Cell Structure General

Question 1

what are the 4 processes of life?

Answer 1

growth, reproduction, responsiveness, metabolism

Question 2

do viruses have membranes?

Answer 2

no they neither have cell walls nor cell membranes

Question 3

give 4 generalities about prokaryotes

Answer 3

lack a nucleus, lack internal structres bound with phospholipid membranes, are 1.0 micrometer in diameter or smaller

Question 4

give the 2 divisions (taxa) of prokaryotes

Answer 4

archaea and bacteria

Question 5

do prokaryotes have cell membranes

Answer 5

yes

Question 6

how do prokaryotes reproduce

Answer 6

asexually

Question 7

how are prokaryotes normally structured

Answer 7

single, in pair, chain or clusters

Question 8

what is the glycocalyx

Answer 8

it is the gelatinous sticky substance made of polysaccharides/polypeptide surrounding the outside of the cell

Question 9

what are the 2 kinds of glycocalyxes

Answer 9

• capsule: made of repeating units of chemicals attaches to cell surface. May prevent bacteria being recognised by host
• slime layer: loosely attached to cell surface, water soluble. sticky layer allows prokaryotes to attach to surfaces

Question 10

dessication

Answer 10

drying out of an organism

Question 11

give 3 functions of the glycocalyx

Answer 11

• prevents dessication
• prevents recognition by phagocytes
• favours attachment to surfaces as biofilm

Question 12

flagella are used to sense wetness ?

Answer 12

true

Question 13

what are the 3 parts of a flagellum

Answer 13

• filament: is hollow, made of globular flagellin proteins in a clockwise manner
• hook: is a proteic curved structure into which the filament inserts
• basal body: is proteic, anchors the filament and hook to cell wall and membrane through integral proteins

Question 14

function of flagella

Answer 14

• propel through environment
• rotation is reversible
• move bacteria in response to stimulus

Question 15

SLIDE

Answer 15

7 8 30 36

- bacteria in biofilms behaves differently than individual bacteria

Question 16

when does motion occur in peritrichous bacteria

Answer 16

runs occur when all of the flagella rotate counterclockwise and become bundled. Tumbles occur when the flagella rotate clockwise

Question 17

what are spirohetes

Answer 17

spiral shaped bacteria, endoflagellum or axial filament is found between the cytoplasmic and outer membranes - this helps corkscrew mobility.

Question 18

bacteria associated with syphilis

Answer 18

treponema pallidum

Question 19

bacteria associated with lyme disease

Answer 19

borrelia burgdorferi

Question 20

what are fimbriae

Answer 20

are rodlike, proteins, sticky, adhere to each other or substances in the environment

Question 21

functions of fimbriae

Answer 21

adhesion to mucous membranes, movement across a surface through attachment and retraction. adhesion to substrate forming biofilms. conduction of electrical signals among cells in a biofilm

Question 22

pilus

Answer 22

special type of fimbria, ONE, longer than fimbria, shorter than flagella, one or few per cell, for transfer of DNA

Question 23

what is a Biofilm

Answer 23

is when layered systems of bacteria and microbes attach to a surface

Question 24

biofilms are harmful?

Answer 24

yes they cause disease, drain clogging, lung infection of CF.

Question 25

how do biofilms communicate

Answer 25

chemical and electrical signals

Question 26

structures of - streptococci - staphylococci - sarcinae

Answer 26

- chains - clusters - cuboidal packets

Question 27

role of bacterial cell wall

Answer 27

protection from osmotic forces. attachment to to other cells, resistance to antimicrobial drugs

Question 28

explain peptidoglycan

Answer 28

``` peptido = tetrapeptides bonded to one another by short connecting chains of other amino acids. remember that the amino acids of cross linking differ among bacteria species glycan = N-acetylglucosamine and N acetylmuramic acid linked chains ```

Question 29

Gram positive cell walls

Answer 29

a thick layer of peptidoglycan containing teichoic acids and lipoteikoic acids anchoring peptidoglycan to the cytoplasmic membrane. . remember that this retains crystal violet dye. Mycobacterium has mycolic acid that protects from dessication - a fast acid stain is used

Question 30

gram negative bacteria

Answer 30

thin layer of peptidoglycan, the outer bilayer membrane has an inner (phospholipids and proteins) and outer (lipid A/endotoxin and sugar) leaflet Have porins, the periplasmic space has peptidoglycan and periplasm

Question 31

explain lipopolysaccharide structure

Answer 31

- O side chain: target for recognition by host antibodies - Core domain - Lipid A: is released upon bacterial death or replication. TLR4 causes fever, shock, vasoldilation, blood clotting, and inflammation

Question 32

function of bacterial cytoplasmic membranes

Answer 32

- energy store - harvest light energy - selectively permeable - impermeable to most substances - maintain gradients

Question 33

TWO, cells without a cell wall are

Answer 33

mycoplasms, animal cells

Question 34

give 2 examples of endospores

Answer 34

bacillus and clostridium

Question 35

what are endospores

Answer 35

A defensive strategy against hostile or unfavorable conditions. A vegetative cell transform into one endospore when multiple nutrients are limited. The spore germinates to grow into only one vegetative cell. spores are extremely resistant

Question 36

give 3 endospore producing toxins

Answer 36

tetanus, anthrax, gangrene

Question 37

bacterial ribosomes are 70S there are 2 possibilities

Answer 37

30S, polyptides and one ribosomal rRNA, | 50S, polyptides and two ribosomal rRNA

Question 38

no archea is

Answer 38

pathogenic

Question 39

archae have cell walls that are not made of

Answer 39

peptidoglycan

Question 40

flagella are the same in prokaryotes and eukaryotes

Answer 40

no, shaft is made of glubular tubulin arrangeed into microtubules

Question 41

ribosomes of eukaryotes

Answer 41

80S = 40S +60S

Question 42

mitochondria ribosomes

Answer 42

70S prokaryotic