Topic 5: Health and diesease

Question 1

What is the lytic cycle of viral replication?

Answer 1

The replication process by which a virus spreads between the cells of the host and multiplies.

Question 2

What s viral nucleic acid?

Answer 2

The DNA strand inside of a viral cell

Question 3

How does the viral nucleic acid enter the bacterial host cell?

Answer 3

It lands on the surface of a cell which has complementary ‘locks’ on the surface to the ‘keys on the surface of the viral cell then it can attach its elf to the surface and inject the viral nucleic acid.

Question 4

How are new viruses produced in the host cell?

Answer 4

When the viral nucleic acid enters the DNA of the host, the DNA then gets copied into mRNA through transcription. The viral mRNA is then read by the ribosomes so that viral proteins are made and assembled into new viruses. These new viruses are released out of cell, usually killing it.

Question 5

What are vectors?

Answer 5

Vectors carry pathogens and infectious diseases from one host to another.

Question 6

How do you reduce the risk of getting infectious diseases?

Answer 6

• wash hands (if spread through touch or bodily fluids)
• clean water/food only
• diagnose infected people promptly and give anti biotic
• isolate infected people
• stay away from vectors
• don’t touch infected people

Question 7

What physical defences does the body have against pathogens?

Answer 7

• unbroken skin forms a barrier
• sticky mucus in the breathing passages and lungs traps pathogens
• Cilia on the cells lining the lungs move in a wave like motion, moving mucus and trapped pathogens out towards the back of the throat where it is swallowed

Question 8

What chemical defences does the body have against pathogens ?

Answer 8

• Lysozyme enzyme in tears, saliva and mucus kill bacteria by digesting their cell walls
• Hydrochloric acid in the stomach kills pathogens

Question 9

What are lymphocytes?

Answer 9

White blood cells which stick to and destroy pathogens

Question 10

How do Lymphocytes immobilise pathogens?

Answer 10

1) One of the millions of lymphocytes in your body will produce antibodies which are complementary to the antigens in the pathogen
2) Once the lymphocytes has found the pathogen, it will begin to duplicate its self and make more lymphocytes with the correct antibodies,
3) Some of these lymphocytes will be memory lymphocytes which stick around after the pathogen has gone
4) The lymphocytes then use the anti bodies to immobilise the pathogen

Question 11

What do phagocytes do?

Answer 11

They are white blood cells which kill the pathogens once they have been immobilised by the lymphocytes

Question 12

How do vaccines cause immunisation from a disease?

Answer 12

The vaccine contain antigens from the pathogen (either dead or weakened) so that the body produces lymphocytes with the complementary antibodies for that disease. Memory lymphocytes will then be left over in the blood stream so will be able to deal with the pathogens quickly if the person ever gets infected again.

Question 13

How do antibiotics kill bacteria?

Answer 13

They inhibit cell processes in the bacterium but not the host organism. For example, some antibiotics stop cell walls forming properly. This does not harm the animal because animal cells don’t have cell walls.

Question 14

What are monoclonal antibodies?

Answer 14

antibodies that carry useful chemical markers or treatment. They are made from hybridoma cells.

Question 15

What is a hybridoma cell and why are they made?

Answer 15

A cell which is made by fusing a lymphocyte cell with a cancer cell.
They are made so that they have antibodies that are complementary to a specific disease but also divide quickly.

Question 16

How are monoclonal antibodies made?

Answer 16

A mouse is injected with a antigen specific to the disease that they are trying to combat. The mouse then produces lymphocytes which have antibodies specific to that pathogen. These lymphocytes are then taken out of the blood stream and fused with a cancer cell. These hybridoma cells clone and produce monoclonal antibodies which are then collected.

Question 17

How do scientists make sure that in the production of monoclonal antibodies they only get the desired antibody?

Answer 17

They do a process called screening which separates the useful from the non useful

Question 18

How are monoclonal antibodies used in pregnancy test??

Answer 18

In pregnancy tests to identify if the pregnancy hormone is present in urine. The monoclonal antibody matches the hormone and causes a reaction with the indicator

Question 19

How are monoclonal antibodies used in diagnosis of disease?

Answer 19

Monoclonal antibodies with fluorescent dyes can stick to cancer cells and blood clots which allows them to be detected.

Question 20

How are monoclonal antibodies used in treatment of disease?

Answer 20

Monoclonal antibodies can by attached to the treatments deliver them straight to the pathogens or cancer cells.

Question 21

Why are monoclonal antibodies better at treating cancer than other ways?

Answer 21

because they only attack the cancer cells as the antibodies would only be specific to the cancer cells antigens. This also means less of the drug needs to be administered so there will be fewer side affects.

Question 22

What are antigens?

Answer 22

Things on the surface of the cells, specific to one body. Immune systems recognise different antigens on cells/virus’s and attacks them.

Question 23

What is the Core practical associated with this topic?

Answer 23

Serial dilutions and microbial cultures.

-used to dilute the bacterial cultures then can be used to see effectiveness of antibiotics

Question 24

How does smoking help cause cardiovascular disease?

Answer 24

Substances in the smoking damages the artery wall and interrupts the flow of blood. This slowed down blood means the cholesterol is deposited and settles, this can build up and form blood clots.

Question 25

How can cardiovascular disease be treated?

Answer 25

Through lifestyle changes, medication or surgery

Question 26

What lifestyle changes can help treat cardiovascular disease?

Answer 26

• giving up smoking
• more exercise
• eat a healthier diet
• losing weight

This is the cheapest and most healthy option although may take time to work or not work effectively

Question 27

How do medicines such as antiplatelet and statins prevent Cardiovascular disease?

Answer 27

• Antiplatelets thin your blood making blood clots less likely
• Statins reduces cholesterol in your blood so there is less fat in your blood to cause blood clots
• beta blockers

Question 28

What are the advantages and disadvantages of medication to treat cardiovascular disease?

Answer 28

\+Starts working immediately
\+easy to use
\+cheaper and less risky than surgery
-need to be taken long term
-may not be effective long side other medication

Question 29

How can surgery be used to treat cardiovascular disease?

Answer 29

• Coronary angioplasty where a balloon is inserted to widen the artery then a wire a frame called a stent can be inserted to hold open the artery
• Heart by-pass surgery can be used by inserting a new blood vessel to carry blood around the blocked artery.

Question 30

What are the advantages and disadvantages of surgery to treat cardiovascular disease?

Answer 30

+usually long term a solution

• there is risk the person will not recover
• surgery is expensive
• more difficult to do than medication
• risk of infection

Question 31

What physical barriers do plants have against pests and pathogens?

Answer 31

• bark
• thick waxy cuticles
• cellulose cell walls are difficult for pathogens to break down
• some have thorns

Question 32

What chemical barriers do plants have against pests and pathogens?

Answer 32

• poisons in their cells which deter pests

- chemicals in the plants which kill pathogens

Question 33

What are the uses of medicines found in plants?

Answer 33

• to treat human diseases like malaria(quinine) to heart disease(digoxin) by killing the pathogen
• to relieve symptoms like pain and fever (aspirin)