save my exams vaccines ,diseases and monoclonal antibodies

Question 1

effectivenemess of vaccines

Answer 1

Highly effective with one vaccination giving a lifetime’s protection (although less effective ones will require booster / subsequent injections)
Generally harmless as they do not cause the disease they protect against because the pathogen is killed by the primary immune response

Question 2

problems with vaccines

Answer 2

poor responses
antigenic variation
antigenic concleament

Question 3

poor responses to vaccines

Answer 3

People can have a poor response (eg. they are malnourished and cannot produce the antibodies – proteins or their immune system may be defective)

Question 4

antigenic variation

Answer 4

the variation (due to major changes) in the antigens of pathogens causes the vaccines to not trigger an immune response or diseases caused by eukaryotes (eg. malaria) have too many antigens on their cell surface membranes making it difficult to produce vaccines that would prompt the immune system quickly enough

Question 5

antigenic concealment

Answer 5

this occurs when the pathogen ‘hides’ from the immune system by living inside cells or when the pathogen coats their bodies in host proteins or by parasitising immune cells such as macrophages and T cells (eg. HIV) or by remaining in parts of the body that are difficult for vaccines to reach

Question 6

live attenuated vaccines

Answer 6

vweakened pathogens multiply slowly allowing for the body to recognise the antigens and trigger the primary immune response (plasma cells to produce antibodies)
These vaccines tend to produce a stronger and longer-lasting immune response
They can be unsuitable for people with weak immune systems as the pathogen may divide before sufficient antibodies can be produced
An example of this type of vaccine is the MMR (Measles, Mumps and Rubella)

Question 7

herd immmunity

Answer 7

when a sufficiently large proportion of the population has been vaccinated (and are therefore immune) which makes it difficult for a pathogen to spread within that population
allows for the individuals who are unable to be vaccinated (e.g. children and those with weak immune systems) to be protected from the disease

Question 8

active immunity

Answer 8

antibodies produced by the body
1-2 weeks before appears in blood
memory cells present
natural -exposure to pathogen
artifical-vaccination

Question 9

passive

Answer 9

antibodies not produced by body
immediately appear in blood
no memoery cells
antibodied from another organism eg.breastmilk
artifical-manufactured and injected or transfered into organism

Question 10

transmssion of hiv

Answer 10

sexual intercourse
blood donation
sharing of needles used by intravenous drug users
from mother to child across the placenta
mixing of blood between mother and child during birth
from mother to child through breast milk

Question 11

strucutre of hiv

Answer 11

Two RNA strands
Proteins
A protein coat
A viral envelope consisting of a lipid bilayer and glycoproteins
Attachment proteins

Question 12

replicaion of hiv

Answer 12

1)hiv attaches to receptors on lymphocyte
2)hiv injects its genetic material into the lymphocytes which becomes a host cell
3)viral rna enters the cell ,reverse transcriptase to produce a dna copy of viral rna
4)inserted into chromosome
5)genetic material into lymphocyte which which becomes a host cell
6)after making many copies of itself the host cell is destroyed by hiv
7)hiv infection leads to decreased lymphocytes numbers and reduced ability to produce antibbodies

Question 13

symptoms of aids

Answer 13

mild flu-like symptoms
infected people might not know they are infected
gradually destroy and reduce the number of helper T cells present in a host

Question 14

problems of aids

Answer 14

When an individual can no longer produce antibodies they are said to have advanced acquired immunodeficiency syndrome (AIDS)
As they can no longer produce antibodies against pathogens they are immuno-comprised and unable to fight off infections
They begin to suffer from diseases that would usually cause very minor issues in healthy individuals
These diseases are described as opportunistic
Tuberculosis (TB) is a common example

Question 15

what happens to t cells if aids didnt exist

Answer 15

T cells play an important role in the specific immune response
They stimulate B cells, the production of antibodies and increased rates of phagocytosis

Question 16

treaatmen of aids

Answer 16

As of yet, there is no cure for AIDS
There are many drugs that are very effective at slowing the spread of the virus within the body
When provided with adequate medical care individuals with HIV have the same life expectancy as those without the virus

Question 17

antibiotics and viruses

Answer 17

Antibiotics are commonly used to kill bacteria or limit bacterial growth
The mechanism by which they work can vary. Some interfere with the metabolism of bacterial cells while others prevent protein synthesis
Antibiotics are ineffective against viruses as they are non-living
Viruses are particles and not cells
They have no metabolism or cell structure for antibiotics to act on and disrupt

Question 18

what can monoclonal antibodies be used for

Answer 18

Pregnancy tests
Diagnosing HIV
Detecting the presence of pathogens such as Streptococcus bacteria
Distinguishing between Herpes I and Herpes II
Blood typing before transfusions and tissue typing before transplants
Detecting the presence of antibiotics in milk
Detecting cancer cells

Question 19

how Monoclonal antibodies can also be used to locate the position of blood clot

Answer 19

Injecting a mouse with human fibrin

This activates the plasma cells to produce antibodies against fibrin

These cells are collected from the mouse spleen

plasma cells are then fused with tumour cells forming hybridomas that produce antifibrin antibodies

detect where the antibodies are binding to fibrin molecules, a radioactive chemical (producing gamma radiation) is attached to the antibodies making them radioactively labelled

detect where these radioactively labelled antibodies have attached to a fibrin molecule, hence indicating where blood clots can be found

Question 20

monoclonal antibodies and hiv

Answer 20

1)hiv antigen is attached to a test plate
2)the blood sample being tested is passed over the test plate and if hiv antibodies are present they bind the antign
3)plate is washed
4)a monoclonal antibody is then passed over the plate its antigen is the hiv antibody and it will bind to it if its present ,the monoclonal antibody is attched to an enxyme
5)enzymes catalyse a colour change in the dye substrate

Question 21

ethical issues of monoclonal

Answer 21

All vaccines are tested on animals before they can move onto human-trials (testing on humans) but some people think animal testing is unethical
possibility of side effects
Even at the human-trial stage, a vaccine carries a small risk (the person being tested on may actually suffer from symptoms of the disease

Question 22

what happens duirng an elisa test

Answer 22

1)hiv antigen bound to bottom of the reaction vessel
2)blood plasma sample added - antibody in vessel is not spec to hiv antigen and there are primary antibodies
3)wash out
4)secondary antibody added - secondary body with attached enzyme
5)secondary antibody added
6)wash out
7)substrate added and there should be a colour chnage whe enzyme reacts with substrate

Question 23

what happens in an indirect elisa test

Answer 23

1)antibodies to psa bound to bottom of the reaction vessel
2)psa binds to primary antibody blood plasma sample added
wash out
3)secondary antibody with attached enzyme
4)secondary antibody added ehich only binds to pirmry antibody if psa is present
5)wash out
6)substrate added enzyme reacts with substrate and if psa is present then colour change