Cell membrane & Transportation

Question 1

What are the functions of the cell membrane?

Answer 1

Separates cell from the outside environment
Provide structure and protection
Gatekeeper-Controls substances entering and leaving the cell

Question 2

What does Fluid Mosaic model mean?

Answer 2

a mosaic of protein molecules bobbing in a fluid bi-layer of phospholipids

Question 3

What are the components of a cell membrane?

Answer 3

phospholipid bilayer
proteins
carbohydrates
Glycolipids
Glycoproteins
Cholesterol

Question 4

What do proteins do in the cell membrane?

Answer 4

Determine membrane function
transmit chemical signals into the cell
act as carriers for specific substances

Question 5

What do the carbohydrates do in the cell membrane?

Answer 5

attached to the outside and allow the cell to recognize itself

Question 6

What do Glycolipids do in the cell membrane?

Answer 6

phospholipids covalently bonded with carbohydrate chains

Question 7

What do Glycoproteins do in the cell membrane?

Answer 7

proteins covalently bonded with carbohydrate chains

Question 8

What does cholesterol do in the cell membrane?

Answer 8

Reduces membrane fluidity by reducing phospholipid movement

Stops membrane from becoming solid at room temp

Question 9

Explain how Glycolipids and Glycoproteins work

Answer 9

Glyco=suger=carbohydrate

lipids=phospolidids

Question 10

What does selectively permeable mean?

Answer 10

the cell membrane selects what it wants to come in and out of the cell
NOT ALLOWED- large, charged and polar things
ALLOWED-small non-polar things

Question 11

How do large, charged or polar things get through the cell membrane?

Answer 11

through glycoprotein channels

Question 12

Passive transport VS active transport?

Answer 12

Passive- molecules move from high concentration to low concentration to establish equilibrium (no energy required)
Active- molecules move from low concentration to high concentration to establish equilibrium (Requires energy)

Question 13

3 types of passive transport. What is being transported?

Answer 13

Diffusion-passive process of moving molecules through the membrane
Osmosis- The diffusion of water due to the concentration gradient of solutes
Facilitated-molecules unable to pass through the membrane (go through a channel or carrier protein)

Question 14

How can the rate of diffusion be affected?

Answer 14

Concentration- bigger C = faster diffusion
Molecular size- smaller substance = faster diffusion
Temp- faster the temp= molecules move faster
Solubility- soluble molecules= will dissolve through the bilayer faster
Charge- charged molecules do not pass easily

Question 15

What is the Tonicity of a solution?

Answer 15

the solute concentration (affects size and shape of cell)

Question 16

High solute =?

Low solute =?

Answer 16

low water

high water

Question 17

Explain an Isotonic Solution

Answer 17

solution concentration is equal on both sides of membrane (equilibrium)

Question 18

Explain Hypertonic solution

Answer 18

higher solute than solvent (less water outside cell)
water moves out of cell
HYPER PEOPLE GET SKINNY

Question 19

Explain Hypotonic solution

Answer 19

Lower solute than solvent (more water inside cell)
water moves into the cell and it explodes (Lysis)
HYPOS ARE FAT

Question 20

Water flows from ______ to ________

Answer 20

Water flows from hypotonic solution to hypertonic solutions

Question 21

What is crenation?

Answer 21

Red blood cells shrinks and shrivels up

Question 22

What is hemolysis

Answer 22

Red blood cells swell and may burst

Question 23

What is Plasmolysis?

Answer 23

plant cell membrane shrinks and pulls away from cell wall

Question 24

What is turgor pressure?

Answer 24

plant cell membrane swells and organ cells are crushed against cell wall

Question 25

What is facilitated diffusion?

Answer 25

Molecules passing through the cell membrane that normally cannot, so they use a channel or carrier protein. Specific channel/protein for each moleule

Question 26

What is active transport?

Answer 26

Molecules move from low concentration to high concentration against the gradient Large charged and polar molecules IONS SUGARS NUCLEOTIDES

Question 27

3 types of active transport

Answer 27

Sodium potassium pump Endocytosis Exocytosis

Question 28

How does the sodium potassium pump work?

Answer 28

Na attaches to carrier protein with ATP and moves across cell membrane Protein pump changes shape so Na can't re-enter but K can enter K attaches and moves across pump resets requires ATP

Question 29

What is endocytosis

Answer 29

Endo=in Movement of molecules from outside the cell to inside by forming a vesicle requires ATP 2 types

Question 30

2 types of endocytosis and how they work?

Answer 30

Phagocytosis-cell eating. large particles are ingested and vesicles form Pinocytosis- cell drinking. small molecules ingested and vesicle forms

Question 31

What is exocytosis?

Answer 31

Exo=out Reverse of endocytosis cell releases contents of vesicle outside the cell

Question 32

Why is cell size important? What is the ideal size/shape

Answer 32

important for function and survival | Smaller and funny shape ideal

Question 33

What four factors regulate cell size?

Answer 33

Surface area/volume ratio- volume increases faster than surface area Metabolic rate- high metabolic rate Nuclear control- to big=nucleus loses control Support- to big=cell will collapse

Question 34

What are enzymes?

Answer 34

Catalysts- speed up chemical reactions without being consumed end in -ase often are proteins hydrolysis reaction

Question 35

Why do we have enzymes?

Answer 35

Speed up reaction rates in low concentration | forms temporary complex (enzyme substrate complex) so reaction can happen at lower temp

Question 36

What is the enzyme active site?

Answer 36

grooves where substrate attaches to enzyme

Question 37

2 models for enzyme attachment?

Answer 37

lock and key model-individual substrate fits perfectly into active site induced fit- substrate binding induces a shape change so substrate can fit

Question 38

What are coenzymes?

Answer 38

enzyme made up of 2 pieces- protein portion and a co-enzyme | Co-enzymes attach at the allosteric site and cause enzyme to change shape in order for substrate to fit

Question 39

Where does the co-enzyme attach?

Answer 39

Allosteric site

Question 40

metabolism

Answer 40

sum of all biochemical reactions

Question 41

Metabolic pathway

Answer 41

organized sequence of reactions from substrates to products

Question 42

What lowers the activation energy of a reaction

Answer 42

Enzymes

Question 43

Factors that affect reaction rate? (PICT)

Answer 43

Concentration- higher=more successful collisions\ Temp-human enzymes are temperature sensitive (above 40 deg =permanent damage) pH- enzymes have optimal pH Inhibitors- chemicals that interfere with enzyme action

Question 44

Types of inhibitors?

Answer 44

Competitive- compete with substrate for activation site non-competitive- binds with allosteric site temporarily changes shape of active site