Infection and Response- Monoclonal Antibodies And Plant Disease

Question 1

What are monoclonal antibodies?

Answer 1

One type of antibody that are specific to one binding site on one protein antigen

Question 2

How are monoclonal antibodies produced?

Answer 2

-a mouse is injected with non self material do antibodies are produced. Another mouse is exposed to radiation causing a tumour to develop
-lymphocytes and the tumours formed are removed
-the lymphocytes and myeloma cells are fused together which enables lymphocytes to divide outside of body.the fused cells are called hybridoma cells
-hybridoma cells can produce antibodies and divide rapidly
-fused cells are separated and cultured
-each clone is tested to check for the correct antibody, antibodies are collected and purified and if correct antibody is present, hybridoma cells can be grown on a large scale

Question 3

What are the uses of monoclonal antibodies?

Answer 3

-used in pregnancy tests
-diagnosis and treatment of cancer
-Detection of pathogens
-measure hormone levels in blood
-attaching markers to identify molecules

Question 4

What are myeloma cells?

Answer 4

Type of tumour cell

Question 5

What do pregnancy kits test for?

Answer 5

HCG in urine

Question 6

What does a pregnancy test consist of?

Answer 6

A stick containing monoclonal antibodies specific to HCG:
-mAbs attached to a blue bead(free to move)
-mAbs fixed to the test stick

Question 7

Describe what happens to the test stick if a woman is pregnant

Answer 7

-urine travels up to reaction zone
-HCG will bind to mobile antibodies attached to a blue bead in reaction zone
-HCG will move up strip and bind to the immobile(fixed) antibodies in the results window
- any antibody that did not bind to HCG will bind to the immobile antibodies in the control window
-blue line will appear in the result and control window

Question 8

What happens to the pregnancy stick if the women is not pregnant?

Answer 8

No HCG in urine so a blue line doesn’t form

Question 9

What are the advantages of using monoclonal antibodies

Answer 9

-can diagnose severe diseases eg cancer
-don’t target healthy cells
-useful outside of body eg pregnancy tests
-less invasive
- very accurate when testing for pathogens
-quick result
Using mice is better than person dying or being ill
-specific to one particular antigen making it good to test for pathogens

Question 10

What are the disadvantages of using monoclonal antibodies?

Answer 10

-people may be allergic
-have some very severe side effects
-using mice is unethical as you are growing a tumour
-don’t know much about this treatment
-expensive

Question 11

Why can monoclonal antibodies be used to target cancer cells?

Answer 11

-cancer cells have specific antigens called tumour markers on their membranes
-mAbs are specific to one type of antigen so can be targeted to tumour markers without damaging other cells

Question 12

How can monoclonal antibodies be used to diagnose cancer?

Answer 12

-mAbs tagged to a radioactive substance
-mAbs injected into patient’s bloodstream
-mAbs bind to tumour markers on cancer cells
-emitted radiation is detected using a specialised scanner enabling doctors to determine the location of cancer cells

Question 13

How can monoclonal antibodies be used to target drugs to cancer cells?

Answer 13

-mAbs attached to an anti-cancer drug
-mAbs injected into the patient’s bloodstream
-mAbs bind to tumour markers on cancer cells
-anti cancer drug destroys cancer cells

Question 14

Why are cancer treatments that use monoclonal antibodies favoured over traditional treatments?

Answer 14

-radiotherapy and chemotherapy target rapidly dividing cells
- healthy cells ( hair follicle cells, bone marrow cells) are damaged as a consequence, producing unpleasant side effects
- mAbs only target cancer cells, reducing damage to normal cells

Question 15

How can monoclonal antibodies be used to locate blood clots?

Answer 15

-mAbs tagged to a radioactive substance
-mAbs target and bind to specific proteins in blood clots
-radiation emitted by mAbs is detected, enabling the location of blood clots to be identified

Question 16

Define humanisation

Answer 16

The modification of antibodies before their use

Question 17

What are the problems with using monoclonal antibodies?

Answer 17

-antibodies from mouse have to be modified
-creates more side effects than expected
-not yet as widely used as hoped

Question 18

How do aphids cause damage to plants?

Answer 18

They use their sharp mouthparts to extract sap from the plant phloem, weakening the plant.
They are also vectors who can transfer pathogens from diseased plants to healthy plants

Question 19

How can we reduce the number of aphids?

Answer 19

-chemical pesticides
-biological pest control- using ladybirds

Question 20

Why do plants need a good supply of nitrate ions?

Answer 20

Are required to convert sugars into proteins which are needed for the plant to grow
So the growth of the plant will be stunted if there is not an adequate supply of nitrates

Question 21

Why do plants need a good supply of magnesium ions?

Answer 21

Are required to synthesis chlorophyll which absorbs light energy during photosynthesis
So the leaves can’t photosynthesise properly and they turn yellow( chlorosis)

Question 22

What are the symptoms of disease in plants?

Answer 22

-stunted growth(lack of nitrate ions)
-spotted leaves (rose black spot fungus)
-decay/rotting
-growths
-malformation of stems/leaves
-discolouration
-presence of pests

Question 23

What are the ways plant disease can be identified?

Answer 23

-using a garden website or manual
-laboratory testing
-monoclonal antibody test kits

Question 24

Give examples of physical defence responses used by plants

Answer 24

To prevent the invasion of microorganisms
-cellulose cell walls - form a physical barrier into the cells
-tough waxy cuticle on leaves - stops entry into leaves
-outside layer on stems/ bark on trees
-leaf fall with the pathogens stops while pant becoming infected

Question 25

Give examples of chemical defence responses used by plants

Answer 25

To deter predators or kill bacteria
-poisons, deter herbivores
-antibacterial compounds kill bacteria eg mint and witch hazel

Question 26

Give examples of mechanical defence responses used by plants

Answer 26

Thorns and hairs- deter or harm predators
Leaves curling or dropping when touched -prevent infection entering
Mimicry- trick vectors/predators

Question 27

Describe the structure of the leaf and the functions of the tissues in the leaf

Answer 27

Top of the leaf there is palisade tissue,they trap light for photosynthesis. At the top so they are able to absorb light, are adapted as they have lots of chloroplasts to absorb light, also have large surface area which means shorter diffusion pathway
-middle of leaf there is a xylem, transports water around the cell, it has lignin wall in a spiral structure,this helps it to transport water quicker
- has waxy cuticle at top to prevent water loss
-has phloem which transports sugars
-has stomata bd guard cells at bottom which allow gases to I’ve in and out and also controls water loss

Question 28

What can plants be infected by?

Answer 28

Viral infections- tabacco mosaic virus
Bacterial infections
Fungal pathogens- rose black spot
-by insect vectors- usually aphids