomposition, as well as aiding human health.

What are examples of harmful prokaryotes?

Pathogenic bacteria that can cause diseases in humans.

What are some examples of human prokaryotic diseases?

Tuberculosis, Whooping Cough, Lyme Disease, and many others.

What contributes to antibiotic resistance in prokaryotes?

Improper prescription of antibiotics and widespread use in agriculture.