Chp 4 prokaryotic diversity

Question 1

What are the main shapes of prokaryotic cells?

Answer 1

Coccus (spherical), Bacillus (rod-shaped), Vibrio (curved rod), Spirillum (stiff spiral), Spirochete (flexible spiral), Coccobacillus (intermediate between coccus and bacillus), and Pleomorphic (variable shape).

Question 2

What is the difference between spirillum and spirochete?

Answer 2

Spirillum is a stiff, spiral-shaped bacterium, while spirochete is a flexible, spiral-shaped bacterium.

Question 3

What is a coccobacillus?

Answer 3

A shape that is intermediate between spherical (coccus) and rod-shaped (bacillus).

Question 4

Define pleomorphic bacteria.

Answer 4

Bacteria that vary in shape and size.

Question 5

What are curved rod-shaped bacteria called?

Answer 5

Vibrio.

Question 6

What bacterial shape is spherical?

Answer 6

Coccus.

Question 7

What bacterial shape is rod-like?

Answer 7

Bacillus.

Question 8

What shape do bacteria with rigid spirals have?

Answer 8

Spirillum.

Question 9

What bacterial morphology involves flexible spirals?

Answer 9

Spirochete.

Question 10

What term describes bacteria with variable shapes?

Answer 10

Pleomorphic.

Question 11

What are the three main methods of prokaryotic reproduction?

Answer 11

Binary fission, snapping division, and budding.

Question 12

What is the most common form of reproduction in prokaryotes?

Answer 12

Binary fission.

Question 13

What is binary fission?

Answer 13

A form of asexual reproduction where a single cell divides into two identical daughter cells.

Question 14

Describe the steps of binary fission.

Answer 14

1. Chromosome replication 2. Cell elongation 3. Septum formation 4. Cell division 5. Repeat process.

Question 15

What is snapping division?

Answer 15

A type of binary fission where only the inner portion of the cell wall is synthesized, causing the outer wall to snap.

Question 16

What bacterial arrangement results from snapping division?

Answer 16

V-shapes and palisades.

Question 17

What is budding in prokaryotes?

Answer 17

An asymmetric form of cell division where a new cell grows from the parent cell as a bud.

Question 18

What type of prokaryotes reproduce by budding?

Answer 18

Some Gram-negative bacteria like Planctomycetes.

Question 19

How does the chromosome replicate in binary fission?

Answer 19

It attaches to the cytoplasmic membrane and replicates before cell elongation.

Question 20

How does snapping division differ from binary fission?

Answer 20

Only the inner cell wall is synthesized, leading to a snap-like break of the outer wall.

Question 21

What structural feature forms during budding?

Answer 21

A stalk for attachment.

Question 22

What is a common outcome if cells remain attached after binary fission?

Answer 22

They form chains.

Question 23

What are the five types of prokaryotic symbiotic relationships?

Answer 23

Mutualism, commensalism, parasitism, amensalism, and neutralism.

Question 24

Define mutualism and provide an example.

Answer 24

Both organisms benefit; e.g., gut microbiota providing vitamins to humans.

Question 25

Define commensalism and provide an example.

Answer 25

One organism benefits while the other is unaffected; e.g., Staphylococcus epidermidis on human skin.

Question 26

Define parasitism and provide an example.

Answer 26

One organism benefits while harming the other; e.g., pathogenic bacteria infecting a host.

Question 27

Define amensalism and provide an example.

Answer 27

One organism is harmed while the other is unaffected; e.g., antibiotic-producing fungi killing nearby bacteria.

Question 28

Define neutralism and provide an example.

Answer 28

Both organisms are unaffected; e.g., dormant endospores next to active bacteria.

Question 29

What is symbiosis?

Answer 29

Close, long-term interaction between two different species.

Question 30

What type of relationship do methanogens have in a cow’s gut?

Answer 30

Mutualism; methanogens help reduce acidity and receive nutrients.

Question 31

How do bacteria contribute to cow digestion?

Answer 31

They break down cellulose into simple sugars for fermentation.

Question 32

What is microbial ecology?

Answer 32

The study of relationships between microorganisms and their environments.

Question 33

Name three structural differences between archaea and bacteria.

Answer 33

Archaea lack peptidoglycan, have ether-linked lipids, and unique attachment structures like hami.

Question 34

What is the main structural difference in cell walls between archaea and bacteria?

Answer 34

Archaea lack peptidoglycan, some have pseudomurein, lipid monolayers rather than bilayers, cytoplasmic mem lipids can be branched or ring form rather than straight chains.

Question 35

How do archaeal membranes differ from bacterial membranes?

Answer 35

Archaea have ether-linked lipids, while bacteria have ester-linked lipids.

Question 36

What unique structure do some archaea use for attachment?

Answer 36

Hami (grappling-hook-like appendages).

Question 37

How do archaeal flagella (archaella) differ from bacterial flagella?

Answer 37

Archaella are powered by ATP hydrolysis, not proton motive force.

Question 38

What type of genetic material do both archaea and bacteria have?

Answer 38

Circular chromosomes.

Question 39

Do archaea or bacteria have histones?

Answer 39

Archaea have histones; bacteria do not.

Question 40

What is the starting amino acid for protein synthesis in archaea?

Answer 40

Methionine (like eukaryotes).

Question 41

Which domain of life can produce methane?

Answer 41

Archaea (methanogens).

Question 42

Are archaea or bacteria more likely to live in extreme environments?

Answer 42

Archaea (extremophiles).

Question 43

What are two types of archaeal cell walls?

Answer 43

S-layer (protein shell) and pseudomurein.

Question 44

What makes archaeal membranes stronger in extreme environments?

Answer 44

Lipid monolayers (ether linkage)) and branched tails (phytanyl).

Question 45

What are methanogens?

Answer 45

Archaea that produce methane by reducing CO2 or organic acids.

Question 46

Where are methanogens commonly found?

Answer 46

Cow guts, wetlands, and ocean sediments.

Question 47

What are extremophiles?

Answer 47

Organisms that thrive in extreme environments.

Question 48

What are halophiles?

Answer 48

Archaea that require high salt concentrations.

Question 49

What are thermophiles?

Answer 49

Archaea that thrive at temperatures above 45°C (DNA, RNA, cytoplasmic membranes, and proteins do not function properly below 45°C). Hyperthermophiles need temp.s over 80°C.

Question 50

What is the temperature range for hyperthermophiles?

Answer 50

Above 80°C.

Question 51

What archaeal genera are hyperthermophiles?

Answer 51

Thermococcus (60°C and 80°C in hydrothermal vents) and Pyrodictium (80°C and 105°C in deep sea thermal vents).

Question 52

What is chemosynthesis?

Answer 52

Using inorganic molecules to produce organic compounds.

Question 53

How do archaea survive in hydrothermal vents?

Answer 53

By using chemosynthesis of sulfur-rich compounds.

Question 54

What structural adaptation helps halophiles balance osmotic pressure?

Answer 54

Osmoprotectants (small organic molecules with a neutral charge & low toxicity). Ramp up concentration of things like amino acids and sugars in their cytoplasm to help balance high salt concentration outside of cells.