Organisms that cause disease 4.1.1

Question 1

What are the different types of pathogens?

Answer 1

• Bacteria
• Virus
• Fungi
• Protoctista

Question 2

What are pathogens?

Answer 2

A microorganism that causes disease

Question 3

Give an example of a bacteria

Answer 3

Bacterial meningitis

Question 4

Give an example of a virus

Answer 4

HIV/AIDS

Question 5

Give an example of a protoctista

Answer 5

Tomato/potato late blight

Question 6

What is a communicable disease

Answer 6

They are caused by an other organism that infects an other, and these infective organisms are known as pathogens

Question 7

What are the most common organism for infection?

Answer 7

Bacteria

Question 8

Are all bacteria pathogens?

Answer 8

No, most bacteria do not cause diseases

Question 9

What are bacteria?

Answer 9

They are prokaryotes, which do not have membrane bound organelles

Question 10

What is gram staining?

Answer 10

How bacteria are classified, by staining their cell wall

Question 11

What colour do bacterial cell walls turn if gram positive?

Answer 11

Look purple/blue under a light microscope

Question 12

What are gram positive bacteria stained with?

Answer 12

Crystal violet

Question 13

Give an example of gram positive bacteria

Answer 13

MRSA

Question 14

What colour do bacterial cell walls turn if gram negative?

Answer 14

Look red under a light microscope

Question 15

What are gram negative bacteria stained with?

Answer 15

Safranin

Question 16

Give an example of gram negative bacteria

Answer 16

E.coli

Question 18

What are the 4 main shapes of bacteria

Answer 18

• Cocci (spherical)
• Vibrio (curved)
• Bacilli (rod shaped)
• Spirilli (spiral)

Question 19

What does cocci bacteria cause?

Answer 19

Acne spots

Question 20

What does vibrio bacteria cause?

Answer 20

Cholera

Question 21

What does bacilli bacteria cause?

Answer 21

Food poisoning

Question 22

What does spiral bacteria cause?

Answer 22

Stomach ulcers

Question 23

Describe the shape of cocci bacteria (detail)

Answer 23

Cocci have less surface area per volume than bacilli or spirillum, and thus can survive in dryer environments

Question 24

Describe the shape of spirillum bacteria

Answer 24

Spirillum are spiral cells, move with a corkscrew motion, and meet less resistance from surrounding water

Question 25

Describe the shape of bacilli and vibrio bacteria

Answer 25

Bacilli and vibrio have a greater surface area to volume ratio and take up nutrients from dilute solutions more efficiently

Question 26

How dio bacteria reproduce?

Answer 26

By binary fission

Question 27

Binary fission

Question 28

What are problems with bacteria reproducing so quickly?

Answer 28

• Food spoilage
• Spread of disease

Question 29

How do bacteria cause disease?

Answer 29

• Produce toxins and cause symptoms by cell damage
• Damage cell membranes, enzymes, or genetic material

Question 30

Describe viral reproduction (steps)

Answer 30

• The virus attaches to a specific host cell
• The genetic material from the virus is injected into the host cell
• The viral genes cause host cell to make new viruses
• The host cell splits open, releasing the new virus

Question 31

State the 6 steps of HIV infection

Answer 31

1. p120 molecules on the HIV bind to CD4 receptor proteins on T helper lymphocytes and macrophages
2. The virus outer envelope fuses with the cell membrane
3. Viral RNA + enzymes from the HIV are injected into the T cell
4. The viral DNA is transcribed and translated by the host cell to produce new viral proteins
5. Transcribed RNA plus viral proteins are assembled together to form new viruses
6. The new viruses leave the cell by budding, taking some of the host cell membrane to form the viral envelope. This kills the T helper cells

Question 32

How does yeast reproduce?

Answer 32

By budding, in asexual reproduction

Question 33

Describe the structure of protoctists

Answer 33

They’re unicellular and have a nucleus