Final 22 FCs

Question 1

What are prokaryotes?

Answer 1

Unicellular organisms lacking a nucleus and membrane-bound organelles. Includes Bacteria and Archaea.

Question 2

What are the two domains of prokaryotes?

Answer 2

Bacteria and Archaea.

Question 3

What is the key difference between Bacteria and Archaea?

Answer 3

Bacteria have peptidoglycan in their cell walls, while Archaea have pseudopeptidoglycan or other polymers.

Question 4

How do prokaryotes reproduce?

Answer 4

Binary fission – a simple, rapid asexual reproduction process.

Question 5

What is the function of the prokaryotic cell wall?

Answer 5

Provides structural support, protects from osmotic stress, and determines shape.

Question 6

What is the difference between Gram-positive and Gram-negative bacteria?

Answer 6

Gram-positive: Thick peptidoglycan, stains purple. Gram-negative: Thin peptidoglycan + outer membrane, stains pink.

Question 7

Why is Gram staining important?

Answer 7

Differentiates bacteria for classification and determines antibiotic susceptibility.

Question 8

What is the purpose of bacterial flagella?

Answer 8

Movement by rotary motion using the proton motive force.

Question 9

What is the function of pili/fimbriae?

Answer 9

Attachment to surfaces or other cells; sex pili are used for conjugation.

Question 10

What is a capsule in bacteria?

Answer 10

A protective polysaccharide layer that prevents desiccation and immune system attack.

Question 11

What are endospores?

Answer 11

Highly resistant dormant structures formed by some bacteria (e.g., Bacillus, Clostridium) for survival in harsh conditions.

Question 12

What is an example of a nitrogen-fixing bacterium?

Answer 12

Rhizobium – converts atmospheric N₂ into ammonia for plants.

Question 13

What are the three types of horizontal gene transfer?

Answer 13

Transformation: Uptake of DNA from environment. Transduction: DNA transfer via bacteriophage. Conjugation: DNA transfer through sex pili.

Question 14

What is the primary function of glycolysis?

Answer 14

Breaks down glucose into pyruvate, producing ATP and NADH.

Question 15

What is the final electron acceptor in aerobic respiration?

Answer 15

Oxygen (O₂).

Question 16

What is the purpose of fermentation?

Answer 16

Regenerates NAD⁺ to allow glycolysis to continue in the absence of oxygen.

Question 17

What are the two main types of fermentation?

Answer 17

Lactic acid fermentation (e.g., in muscle cells, yogurt bacteria) and Ethanol fermentation (e.g., in yeast).

Question 18

What is the final electron acceptor in anaerobic respiration?

Answer 18

Alternatives to oxygen, such as nitrate (NO₃⁻), sulfate (SO₄²⁻), or carbon dioxide (CO₂).

Question 19

What is methanogenesis?

Answer 19

A process in Archaea where CO₂ is reduced to methane (CH₄) in anaerobic environments.

Question 20

What is an extremophile?

Answer 20

A prokaryote that thrives in extreme environments (e.g., thermophiles in hot springs, halophiles in salt lakes).

Question 21

Why are Archaea more resistant to extreme conditions?

Answer 21

They have ether-linked lipids in their membranes, which are more stable than bacterial ester-linked phospholipids.

Question 22

Which prokaryotes contributed to Earth’s oxygen?

Answer 22

Cyanobacteria – they performed oxygenic photosynthesis, leading to the Great Oxygenation Event.

Question 23

What are autotrophs?

Answer 23

Organisms that fix their own carbon (e.g., cyanobacteria use CO₂ to make sugars).

Question 24

What are heterotrophs?

Answer 24

Organisms that consume organic molecules for carbon (e.g., E. coli).

Question 25

What are phototrophs?

Answer 25

Organisms that use light as an energy source (e.g., cyanobacteria).

Question 26

What are chemotrophs?

Answer 26

Organisms that use chemical compounds as an energy source (e.g., sulfur-oxidizing bacteria).

Question 27

What is denitrification?

Answer 27

A process where bacteria convert nitrate (NO₃⁻) into nitrogen gas (N₂), returning nitrogen to the atmosphere.

Question 28

Which bacteria are used in antibiotic production?

Answer 28

Streptomyces – produces streptomycin and other antibiotics.

Question 29

What is bioremediation?

Answer 29

The use of prokaryotes to remove pollutants (e.g., oil spill cleanup using hydrocarbon-degrading bacteria).

Question 30

What is an example of a facultative anaerobe?

Answer 30

Escherichia coli (E. coli) – can grow with or without oxygen.

Question 31

What is an example of an obligate anaerobe?

Answer 31

Clostridium botulinum – poisoned by oxygen.

Question 32

What is an example of an obligate aerobe?

Answer 32

Mycobacterium tuberculosis – requires oxygen for survival.

Question 33

What is quorum sensing?

Answer 33

A communication system where bacteria coordinate behaviors based on population density (e.g., biofilm formation).

Question 34

What is the main component of the bacterial cell wall?

Answer 34

Peptidoglycan (except in Archaea, which use different materials).

Question 35

What are cyanobacteria, and why are they important?

Answer 35

Photosynthetic bacteria that produce oxygen and fix nitrogen. They played a role in forming Earth's atmosphere.

Question 36

What is a biofilm?

Answer 36

A community of bacteria encased in a self-produced extracellular matrix, increasing resistance to antibiotics.

Question 37

Why are Gram-negative bacteria more resistant to antibiotics?

Answer 37

Their outer membrane prevents many antibiotics from entering the cell.

Question 38

What is the role of sulfur-reducing bacteria in ecosystems?

Answer 38

They convert sulfate (SO₄²⁻) into hydrogen sulfide (H₂S), influencing sulfur cycling.

Question 39

What is the main role of nitrifying bacteria?

Answer 39

They convert ammonium (NH₄⁺) into nitrate (NO₃⁻), making nitrogen available to plants.

Question 40

What is the importance of prokaryotes in the carbon cycle?

Answer 40

Decomposers break down dead matter, releasing CO₂ for photosynthesis.

Question 41

Which domain of life is more closely related to Eukarya: Bacteria or Archaea?

Answer 41

Archaea – they share more similarities in genetics and transcription with Eukarya.