microbiology

Question 1

what are the 4 parts of a virus?

Answer 1

capsid, dna, sheath and legs/tails

Question 2

what is the function of the capsid?

Answer 2

to protect the viral genome from environmental conditions and to deliver the genome to the interior of a homologous host cell

Question 3

what is the function of the sheath?

Answer 3

acts as a channel for viral genome delivery

Question 4

what is the function of the tail/legs?

Answer 4

contracts and the tails plugs into the cell wall, and underlying membrane, injecting the viral nucleic acids into the cell

Question 5

what is the first event of the lystic cycle and what happens during this step?

Answer 5

infection:
by chance, a virus attaches to host cell and injects it’s genetic material

Question 6

what is the second event of lystic cycle and what happens during this stage?

Answer 6

take over:
host cell cannot distinguish between its own dna and the virus’
(the host cell will then start making rna which will start shutting down and take over)

Question 7

what is the third event of the lystic cycle and what happens during this stage?

Answer 7

replication:
viruses use materials from host cell to make copies of its own genetic material and protein coat.
(genetic material and protein coats are assembled into hundreds of new viruses.)

Question 8

what is the fourth event of lystic cycle and what happens during this stage?

Answer 8

cell lysis:
infected cell bursts and releases new viruses

Question 9

what is the first event of lysogenic cycle and what happens during this stage?

Answer 9

infection
by chance a virus attaches to host cell and injects it’s genetic material

Question 10

what is the second event of lysogenic cycle and what happens during this stage?

Answer 10

incorporation:
virus’ dna is incorporated into hosts dna (prophage/pro virus is viral dna once incorporated)

Question 11

what is third event of lysogenic cycle and what happens during this stage?

Answer 11

dormancy:
host cell continues as if it wasn’t infected
may replicate for many generations
ADVANTAGE: precense of prophage may prevent other viral infections and create useful dna.

Question 12

what is the fourth event of the lysogenic cycle and what happens during this stage?

Answer 12

lystic cycle:
certain conditions (triggers) cause prophage dna to become active, removes itself from hosts dna and enters the lystic cycle.

Question 13

how is a retro virus different from an average virus?

Answer 13

retroviruses work backwards, they start with rna and make dna

Question 14

what are the three theories of a viral origin?

Answer 14

-fragments of ancient extinct cells
-primitive “life-non life” forms left over from the beginning of life 3-4 billion years ago that coevolved with their current hosts
- specialized parasitic cells which have lost most of their cell structures via natural selection.

Question 15

what factors do viruses have that make them living and nonliving?

Answer 15

LIVING: they replicate within their environment, inside another life form.
NON-LIVING: they do not maintain stable environment, not made of cells, don’t grow, don’t produce energy

Question 16

ways to prevent viral infection:

Answer 16

-hand washing
-masks
-properly prepare food
-proper sanitation
-insect repellent
-mosquito nets
-do not share needles
-vaccine

Question 17

what’s the difference between a simple, compound and electron microscope?

Answer 17

simple microscope: utilizes the visual capacity of single or multiple lenses to enlarge objects
compound microscope: one lens is placed close to the substance for viewing it
electron microscope: uses electron beams to capture and image and enlarge it

Question 18

similarities of eubacteria and archaebacteria:

Answer 18

prokaryotic
unicellular
both have cell wall
live in diverse environments

Question 19

differences of archaebacteria and eubacteria:

Answer 19

archaebacteria live in harsh conditions whereas eubacteria live everywhere
eubacteria has peptidoglycan and archaebacteria does not

Question 20

what does bacilli look like?

Answer 20

rod shaped

Question 21

what does cocci look like?

Answer 21

spherical shaped

Question 22

what does spirilla look like?

Answer 22

spiral and corkscrew shaped

Question 23

what does paired bacteria look like?

Answer 23

diplo: 2 bacteria pieces together

Question 24

what does filamentous bacteria look like?

Answer 24

strepto: chain like

Question 25

what does colonial bacteria look like?

Answer 25

staphylo: grape-like clusters

Question 26

what does solitary bacteria look like?

Answer 26

single pieces of bacteria

Question 27

difference between gram positive and negative based on cell wall and staining:

Answer 27

gram positive: thick cell walls with large amounts of peptidoglycan PURPLE OR BLUE
gram negative: thinner cell walls inside an outer lipid layer PINK OR RED

Question 28

what are the differences between obligate aerobes, obligate anaerobes, and facultative anaerobes?

Answer 28

OBLIGATE AEROBES: survive and grow only in oxygen
OBLIGATE ANAEROBES: cannot survive or grow in oxygen containing environments (leads to cell death)
FACULTATIVE ANAEROBES: they can survive in oxygen and no oxygen environments

Question 29

what is binary fission?

Answer 29

asexual reproduction where two bodies are formed from one body

Question 30

what is conjugation?

Answer 30

where one bacterium transfers all it’s genetic information through direct contact

Question 31

what’s endospore?

Answer 31

the bacterium produces thick internal wall that encloses its dna and some of its cytoplasm

Question 32

what are positive uses of bacteria/ their role

Answer 32

their roles:
produce oxygen
decomposes, break down nutrients from dead matter
convert nitrogen from the air into a form plants can use

positive uses:
food and beverage
sewage treatment
cleaning up oil spills
produce vitamins in human intestines

Question 33

how to prevent bacterial infection?

Answer 33

wash hands
social distance
wear mask
vaccine
use heat/chemicals to help stop bacterial growth