HIV

Question 1

Name the main difference between pictures obtained with a SEM and TEM

Answer 1

1 3D with SEM but 2D with TEM
2 because electrons deflected using SEM

Question 2

The resolution of an image obtained using an electron microscope is higher than the resolution of an image obtained using an optical microscope.
Explain why.

Answer 2

Shorter wavelength between electrons

Question 3

Name two structures found in all bacteria that are not found in plant cells.

Answer 3

1 circular DNA molecule in cytoplasm
2 murein cell wall

Question 4

Name two features of HIV particles that are not found in bacteria.
Do not include attachment protein in your answer

Answer 4

1 capsid
2 reverse transcriptase

Question 5

Describe how HIV is replicated

Answer 5

1 attachment proteins attach to receptors on helper T cell
2 nucleic acid enters cell
3 reverse transcriptase coverts RNA to DNA
4 viral protein produced

Question 6

Describe how HIV is replicated once inside helper T cells

Answer 6

1 RNA converted into DNA using reverse transcriptase
2 DNA incorporated into helper T cell DNA
3 DNA transcribed into HIV mRNA
4 HIV mRNA translated into new viral proteins (for assembly into viral particles)

Question 7

Explain how HIV affects the production of antibodies when AIDS develops in a person.

Answer 7

1 less antibody produced
2 because HIV destroys helper T cells
3 so few B cells activated

Question 8

Describe the structure of the human immunodeficiency virus

Answer 8

1 RNA as genetic material
2 reverse transcriptase
3 protein capsid
4 phospholipid envelope
5 attachment proteins
4 MAX

Question 9

Describe how the complementary strand of HIV DNA is made

Answer 9

1 complementary nucleotides
2 DNA polymerase
3 nucleotides join together to form new strand, phosphodiester bonds form