semester 1 unit 3

Question 1

Amphipathic

Answer 1

molecule that has hydrophilic and hydrophobic part

Question 2

Peripheral proteins

Answer 2

temporarily adhere to the membrane

Question 3

Integral proteins

Answer 3

permanently adhere to the membrane

Question 4

Davson & Danielli model

Answer 4

suggested that cell membrane comprises a lipid bilayer where 2 layers of polar lipid molecules are arranged with their hydrophilic head outwards

Question 5

Singer & Nicolson model

Answer 5

suggested that proteins are individually embedded in the phospholipid bilayer instead of laying on both sides

Question 6

Channel membrane proteins

Answer 6

have a pore/channel that allows transport of substances in and out of the cell

Question 7

Carrier membrane proteins

Answer 7

bind to substances on one side of the membrane and then change shape to transport them to the other side

Question 8

Recognition membrane proteins

Answer 8

help cell in differentiating between self and non-self cells

Question 9

Receptor membrane proteins

Answer 9

span the whole cell membrane to relay info. in and out of the cell

Question 10

Cholesterol

Answer 10

is a steroid and an amphipathic molecule, it controls membrane fluidity by restricting movement of phospholipids to other molecules which prevents solidification

Question 11

Oparin-Haldane Hypothesis

Answer 11

suggests that life arose gradually from inorganic molecules

Question 12

Endosymbiotic theory

Answer 12

explains origin of eukaryotic cells (originally prokaryotes that were taken in by larger prokaryotic cells and remained inside host cells instead of being digested/broken down), cells that could provide energy became mitochondria, cells that could convert light energy to chemical energy became chloroplasts… mitochondria and chloroplasts both have double membranes, have circular naked DNA, have 70S ribosomes, divide by binary fission, are susceptible to some antibiotics

Question 13

Relationship between cell size and SA:V ratio of the cell

Answer 13

when a cell is small it has a large surface area relative to its volume, as a cell becomes larger its surface area relative to its volume is smaller

Question 14

Why are cells small?

Answer 14

to perform their functions like absorption and excretion efficiently

Question 15

Passive transport

Answer 15

is diffusion and osmosis, it does not require energy

Question 16

Active transport

Answer 16

is bulk transport via pump proteins, does require energy

Question 17

Simple diffusion

Answer 17

process of transport that does not require help from membrane proteins (oxygen and carbon dioxide move by SD)

Question 18

Facilitated diffusion

Answer 18

process of transport that does require help from membrane proteins (carbohydrates, amino acids, nucleosides, and ions move through FD)

Question 19

osmosis

Answer 19

passive movement of water molecules from low to high concentration

Question 20

Effect on cell of hypertonic solution

Answer 20

cell will shrink (higher concentration of solutes)

Question 21

Effect on cell of hypotonic solution

Answer 21

cell will largen (lower concentration of solutes)

Question 22

Effect on cell of isotonic solution

Answer 22

cell will remain the same size

Question 23

Endocytosis

Answer 23

cells take in molecules/substances from outside of cell by engulfing them into cell membrane, pinocytosis (cell drinking) & phagocytosis (cell eating)

Question 24

Exocytosis

Answer 24

ejection of substances from inside the cell via vesicles, excretion & secretion