View the animation below, then complete the quiz to test your knowledge of the concept.

1	The HIV protein that is involved in attachment of the virus to host cells is
	A)	reverse transcriptase.
	B)	gp120.
	C)	CD4.
	D)	CCR-5.
	E)	CXCR-4.
2	The HIV enzyme that makes a double-stranded DNA copy of the viral genome is
	A)	DNA polymerase.
	B)	RNA polymerase.
	C)	reverse transcriptase.
	D)	endonuclease.
	E)	gyrase.
3	The type of cells infected by HIV are ________ early in the course of an infection and ________ late in the infection.
	A)	helper T cells ; cytotoxic T cells
	B)	helper T cells ; macrophages
	C)	macrophages ; cytotoxic T cells
	D)	macrophages ; helper T cells
	E)	macrophages ; helper B cells
4	Attachment of HIV to a host cell requires a receptor and co-receptor on the surface of the host cell.
	A)	True
	B)	False
5	HIV leaves an infected cell by breaking down its cell membrane.
	A)	True
	B)	False