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Y2 EMS > 2.1 MoD Microbiology & Metabolism > Flashcards

2.1 MoD Microbiology & Metabolism Flashcards

1
Q

Bacteria are eukaryotes.

True or False?

A

FALSE
prokaryotes

they lack a membrane bound nucleus

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2
Q

The bacterial organ of locomotion which enables them to find sources of nutrition and penetrate cells.

A

Flagella

different names based on where the flagella is attached + number e.g. monotrichous, amphitrichous

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3
Q

Specialised hair-like structures on bacteria which aid adhesion to host cells and colonisation.

A

Pili and fimbriae

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4
Q

What feature of a bacterial cell is ‘india ink’ used to identify?

A

If the bacterium has a capsule or slime layer.

Capsule = no stain

Slim layer = stain

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5
Q

Polysaccharide material which protects bacteria against phagocytosis, desiccation, immune attack, antibiotics.

A

Capsule or Slime layer

biofilm = the outer barriers of many cells combined

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6
Q

What are endospores?

A

Metabolically inert form of bacteria, adapted for long term survival (can last for hundreds of years).
Activated when the conditions are right to cause disease again.

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7
Q

What colour does a gram-negative bacterium turn when stained?
Why?

A

RED
it has a thin cell wall which cannot retain the dye.

(gram positive = purple)

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8
Q

List 6 ways in which bacteria can be classified.

A
  1. Gram stain
  2. Shape
  3. Endospore
  4. Atmospheric preference (aerobic vs anaerobic)
  5. Fastidiousness (what it uses for nutrients)
  6. Key enzymes
  7. DNA (16S sequence)
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9
Q

What shape does ‘cocci’ refer to?

A

Round / sphere

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10
Q

What shape does ‘bacilli’ refer to?

A

Rod / rectangular

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11
Q

What is binary fission?

A

Bacterial replication mechanism.
Binary fission - cell divides to give 2 genetically identical daughter cells.

(different bacteria take different lengths of time to replicate)

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12
Q

The transfer of transposable material (e.g. plasmid) between bacteria.

A

Conjugation

because its transferred through a conjugation tube.

(no new bacteria is made, but it introduced genetic diversity into the population)

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13
Q

Bacteria pick up genetic material (e.g. plasmids from destroyed cells) from the environment and integrate it into their own DNA.

A

Transformation

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14
Q

What is transduction?

A

a VIRAL vector injects its DNA into a bacterium and is integrated into the bacterial DNA.
The virus can then be replicated.

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15
Q

All fungi are eukaryotic.

True or False?

A

TRUE

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16
Q

The cell wall of most fungi is made from this material.

A

Chitin

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17
Q

The most common yeast infection is thrush.

What is this caused by?

A

C. albicans

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18
Q

What are common infections such as Athlete’s foot and ringworm caused by?

A

Moulds - filamentous fungi

e.g. Aspergillus, Trichophyton, Epidermophyton

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19
Q

Fungal replication is asexual.

True or False?

A

FALSE

asexual AND sexual replication is possible.

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20
Q

What are the 2 types of parasite?

A

Protozoa - unicellular eukaryotic organisms

Helminths - worms

(these can all be intestinal or non-intestinal)

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21
Q

How are protozoa classified?

A
  1. Flagellates (flagella)
  2. Amoeba (ability to change shape)
  3. Cilliates (type of cillia)
  4. Apicomplexa / sporozoa (ability to produce spores)
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22
Q

In order for protozoa to replicated asexually, what may be required to complete their life cycle?

A

2nd / 3rd host.

e.g. malaria in mosquito > human > mosquito

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23
Q

What is the structure of a virus?

A

Nucleic acid core wrapped in a protein coat (capsid).

Some viruses also have an envelope (lipid layer derived from a host cell).

Viral proteins are on the outermost layer.

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24
Q

What is the mechanism by which a virus replicates?

A
  1. Attachment - attachment proteins on virion bind to receptors on the target cell and then penetrate the cell.
  2. Uncoating - genetic material is released to nucleus of host cell.
  3. Viral protein production - cellular machinery is hijacked to replicate viral genetic info and produce viral proteins.
  4. Virion assembly - new virus is assembled
  5. Virion release - enveloped viruses bud through the membrane and leave cell.
    non-enveloped virus are released by cell lysis (kill the host cell).
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25
Q

How are viruses classified?

A

Based on characteristics.

  1. DNA or RNA?
  2. Symmetry of capsid
  3. Envelope?
  4. Size of virus + capsid
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26
Q

What are prions?

A

Misfolded proteins with NO genetic material (unlike virus).

