Summary AQA ALEVEL BIOLOGY NOTES ON HIV AS LEVEL

The Human Immunodeficiency Virus
=

HIV
→
causes the disease acquired immune
deficiency syndrome ( AIDS ) .




AIDS is condition where the immune deteriorates and
eventually fails This makes someone with
system
a
-


.




AIDS more vulnerable to other infections , like pneumonia .




What are the host cells for HIV ?



HIV CD4X cells , cells that have specific CD4 their
targets meaning this molecule called
-


on


membrane I CD4 is used to help




:m→:tf
.




immune cells communicates CD4X cells
÷
→ ~
9 9 ,• dendritic
\
- -
, ?
a•
,• cells
-

,
. .




r -
O
B- too



ai /
I
B- hoo n


• ↳
• b.
%
• "




r

macrophage
HIV infects and
eventually kills helper T cells ( a CD4X cell )
-

-
.




•
The CD4 -1 cells ( Tn cells ) act as hosts cells
e.g
-




Remember helper ( via called
T send chemical signals molecules
cytokines) that activate
-


cells


phagocytes ( macrophages Ineutrophils ) ,
cytotoxic T-cells and B- cells .




How does HIV
develop AIDS ?



Without T-cells
enough helper (due
hijacking helper T-cells) the
system unable have
-



to HIV ,
immune is to

effective infections because don't behave how
an
response to other immune
system cells
they should .




People infected with HIV develop AIDS when the helper T their
body reach
-
-
cell numbers in a



low level
critically .




Structure of HIV

,*.. :* .




.io/gq
Bo
Of
mate attachment
genetic µ ,
protein
'
On the outside is a
lipid envelope ,
embedded in


g•




⑧
( RNA
) which are -
like attachment proteins
✓ peg
⑧⑧\ food Inside the
.




, envelope is a
protein layer called the


capsid that encloses two
single strands of RNA and




IE 3. cars .
÷:÷÷÷::÷÷:c:*:*:c:*:÷:
Bol n
hope DNA from RNA -
the reverse reaction to that


too carried
r
by transcriptase )
Boo
out
lipid envelope

& &
r
reverse
B
transcriptase
(enzyme )
matrix