Biology Presentation by Dehami Methusala

Presented by

methudehami2007 — 2021-09-25 10:56:45 UTC

Dehami and Pulathi

Dehami, Pulathi, Sinali, Tharana, Isala, Disala, Modika

methudehami2007 — 2021-09-25 10:57:25 UTC

Presented by

methudehami2007 — 2021-09-25 10:57:47 UTC

Modika

Presented by

methudehami2007 — 2021-09-25 10:58:49 UTC

Tharana and Disala

Presented by

methudehami2007 — 2021-09-25 10:59:16 UTC

Sinali and Isala

What is diffusion?

methudehami2007 — 2021-09-25 11:35:43 UTC

Diffusion is the net movement of particles from an area of higher concentration to an area of lower concentration.

Dehami

What is Active transport?

2021-09-25 12:06:41 UTC

Active transport is net movement of particles from a region of low concentration to a high concentration.

Tharana

2021-09-25 12:10:38 UTC

Tharana

2021-09-25 12:10:41 UTC

The factors which affect the rate of diffusion includes -temperature, Diffusion distance, concentration gradient and surface area : volume

Isala

The Temperature

2021-09-25 12:12:15 UTC

Higher the temperature, the more kinetic energy the particles will have, so they will move and collide even more quickly and would diffuse even more quickly!

Sinali

2021-09-25 12:14:09 UTC

https://youtu.be/HLdNTvY2UkM

Isala

2021-09-25 12:28:01 UTC

For living cells, the precept of the movement down a concentration gradient is the same, but the cell is encircled by a cell membrane, which can constrain the free movement of the molecules.

The cell membrane is somewhat permeable – this implies it enables some molecules to cross easily, but others with difficulty or not at all
The easiest sort of choice is established on the size of the molecules.

Diffusion assists living organisms to:
|Collect many of their requirements.
|Get rid of numerous of their waste products.
|Carry out gas exchange for respiration.

Pulathi

2021-09-25 12:29:13 UTC

Dehami

Demonstrating diffusion in agar jelly

methudehami2007 — 2021-09-25 13:27:39 UTC

Procedure -
Prepare a 2 cm deep layer of agar jelly.
Add potassium permanganate to it.
Then it turns to purple colour.
Next, cut out three cubes of side lengths 2 cm 1 cm and 0.5 cm.
Place each cube in dilute hydrochloric acid and observe the time taken for the jelly to turn colourless.

Observation-
The cube with the largest surface area to volume ratio quickly becomes colourless

Conclusion-
When there is low surface area to volume ratio diffusion is increased. When there is higher surface area to volume ratio diffusion is decreased.

Isala

What is osmosis?

methudehami2007 — 2021-09-25 13:36:12 UTC

Osmosis is the net movement of water from a region of high water potential to a region of low water potential across a semi permeable membrane.

Demonstrating the effect of osmosis on RBCs (Red Blood Cells)

methudehami2007 — 2021-09-25 13:50:20 UTC

Procedure-
Take 3 boiling tubes and add 1 cm3 of fresh blood sample into each.
Then add 10 cm3 of distilled water into one test tube, 0.85% NaCl into another test tube and 3% of NaCl to the last test tube. Mix them well and keep for 20 minutes.
Then observe under a microscope.

Observation-
-In the first test tube osmosis occurs from outside to inside of thee cells. This causes the RBCs to burst.
-In the second test tube osmosis does not occur because both the solutions have the same water potential. Therefore there is no change in shape in the RBCs
-In the third test tube osmosis occurs from inside to outside. So RBCs shrink.

Diffusion Distance

ayesinali085 — 2021-09-25 13:50:58 UTC

The diffusion distance is a factor which affects the diffusion rate.If the diffusion distance is high then the diffusion rate decreases, on the other hand if the diffusion distance is low then the diffusion rate increases.

Sinali

methudehami2007 — 2021-09-25 13:52:08 UTC

https://www.youtube.com/watch?v=fxAxsOa_icE

ayesinali085 — 2021-09-25 13:56:17 UTC

Alveoli is made out of a single-celled wall and the capillaries are also made up of singled cell walls ,thus it decreases the diffusion distance, while increasing the diffusion rate!

Sinali

methudehami2007 — 2021-09-25 14:01:25 UTC

https://www.youtube.com/watch?v=xU0u7jpmeP8

Pulathi

What Are The Factors That Affect Osmosis

modikaherath — 2021-09-25 14:02:18 UTC

Factors that are affecting osmosis are temperature , water potential gradient and surface area to volume ratio

methudehami2007 — 2021-09-25 14:07:45 UTC

https://youtu.be/qNk3GMAZLm4

Isala

Temperature

modikaherath — 2021-09-25 14:11:56 UTC

As you see in the picture warmer the temperature the faster that osmosis occurs .

Examples of Active Transport

methudehami2007 — 2021-09-25 14:12:11 UTC

-Energy is needed because particles are being moved against a concentration gradient, in the opposite direction from which they would naturally move (by diffusion)

-Examples of active transport include:

*uptake of glucose by epithelial cells in the villi of the small intestine and by kidney tubules in the nephron

*uptake of ions from soil water by root hair cells in plants

Disala

methudehami2007 — 2021-09-25 14:13:00 UTC

https://www.youtube.com/watch?v=bQZ0heYYSl0

Disala

methudehami2007 — 2021-09-25 14:18:34 UTC

https://www.youtube.com/watch?v=qqe2NhQt8bY

Surface area to volume ratio

methudehami2007 — 2021-09-25 14:34:48 UTC

-The bigger a cell or structure is, the smaller its surface area to volume ratio is, slowing down the rate at which substances can move across its surface

-Many cells which are adapted for diffusion have increased surface area in some way – e.g. root hair cells in plants (which absorb water and mineral ions) and cells lining the ileum in animals (which absorb the products of digestion)

Isala

Concentration gradient

methudehami2007 — 2021-09-25 14:37:44 UTC

-The greater the difference in concentration on either side of the membrane, the faster movement across it will occur

-This is because on the side with the higher concentration, more random collisions against the membrane will occur

Sinali

Water Potential Gradient

modikaherath — 2021-09-25 14:44:30 UTC

when the water potential gradient is high the rate of osmosis also high

Surface Area To Volume Ratio

modikaherath — 2021-09-25 14:46:26 UTC

Surface area will increase the speed of reaction as the greater the surface of the solid reactants, the more particles are required to expose and ‘cover’ the capacity of the solid. Increased surface area results in an increased chance of collisions between reactant particles.

methudehami2007 — 2021-09-25 14:46:33 UTC

It is also important to understand that diffusion is quite often how molecules move in and out of our cells through the cell membrane.

For example, the diagram above demonstrate a cell surrounded by nutrients (red dots). We can see that on the left, there are a lot more nutrients outside the cell than inside the cell.

By diffusion, the nutrients will diffuse into the cell (from higher to lower concentration) until the number of nutrients inside and outside the cell are balanced.

Pulathi

ayesinali085 — 2021-09-28 07:06:10 UTC

THANK YOU!!
HOPE YOU ALL LEARNED SOMETHING FROM OUR PRESENTATION!