Immunity

Question 1

Which is the order of size of viruses and bacteria?

Answer 1

Viruses are smaller than bacteria.

Question 2

What is the structure of bacteria?

Answer 2

• single-celled
• have a cell wall, cell membrane, cytoplasm ad plasmids
• no nucleus
• contain a circular chromosome of DNA

Question 3

What is the structure of protoctista?

Answer 3

• single-celled
• some have features similar to animal cells, other have features like plant cells
• contain a nucleus

Question 4

What is the structure of viruses?

Answer 4

• not made up of cells
• have a protein coat containing genetic material
• have one type of nuceic acid (either DNA or RNA)
• made from thread-like structues called hyphae

Question 5

How do bacteria get their energy?

Answer 5

Either by feeding off other living/dead organisms or by carrying out photosynthesis.

Question 6

How do viruses reproduce?

Answer 6

Only possible inside other living (host) cells - parasitically.

Question 7

What are some examples of bacteria?

Answer 7

• Lactobacillus bulgaricus (used to make yoghurt from milk).
• Pneumococcus (acts as the pathogen causing pneumonia).

Question 8

What are some examples of protoctista?

Answer 8

• Amoeba (live in pond water).
• Chlorella.
• Plasmodium (causes malaria).

Question 9

What are some examples of viruses?

Answer 9

• Tobacco mosaic virus (discolours the leaves of tobacco plants by preventing the formation of chloroplasts).
• Influenza (causes ‘flu’).
• HIV virus (causes AIDS).

Question 10

What are the different types of pathogens?

Answer 10

Fungi, bacteria, viruses and protoctista.

Question 11

How do fungi get their energy?

Answer 11

Secretes enzymes to breakdown starch into glucose which then is diffused into the fungi - saprotrophic.

Question 12

How do phagocytes help to protect the body against disease?

Answer 12

Phagocytes engulf pathogens and release enzymes which digest and destroy the pathogen.

Question 13

How do lymphocytes help to protect the body against disease?

Answer 13

• Lymphocytes have antibodies which bind to antigens on the surface of pathogens. Different lymphocytes produce different types of antibodies specific for a particular antigen.
• Lymphocytes meet pathogens and reproduce quickly to bind many copies of the antibodies to the pathogen.
• Sometimes a lymphocyte will produce antitoxins which neutralise the action of toxins (released by bacteria and some viruses and can cause illness).

Question 14

Draw and label a phagocyte

Answer 14

Question 15

How does blot clot?

Answer 15

Platelets (tiny cells in the blood) prevent blood loss by forming a scab to help clot the blood.

Question 16

How does vaccination help with immunity in the body?

Answer 16

• Antigens of a pathogen are injected into the body.
• The vaccination triggers lymphocytes to produce antibodies.
• Memory cells are made.
• Upon reinfection, the body (with the help of memory cells) can immediately recognise the antigen to quickly produce many more antibodies.

Question 17

When making beer using yeast, why would tjere be oil on the surface of the yeast and glucose mixture?

Answer 17

To prevent any oxygen getting in and ensure that the respiration was anaerobic.

Question 18

What is the word equation for anaerobic respiration in yeast (fermentation)?

Answer 18

glucose → carbon dioxide and alcohol

Question 19

What is the word equation for anaerobic respirayion in Lactobacillus bacteria (lactic fermentation)?

Answer 19

lactose (milk energy) → lactic acid

Question 20

How can one produce large quantities of microorganisms (at a factory scale)?

Answer 20

industrial fermenter

Question 21

What does each letter of the diagram represent?

Answer 21

a) motor
b) cooling jacket
c) paddles
d) temperature recorder
e) cooling water in
f) air out
g) cooling water in
h) air filter

i)

Question 22

In an industrial fermenter why are there paddles to stir the mixture?

Answer 22

So that everything is mixed evenly and the temperature and pH are constant throughout the mixture.

Question 23

What factors need to be controlled in an industrial fermenter?

Answer 23

temperature and pH

Question 24

Why is oxygen pumped into an industrial fermenter?

Answer 24

So that the microorganisms can respire and release energy for their growth.