Causes a chain reaction of mis-folding native proteins and causing disease.

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27
Q

Creutzfeldt-Jakob disease
Bovine spongiform encephalopathy
Scrapie
These are all diseases caused by prions, which of these occurs in humans? cows? sheep?

A

Humans = CJD

Cows = BSE (mad cow disease)

Sheep = Scrapie

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28
Q

Toxic chemical which accumulates in patients with urea cycle defects.

A

Ammonia (produced from the break down of protein)

medical emergency

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29
Q

Class of drugs used to treat water or salt retention by increasing urine output.

A

Diuretics

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30
Q

Increased acidity in body fluids may be counteracted by this buffering system.

A

Bicarbonate

31
Q

Ammonia accumulates in patients with defects in this metabolic pathway.

A

Urea cycle

32
Q

Electrolyte imbalance associated with dehydration.

A

Hypernatraemia

33
Q

Form of alkalosis due to hyperventilation.

A

Respiratory

34
Q

Give 4 clinical effects of acute hyperammonaemia toxicity.

A
  1. Tachypnoea (rapid breathing) - leads to metabolic alkalosis
  2. Poor feeding
  3. Vomiting
  4. Lethargy
  5. Convulsions (sudden involuntary movement)
  6. Coma
  7. Death
35
Q

A defective enzyme in a metabolic pathway can lead to an accumulation of intermediates which is problematic.
Why?

How can you determine where the block in a pathway is so that you can treat it?
(which enzyme is defective)

A
  1. Intermediates may be toxic
  2. Deficiency in desired product
  3. Metabolites find other pathways which can be potentially toxic

Measure how much of each metabolite there is.
(metabolite with the highest levels will be just prior to the block)

36
Q

Presents like an enzyme deficiency, treating it also increases enzyme function.

A 
Cofactor deficiency
(vitamins + minerals e.g. B6, B12)
37
Q

Porphyrin accumulation occurs in a defect in which metabolic pathway?

A

Haem production pathway.

only partial block, you would die from a complete block in this pathway because you cant make any red blood cells

38
Q

Form of porphyria resulting in blisters, itching, fragile skin, painful lesions.
How does this arise?

A

Photosensitive porphyria.

A block LATER in the haem production pathway.

(werewolf legend probs started from this because you also get increased hair growth)

39
Q

Form of porphyria resulting in severe abdominal pain, vomiting, seizures, insomnia.
How does this arise?

A

Acute porphyria.

an EARLY block in the haem production pathway.

40
Q

Condition caused by defective receptors which result in a genetic male having a female phenotype.

How does it normally present?

A

Androgen insensitivity syndrome.

(Partially defective receptors result in ambiguous genitalia)

Presentation:

  1. Primary amenorrhoea (failure to have a period by 16)
  2. Infertility
41
Q

This class of molecule makes up most intermediates in metabolic pathways.

A

Organic acids

42
Q

The classic organic acidaemia’s such as MSUD, IVA, PA, MMA are due to defects in which metabolic pathway?

A

Branched chain amino acid catabolism.

leucine, valine, isoleucine

43
Q

What is homocystinuria?

A

Disorder of methionine metabolism leading to abnormal accumulation of homocysteine and its metabolites in blood + urine.

44
Q

What is the normal reference range for [H+]?

A

35 - 45 nmol/L

(pH = 7.45 - 7.35)

(note: Nano mol)

45
Q

A solution which resists change in pH when an acid/base is added.

A

Buffer

e.g. haemoglobin, bicarbonate

46
Q

H+ donors

A

Acid

47
Q

H+ acceptors

A

Base

48
Q

What is the equation for acid base dissociation?

A

H+ + HCO3- <> H2CO3 <> CO2 + H2O

49
Q

Bicarbonate can buffer high levels of CO2.

True or False?

A

FALSE

bicarbonate will cause the acid-base dissociation equation to produce more CO2.

50
Q

Which of these is not a buffer system?

  1. Phosphate
  2. Bicarbonate
  3. Ammonia
  4. Glucose
  5. Haemoglobin
  6. Proteins
A

Glucose

51
Q

What 3 factors cause the oxygen-haemoglobin dissociation curve to shift to the right?

A

R = LOWER affinity for oxygen

  1. INCREASED temperature
  2. INCREASED [H+] (acidosis)
  3. INCREASED 2,3-DPG
52
Q

Urine is acidic.

True or False?

A

TRUE

53
Q

What is the function of the kidneys in acid-base metabolism?

A
  1. Excretion of H+
  2. Reabsorption of bicarbonate (proximal tubule)
  3. Regeneration of bicarbonate (distal tubule)

(bicarbonate cannot be directly reabsorbed)

54
Q

Mineralocorticoid which causes ↑ H+/K+ excretion and ↑ Na+ reabsorption in distal tubule of kidney.

