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Biology - Year 1 > Microbiology > Flashcards

Microbiology Flashcards

0
Q

What are Archaea?

A

A kingdom of single celled microorganisms. They live in extreme environments and are prokaryotes as they have no cell nucleus.

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1
Q

What are the differences between prokaryotes and eukaryotes?

A

P have a petidoglycan cell wall, E have simple cell membrane.
P have no organelles or true nucleus.
Some P have flagella.
P have small ribosomes E have larger.
P cells tend to be smaller.
P have circular DNA, E have chromosomes.
P replicate by binary fission, E by mitosis or meiosis.
P are unicellular, E are usually multicellular

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2
Q

What is a bacterial cell wall made of? How many types are there, how can you identify them?

A

Peptidoglycan. There are two types that can be identified by a gram stain.

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3
Q

Describe the features of a gram negative bacteria.

A

They have a thin peptidoglycan cell wall as they have a outer membrane. They have lipopolysaccharides on the outside. These are important for evading phagocytosis.

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4
Q

Describe the features of a gram positive bacteria.

A

No outer membrane so has thick peptoglycan wall. Has teicholic acids on the surface. More susceptible to antibiotics.

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5
Q

What is a capsule? What does it do?

A

They are a sticky substance made of polysaccharide/ peptide or both. The capsule helps the evade the immune system.

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6
Q

What’s the difference between a capsule and slime layer?

A

Capsules are firmly attached and highly organised.

Slime layers are unorganised and loosely attached.

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7
Q

What are fibriae/ pili? What are they for?

A

Hair like appendages used by bacteria to attach to cells and to transfer DNA (conjugation).

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8
Q

What is an endospore?

A

A dormant form of a bacteria, resistant to harsh environments.

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9
Q

What type of bacteria have a outer membrane?

A

Gram negative

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10
Q

What is a chemoheterotroph?

A

An organism that obtains energy and nutrients from the oxidation of organic compounds that it cannot make itself.

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11
Q

What does phagocytic mean?

A

Obtaining large nutrient particles by endocytosis (engulfing food).

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12
Q

What happens during budding in fungi?

A

Parent cell forms bud on outer surface. Parent nucleus divides and one nucleus migrates into bud. Cell wall material laid down between bud and parent cell. Bud breaks away leaving scar.

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13
Q

What is a lichen?
What do its component parts do?
What does a lichen do?

A

An association between a fungi and photosynthetic cell (Cyanobacteria and green algae).
Fungi is for structure, cyanobacterium provides food.
First life forms to colonise bare rock/ soil. Act as a barometer for air quality.

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14
Q

What is a mycorrhizal relationship?

A

Mutualistic relationship between fungus and plant root.

Fungus absorbs nutrients and plant provides it with sugars for energy.

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15
Q

What does:

  • Infectious mean?
  • Non infectious mean?
A

An infectious disease is one that is transmitable e.g. Measles, mumps, HIV.

A non-infectious disease is one that is non-transmitable e.g. Stroke heart disease diabetes.

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16
Q

What does:

  • Contagious mean?
  • Non-contagious mean?
A

Transmitted by contacted with infected individual, their secretions or surfaces they have touched e.g. Flu, colds, strep throat.

Spread usually requires a mode of transmission such as a vector or transfer of bodily fluids (e.g. blood transfusions, sexual contact) e.g. Lyme disease.

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17
Q 
What makes up the cell wall of a:
Fungus
Plant
Animal
Bacteria
A

Chitin
Cellulose
No cell wall
Peptidoglycan

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18
Q

What is a viral plaque? How is it made?

A

It is used to study bacteriophages. A sample is mixed with phages. Viral infection kills cells and the clearing is called a plaque.

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19
Q

What is the incidence of a disease?

What is the prevalence of a disease?

A

No. of people in a population who develop a disease at a particular time.

No. of people in a population with a disease at a particular time, takes both old and new cases into account.

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20
Q

What is an epidemic?

A pandemic?

An endemic?

A

A disease that occurs in an unusually high number of individuals in a population at the same time.

A widespread, usually global, epidemic.

A disease that is constantly present in the population usually at low incidence.

21
Q

What is an anabolic reaction?

What is a catabolic reaction?

A

The phase of metabolism in which simple substrates are synthesised into complex materials that make up the living cell.

The phase of metabolism where complex materials are broken down, often with the release of energy.

22
Q

What are the 4 types of Protozoa?

A

Ciliates, flagellates, apicomplexans and amoebae.

23
Q 
What is a:
Obligate aerobe
Facultative aerobe
Obligate anaerobe
Facultative anaerobe
Microaerophilic organism
A

Can’t survive without oxygen

Prefer anaerobic but can respire using oxygen

Cannot survive in the presence of oxygen

Prefer anaerobic conditions but can respire anerobically

Gross best in a small amount of oxygen

24
Q

What are the two ways phagocytes kill organisms? Describe them.

A

Oxygen independent: phagocyte consumes organisms and lysosomes fuse with intracellular compartments.

Oxygen dependent: reactive oxygen species used. Superoxide kills microbes ( by destroying DNA, membranes etc…). Reactive nitrogen species are strongly micribicidal.

25
Q

What are NK cells? How do they work?

A

Natural killer cells. Contain toxic chemicals in granules, granules punch holes in cell membrane, kill infected cells.

26
Q

What are the two main types of t-cell? What do they do?

What are the two types of t-helper cell? What do they do?

What do cytotoxic t-cells do?

A

CD4 - helper cell
CDA - cytotoxic cell
They recognise protein antigens.

