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Title: Cells and Immune System Summary
Description: PDF summary of topc 2C from A Level Biology AQA Revision Book
Description: PDF summary of topc 2C from A Level Biology AQA Revision Book
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Cells and the Immune System
Created
Class
@February 12, 2025 9:04 PM
Cells to Systems
Immune Response
Generated by antigens
Found on cell surfaces
Used by immune system to identify foreign substances/cells e
...
antibodies binds to anything and can be specific
Vaccines and Ethics
Vaccines are tested on animals which cause disagreements
Testing on people involves risk of contracting disease
Some groups avoid vaccines due to possible side effects
Still protected due to herd immunity
HIV Causes AIDS
HIV is a virus impacting the immune system leading to aids
Having AIDs means the immune system worsens and fails
AIDS patients are more vulnerable to infections
HIV infects and kills helper t-cells
The lack of helper t-cells means the body can’t produce a sufficient
immune response
AIDS develops when helper t-cell lvls are extremely low
Cells and the Immune System
4
HIV Structure
Core contains RNAs and proteins
Capsid
Outer coating
Envelope
Extra outer layer
Made from stolen cell membrane
Attachment proteins stick out of envelope to help HIV attach to helper tcells
HIV Replication
Attachment protein attaches to receptor molecule on helper t-cell
Capsid released into cell and releases RNA into cytoplasm
DNA is made from reverse transcriptase and viral RNA template
‘Fake’ DNA is placed in host DNA
Enzymes in host produce viral proteins from viral DNA placed earlier in
normal DNA
Viral proteins are sorted into new viruses and infect other cells
Illness Susceptibility Due to AIDS
Starting symptoms of AIDS include small infections of mucous membranes
and respiratory infections
Cells and the Immune System
5
Immune system cells decrease and patient is more vulnerable to serious
infections
Late stage AIDS patients have very low number of immune system cells
Increases their chances of contracting serious infections
Antibiotics
Kills bacteria and targets bacterial enzymes and ribosomes
Antibiotics designed to target only bacterial enzymes to avoid damage to
human cells
Viruses don’t have enzymes or ribosomes so avoid inhibition from
antibiotics
Antiviral drugs targets virus specific enzymes
No Cure
Currently no cure or vaccine for HIV
Antiviral drugs can slow HIV infections and AIDS down
Reducing spread is the best countermeasure
HIV can spread via unprotected sex and infected bodily fluids
HIV Spread
Unprotected sex
Infected bodily fluids
Can spread from HIV mother to fetus but not all babies born are
infected
Taking antivirals can reduce chances of baby contracting virus
Cells and the Immune System
6
Title: Cells and Immune System Summary
Description: PDF summary of topc 2C from A Level Biology AQA Revision Book
Description: PDF summary of topc 2C from A Level Biology AQA Revision Book