Chapter 3

Question 1

what are the three main parts of human cells?

Answer 1

1. plasma membrane
2. cytoplasm
3. nucleus

Question 2

plasma membrane

Answer 2

forms the cells outer boundary; separates the cells internal environment from the outside environment; has a selectively permeable barrier; plays a role in cellular communication

Question 3

what kind of permeability does the plasma membrane have?

Answer 3

selective permeability

Question 4

cytoplasm

Answer 4

all the cellular contents between the plasma membrane and the nucleus; the cytosol is the fluid portion and is made up of mostly water; organelles are structures embedded in the cytosol

Question 5

what kind of structures can be found embedded in the cytosol?

Answer 5

organelles

Question 6

nucleus

Answer 6

large organelle that contains DNA in molecules called chromosomes (think of it like the brain of the cell)

Question 7

how many different types of cells are there?

Answer 7

200

Question 8

how many cells does the average adult have?

Answer 8

100 trillion

Question 9

what are four functions of the plasma membrane?

Answer 9

1. covers and protects the cell
2. controls what goes in and comes out
3. links to other cells
4. flies certain flags to tell other cells who it is

Question 10

what is the fluid mosaic model?

Answer 10

a sea of lipids with proteins floating and attached; its proteins are constantly changing with DNA expression

Question 11

what makes up the structure of the plasma membrane?

Answer 11

1. phospholipids
2. integral proteins (to include transmembrane proteins)
3. peripheral proteins
4. glycoproteins
5. glycolipids
6. cholesterol

Question 12

what are examples of different membrane proteins?

Answer 12

1. channels
2. carriers
3. receptors
4. enzymes
5. anchoring proteins
6. recognition proteins

Question 13

phospholipids

Answer 13

form a lipid bilayers - cholesterol and glycolipids also contribute

Question 14

integral proteins

Answer 14

extend into or through the bilayer

Question 15

transmembrane proteins

Answer 15

span the entire lipid bilayer; most integral proteins are also transmembrane proteins

Question 16

peripheral proteins

Answer 16

attach to the inner or outer surface but do not extend through the membrane

Question 17

glycoproteins

Answer 17

membrane proteins with a carbohydrate group attached that protrude into the extracellular fluid

Question 18

glycolipids

Answer 18

lipids with attached carbohydrate

Question 19

what does cholesterol do for the plasma membrane?

Answer 19

provides strength and structure

Question 20

What is the function of channel membrane proteins?

Answer 20

allows specific ions to pass through water filled pores

Question 21

what is the function of carrier membrane proteins?

Answer 21

carries specific substances across membranes by changing shape

Question 22

what is the function of receptor membrane proteins?

Answer 22

recognize specific ligand and alters cell functions in some way

Question 23

what is the function of enzyme membrane proteins?

Answer 23

catalyzes reaction inside or outside cell

Question 24

what is the function of anchoring proteins?

Answer 24

anchors filaments inside and outside the plasma membrane providing structural stability and shape for the cell

Question 25

what is the function of recognition proteins?

Answer 25

distinguishes your cells from anyone else

Question 26

what are three types of permeability?

Answer 26

1. selectively permeable 2. impermeable 3. freely permeable

Question 27

what is (the definition of) a passive transport process?

Answer 27

a passive process involves substances moving across the cell membranes without the input of any energy; they are said to move "with" or "down" their concentration gradient

Question 28

what is (the definition of) an active transport process?

Answer 28

an active process involves the use of energy, primarily from the breakdown of ATP, to move a substance against its gradient

Question 29

diffusion

Answer 29

diffusion is the passive spread of particles through random motion, from areas of high concentration to areas of low concentration

Question 30

what factors affect the rate of diffusion?

Answer 30

1. the amount of substance and the steepness of the concentration gradient 2. temperature 3. diffusion distance 4. electrical forces

Question 31

osmosis

Answer 31

the net movement of water through a selectively permeable membrane from an area of high water concentration to one of lower water concentration

Question 32

what are two ways that water can pass through a plasma membrane?

Answer 32

1. through the lipid bilayer by simple diffusion | 2. through a channel protein

Question 33

vesicle

Answer 33

small spherical sac formed by bidding off a membrane

Question 34

endocytosis

Answer 34

when materials move into a cell in a vesicle formed from the plasma membrane

Question 35

exocytosis

Answer 35

when vesicles fuse with the plasma membrane, releasing their contents into the extracellular fluid

Question 36

what are the three types of endocytosis?

Answer 36

1. receptor-mediated endocytosis 2. phagocytosis 3. pinocytosis