prokaryotes

Question 1

what do prokaryotes lack

Answer 1

• nucleus and membrane bound organelles

Question 2

where is their DNA

Answer 2

• nucleiod

Question 3

what shape is their DNA

Answer 3

circular

Question 4

do they have a cytoskeleton

Answer 4

no, they have cell wall

Question 5

what is a plasmid

Answer 5

small molecule of DNA seperate from chromosome

Question 6

what are some extra things prokaryotes have to protect themselves

Answer 6

• capsule (large polusac coting)
• endospores: form in response to bad conditions, bacteria in endospores can lay dormant, until conditions get better , prevent from dying

Question 7

what is different with archae cell wall compared to bacteria

Answer 7

No peptidoglycan , chemical composition is diff

Question 8

what does archae have in common with bacteria

Answer 8

• no membranous organelles
• no nucleus
• circular DNA

Question 9

what are the different groups of archae

Answer 9

• mathanogens (release methan, found in anaerobic environements)
  -halophiles (found is saline conditions)
• thermophiles (hot environemtns)

Question 10

how do bacteria introduce genetic variability

Answer 10

• bacteriel conjugation

Question 11

what is bacteriel conjugation

Answer 11

• direct transfer of genetic materiel between two physically linked bacteriel cells by pilus

Question 12

what is the use of plasmids

Answer 12

• constitute an extra pool of genes
• can be resistant to certain antibiotics, which then makes creation of bacteria resistent to that antibiotic possible
• when antiobiotic given, kills non resistant bacteria, but the one’s that survive procreate and then more resistant bacteria are formed

Question 13

what is the ecological significance of bacteria

Answer 13

• decomposers, saphrophytes (organisms that feed on dead organic matter)
• mutualistic symbionts (two animals life together, in a useful manner)
• producers in phytoplankton
• nitrogen fixation

Question 14

what are different ways they can get their carbon

Answer 14

• autotrophs ; atmospheric CO2 (from air)
• Heterotrophs ; organic compounds like sugar, ats, amino-acids and proteins

Question 15

what are different ways they can get their energy

Answer 15

• chemotrophs : energy from chemical bonds (organic or inorganic)
• phototrophs : radiant energy from the sun

Question 16

what are the different nutritional modes

Answer 16

• photoautotrophs
• photoheterotrophs
• chemoautotrophs
• chemoheterotrophs

Question 17

what are photoautotrophs

Answer 17

• most plants, some prokaryotes, some protists
• energy from sun, carbon from athmosphere

Question 18

what are photoheterotrophs

Answer 18

• prokaryotes only
• energy from sun , carbon in organic form (other living things)

Question 19

what are chemoautotrophs

Answer 19

• prokaryotes
• energy from chemical bonds (organic or inorganic), carbon from athm. CO2

Question 20

what are chemoheterotrophs

Answer 20

• all animals, fungi, many protists and prokaryotes
• energy from chemical bonds (organic or inorganic) , carbon in organic form

Question 21

what are obligate aerobes

Answer 21

need oxygen for cell resp

Question 22

what are obligate anaerobes

Answer 22

oxygen is toxic, not used for cell resp

Question 23

what are faculative anaerobes

Answer 23

can perform cellular respiration with or without oxygen

Question 24

how do prokaryotes reproduce

Answer 24

binary fission

Question 25

how do some bacteria survive hostile conditions

Answer 25

produce endospores

Question 26

what are methanogens

Answer 26

- anaerobic environenments - release methane as waste product

Question 27

what are halophiles

Answer 27

- found in dead sea - extreme saline conditions

Question 28

what are thermophiles

Answer 28

- hot environments (45 to 104 degres)

Question 29

how does archae differ from bacteria regarding DNA and RNA

Answer 29

- they have histones associated to their DNA like eukaryotes - have unique RNA sequences

Question 30

what are the different cell shapes

Answer 30

- cocci = sphere - bacilli = rods Spirilla = spirals

Question 31

what is the prefix for a chain shaped colony

Answer 31

strepto

Question 32

what is the prefix for a clumped shaped colony

Answer 32

staphylo

Question 33

what is the prefix for a spiral shaped colony

Answer 33

spirilla

Question 34

where is the DNA located in prokaryotes

Answer 34

- in the cytoplasm, not surrounded by membrane, nucleiod region

Question 35

what do they have , additionally to their DNA, what is special about it

Answer 35

- plasmids , small fragment of DNA - can be transfered during bacteriel conjugation

Question 36

what does bacteria use for the gene transfers ?

Answer 36

- they use a sex pilus

Question 37

check evolutionary importance of plasmids *

Question 38

do antibiotics cause resistance ?

Answer 38

No, they create an environment that favors the growth of resistant variants , by not killing those variants

Question 39

what is the major role of bacteria in the environment

Answer 39

- decomposition of organic materiels and recycling of nutrients -

Question 40

what is a saprophyte

Answer 40

Organisms that get substances it needs from decomposing organic matter

Question 41

what is another role of bacteria in the environment

Answer 41

mutualistic symbionts , they live in the guts of herbivores, who eat plants, but do not produce the enzymes to decompose the cellulose

Question 42

how are bacteria mutual symbionts with humans

Answer 42

- gut symbionts produce essential vitamins like e. coli - they also help pathogens from invading - symbionts of the skin and mucosas prevent infection

Question 43

what is bacteria's relationship with nitrogen

Answer 43

they are nitrogen fixers , so organisms can use them - fix nitrogen in nodules on plant roots

Question 44

where does nitrogen fixation occur

Answer 44

cyanobacteria colonies have specialised cells, heterocysts, where nitrogen fixation occurs