Lecture 19- Prokaryotes

Question 1

Prokaryotes

Answer 1

Single celled organisms that make up domains Bacteria and Archaea; adapted to diverse and extreme environments and are the make abundant organisms on Earth

Question 2

prokaryote shapes

Answer 2

cocci (spheres), bacilli (rods), spirals

Question 3

function of prokaryotic cell wall

Answer 3

Maintains shape, protects the cell, prevents bursting in hypotonic environment

Question 4

bacterial cell wall

Answer 4

contain peptidoglycan, a network of sugar polymers cross linked by polypeptides

Question 5

archaea cell walls

Answer 5

contain a variety of polysaccharides and proteins, but lack peptidoglycan

Question 6

gram positive bacteria

Answer 6

Simpler walls with large amount of peptidoglycan

Question 7

gram negative bacteria

Answer 7

Less peptidoglycan, more complex with an outer membrane that contains lipopolysaccharides, stains pink

Question 8

Capsule

Answer 8

Dense and well defined sticky layer of polysaccharide or protein surrounding the cell wall; slime wall if not well organized; sticky layer of polysaccharides or proteins

Question 9

capsule functions

Answer 9

enable adherence to substrate or others, prevent dehydration, protest cell from host’s immune system

Question 10

Fimbriae

Answer 10

hairlike appendages to stick to their substrate or others;

Question 11

Pili

Answer 11

sex pili; longer than fimbriae and put cells together enabling exchange of DNA

Question 12

endospores

Answer 12

a response to rapid environmental changes; metabolically inactive; cell copies chromosome and surrounds with multilayered structure; EXTREME CONDITIONS

Question 13

Taxis

Answer 13

the ability to move towards or away from a stimulus; flagella commonly used

Question 14

flagella

Answer 14

operate on harnessing a chemical gradient to power movement; kinetic;

Question 15

internal organization of prokaryotic cells

Answer 15

lack complex compartmentalization, some have specialized membranes that perform metabolic functions- infoldings of the cell membrane; aerobic vs. photosynthetic

Question 16

prokaryotic genetic material

Answer 16

one circular chromosome, contained in nucleoid (no membrane); some contain plasmid

Question 17

plasmid

Answer 17

smaller rings of independently replicating DNA; carry addition genes that can be beneficial (antibody resistance), easy to manipulate

Question 18

high levels of prokaryotic genetic diversity due to

Answer 18

rapid reproduction, mutation, genetic recombination

Question 19

prokaryotic rapid reproduction

Answer 19

binary fission, divide every 1-3 hours; (small, binary fission, short generation times)

Question 20

prokaryotic mutation

Answer 20

mutation rates low, but accumulate with short generation times and large populations; rapid adaptation

Question 21

prokaryotic genetic recombination

Answer 21

transformation, conjugation, transduction; horizontal gene transfer (vertical is hereditary)

Question 22

transformation

Answer 22

incorporate foreign DNA taken up by their surroundings, bacteria must be competent (permeable by chemical or heat shock)

Question 23

transduction

Answer 23

phages (bacteriophages) carry prokaryotic genes from one host cell to another; unintended result of phage replicative cycle

Question 24

conjugation

Answer 24

DNA is transferred between two prokaryotic cells, PILUS of donor attaches to recipient, cells pulled together, DNA transferred through mating bridge

Question 25

F factor

Answer 25

piece of DNA required for the production of pili, exists as plasmid or segment of DNA in bacterial chromosome (fertility)

Question 26

F plasmids

Answer 26

cell containing F plasmid acts as DNA donor; encodes genes for sexual pili and activate DNA synthesis, F+ can convert F- to F+ if full plasmid transferred, recombinant is only part

Question 27

conjugation and chromosome

Answer 27

Hfr cells function as donors during conjugation, homologous segments recombine with segments of F- chromosome, new DNA incorporated need to be genetically similar!

Question 28

metabolism

Answer 28

the totality of an organism’s chemical reactions, emergent property

Question 29

metabolic pathways

Answer 29

begin with specific substrate or reactant and end with a product, digestion

Question 30

catabolic pathways

Answer 30

release energy by breaking down complex molecules into simpler compounds (cellular respiration) CAT

Question 30

prokaryotic metabolism

Answer 30

energy and carbon sources combined to give 4 groups

Question 30

anabolic pathways

Answer 30

consume energy to build complex molecules from simpler ones (photosynthesis) WEIGHT LIFTING

Question 31

anabolic prokaryotic pathways

Answer 31

photoautotroph, chemoautotroph

Question 32

catabolic prokaryotic pathways

Answer 32

photoheterotrophh, chemoheterotroph

Question 33

chemoautotrophs

Answer 33

use inorganic molecules to synthesize larger molecules (chemosynthesis), feed on chemicals that are good electron donors, most are extremophiles (living in extreme envcironments)

Question 34

photoautotrophs

Answer 34

trap light energy and convert it to chemical energy, chloroplasts evolve form them (cynobacteria),may be oxygenic or anoxygenic

Question 35

chemoheterotrophs

Answer 35

obtain carbon from other living organisms, break down bonds in complex molecules and harvest energy (cellular respiration), mitochondria evolved (alpha protobacterium)

Question 36

obligate aerobes

Answer 36

require oxygen for cellular respiration

Question 37

obligate anaerobes

Answer 37

poisoned by oxygen and live by fermentation or use other substances

Question 38

facultative anaerobes

Answer 38

can use oxygen if presents or carry out fermentation or anaerobic respiration if not

Question 39

photoheterotrophs

Answer 39

can’t use carbon dioxide so they break down larger organic molecules; capture light energy to convert to chemical energy