Ch. 5 - Cellular Function

Question 1

6 basic functions of proteins

Answer 1

• maintain cell shape
• coordinate changes inside and outside the cell via attachments to the cytoskeleton and EM
• receptors for chemical messengers from other cells (cellular communication via signal transduction)
• enzymes that catalyze reactions
• glycoproteins are involved in cellular recognition (help to recognize self as self and alert the immune system to intruders)
• transport of substances across the membrane

Question 2

bilayers (2)

Answer 2

• automatically forms when phospholipids is when mixed with water
• surround and encase areas of water resulting in Walter filled bubbles surrounded by lipid bilayers

Question 3

passive transport (2)

Answer 3

• cellular membranes are semi-premiable - all may not pass

- requires no energy

Question 4

diffusion (3)

Answer 4

• movement of a substance down its concentration gradient from an area of higher to lower concentration
• diffusion of different substances is independent
• happens in air as well as water

Question 5

what happens when concentration is equal on both sides of a membrane (diffusion)?

Answer 5

diffusion in both directions doesn’t stop, but is equal, so there’s no net change in concentration

Question 6

facilitated diffusion (2)

Answer 6

• passive (requires no energy)

- needs transport protein to cross the membrane down its concentration gradient

Question 7

osmosis (2)

Answer 7

• diffusion of water across a membrane
• the solute molecule is too large to cross the semi-permeable membrane but water can cross the membrane quickly (3 billion aquaporin/s)

Question 8

isotonic (2)

Answer 8

• iso=the same

- concentration of diluted in solution is the same inside and outside the membrane

Question 9

hypertonic (2)

Answer 9

• hyper=lots
• concentration of splinted is greater than the concentration inside the cell (cell is hypotonic relative to the solution)

Question 10

hypotonic (2)

Answer 10

• hypo=beneath/below

- concentration of solutes is less than the concentration inside the cell (cell is hypertonic relative to solution)

Question 11

active transport (3)

Answer 11

• requires transport protein
• pumping solute against its concentration gradient
• requires energy which it gets from ATP

Question 12

how do cells deal with larger molecules?

Answer 12

exocytosis or endocytosis

Question 13

exocytosis (2)

Answer 13

• way to get large substances exported from the cell

- exo=outside kytos=cell

Question 14

endocytosis (2)

Answer 14

• endo=inside

- way for cells to get things from the outside of the cell to inside of the cell

Question 15

3 types of endocytosis

Answer 15

• phagocytosis (cell eating)
• pinocytosis (cell drinking)
• receptor-mediated endocytosis