Cell Structure and Function

Question 1

cell

Answer 1

• the basic unit of all living things

Question 2

Cell Theory

Answer 2

• all living things are made of cells
• cells are the basic unit of structure and function in living things
• new cells are produced from existing cells

Question 3

cell membrane

Answer 3

• a thin, flexible barrier surrounding a cell, also called a plasma membrane

Question 4

nucleus (plural nuclei)

Answer 4

• a large membrane-enclosed structure that contains genetic material in the form of DNA

Question 5

eukaryotes

Answer 5

• cells that enclose their DNA in nuclei

Question 6

prokaryotes

Answer 6

• cells that do not enclose DNA in nuclei

Question 7

cytoplasm

Answer 7

• the portion of the cell outside the nucleus

Question 8

organelles

Answer 8

• a single major component of a plant or animal eukaryotic cell that acts as a specialized organ

Question 9

ribosomes

Answer 9

• small particles of RNA and protein found throughout the cytoplasm in both eukaryotes and prokaryotes

Question 10

endoplasmic reticulum

Answer 10

• an internal membrane system which eukaryotic cells contain

Question 11

Golgi apparatus

Answer 11

• an organelle which appears as a stack of flattened membranes; puts the finishing touches on proteins before they’re ready to leave the “factory”

Question 12

vacuoles

Answer 12

• large saclike membrane enclosed structures that store materials in a cell

Question 13

lysosomes

Answer 13

• small organelles filled with enzymes that break down lipids, carbohydrates, and proteins

Question 14

cytoskeleton

Answer 14

• a network of protein filaments that give eukaryotic cells their shape and internal organization

Question 15

chloroplasts

Answer 15

• the biological equivalence of solar power plants; capture the energy from sunlight and convert it into chemical energy stored in food during photosynthesis

Question 16

mitochondria

Answer 16

• the power plants of a cell; convert the chemical energy stored in food molecules into compounds that are more convenient for the cell to use

Question 17

cell wall

Answer 17

• a strong, supporting layer around the membrane of a cell

Question 18

lipid barrier

Answer 18

• a double-layered sheet that gives cell membranes a flexible structure that forms a strong barrier between the cell and its surroundings

Question 19

selectively permeable (semipermeable membranes)

Answer 19

• a characteristic of most cell membranes in which some substances can pass across the membrane, and some cannot

Question 20

homeostasis

Answer 20

• a state of relatively constant internal physical and chemical conditions

Question 21

diffusion

Answer 21

• the process by which particles move from an area of higher concentration to an area of lower concentration

Question 22

facilitated diffusion

Answer 22

• when molecules that cannot directly diffuse across the membrane pass through special protein channels

Question 23

aquaporins

Answer 23

• water channel proteins found in many cells that allow water to pass right through them

Question 24

osmosis

Answer 24

• the diffusion of water through a selectively permeable membrane

Question 25

isotonic

Answer 25

• when two solutions have the same amount of solute; “same strength” inside and outside a cell

Question 26

hypertonic

Answer 26

• when the solution has a higher solute concentration than the cell; a net movement of water molecules out of the cell causes it to shrink

Question 27

hypotonic

Answer 27

• when the solution has a lower solute concentration than the cell; a net movement of water molecules into the cell causes it to swell

Question 28

osmotic pressure

Answer 28

• a force produced by the net movement of water out of or into a cell; driven by differences in solute concentration