Chapter 3 - Cells

Microfilaments and microtubules are part of the cytoskeleton.

• True

• False

About how many cells constitute the adult human body?

• 50 to 100 quadrillion

• 50 to 100 trillion

• 50 to 100 million

• 50 to 100 billion

Which of the following correctly describes the structural organization of the cell membrane?

• A bilayer of phospholipid molecules in which protein molecules are embedded and can move.

• Rigid layers of protein molecules in which carbohydrate molecules are suspended.

• A solid, rigid layer of phospholipid with loosely bound protein molecules.

• Three layers; lipid on the inside, protein in the middle, and carbohydrates on the outside.

Red blood cells are placed in a solution of 0.9% NaCl and no diffusion or osmosis is observed. This means the solution is _____

• Hypertonic

• Isertonic

• Isotonic

• Hypotonic

What characteristic does simple diffusion and facilitated diffusion have in common?

• Both require a special carrier molecule to move substances across the membrane.

• Both require cellular energy for the transport of substances.

• Both move water across a semipermeable membrane.

• Both move a substance from a region of higher concentration to one of lower concentration without using cellular energy.

Certain white blood cells take in bacteria by phagocytosis.

• True

• False

Fred discovers a rapidly growing lump that doubles in size over a month. A doctor does a biopsy and discovers it's a form of cancer. What went wrong in the cell cycle to result in the cancer?

• Mitosis was too frequent.

• Mitosis was not frequent enough.

• The cell cycle ran backwards.

• The cell cycle stopped.

What is the name for programmed cell death?

Smooth endoplasmic reticulum has ribosomes, and rough endoplasmic reticulum does not

• True

• False

What is the function of the nucleus?

• To form mitochondria

• To transfer energy throughout the cell

• To direct the activities of the cell

• To provide shape to the cell