Microbiology Flashcards

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1
Q

What is a disease

A

A disease is a state in which there is a structural or functional abnormality of the body causing a disturbance of normal health.

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2
Q

What process in the body brings about significant changes but is not a disease?

A

Pregnancy

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3
Q

what are the causes of disease

A

Genetics
Autoimmune diseases
Tumors and cancer
Inflammation
Malnutrition and obesity
Pathogens
Physical and Chemical agents

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4
Q

what are pathogens

A

are disease-producing microbes including bacteria, viruses,fungi,protozoa

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5
Q

what are parasites

A

are multi-cellular worms and are often clearly visible to the naked eye such as tapeworms

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6
Q

what is a bacterium

A

A bacterium is a tiny, primitive cell without a nucleus some bacteria live harmlessly in the body making up normal flora

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7
Q

what is commensals

A

which and receive shelter and benefit the host by keeping potentially harmful microbes at bay.if they migrate to a different anatomical location, they can cause infection

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8
Q

what is pathogenic bacteria

A

this is where Bacteria are able to cause a disease

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9
Q

what is Virulence

A

This is the extent to which they CAN cause a disease.refers to the degree of pathogenicity or the ability of a microorganism to cause disease in a host organism.

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10
Q

What is opportunistic bacteria

A

They cause infection only in people whose immune status is compromised by illness, drugs or the invasive procedures they have undergone (e.g. surgery, endotracheal intubation, IV access).
They do not attack healthy tissues

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11
Q

what are the three Classification of Bacteria

A

Shape
Staining
Function

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12
Q

what are the three basic bacteria shapes

A

Bacilus - roldlike
Coccus - spherical
Vibrio spirillum, or spirochete - curved

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13
Q

What are the Classification by Shape: Bacilli

A

Bacillus
Diplobacillus
Streptobacillus

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14
Q

what are the classification by shape Cocci

A

Cocci are round bacteria.
Monococcus
Diplococcus

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15
Q

what is the Classification by Shape: Staphylococci

A

Clusters of cocci are termed staphylococci

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16
Q

What is the classification by shape Streptococci

A

Streptococci are round bacteria found in chains

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17
Q

What is the classification by shape Vibrios

A

Vibrio are curved rods

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18
Q

What is the classification by shape Spirochettes

A

Spirochaetes are very small, flexible spirally shaped bacteria

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19
Q

Classification by Staining properties gram negative

A

Gram negative bacteria cannot retain the crystal violet stain, instead taking up the counter-stain and appear red or pink.

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20
Q

What is the classification by function aerobic

A

Aerobic bacteria need oxygen for their metabolism.

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21
Q

What is the classification by function anaerobic

A

Anaerobic bacteria metabolise in the absence of oxygen

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22
Q

What is the process of bacterial infections

A

Secrete toxic substances that damage human tissues
Become parasites inside human cells
Form colonies in the body that disrupt the cell and ultimately disrupt normal human function.

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23
Q

what are the stages of infection

A
  1. Gain access to the host tissue
  2. Move to a favourable site
  3. Multiply successfully in spite of the host defence mechanisms
  4. Reproduce so new pathogens can be disseminated
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24
Q

What are the portals of entry

A

Inhalation
Ingestion
skin and mucous membranes
vertical transmission
urogenital tract

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25
Q

What is inhalation

A

The respiratory tract serves as the gateway. Airborne particles are released as infectious aerosols—droplet transmission via forceful exhalation, sneezing, or coughing. Longer exposure increases the risk of transmission.

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26
Q

What is skin and mucous membranes

A

Pathogens inoculated through surgical procedures, injuries, or needles.

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26
Q

What is ingestion

A

Gastrointestinal tract invasion through contaminated food or water.

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27
Q

What is vertical transmission

A

Placental transmission from mother to fetus.Birth canal contamination: Neonatal conjunctivitis from infected mothers.

27
Q

What is urogenital tract

A

Urinary pathogens enter through the urethra—route for sexually transmitted infections.

28
Q

What is the virulence factors

A

The inoculating dose
Site of invasion
The ability to invade

29
Q

what is the inoculating dose

A

Many microbes can overwhelm host defences and have a greater chance of reaching a cozy site for growth and multiplication.

30
Q

What is exotoxins

A

Toxins secreted by gram-positive bacteria wreak havoc on host cells.exit

30
Q

What is the ability to invade

A

Some bacteria have hair-like structures for easy attachment to host cells.Enzyme production is their secret weapon.
For example, haemolytic enzymes destroy red blood cells.
Coagulase enzyme clots plasma, protecting from phagocytosis.

31
Q

What is endotoxins

A

Toxins form a part of gram-negative bacterial cell walls.
Released on death causing disease. kept in

31
Q

What is the site of invasion

A

Pathogens have their favourite spots for invasion.Cold viruses strike the nasal epithelia, not the oral mucosa.

32
Q

What do bacteria do to the body

A

cause structural and physiological damage to host cells.