A

↑ aldosterone

55
Q

Secreted from the pancreas into the duodenum to neutralise stomach acid.

A

Bicarbonate

56
Q

Dominant site of lactate metabolism.

A

Liver (cori cycle)

57
Q

Lactic acidosis is a form of metabolic acidosis.

How can it arise?

A
  1. Excessive PRODUCTION of lactate in muscles
  2. Decreased CONSUMPTION of this lactate in the liver e.g. liver disease (lactate should normally be converted into glucose in the liver)
58
Q

In liver failure, patients can suffer hyperammonemia which stimulates the respiratory system to hyperventilate.
What is the result?

  1. Respiratory acidosis
  2. Respiratory alkalosis
  3. Metabolic acidosis
  4. Metabolic alkalosis
A
  1. Metabolic alkalosis

Urea cycle failure leads to ammonia build up = metabolic
Hyperventilation causes ↓ CO2 = ↑ pH = alkalosis

(primary disorder is caused by a non-respiratory element)

59
Q

The standard sample taken for blood gas analysis is arterial.
True or False?

A

TRUE

venous can also be used, but standard is arterial.
they have different reference ranges depending on which you use

60
Q

What blood pH is considered acidaemia?

A

pH <7.35

61
Q

What blood pH is considered alkalaemia?

A

pH >7.45

62
Q

pH 7.55, pCO2 normal, HCO3- high, O2 low

is this:

  1. Respiratory acidosis
  2. Respiratory alkalosis
  3. Metabolic acidosis
  4. Metabolic alkalosis
A
  1. Metabolic alkalosis

(CO2 can be normal or high)

Compensation:
- reduced respiratory rate

63
Q

pH 7.38, pCO2 low, HCO3- low, O2 high

is this:

  1. Respiratory acidosis
  2. Respiratory alkalosis
  3. Metabolic acidosis
  4. Metabolic alkalosis
A
  1. Metabolic acidosis

Compensation:

  • bicarbonate is being used up
  • hyperventilation
  • urine H+ excretion maximised
  • increased rate of bicarbonate regeneration
64
Q

pH 7.48, pCO2 low, HCO3- normal, O2 high

is this:

  1. Respiratory acidosis
  2. Respiratory alkalosis
  3. Metabolic acidosis
  4. Metabolic alkalosis
A
  1. Respiratory alkalosis

(bicarbonate can be normal or low)

Compensation:
- reduced renal bicarbonate regeneration

65
Q

The difference between the sum of measured anions and cations. Indicates if there are unusual levels of ketones, lactate, proteins etc.

A

Anion gap

66
Q

What can cause metabolic alkalosis?

A
  1. Vomiting
  2. Administration of bicarbonate
  3. Hypokalaemia
    (H+ is used instead for aldosterone-controlled renal transporter. K+ moves out of RBCs into plasma to increase conc, therefore H+ moves into cells to maintain electroneutrality)
67
Q

pH 7.30, pCO2 high, HCO3- high, pO2 low

is this:

  1. Respiratory acidosis
  2. Respiratory alkalosis
  3. Metabolic acidosis
  4. Metabolic alkalosis
A
  1. Respiratory acidosis

(bicarbonate can be normal or high depending on compensation)

Compensation:

  • maximal bicarbonate reabsorption
  • most phosphate is excreted as H2PO4 rather than HPO4
  • increase in urinary NH4+
68
Q

Mixed acidosis (respiratory and metabolic) is seen in what condition?

A

Severe asthma

respiratory acidosis = difficulty breathing so CO2 buildup
metabolic acidosis = muscles anaerobically respire producing lactic acid

69
Q

Illness caused by a doctor or medical treatment.

A

Iatrogenic

70
Q

Hormone which increases thirst and renal water retention.

A

ADH

71
Q

Hormone which causes renal Na retention.

What system/pathway is this hormone part of?

A

Aldosterone

Renin-angiotensin system.

(renin from kidneys is converted to angiotensin which stimulates aldosterone secretion from adrenal glands)

72
Q

Define hyponatraemia.

A

Low blood sodium.

can be due to excess water or too little Na in extracellular fluid.

73
Q

What affect does acidosis and alkalosis have on potassium?

A

Acidosis = potassium moves out of cells - hyperkalaemia

Alkalosis = potassium moves into cells - hypokalaemia

(in acidosis when H+ enters the cell, it pushes K+ out of the cell. vice versa in alkalosis)

Y2 EMS (4 decks)

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