Chapter Three

Question 1

Cell (definition)

Answer 1

The cell is the basic unit of structure and function in the

body

Question 2

Cell (characteristics)

Answer 2

Measured in micrometers
Cells with special characteristics are said to be differentiated.
Cells vary in size and shape; structure and function are inter-related.

Question 3

Major Parts of a Cell

Answer 3

Nucleus
Cytoplasm
Cell membrane

Question 4

Cytoplasm (definition)

Answer 4

Cytoplasm consists of organelles, with specific functions, suspended in a liquid called cytosol. Contains all
organelles and cell parts.

Question 5

Cell (Plasma) Membrane (characteristics)

Answer 5

Outer boundary of the cell
Maintains integrity of cell
Selectively permeable: regulates entry and exit of substances
Signal transduction: permits cell to receive and respond to messages
Consists mainly of lipids and proteins, with some carbohydrates

Question 6

Nucleus (characteristics)

Answer 6

Organelle found in eukaryotic cells. Inside its fully enclosed nuclear membrane, it contains the
majority of the cell’s genetic material

Question 7

Mitochondria (characteristics)

Answer 7

The main job of mitochondria is to perform cellular respiration. This means it takes in nutrients from the cell, breaks it down, and turns it into energy.

Question 8

Lysome (characteristics)

Answer 8

Lysomes are intercellular stomachs full of digestive enzymes that operate at low pH.

Question 9

Peroxisome (characteristics)

Answer 9

Membrane bound sacs used to break down fatty acids and other molecules, generating hydrogen peroxide in the process.

Question 10

Vesicles (characteristics)

Answer 10

Vesicles are lysosomes, that contain digestive enzymes used to break down food particles and to get rid of unneeded cellular materials.

Question 11

Diffusion (describe)

Answer 11

Movement of atoms, molecules, or ions, from region of higher concentration to region of lower concentration

Question 12

Osmosis (describe)

Answer 12

Movement of water across a selectively permeable membrane from region of higher water concentration to region of lower water concentration

Question 13

Osmotic Pressure (describe)

Answer 13

Ability of osmosis to generate enough pressure to lift a volume of water. Osmotic pressure increases as the concentration of impermeant solutes increases

Question 14

Isotonic Solution (describe)

Answer 14

Same osmotic pressure. Cells in an isotonic solution have no net gain or loss of water

Question 15

Hypertonic Solution (describe)

Answer 15

Higher osmotic pressure. Cells in a hypertonic solution lose water

Question 16

Hypotonic Solution (describe)

Answer 16

Lower osmotic pressure. Cells in a hypotonic solution gain water

Question 17

Filtration (describe)

Answer 17

Process that forces molecules through membranes by exerting pressure. Used to separate solids from water, or small particles from large ones

Question 18

Active Transport (describe)

Answer 18

Movement of substances across a membrane from region of lower concentration to region of higher concentration (against concentration gradient).

Uses carrier molecules in cell membrane

Question 19

Endocytosis (describe)

Answer 19

Movement of a substance into the cell inside a vesicle. Substances too large to enter by other methods can enter cell this way

Question 20

Pinocytosis (describe)

Answer 20

Type of endocytosis: membrane engulfs droplets of liquid

Question 21

Phagocytosis (describe)

Answer 21

Type of endocytosis: membrane engulfs solid particles

Question 22

Receptor-mediated endocytosis (describe)

Answer 22

Type of endocytosis: membrane engulfs specific substances, which have bound to receptor proteins on the membrane

Question 23

Exocytosis (describe)

Answer 23

Release of substances/particles from cell. Vesicles containing particles fuse with cell membrane and release contents

Question 24

Differentiation (define)

Answer 24

The maturation and specialization of cells

Question 25

Apoptosis (describe)

Answer 25

Programmed cell death