Download presentation
Presentation is loading. Please wait.
1
Movement of Substances
CHAPTER 3 Movement of Substances 1
2
Movement of Substances
Chapter 3 Movement of Substances 3.1 Diffusion 3.2 Osmosis 3.3 Surface Area to Volume Ratio 3.4 Active Transport 2
3
3.1 Diffusion Learning Outcomes
After this section, you should be able to: define diffusion; and discuss the importance of diffusion in nutrient uptake and gaseous exchange in plants and humans. 3
4
3.1 Diffusion How do particles move?
Think of a time when you detected the smell of perfume in a room. How has the smell travelled to your nose? Region B with lower concentration of particles Region A with higher concentration of particles Movement of particles 4
5
3.1 Diffusion What is diffusion?
Diffusion is the net movement of particles from a region where they are of higher concentration to a region where they are of lower concentration, that is, down a concentration gradient. 5
6
Concentration gradient
3.1 Diffusion Concentration gradient Concentration gradient is the difference in concentrations between two regions. direction of movement of particles Point A Point B Distance Concentration molecules diffuse down a concentration gradient 6
7
How is a concentration gradient related to diffusion?
3.1 Diffusion How is a concentration gradient related to diffusion? The movement of fluid particles is diffusion . Particles will diffuse down their concentration gradient. The steeper the concentration gradient, the higher the rate of diffusion. URL 7
8
Diffusion of a dissolved substance
3.1 Diffusion Diffusion of a dissolved substance A copper sulfate crystal is dropped into a gas jar containing water. The gas jar is allowed to stand for a few days. The blue colour gradually spreads throughout the water. The copper sulfate particles diffuse evenly throughout the water. gas jar water copper sulfate crystal 8
9
Diffusion across a membrane
3.1 Diffusion Diffusion across a membrane Both the ___________ and ___________ are able to pass through a _________________________. potassium iodide particle permeable membrane copper sulfate particle Copper sulfate and potassium iodide particles evenly distributed 9
10
Diffusion of gases in the lungs
3.1 Diffusion Diffusion of gases in the lungs ______________________ in the lungs occurs via diffusion. air space in the lungs lung cell red blood cell CO2 diffuses from blood into the lungs O2 diffuses from lungs into the blood 11
11
Movement of Substances
Chapter 3 Movement of Substances 3.1 Diffusion 3.2 Osmosis 3.3 Surface Area to Volume Ratio 3.4 Active Transport 12
12
3.2 Osmosis Learning Outcomes
After this section, you should be able to: define osmosis; and discuss the effects of osmosis on plant and animal tissues. 13
13
3.2 Osmosis What is osmosis?
A _______________________________ allows some substances to pass through it but not others. partially permeable membrane water molecule sucrose molecule B A 10% sucrose solution (less water, more sucrose) 5% sucrose solution (more water, less sucrose) 14
14
3.2 Osmosis What is osmosis?
The partially permeable membrane allows water molecules to pass through but not sucrose molecules. partially permeable membrane B A rise in level of solution drop in level due to movement of water molecules to A 15
15
How can we demonstrate osmosis?
3.2 Osmosis How can we demonstrate osmosis? An experiment is set up as shown. The level of the solution in the thistle funnel is observed to rise. This is due to water molecules moving into the thistle funnel from the beaker. thistle funnel retort stand sucrose solution cellophane paper beaker water 16
16
What is water potential and how is it related to osmosis?
3.2 Osmosis What is water potential and how is it related to osmosis? The ____________________________________ is known as water potential. A dilute solution has a higher water potential. A concentrated solution has a lower water potential. 17
17
What is water potential and how is it related to osmosis?
3.2 Osmosis What is water potential and how is it related to osmosis? A _____________________________ is established when a partially permeable membrane separates two solutions of different water potentials. more solute, lower water potential less solute, higher water potential partially permeable membrane water moves down the gradient water potential gradient established 18
18
What is water potential and how is it related to osmosis?
3.2 Osmosis What is water potential and how is it related to osmosis? _____________ is the net _________________ _____________ from a solution of higher water potential to a solution of lower water potential, through a ______________________________. URL 19
19
How does osmosis affect living organisms?
3.2 Osmosis How does osmosis affect living organisms? Cells are living ________________________. Plant cell Animal cell partially permeable cell surface membrane fully permeable cellulose cell wall enclosed nucleus and cytoplasm containing various dissolved substances 20
20
What happens to a cell in a solution with higher water potential?
3.2 Osmosis What happens to a cell in a solution with higher water potential? cell sap has lower water potential than surrounding solution 1 water enters by osmosis 2 in solution of higher water potential cell sap in vacuole plant cell cell expands and becomes __________ 3 cell wall prevents cell from bursting 4 21
21
What happens to a cell in a solution with higher water potential?
