Anatomy ck-12 ch4

_____ are the basic units of structure and function in living things.

• cells
• plasma membranes
• mitochondria
• lysosomes

The _____ states that all organisms are made of cells, that all life functions occur in cells, and that all cells come from other cells.

• active transport
• passive transport
• cell theory
• microscope theory

The invention of the _____ allowed scientists to see organelles and other structures smaller than cells.

• light microscope
• cell
• electron microscope
• cell theory

_____ have a plasma membrane, cytoplasm, ribosomes, and DNA.

• only some cells
• all cells

Cells must be very small so they have a _____ large enough to maintain normal cell processes.

• volume
• shape
• surface area-to-volume ratio

Cells with different functions often have _____.

• different organelles
• different plasma membranes
• different shapes
• different type of nucleus

_____ do not have a nucleus.

• prokaryotic cells
• eukaryotic cells

_____ do have a nucleus, along with other organelles.

• prokaryotic cells
• eukaryotic cells

The _____ forms a barrier that allows only certain substances to pass in or out of the cell.

• mitochondrion
• plasma membrane
• vacuole
• flagellum

The plasma membrane is composed mainly of a _____.

• bilayer of phospholipid molecules
• cilia and flagella
• cytosol
• cytoplasm