14 - Prokaryotes: Structure and Function

Question 1

Prokaryote

Answer 1

Single-celled organism without a nucleus or membrane-bound organelles.

Question 2

Domains

Answer 2

Bacteria and Archaea.

Question 3

Unicellular

Answer 3

One-celled organism performing all life functions within one cell.

Question 4

Circular chromosome

Answer 4

Single loop of DNA containing essential genes.

Question 5

Operon

Answer 5

Cluster of genes transcribed together in bacteria.

Question 6

Binary fission

Answer 6

Asexual reproduction by simple cell division.

Question 7

Nucleoid

Answer 7

Region in prokaryote where DNA is concentrated (no membrane).

Question 8

Plasmid

Answer 8

Small circular DNA carrying extra genes for survival.

Question 9

Extremophile

Answer 9

Archaea adapted to extreme conditions (e.g., high temp, salt).

Question 10

Mesophile

Answer 10

Bacteria adapted to moderate environments.

Question 11

Cell wall

Answer 11

Maintains cell shape, protects, prevents bursting.

Question 12

Peptidoglycan

Answer 12

Polymer of sugars and amino acids forming bacterial walls.

Question 13

Gram-positive bacteria

Answer 13

Thick peptidoglycan wall; no outer membrane.

Question 14

Gram-negative bacteria

Answer 14

Thin peptidoglycan wall + toxic outer membrane (lipopolysaccharides).

Question 15

Capsule

Answer 15

Dense, sticky outer layer for protection and adherence.

Question 16

Slime layer

Answer 16

Loosely organized, sticky coating outside cell wall.

Question 17

Endospore

Answer 17

Dormant, tough bacterial cell form that resists harsh conditions.

Question 18

Fimbriae

Answer 18

Short hairlike structures for sticking to surfaces or other cells.

Question 19

Pilus (sex pilus)

Answer 19

Long appendage that connects cells for DNA transfer.

Question 20

Flagella

Answer 20

Tail-like structures used for movement.

Question 21

Taxis

Answer 21

Directed movement toward or away from a stimulus.

Question 22

Rapid reproduction

Answer 22

Binary fission allows quick population growth.

Question 23

Mutation

Answer 23

Random DNA changes; accumulate quickly due to fast division.

Question 24

Genetic recombination

Answer 24

Combining DNA from two sources.

Question 25

Horizontal gene transfer

Answer 25

Gene movement between different species.

Question 26

Transformation

Answer 26

Cell takes up foreign DNA from environment.

Question 27

Transduction

Answer 27

Virus (phage) transfers bacterial DNA between cells.

Question 28

Conjugation

Answer 28

DNA transferred between cells via a mating bridge.

Question 29

F factor

Answer 29

DNA segment or plasmid controlling pilus formation (“fertility factor”).

Question 30

F+ cell

Answer 30

Donor cell with F factor plasmid.

Question 31

F– cell

Answer 31

Recipient cell lacking F factor.

Question 32

Hfr cell

Answer 32

High-frequency recombination cell with F factor integrated in chromosome.

Question 33

Metabolism

Answer 33

All chemical reactions in an organism.

Question 34

Anabolic pathway

Answer 34

Builds complex molecules using energy (e.g., photosynthesis).

Question 35

Catabolic pathway

Answer 35

Breaks down molecules to release energy (e.g., respiration).

Question 36

Photoautotroph

Answer 36

Uses light for energy and CO₂ for carbon (e.g., cyanobacteria).

Question 37

Chemoautotroph

Answer 37

Uses inorganic chemicals for energy and CO₂ for carbon (deep-sea vent bacteria).

Question 38

Photoheterotroph

Answer 38

Uses light for energy but gets carbon from organic compounds.

Question 39

Chemoheterotroph

Answer 39

Gains both energy and carbon from other organisms (e.g., humans).

Question 40

Obligate aerobe

Answer 40

Needs oxygen to survive.

Question 41

Obligate anaerobe

Answer 41

Killed by oxygen; uses fermentation or anaerobic respiration.

Question 42

Facultative anaerobe

Answer 42

Can survive with or without oxygen.