biology chapter 7

Question 1

cells

Answer 1

basic unit of all life

Question 2

cell theory

Answer 2

• all living things are made of cells
• cells are the basic units of function and structure
• new cells come from existing cells

Question 3

cell membrane

Answer 3

thin flexible barrier that surrounds all cells

Question 4

nucleus

Answer 4

large membrane-enclosed structure containing dna

Question 5

eukaryotes

Answer 5

cells that enclose their dna in nuclei

Question 6

prokaryotes

Answer 6

cells that do not enclose their dna in nuclei

Question 7

cytoplasm

Answer 7

portion of the cell outside the nucleus

Question 8

organelles

Answer 8

structures that act like specialized organs

Question 9

vacuoles

Answer 9

store materials like water, salts, proteins, and carbohydrates. large saclike membrane-enclosed structures

Question 10

lysosomes

Answer 10

filled with enzymes. break down lipids, carbs, and proteins. also break down organelles that have outlived their usefulness

Question 11

cytoskeleton

Answer 11

eukaryotic cells are given their shape and internal organization by a network of protein filaments

Question 12

centrioles

Answer 12

located near the nucleus and help organize cell division

Question 13

ribosomes

Answer 13

small particles of RNA and protein found throughout the cytoplasm in all cells

Question 14

endoplasmic reticulum

Answer 14

eukaryotic cells contain an internal membrane system. its where lipid components of the cell membrane are assembled, along with proteins and other materials that are exported from the cell

Question 15

golgi apparatus

Answer 15

stack of flattened membranes. it modifies, sorts, and packages proteins and other materials from the endoplasmic reticulum for storage in the cell or release outside the cell

Question 16

chloroplasts

Answer 16

capture energy from sunlight and convert it to food that contains chemical energy in a process called photosynthesis

Question 17

mitochondria

Answer 17

power house of the cell; they convert the energy stored in food into compounds that are more convenient for the cell to use

Question 18

cell wall

Answer 18

strong supporting layer around the membrane

Question 19

lipid bilayer

Answer 19

gives cell membranes a flexible structure that forms a strong barrier between the cell and its surroundings

Question 20

selectively permeable

Answer 20

some substances can pass across them and others cannot

Question 21

diffusion

Answer 21

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

Question 22

facilitated diffusion

Answer 22

process in which molecules that cannot directly diffuse across the membrane pass through special protein channels

Question 23

aquaporins

Answer 23

water channel proteins, allow water to pass right through them

Question 24

osmosis

Answer 24

diffusion of water through a selectively permeable membrane

Question 25

isotonic

Answer 25

“same strength”

Question 26

hypertonic

Answer 26

“above strength”

Question 27

hypotonic

Answer 27

“below strength”

Question 28

osmotic pressure

Answer 28

net movement of water out of or into a cell produces a force known as osmotic pressure

Question 29

homeostatis

Answer 29

to maintain it, unicellular organisms grow, respond to the environment, transform energy, and reproduce

Question 30

tissue

Answer 30

group of similar cells that perform a particular function

Question 31

organ

Answer 31

group of tissues that work together

Question 32

organ system

Answer 32

a group of organs that work together to perform a specific function

Question 33

receptor

Answer 33

some are on the cell membrane, receptors for other types of signals are inside the cytoplasm.