33
Q

What are the clinical Features of Bacterial Infection

A

Fever
Chills and shivering.
Changes in vital signs.
General bone, muscle and joint pain.
Enlarged and tender lymph nodes

34
Q

Microscopic

A

Viruses: are tiny

35
Q

What is the anatomy virus

A

Protecting the nucleic acid, is a protein coat called a capsid.
The capsid shields the DNA or RNA against harsh environmental conditions, ensuring the virus stays battle-ready.

36
Q

What is enveloped virus

A

have a lipid and protein capsule

37
Q

What is naked virus

A

are without a envelope

38
Q

What are the classification of viruses

A

Helical - RNA
polyhedral - DNA
spherical - RNA
complex -DNA

39
Q

How do DNA viruses work

A
  1. Attachment and Entry
  2. Uncoating the protein coat is shed
  3. Replication of DNA using the host cells’ resources
  4. Transcription the viral DNA is copied onto the cells Messenger RNA
  5. Translation messenger RNA leaves the nucleus and ribosomes synthesise new viral proteins
    6.Assembly and Release
40
Q

How do RNA Viruses work?

A

1.Attachment and Entry
2. Uncoating the protein coat is shed
3. Replication of DNA using the host cells’ resources
4.Transcription NOT NEEDED
5.Translation messenger RNA leaves the nucleus and ribosomes synthesise new viral proteins
6.Assembly and Release

41
Q

What is tissue specificity

A

Entry by interaction with a specific cellular receptor.
Fusion directly with the cell membrane.

42
Q

What is the life cycle of a virus

A

The virus gains entry by endocytosis
carried into the cytoplasm in a vacuole via the cell membrane, leaving its protein capsule on the cell’s surface.
Viral nucleic acid is then released to take over the genetic machinery of the host cell
RNA viruses use an enzyme

42
Q

What is RNA viruses

A

have high mutation rates leading to changes in their antigenicity, enabling RNA viruses to escape from host immunity.
HIV, influenza

43
Q

What is Tissue Specificity: Tropism

A

which results from the fact that the virus must first bind a specific receptor present on a limited range of cells.

44
Q

What is direct cytoplasm effect

A

The presence of viruses can damage cells. This can happen when the cell membrane is injured, causing a fatal imbalance of ions in relation to the extracellular concentrations, or when the cell is deprived of its nucleic materials or amino acids.

45
Q

What is induction of immune response

A

Some viruses do not harm cells directly but cause new antigens to appear on the cell surface. These antigens are recognised as foreign bodies by the host’s immune system and the virus-infected cells are destroyed

46
Q

What is Incorporation of viral genes into the host’s chromosomes

A

Some viruses are able to be integrated in the host chromosomes and transform their behaviour. This mechanism underlies the ability of some viruses to induce tumours

47
Q

What is funghi

A

similar to plants but without chlorophyll (green pigment)

48
Q

what is pathogenic fungi

A

cannot produce their own food, so they must consume or parasite other organisms

49
Q

What is mycelium

A

complex forms exist as an extensive interwoven mesh are visible to the naked eye

50
Q

What are the classification of mycoses

A

Superficial mycoses
Cutaneous mycoses
Subcutaneous mycoses
Systemic mycoses

51
Q

What is protozoa

A

are unicellular microorganisms, larger than bacteria and their DNA is organised in a nucleus.

52
Q

What is protoza amoeba

A

Large cells of changing shape;
Amoebas extend their membranes to form pseudopodia that pull them along.

53
Q

What is cilia

A

Move by means of short, hair-like projections

54
Q

What is flagella

A

Move by long, whip-like extensions

55
Q

What is Sporozoa

A

have organelles at their tips which allow them to enter the host cells.
Usually they invade two different hosts to complete their life cycle.

56
Q

What are the two host in sporozoa

A

Host 1: The Infected Mosquito
Infected mosquito feeds on human and injects sporozoites into the human’s bloodstream.

Host 2: The Human Host
The sporozoites travel to the liver, invade cells and multiply making new parasites called merozoites

Host 3: The Mosquito Host
An infected mosquito bites the infected human and ingests the merozoites along with the blood meal.

57
Q

What is parasites

A

Parasites are pathogenic large, multi-cellular organisms ,complex life cycles requiring more than one host

58
Q

What is platyhelminths (flat worms)

A

Large parasites that can infest several different human organs

59
Q

What is Nematodes (roundworms)

A

Large parasites that infect a variety of different human tissues.
Often transmitted by food or by flies which bite.

60
Q

What is Arthropods

A

Parasites include mites, ticks, lice and fleas.
All can cause injury, but also can carry other microscopic pathogenic organisms.

61
Q

What are prions

A

Pathogenic protein molecules that hijack normal proteins in the body.
Convert them into abnormal proteins, leading to functional abnormalities.

62
Q

What is Rickettsiae and chlamydiae

A
  1. Bridge the gap between viruses and bacteria.
  2. Small like viruses, yet susceptible to antibiotics.
  3. Depend on hosts for growth and reproduction.
63
Q
A