Chapter 1 Diffusion And Osmosis

Question 1

Diffusion definition

Answer 1

Diffusion is the passage of «molecules»
from high concentration to a low concentration medium

Question 2

Concentration gradient

Answer 2

The difference in concentration between 2 mediums

Question 3

How do molecules diffuse?

Answer 3

Molecules diffuse down a concentration gradient toward the area of least concentration

Question 4

Plasma membrane

Answer 4

It surrounds the cell , and separate it from the outside environment. It regulates the substances that pass inside our outside the cell

Question 5

Plasma membrane structure

Answer 5

Plasma membrane is formed of phospholipid bilayer
Hydrophilic head
And 2 hydrophobic tails

Question 6

Plasma membrane

Answer 6

Plasma membrane is selectively permeable
Only small , uncharged (non polar) molecules , and hydrophobic can passes by «diffusion»

Question 7

Types of transport across a plasma membrane

Answer 7

Passive : 3 types
1-simple diffusion
2-facilitated diffusion
3-osmosis
they do not require ENERGY

Question 8

Simple diffusion

Answer 8

Small molecules , ex: co2 , 02
Lipid and vitamins

Question 9

Facilitated diffusion

Answer 9

They’re large molecules so they need carrier protein!!!
Molecules : ions (polar molecules)
Nacl and glucose

Question 10

Osmosis

Answer 10

It is the movement of water across the plasma membrane from high concentration to low concentration

Question 11

Types of transport across the plasma membrane

Answer 11

Active transport : needs energy ( atp)

Question 12

Passive transport

Answer 12

Simple , facilitated, and osmosis they’re all the same
They go from high concentration to low concentration
In diffusion : molecules
In osmosis : water

Question 13

Tonicity of solution

Answer 13

We have 3 types
Hypertonic , hypotonic , isotonic

Question 14

Hypertonic

Answer 14

high concentration of solute outside the cell
and inside the cell -> low concentration(hypotonic).
water will move from hypo to hyper —> from inside to outside

Question 15

hypertonic solution

Answer 15

The cell will shrinks

Question 16

Hypotonic solution

Answer 16

Means low concentration
Outside : low concentration (hypo)
Inside : high concentration (hyper)
The water moves from hypo to hyper —> water moves from outside to inside

Question 17

Hypotonic solution

Answer 17

Cell is going to swell

Question 18

Isotonic

Answer 18

Outside and inside the cell they’re equal

Question 19

In animal cell

Answer 19

Always inside the cell it contains : 0.9% of nacl

Question 20

Dialysis experiment

Answer 20

We put in a beaker water + iodine
We soak a dialysis tube inside that contains starch + glucose

Question 21

Observation of dialysis experiment

Answer 21

We observe what is going to happen
* Initial reading :
Inside the beaker : yellow
Inside the dialysis bag : colorless
*final reading :
Inside the beaker : yellow
Inside the dialysis bag : dark blue

Question 22

Dialysis experiment

Answer 22

We remove from the beaker 2 drops of the water and iodine and we add them to a new test tube
Then we add drops of benedict solution
After heating the test tube will become red brick/ orange —> indicates the presence of glucose

Question 23

What we conclude from the dialysis experiment

Answer 23

Starch : did not diffuse from the dialysis bag. It id larger than the pore of the plasma membrane

Question 24

What we concluded from the dialysis experiment

Answer 24

Iodine : diffused inside the dialysis bag because of the color dark blue that appeared. It is smaller than the pores of the plasma membrane

Question 25

What we concluded from the dialysis experiment

Answer 25

Glucose : has diffused outside the dialysis bag to the beaker because of the brick precipitated formed by benedic test . It is smaller than the pores of plasma membrane