2.2

Question 1

what does the bacteria cell wall do

Answer 1

hypertonic contents so water moves in by osmosis
prevents swelling and bursting
maintains the shape of the bacterium
support and protection to contents of cell
some have slime capsule protects from phagocytis by white blood cells

Question 2

peptidoglycan

Answer 2

all cell walls consist of a layer
made up of many parallel polysaccharide chains with short peptite cross linkages making net like structure

Question 3

pili

Answer 3

some bacteria have one to several hundred protein projections
used for attachment to host cell and sexual reproduction
more vunrable to bacteriaphage (virus)

Question 4

cell surface membrane

Answer 4

similar in both pro and eu but pro have no mitochondria so membrane is site of some respiratory enzymes
some have mesomes

Question 5

plasmid

Answer 5

small circles of dna
codes for a particular aspect of the bacterial phenotype
can reproduce independently of the nucleoid
can be transfered by pili

Question 6

nucleoid

Answer 6

genetic material conists of single length of dna often circular not contained in the membrane bound nucleus found in the nucleoid

Question 7

gram postive

Answer 7

thick later of peptidoglycan
staining trapped in layer so remains purple
has teicholic acid
no outer membrane
no lipids

Question 8

gram negative

Answer 8

thin later of peptidoglycan
staining goes pink
no teichonic acid
outer membrane
has lipids

Question 9

antibiotics

Answer 9

some inhibit formation of peptioglycan therfor affective against positive
some can penetrate thin negative layer but cannot get through positive

Question 10

shapes of bacteria

Answer 10

spherical - cocci
rod - bacilli
twisted - spirilla
comma - vibrios

Question 11

obligate aerobes

Answer 11

need oxygen for respiration

Question 12

faculitative aerobes

Answer 12

use if available but can manage without

Question 13

obligate anerobes

Answer 13

can only respire when no oxygen

Question 14

virus structure

Answer 14

some have envelope which makes easy to pass but more vunrable to substances entering
capsid (protein coat) is made of repeating units (capsomeres)

Question 15

dna viruses

Answer 15

genetic material is dna
acts as template for both new dna and mrna needed for viral proteins
e.g
- small pocks
-lamda phage

Question 16

rna viruses

Answer 16

70% have rna
much more likely to mutate
positive sense
can be translated at ribosomes
-tobacco mosaic
-polio
-hepatitis c
negative sense
- ebola
-measles
must be translated before translated at the ribosomes

Question 17

lytic pathway

Answer 17

virus attaches to host cell
inserts genetic material
viral proteins made
virus multiplys by DNA replication
cells lyses viruses released
virulent (disease causing)

Question 18

viral entering cell

Answer 18

endocytosis then host digests capsid releasing genetic material
viral envelope fuses with the host cell surface releasing rest of the virus
vector

Question 19

lysogenic

Answer 19

non virulent
they insert their dna into the host dna so it is replicated everytime the host replicates
host is a provirus
virus is latent
however if the host is damaged it can enter the lytic pathway

Question 20

rna retrovirus

Answer 20

protein capsid and lipid envelope
single strand rna directs enzyme reverse transcriptase this goes on to make dna corresponding to the viral genome
incorporated into the host cell dna and used as template
-hiv

Question 21

positive rna virus replication

Answer 21

makes rna polymerase which replicates the viral rna

Question 22

negative rna replication

Answer 22

antisense strand must be translated into sense strand by rna replicase

Question 23

rna retrovirus replication

Answer 23

translate the viral rna into dna by reverse transcriptase then passes into the nucleus of host cell and inserted into dna new viral material is syntehsised and the new particles leave by exocytosis and the host cell continues function and virus making

Question 24

how to stop virus

Answer 24

target enzymes help translate or replicate the viral dna or rna
inhibit the enzymes that enable new virus particles to bud

Question 25

development of medicines

Answer 25

research and development
pre clinical research - tests on cells and animals
cinical research - human trials
fda approval
post market safety monitering

Question 26

ethics of fast tracking vaccines

Answer 26

severtiy
availably of other treatments
freedom of choice
involvement in the community
who gets drug
informed consent

Question 27

methods of identification

Answer 27

lab tests
spinal tap
blood tests
urine tests
biopsies

Question 28

needs oxygen for respiration

Answer 28

obligate aerobes

Question 29

cannot respire in oxygen

Answer 29

obligate anaerobes

Question 30

can respire with and without oxygen

Answer 30

facculate aerobes

Question 31

why can you not use antibiotics on viruses

Answer 31

viruses are non living
no cell wall
so can mean antibiotic resistance

Question 32

dna viruses

Answer 32

lambda phage
-complex protein capsid
-non enveloped

Question 33

salmonella

Answer 33

gram negative
endotoxins

Question 34

delay before lysing in cells

Answer 34

genetic material needs to enter
synthesis of DNA
protein synthesis
new virus particles

Question 35

latent

Answer 35

virus dna integrated into host cell
virus is dormant
virus nucelic acid replicates when host divides

Question 36

rna virus

Answer 36

surrounded by protein coat
Hiv
- reverse transcriptase
-polyhedral capsid
-enveloped
ebola
-enveloped
tobacco mosaic
-non enveloped