Lecture 21 - Prokaryotes 1 (SI)

Question 1

Cell wall

Answer 1

• maintains cell shape
• protects cell
• prevents it from bursting (hypotonic)

Question 2

Chitin

Answer 2

makes up fungal (+heliozoa) cell walls

Question 3

Cellulose

Answer 3

makes up plant cell walls

Question 4

What is archae cell wall composed of?

Answer 4

• polysaccharides

- proteins

Question 5

Peptidoglycan

Answer 5

• cross-linked sugar polymers
• make up bacteria cell walls
• targeted by antibiotics

Question 6

_____ contains a lot of peptidoglycan and ______ contains little peptidoglycan

Answer 6

• gram pos. contains a lot

- gram neg. contains little

Question 7

Which type of bacteria tends to be more toxic/pathogenic?

Answer 7

gram negative

Question 8

Capsule

Answer 8

-polysaccharide or protein layer covering most prokaryotes

Question 9

Nucleoid

Answer 9

chromosomal region in prokaryotes

Question 10

Endospore

Answer 10

• original cell produces copy of its chromosomes

- surrounds that copy with tough multilayered structure

Question 11

Plasmids

Answer 11

• smaller rings of DNA scattered throughout prokaryotic cells
• R carries resistance quality

Question 12

What do fimbriae do?

Answer 12

-allow them to stick to their substrate + other individuals in a colony

Question 13

Pili

Answer 13

• longer than fimbriae

- allow prokaryotes to exchange DNA

Question 14

Flagella

Answer 14

• scattered on surface

- spin for propulsion

Question 15

Convergence

Answer 15

evolved independently in each domain

Question 16

Exaptation

Answer 16

• bacterial model composed of motor + hook + filament

- from ancestral secretory system

Question 17

What is the order of structures of a gram-neg. bacteria from outside to in?

Answer 17

1. capsule
2. membrane composed mostly of lipopolysaccharide
3. peptidoglycan
4. membrane composed mostly of phospholipids

Question 18

What are 3 key features of prokaryote reproduction?

Answer 18

1. prokaryotes are small (.5-5mm)
2. short regeneration time (except endoliths)
3. binary fission

Question 19

3 reasons why prokaryotes have rapid evolution?

Answer 19

1. exchange of genetic material
2. short generation times
3. large populations

Question 20

What are endoliths?

Answer 20

• organisms that live inside rocks + between mineral grains
• chemoautotrophs
• reproduce maybe once per century

Question 21

What is genetic recombination?

Answer 21

• combining DNA from 2 sources

- contributes to diversity

Question 22

Conjugation

Answer 22

• DNA is transferred between 2 prokaryotic cells (usually of same species) that are temporarily joined
• bacteria, DNA transfer always one way
• cell donates DNA, other receives it

Question 23

F factor

Answer 23

• presence of this particular piece of DNA determines ability to form pili
• donate DNA during conjugation

Question 24

R plasmid

Answer 24

• carry genes for antibiotic resistance

- fraction of bacteria with genes from resistance increase in population exposed to antibiotics

Question 25

Transduction

Answer 25

-gene movement between bacteria by bacteriophages

Question 26

Transformation

Answer 26

-change in genotype and phenotype due to assimilation of external DNA by a cell

Question 27

What are the 4 major modes of nutrition

Answer 27

1. photoautotrophy 2. chemoautotrophy 3. photoheterotrophy 4. chemoheterotrophy

Question 28

Photoautotroph

Answer 28

(autotroph) E source: light C source: CO2, HCO3 etc EX: cynatobcteria, plants, algae

Question 29

Chemoautotroph

Answer 29

(autotroph) E source: inorganic chemicals C source: CO2, HCO3 etc EX: sulfolobus

Question 30

Photohetertroph

Answer 30

(heterotroph) E source: light C source: organic compounds EX: aquatic + salt-loving (Rhodobacter)

Question 31

Chemohetertroph

Answer 31

(heterotoph) E source: organic compounds C source: Organic Compounds EX: clostridium, many fungi/animals/plants

Question 32

Nitrogen fixation

Answer 32

-convert N2 to ammonia -essential for production of amino acids + nucleic acids EX: anbaena

Question 33

Obligate aerobes

Answer 33

require O2 for cellular respiration

Question 34

Obligate anaerobes

Answer 34

- poisoned by O2 | - use fermentation/anaerobic respiration

Question 35

Facultative anaerobes

Answer 35

-survive with or without O2

Question 36

What are heterocysts?

Answer 36

- photosynthetic cells + nitrogen fixing cells in Anabaena | - exchange metabolic products

Question 37

What are taxis?

Answer 37

-ability to move toward or away from stimulus

Question 38

What is an example of an extremophile bacteria?

Answer 38

- endollith | - grow very slowly

Question 39

What are the two domains of prokaryotes?

Answer 39

1. bacteria | 2. arcahaea

Question 40

Archaea are more closely related to ___ than ____

Answer 40

eukaryotes, bacteria