2.4 Immune system ppq Flashcards
Describe how HIV is replicated (4 marks)
- Attachment proteins attach to receptors on T helper cells
- Nucleic acid/ RNA enters cell
- Reverse transcriptase converts RNA to DNA
- Viral protein produced
- Virus assembled and released
Describe how HIV is replicated ONCE INSIDE the T helper cell
- RNA converted to DNA using reverse transcriptase
- DNA inserted into T helper cells nucleus
- DNA transcribed into HIV mRNA
- HIV mRNA translated into viral proteins
Describe how a phagocyte destroys a pathogen present in the blood
- Engulfs
- Forming a phagosome and fuses with lysosome
- Enzymes/ lysozymes digest
Give 2 types of cells, other than pathogens, that can stimulate an immune response
- Cells from transplant
- Tumour cells
What is the role of the disulphide bridge in forming the quaternary structure of an antibody
Joins 2 different polypeptides
Explain how HIV affects the production of antibodies when AIDS develops in a person
- Less/ no antibodies produced
- Because HIV destroys T helper cells
- So, few/ no B cells activated
Determining the genome of the viruses could allow scientists to develop a vaccine
- Could identify proteins/ proteome
- Could then identify potential antigens to use in vaccine
Describe how B lymphocytes of a frog would respond to vaccination against Ranavirus, assuming the act the same way as humans- DONOT include details of the cellular response
- B cells bind to complementary antigen
- B cell clone
- Plasma cells release antibodies
- B cells produce memory cells
What is a monoclonal antibody
Antibodies with same tertiary structure
After a disease is diagnosed, monoclonal antibodies are used in some medical treatments. Give 1 example of using monoclonal antibodies in a medical treatment
Block antigens on cells
Describe the role of antibodies in producing a positive result in an ELISA test
- First antibody binds to antigen
- Second antibody with enzyme attached is added
- Second antibody attaches to antigen
- Substrate changes colour
Describe and explain the role of antibodies in stimulating phagocytosis - DO NOT include details about the process of phagocytosis
- Bind to antigen
- Antibodies cause agglutination / attract phagocytes
Give all 3 structural features in all virus particles and describe the function of one of these features (2 marks)
- Genetic material, capsid and attachment protein
- Genetic material codes for viral protein
- Capsid protects the genetic material
- Attachment protein bind to receptors
Explain why viruses are describe as acellular and non-living (2 marks)
- Acellular: no cell-surface membrane
- Non-living: cannot independently replicate
Give one reason why antiobiotics are not effective against viruses (1 mark)
- Do not have a cell wall
