Science Topic 2 Lessons 1 and 2

Anton Van Leeuwenhoek was the first person to observe cells that...

• were alive

• came from plants

• had no cell walls

• could only be seen with a compound microscope

What is the function of the cell wall?

• to perform different functions in each cell

• to prevent water from passing through it

• to protect and support the cell

• to prevent oxygen from entering the cell

Which organelle is the control center of the cell?

• mitochondria

• chloroplast

• nucleus

• ribosome

Specialized cells are only found in...

• animals

• many-celled organisms

• single celled organisms

• bacteria

How does magnification occur in an electron microscope?

• an electron beam makes an object become larger

• light is changed into electrons by a convex lens

• light is reflected by an electron beam

• beams of electrons scan the surface of the specimen

The invention of the microscope made it possible for people to observe...

• skin

• plants

• animals

• cells

You can't see cells in your body because most of them are very small.

• True

• False

Organelles that use energy from sunlight to make food are called...

• mitochondria

• Ribosomes

• chloroplasts

• vacuoles

The cells in many celled organisms often have different sizes and shapes.

• True

• False

The cell theory states that cells are produced from what kind of cells?

• living

• nonliving

• single celled

• multi celled