There are many different types of virus that can infect animal cells.

Mark scheme

Marking points from the official mark scheme (May/June 2022). The mark or mark type is shown in brackets.

1. [4] any four from: virus is smaller ORA ; both contain genetic material ; animal cell always DNA + virus DNA or RNA ; animal cell has (cell surface) membrane ORA ; virus has a protein coat / capsid ORA ; animal cell has a nucleus / nuclear membrane ORA; animal cell contains cytoplasm / organelles / named organelle ORA ;
2. [3] any three from: sexually transmitted ; blood transfer / blood transfusion AW; sharing AW + needles / razors ; from mother to baby + across placenta / during pregnancy / during birth / breastfeeding ;
3. [3] any three from: number infected increasing / more people infected in 2018 than 2000; rate of infection decreasing / slowing down ; correct data manipulation + data quoted to illustrate either point ; number treated for HIV increasing / more people treated in 2018 than 2000; a much bigger proportion of those infected being treated ; correct data manipulation + quoted to illustrate the point e.g. in 2000 less than 5% treated in 2000 and in 2018 over 60% treated ;