Lecture 21 - Prokaryotes 1

Question 1

Where do prokaryotes thrive?

Answer 1

• almost everywhere

- even too acidic, salty, cold , or hot for other organisms

Question 2

Are prokaryotes macroscopic or microscopic?

Answer 2

microscopic

Question 3

What are the two domains of prokaryotes?

Answer 3

1. bacteria

2. archaea

Question 4

What are the 3 elements of the tree of life?

Answer 4

1. bacteria
2. archaea
3. eukaryotes

Question 5

Archaea are more closely related to ______ than to ________

Answer 5

Eukaryotes, Bacteria

Question 6

What were earth’s first organisms?

Answer 6

prokaryotes

Question 7

Are prokaryotes uni or multicellular?

Answer 7

unicellular, but some species form colonies

Question 8

How small are most prokaryotic cells?

Answer 8

0.5-5 micron

Question 9

What are the 3 most common shapes of prokaryote cells?

Answer 9

1. spheres (cocci
2. rods (bacilli)
3. spirals

Question 10

What is trichodesmium?

Answer 10

colonial marine nitrogen-fixing cyanobacterium

Question 11

What is the important feature of nearly all prokaryotic cells?

Answer 11

cell wall

Question 12

What do cell walls do?

Answer 12

• maintains cell shape
• protects cell
• prevents it from bursting in a hypotonic environment

Question 13

What are eukaryote cell walls made of?

Answer 13

• cellulose

- chitin

Question 14

What are bacterial cell walls made of?

Answer 14

peptidoglycan

Question 15

What is peptidoglycan?

Answer 15

• network of sugar polymers

- cross-linked by polypeptides

Question 16

What doe archaea contain? lack?

Answer 16

• polysaccharides + proteins

- lack peptidoglycan

Question 17

What is a gram stain used for?

Answer 17

to classify bacteria by cell wall composition

Question 18

What will a gram-positive bacteria have?

Answer 18

-simpler walls with a large amount of peptidoglycan

Question 19

What do gram-neg bacteria have?

Answer 19

• less peptidoglycan

- outer membrane that can be toxic

Question 20

What do many antibiotics target? What do they do?

Answer 20

• peptidoglycan

- damage bacterial cell walls

Question 21

Which type are more likely to be antibiotic resistant?

Answer 21

gram-negative

Question 22

What also covers many prokaryotes?

Answer 22

capsule (slime layer)

Question 23

What is an endospore?

Answer 23

• seed that forms inside cell (with DNA)

- inactive, can remain viable in harsh conditions for centuries

Question 24

What do fimbriae do?

Answer 24

-allow prokaryotes to stick to their substrate or other individuals in a colony

Question 25

What are pili?

Answer 25

- longer than fimbriae | - allow prokaryotes to exchange DNA

Question 26

What are taxis?

Answer 26

ability to move toward or way from a stimulus

Question 27

What is chemotaxis?

Answer 27

-movement toward or away from chemical stimulus

Question 28

How do motile bacteria propel themselves?

Answer 28

-flagella scattered about the surface or concentrated at one or both ends

Question 29

What are flagella composed of?

Answer 29

- different proteins | - likely evolved independently

Question 30

What is phototaxis?

Answer 30

-movement toward or away from light

Question 31

What are the 3 parts of a flagella?

Answer 31

1. motor 2. hook 3. filament

Question 32

What is exaptation?

Answer 32

existing structures take on new functions through descent with modification

Question 33

prokaryotic cells usually lack

Answer 33

- complex compartmentalization | - organelles

Question 34

what do some prokaryotes have? specialized _____

Answer 34

membranes that perform metabolic functions

Question 35

the _____ genome has less DNA than the _____ genome

Answer 35

prokaryotic, eukaryotic

Question 36

what does most of the genome consist?

Answer 36

circular chromosome

Question 37

where is the chromosome located?

Answer 37

in the nucleoid region

Question 38

What are plasmids?

Answer 38

smaller rings of DNA

Question 39

What is the benefit of having differences between prokaryote and eukaryotic DNA replication, transcription, translatioN/

Answer 39

-allow people to use some antibiotics without harming themselves

Question 40

How do prokaryotes reproduce?

Answer 40

binary fission

Question 41

What are 3 key features of prokaryotic reproduction?

Answer 41

1. they are small 2. they reproduce by binary fission 3. short generation times

Question 42

What is an example of an extremophile bacteria?

Answer 42

-endoliths

Question 43

What are endoliths?

Answer 43

live inside rocks + between mineral grains

Question 44

What are 3 qualities of endoliths?

Answer 44

1. found as deep as 2 miles below surface 2. most are chemoautogtorphs 3. reproduce maybe once per century

Question 45

What is characteristic of prokaryotic offspring?

Answer 45

generally identic

Question 46

Mutation rates are ____ during binary fission

Answer 46

low

Question 47

What is a result of rapid reproduction?

Answer 47

mutations can accumulate rapidly in a population

Question 48

Are prokaryotes primitive?

Answer 48

highly evolved

Question 49

What is the Lenski long-term evolution experiment?

Answer 49

- ongoing study in experimental evolution | - tracking genetic changes in 12 initially identical populations

Question 50

How can prokaryotic DNA be brought together?

Answer 50

-transformation, transduction, conjugation

Question 51

what is horiziontal gene transfer

Answer 51

-move through completely unrelated bacteria species

Question 52

what happens in transformation?

Answer 52

-prokaryotic cell take up and incorporate DNA from surrounding environment

Question 53

What is transduction?

Answer 53

movement of genes between bacteria by bacteriophages

Question 54

What are the 5 steps of a virus infecting bacteria?

Answer 54

``` 1. 2. 3. 4. 5. ```

Question 55

What is conjugation?

Answer 55

process where genetic material is transferred between prokaryotic cells

Question 56

What happens when a donor cell attaches to a recipient?

Answer 56

pulls it closer, transfers DNA

Question 57

what is the F factor?

Answer 57

piece of DNA required for the production of the pili

Question 58

What are 4 steps of conjugation?

Answer 58

1. 2. 3. 4.

Question 59

What does a cell with the F factor built into its chromosomes function as?

Answer 59

donor during conjugation

Question 60

What does the recipient become?

Answer 60

recombinant bacterium (DNA from 2 different cells)

Question 61

What are R plasmids?

Answer 61

carry genes from antibiotic resistance

Question 62

How do R plasmids work with antibiotics?

Answer 62

resistant to antibiotics

Question 63

What are phototrophs?

Answer 63

obtain energy from light

Question 64

What are chemotrophs?

Answer 64

obtain energy from chemicals

Question 65

What are autotrophs?

Answer 65

require CO2 as carbon source

Question 66

What are heterotrophs?

Answer 66

require organic nutrient to make organic compounds

Question 67

What are 4 major modes of nutrition?

Answer 67

1. photoautotorphy 2. chemoautotrophy 3. photoheterotrophy 3. chemoheterotropy

Question 68

What are obligate aerobes?

Answer 68

require O2 for cellular respiration

Question 69

What are obligate anaerobes?

Answer 69

- poisoned by O2 | - use fermentation or anaerobic respiration

Question 70

What are facultative anaerobes?

Answer 70

can survive with or without O2

Question 71

What is nitrogen essential for?

Answer 71

production of amino acids, nucleic acids

Question 72

What is nitrogen fixation?

Answer 72

some prokaryotes convert N2 to NH3

Question 73

what are heterocysts?

Answer 73

nitrogen fixing cells

Question 74

what happens in cyanobacterium Anabaena?

Answer 74

-photosynthetic cells + heterocysts exchange metabolic products