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Biology Upper Sixth > Topic 6 - LQC 3A And 3B > Flashcards

Topic 6 - LQC 3A And 3B Flashcards

1
Q

How do bacteria reproduce?

A

Binary fission, asexual reproduction

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2
Q

What do they not make in this process that animal cells do?

A

Spindle fibres

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3
Q

B VS V: Where is a mesosome found? What is it?

A

Bacterial cell, Inner folding of the membrane

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4
Q

B VS V: Where is a slime capsule found? What is it?

A

Bacterial cell.
Protective outer layer, prevents dehydration

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5
Q

B VS V: Where is a flagella found? What is it?

A

Bacterial cell.
Movement

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6
Q

B VS V: Where is main circular DNA found?

A

Bacterial cell

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7
Q

B VS V: Where is a cell membrane found?

A

Bacterial cell

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8
Q

B VS V: Where is ribosome found? What is it? What size are they?

A

Bacterial cell
small 70S
site of translation

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9
Q

B VS V: Where are pilli found? 3 functions?

A

Aid movement
allow bacteria to attach to surfaces
involved in conjugation (cell to cell contact)

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10
Q

B VS V: Where is a plasmid found? What is it?

A

Bacterial cell
Small loop of DNA

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11
Q

B VS V: Where is a cell wall found? What is it made of? What does that determine?

A

Bacterial cell
Made of peptidoglycan
It’s composition makes bacteria either gram-positive or gram-negative

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12
Q

B VS V: Where is a capsid found? What is it?

A

Virus
Repeating protein sub units, to protect the nucleic acid (RNA or DNA)

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13
Q

B VS V: Where are enzymes found? What are they used for?

A

Virus, contain enzymes for replication processes

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14
Q

B VS V: Where are nucleic acid found? What are they?

A

Virus
RNA - single stranded
DNA - Double or single stranded

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15
Q

B VS V: Where is the envelope found? What is it?

A

Virus
Taken from host cell surface membrane, contains lipids and proteins.
Helps virus to attach to host cell and penetrate the cell surface membrane.

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16
Q

B VS V: Where are glycoproteins found? What are they?

A

Virus
Recognise by host immune system as non-self
Act as antigens

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17
Q

What do viruses require for reproduction?

A

HOST CELL - they lack the internal structures for growth and reproduction

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18
Q

What is cell lysis?

A

Cells swelling and bursting, releasing virus particles

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19
Q

Describe process of how viral particles are released?

A
  • virus attaches
  • virus inserts nucleic acid
  • viral nucleic acids replicate
  • viral protein coats synthesised
  • new virus particles formed
  • virus particles released due to cell lysis
20
Q

Bacterial cells have no…. And no ….

A

Nucleus and other membrane bound organelles

21
Q

What are the two classes of Bacteria, based on their cell walls?

A

Gram positive and gram negative

22
Q

What happens to gram positive bacteria in presence of the stain?

A

Take up the stain, turn purple

23
Q

What happens to gram negative bacteria in presence of the stain?

A

Reject the stain, pink

24
Q

Why do gram positive bacteria retain the stain?

A

Only made up of cell wall and inner membrane
They have more peptidoglycan in their cell walls

25
Q

Why does gram negative bacteria not retain the stain?

A
  • more complex cell wall (containing lipopolysaccharides)
  • thinner layer of peptidoglycan
  • lipopolysaccharides is an endotoxin, which blocks dyes, detergents and antibiotics
  • periplasmic space between cell wall and cell membrane
26
Q

Describe the process of binary fission (7)

A
  • DNA is replicated
  • old cell wall begins to break down around the middle of the cell
  • DNA is associated with the cell membrane
  • cell pinches forming septum
  • two identical daughter cells formed
  • plasmids often divide at the same time
    Time between divisions is generation time
27
Q

Bacteria can reproduce by …

A

Binary fission and sexual reproduction

28
Q

What are the three types of sexual reproduction bacteria can reproduce by?

A
  • transformation
  • transduction
  • conjugation
29
Q

Describe the process of transformation

A

– A bacterium takes in DNA from environment (shed by other bacteria / introduced to in lab)
– DNA is in form of circular DNA called plasmid
– it can be copied in the receiving cell and passed onto its descendants

30
Q

Describe the process of transduction

A

– Virus transfers bacterial DNA from one bacterium to another
– viruses called bacteriophages are able to infect bacterial cells and use them as hosts
– after multiplying viruses assemble and remove portion of the host cells bacterial DNA
– when bacteriophage later infects new host cell, a piece of bacterial DNA is incorporated into genome of new host

31
Q

Describe the process of conjugation

A

– DNA is transferred from one bacterium to another
– pilus allows donor to pull itself close to recipient, DNA is transferred between cells
– in most cases DNA is in form of a plasmid

32
Q

Viral envelope contains …

A
  • host protein and lipids
  • viral proteins (glycoproteins, called antigens)
  • VAPs, virus attachment particles
33
Q

Two adaptations of a virus

A
  • extremely small, easily get into body
  • simple structure of protein coat and genetic material, withstand harsh conditions and retain infectivity
34
Q

What are the six major transmission routes?

A

Inoculation, inhalation, fomites, direct contact, vectors, ingestion

35
Q

Describe inhalation

A

Breathing in leopard drop which contains pathogen through airways. These were expelled from more respiratory tract of individual.
E.g. flu, cold

36
Q

Describe Direct contact

A

Transfer of pathogen directly onto skin/physical barrier, due to close contact with infected person

37
Q

Describe inoculation

A

Pathogen enters directly into body through a break in the skin, e.g. dog bite, tattoo

38
Q

Describe vector

A

Another organism transferring the pathogen to another organism, e.g. mosquitoes and malaria

39
Q

Describe ingestion

A

Contaminated food or drink bleeding to vomiting and diarrhoea, greatest risk from raw/undercooked food e.g. E. coli, salmonella

40
Q

Describe fomites

A

Inanimate objects that carry pathogens from one host to another e.g

41
Q

Four major barriers to entry of pathogens

A

Skin, mucosal membrane, gut flora, stomach acid

42
Q

Describe how skin provide provides a barrier to pathogen entry

A

– Hard protein keratin outer layer preventing microorganism entry
– skin flora outcompetes and prevents colonisation by other bacteria, as microbes live on the skin
– skin can be breached by wounds, blood clotting helps prevent this

43
Q

Describe how mucosal membranes provide a barrier to pathogen entry

A
  • Mucus lines airways and gut, goblet cells produce mucus
  • Mucus traps microbes and other particles, cilia beats mucus to throat where it swallowed or coughed up
  • secretions from eyes and nose contain the enzyme lysozyme, it breaks down bacterial cell walls causing them to burst
44
Q

Describe how stomach acid provides a barrier to entry of pathogens

A
  • Contains hydrochloric acid, giving a pH of less than 2.0, optimum pH for the enzyme Pepsin
  • This kills most bacteria enter with food or drink
45
Q

Describe how gut flow provides a barrier to the entry of pathogens

A

– intestines contain friendly bacteria which we have mutualistic relationship with
– they aid digestion and outcompete pathogenic bacteria, for food and space
– bacteria also secrete chemicals to aid defence against pathogens

Biology Upper Sixth (8 decks)

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