Lecture 21 - Prokaryotes 1 (SI) Flashcards Preview

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Flashcards in Lecture 21 - Prokaryotes 1 (SI) Deck (40):
1

Cell wall

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

2

Chitin

makes up fungal (+heliozoa) cell walls

3

Cellulose

makes up plant cell walls

4

What is archae cell wall composed of?

-polysaccharides
-proteins

5

Peptidoglycan

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

6

_____ contains a lot of peptidoglycan and ______ contains little peptidoglycan

-gram pos. contains a lot
-gram neg. contains little

7

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

gram negative

8

Capsule

-polysaccharide or protein layer covering most prokaryotes

9

Nucleoid

chromosomal region in prokaryotes

10

Endospore

-original cell produces copy of its chromosomes
-surrounds that copy with tough multilayered structure

11

Plasmids

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

12

What do fimbriae do?

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

13

Pili

-longer than fimbriae
-allow prokaryotes to exchange DNA

14

Flagella

-scattered on surface
-spin for propulsion

15

Convergence

evolved independently in each domain

16

Exaptation

-bacterial model composed of motor + hook + filament
-from ancestral secretory system

17

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

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

18

What are 3 key features of prokaryote reproduction?

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

19

3 reasons why prokaryotes have rapid evolution?

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

20

What are endoliths?

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

21

What is genetic recombination?

-combining DNA from 2 sources
-contributes to diversity

22

Conjugation

-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

23

F factor

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

24

R plasmid

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

25

Transduction

-gene movement between bacteria by bacteriophages

26

Transformation

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

27

What are the 4 major modes of nutrition

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

28

Photoautotroph

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

29

Chemoautotroph

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

30

Photohetertroph

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

31

Chemohetertroph

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

32

Nitrogen fixation

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

33

Obligate aerobes

require O2 for cellular respiration

34

Obligate anaerobes

-poisoned by O2
-use fermentation/anaerobic respiration

35

Facultative anaerobes

-survive with or without O2

36

What are heterocysts?

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

37

What are taxis?

-ability to move toward or away from stimulus

38

What is an example of an extremophile bacteria?

-endollith
-grow very slowly

39

What are the two domains of prokaryotes?

1. bacteria
2. arcahaea

40

Archaea are more closely related to ___ than ____

eukaryotes, bacteria