TH1 - activates macrophages
TH2 - humoral antibody response

Recognise infected cells (by surface antigens). Punch holes in cell.

27
Q

What is the cell that gives rise to t and b cells?

What cell gives rise to all other blood cells?

A

Common lymphoid progenitor

Myeloid progenitor

28
Q

Describe the life cycle of malaria.

A
  1. A female Anopheles mosquito carrying malaria-causing parasites feeds on a human and injects the parasites in the form of sporozoites into the bloodstream. The sporozoites travel to the liver and invade liver cells.
  2. Over 5-16 days, the sporozoites grow, divide, and produce tens of thousands of haploid forms, called merozoites, per liver cell.
  3. The merozoites exit the liver cells and re-enter the bloodstream, beginning a cycle of invasion of red blood cells, asexual replication, and release of newly formed merozoites from the red blood cells repeatedly over 1-3 days. This multiplication can result in thousands of parasite-infected cells in the host bloodstream, leading to illness and complications of malaria that can last for months if not treated.
  4. Some of the merozoite-infected blood cells leave the cycle of asexual multiplication. Instead of replicating, the merozoites in these cells develop into sexual forms of the parasite, called male and female gametocytes, that circulate in the bloodstream.
  5. When a mosquito bites an infected human, it ingests the gametocytes. In the mosquito gut, the infected human blood cells burst, releasing the gametocytes, which develop further into mature sex cells called gametes. Male and female gametes fuse to form diploid zygotes, which develop into actively moving ookinetes that burrow into the mosquito midgut wall and form oocysts.
  6. Growth and division of each oocyst produces thousands of active haploid forms called sporozoites. After 8-15 days*, the oocyst bursts, releasing sporozoites into the body cavity of the mosquito, from which they travel to and invade the mosquito salivary glands. The cycle of human infection re-starts when the mosquito takes a blood meal, injecting the sporozoites from its salivary glands into the human bloodstream .
29
Q

What is a:

  • Primary pathogen
  • Opportunistic pathogen
  • Carrier
A

Causes disease in healthy individuals

Can be part of the normal flora and can cause disease when the body is weakened or competitors are removed

Someone who carries a pathogen but shows no signs of disease

30
Q

What are the universal features of Protozoa?

A

They all are chimeraeric (have two or more genetically distinct cells).
They have a mixture of eukaryotic and prokaryotic organelles.
They are all eukaryotes.
Are mostly uni-cellular.
Have no cell wall.
Are polyphyletic (originate from several lines of decent).

31
Q

What is a diatom?

A

The most common kind of algae

32
Q

What are slime moulds?

A

A type of Protozoa with fungal and amoeba characteristics.

33
Q

How do bacteria grow?

A

By multiplying by binary fission

34
Q

How are fungi classified?

What are the four main types of fungi classifications?

A

Based on the spore structure they produce

Chytridiomycota - motile zoo spores
Zygomycota - zygospores
Ascomycota - ascospores
Basidiomycota - basidiospores

35
Q

What is the type of evolution called where there is more than one line of ancestry?

A

Chimera process

36
Q

How is bacterial growth normally expressed?

A

Optical density

37
Q

What are the 4 groups of Protozoa?

A

Ciliates
Flagellates
Apicomplexans
Amoebae

38
Q

What are the four phases on a bacterial growth curve? Briefly describe each stage.

A

Lag phase - slow growth
Exponential phase - nutrients in excess, cells growing
Stationary phase - numbers remain stable
Death phase - population decreases, cell death > cell growth

39
Q

Describe the structure of a filamentous fungi?

A

Main body made of thin filaments called hyphae. Hyphae form a mass called a mycelium. Septa te hyphae have septa (cross walls), which divide them into distinct uni-nucleate cell like units.
Coenoytic hyphae have no cross walls.

40
Q

How do people become infected with:

  • Cholera
  • Thyphoid fever (salmonella typhi)
  • Legionnaires disease
  • Leptospirosis
A

Drinking infected water

Sewage in water (no animal reservoir)

Inhaling water droplets (e.g. shower spray)

Carried by rats, passed out in urine and can go into river water. Bacteria can enter through breaks in skin.

41
Q

How do people become infected with:

  • Capylobacter jejuni
  • Bacillus cereus
  • Enterohaemhorragic E. coli
  • Listeria monocytogenes
A

Undercooked chicken

Found in soil, affects rice, pulses and vegetables

Ground beef products (cattle)

Soft cheese, vacuum-packed food, unwashed vegetables

42
Q

Who developed the rabies vaccine?

A

Louis Pasteur

43
Q

What cells come from the common lymphoid progenitor?

A

B cell, T cell, NK cell

44
Q

What are antigens?

A

Foreign macromolecules that induce specific immunity

45
Q

What do these antibiotics target:

  • Penicilin
  • Polymixin
  • Sulphonamides
  • Streptomycin
  • Rifampicin
A

Cell wall

Cell membrane

Cell metabolism

Protein synthesis

Nucleic acid replication

46
Q

What are the three domains of life (and any sub domains)?

A

Bacteria

Archaea

Eukarya
Kingdoms:
-Animalia
-Plantae
-Fungi
-Protista
47
Q

What do virulence factors aid in?

A

The establishment and maintenance of the organism in the host.
The establishment and maintenance of the disease caused by the organism.

48
Q

What cell does all the blood cells come from?

A

Pluripotent hematopoietic stem cell

49
Q

What are microbial polysaccharides used as?

A

Viscosity extenders in aqueous solutions

50
Q

What is a formite?

A

An object that harbours infectious agents

Biology - Year 1 (6 decks)

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