Exam 2: Lecture 9 (Ch. 27)

Question 1

What are Prokaryotes

Answer 1

Single-celled organisms that make up the Bacteria and Archaea domain

Question 2

The _____ ______ maintains shape, protects the cell, and prevents it from bursting

Answer 2

Cell Wall

Question 3

Bacterial cell walls contain ________, which is a network of ________ cross-linked by _______.

Answer 3

Peptidoglycan, sugar polymers, polypeptides.

Question 4

Gram staining

Answer 4

A method of cell staining that identifies bacteria by cell wall composition

Question 5

Gram-positive

Answer 5

Simpler bacterial walls, large amounts of peptidoglycan

Question 6

Gram-negative

Answer 6

More complex walls with outer membranes that contain lipopolysaccharide and less peptidoglycan

Question 7

How does penicillin act as an antibiotic

Answer 7

Penicillin inhibits the synthesis of new bacterial cell walls, leading to death

Question 8

Define how “capsules” and “slime layers” define the structure of prokaryotic cells

Answer 8

Capsules: if bacteria is dense and well defined
Slime Layer: If bacteria is not well organized

Question 9

What is the function of Fimbriae

Answer 9

Allow prokaryotes to stick to their substrates, or others in a colony

Question 10

Pili (sex pili)

Answer 10

Essentially longer fimbriae that allow for cells to pull together and share DNA

Question 11

How are prokaryotes motile

Answer 11

Because they have Flagella, allowing them to move
- Some have many, some have few; and they all differ in their mechanisms for movement

Question 12

What is a Nucleoid

Answer 12

A region with no membrane that holds the prokaryote chromosomes; they lack a nucleus

Question 13

Define the function of plasmids

Answer 13

Independently replicating rings of DNA, different from chromosomes

Question 14

Prokaryotic Transformation

Answer 14

When prokaryotes incorporate foreign DNA from surroundings (not from same species)

Question 15

Prokaryotic Transduction

Answer 15

The carrying of genetic material through phages (viruses for bacteria) from one host to another

Question 16

Prokaryotic Conjugation

Answer 16

When DNA is transferred between two prokaryotic cells
- occurs with Pilus, hairlike structure enabling adhesion, colonization and infection

Question 17

_ ______ carry resistance genes allowing bacteria to survive antibiotics

Answer 17

R Plasmids

Question 18

What are the four metabolic adaptations of prokaryotes

Answer 18

1. Phototrophs: Energy from light
2. Chemotrophs: Energy from chemicals
3. Autotrophs: Energy from CO2 or other carbon materials
4. Heterotrophs: Organic nutrient intake to make other organic compounds (usually eat autotrophs, ex; humans eat plants)

Question 19

Name and define the three oxygenic prokaryotic metablisms

Answer 19

1. Obligate Aerobes: require O2 for cellular respiration
2. Obligate Anaerobes: poisoned by O2, live by fermentation
3. Facultative Anaerobes: can use O2 if present, if not they fall back on fermentation.

Question 20

How do prokaryotes cooperate

Answer 20

Photosynthetic prokaryotes feed carbohydrates to nitrogen-producing prokaryotes.

Question 21

the process of metabolic cooperation

Answer 21

Cells cooperate to produce surface-coating colonies (bio-films) —> cells near edge signal to recruits more cells —> biofilm allows nutrients to reach cells, and waste to be expelled

Question 22

What are of the harms of biofilms

Answer 22

• Corrosion of metals
• Contamination of medical devices
• Tooth Decay
• Antibiotic resistant infection

Question 23

Extremophiles

Answer 23

Archaea that live in extreme environments
- halophiles: tolerate highly saline environments
- Thermophiles: tolerate high temperatures

Question 24

Define T A C K

Answer 24

TACK is the supergroup composed of the closely-related clades of archaea
1. Thaumarchaeota
2. Aigarchaeota
3. Crenarchaeota
4. Korarchaeota

Question 25

__________ are obligate anaerobes that produce _______ as a byproduct of their metabolism

Answer 25

Methanogens, methane