3.2 Osmosis What happens to a cell in a solution with higher water potential? cytoplasm has lower water potential than outside solution, water enters by osmosis animal cell in solution of higher water potential cell expands and _________ 22
22
What happens to a cell in a solution with lower water potential?
3.2 Osmosis What happens to a cell in a solution with lower water potential? 1 cell sap has higher water potential than surrounding solution plant cell cell sap in vacuole in solution with low water potential water leaves by osmosis 2 cytoplasm shrinks away from cell wall and cell becomes _____________ 3 cell becomes ___________ 4 23
23
What happens to a cell in a solution with lower water potential?
3.2 Osmosis What happens to a cell in a solution with lower water potential? cytoplasm has higher water potential than surrounding solution, water leaves by osmosis animal cell in solution of lower water potential cell shrinks in size and becomes _____________ URL 24
24
What happens to a cell in a solution of the same water potential?
3.2 Osmosis What happens to a cell in a solution of the same water potential? A cell immersed in a solution with the same water potential as its cytoplasm _____________________ ____________________. 25
25
Why is turgor important in plants?
3.2 Osmosis Why is turgor important in plants? Turgor plays an important role in _____________ _____________________ in plants. It keeps herbaceous (non-woody) plants ________________________________. Loss of turgidity causes the plant to __________. 26
26
Why is turgor important in plants?
3.2 Osmosis Why is turgor important in plants? Changes in turgor also cause the movements of some plant parts, e.g. opening and closing of stomata. turgor in guard cells causes stoma to open in the day lack of turgor in guard cells causes stoma to close at night 27
27
Why is turgor important in plants?
3.2 Osmosis Why is turgor important in plants? Plasmolysis causes tissues to become limp or ________________. When cells of a plant become flaccid, the plant _____________. Water may be added to the soil to dilute the soil solution. This causes water moelcules to enter the plant cells and keeps the plant firm and upright. 28
28
Movement of Substances
Chapter 3 Movement of Substances 3.1 Diffusion 3.2 Osmosis 3.3 Surface Area to Volume Ratio 3.4 Active Transport 29
29
Surface Area to Volume Ratio
3.3 Surface Area to Volume Ratio Learning Outcomes After this section, you should be able to: explain how surface area to volume ratio affects the rate of movement of substances. 30
30
What does surface area to volume ratio mean to a cell?
3.3 Surface Area to Volume Ratio What does surface area to volume ratio mean to a cell? The ___________ the surface area to volume ratio, the _____________ the rate of _____________. 31
31
What does surface area to volume ratio mean to a cell?
3.3 Surface Area to Volume Ratio What does surface area to volume ratio mean to a cell? Cube Surface area/cm2 Volume/cm3 Surface area: volume Cell A1 (side 1 cm) Cell A2 (side 2 cm) Cell A3 (side 3 cm) 6 1 _________ 24 8 _________ 54 27 _________ As a cell becomes bigger, its surface area to volume ratio decreases. 32
32
Surface Area to Volume Ratio
3.3 Surface Area to Volume Ratio food + O2 in Each shaded square represents a unit volume of protoplasm waste products out loss in surface area Cell A1 Cell A2 Cell A3 X Y Z 33
33
How are cells adapted for the absorption of materials?
3.3 Surface Area to Volume Ratio How are cells adapted for the absorption of materials? Cells which function in absorption have an ____________________________________. For example, root cells have long processes and epithelial cells have a folded cell membrane. Epithelial cell Root hair cell 35
34
Movement of Substances
Chapter 3 Movement of Substances 3.1 Diffusion 3.2 Osmosis 3.3 Surface Area to Volume Ratio 3.4 Active Transport 36
35
3.4 Active Transport Learning Outcomes
After this section, you should be able to: define active transport; explain that active transport is an energy-consuming process by which substances are transported against a concentration gradient; and 37
36
What is active transport?
3.4 Active Transport What is active transport? ______________________ is the process in which energy is used to move the particles of a substance across a membrane _________ _________________, that is, from a region where the particles are of lower concentration to a region where they are of higher concentration. 38
37
_______________ against a concentration gradient requires ___________
3.4 Active Transport ______________ down a concentration gradient _______________ against a concentration gradient requires ___________ higher concentration of solute molecules, e.g. glucose. lower concentration of solute molecules, e.g. glucose. 39
38
3.4 Active Transport Since active transport requires energy, active transport occurs only in ___________________. Dissolved mineral salts are taken up by root hair cells via active transport. soil solution root hair cell path taken by substances absorbed by root hair cell mineral salts 40
39
Movement of Substances
Chapter 3 Movement of Substances 42
40
Movement of Substances
Chapter 3 Movement of Substances The URLs are valid as at 15 January 2014.
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.