Recap - You have 5 minutes!

Slides:



Advertisements
Similar presentations
WHY DO CELLS DIVIDE? 10-1.
Advertisements

Surface Area to Volume Ratios
One blood cell contains about 280 million molecules of haemoglobin What is this?
Exchange Systems F211.
Agar Cell Diffusion Vanderbilt Student Volunteers for Science
Topic 2 Diffusion and Osmosis
Surface Area to Volume ratio
Movement of Molecules Revision. Movement across Membranes All cells must be able to take in and expel various substances across their membranes in order.
December 1 st, Chapter 10 Big Ideas in Biology = 1) 2) Essential Question = How does a cell produce a new cell?
10.2 Oxygen Dissociation Curves
Exchanging materials – the lungs
How Many Cells Are in the Human Body???
Homework for next week P.176 green P.176 red 2nd lesson
13.1 Exchange between organisms and their environment.
Unit C Cycling of Matter in Living Systems.  Plasma membrane, semi permeable membrane  Protective layer between environment & cell’s fragile contents.
AS Level Biology Lesson 2. Gas exchange and respiration If cells are to stay active, grow and divide they need energy. This energy comes from the oxidation.
Gas Exchange with the environment
18.5 TRANSPORT Blood and Circulation. Mammalian Transport system  The transport system in humans is typical of all mammals. Materials are transported.
Sugar Cubes by Uwe Hermann on Flickr (CC) Which dissolves faster: sugar cubes or sugar crystals? Why?
Cell Growth and Division 10-1 Cell growth Biology Mr. Hines.
Cell Size Limitations.
LESSONS 2-3: Movement of Substances Across Membranes By the end of these lessons you should be able to: Define diffusion, osmosis and active transport.
To describe and explain how O 2 and CO 2 are carried in blood and the effect of exercise Transport of Oxygen and Carbon Dioxide Lesson Objective : To describe.
Gas Exchange. Aims Understand the relationship between the size of an organism and its surface area:volume. Understand the relationship between the surface.
10.1 Cell Growth, Division, and Reproduction
C2.4 Is Bigger Better? Science 10. Why are cells so small?  Cells are small so they can be efficient in transporting materials across their membranes.
Do Now: Calculate the volume of the shapes below: 8 cm 2 cm 1 cm 2 cm.
Measuring the Rate of Diffusion of Hydrochloric Acid (HCl) through Agar Gel of different sizes.
LAB: CELL SIZE & DIFFUSION 1-cut 3 cubes in agar—  calculate SA & vol for each cube 2-place 3 cubes in beaker w/NAOH  DO NOT touch NAOH—MUST wear goggles!!
Aims To consider how organisms vary in terms of size. To consider how organisms vary in terms of size. What are the implications of this for the What are.
1.Turn in your Bell Work page – make sure your name is on it! 2.Open your journal to page 11 and set it up like the next slide. 3.DO NOT TOUCH ANY MATERIALS.
Exchange between Organisms and their Environment.
Determine which cube size shows the most amount of diffusion using surface area to volume ratio calculations Relate lab data to explain why cells remain.
Cell Biology: The Cell Membrane Lesson 2 – Transport Across the Cell Membrane ( Inquiry into Life pg )
Transport in Animals May The Importance of a Transport System Exchange materials with external environment Materials are  taken in  distributed.
Movement in and out of cells. You need to learn this definition:  Diffusion is the net movement of molecules from a region of their higher concentration.
6.1 Gas exchange. Learning objectives To DESCRIBE the relationship between the size of an organism or structure and its surface area to volume ratio To.
Why can you smell something that is across the room?
The need for an exchange system in multicellular organisms
Exchange Surfaces and Exchanging Substances
Why are cells so small? Cells are found in every living organism, ranging from unicellular (one-celled) organisms, such as amoebas, to multicellular (many-celled)
AP Lab 4 Diffusion and Osmosis
Adaptations for Gas Exchange
LESSONS 2-3: Movement of Substances Across Membranes
HAEMOGLOBIN Lesson Objectives:
Growth and Development of different organisms
Module 2 Exchange and transport
CELL FORM AND FUNCTION pp
Module F Exchange surfaces and breathing
Passive and Active Transportation
Cell Surface Area and Volume
The principles of exchange and transport.
Homeostasis.
Chapter 1: Cells – the Basic Building Blocks of Life
Cellular Processes and structure
Module 3 Exchange Surfaces
Cell Size Limitation Notes
Surface Area to Volume.
Surface Area to Volume Ratio - video
Cell Size.
Cubes and cube roots.
Investigating The Effect of SA:V On The Rate Of Diffusion
Cell Size Surface area : Volume
Surface area to volume ratios
Module 2 Exchange and transport
CELL SIZE AND SHAPE PP
Q Why do multi cellular organisms need mass transport systems (3)
Shapes of cells.
Presentation transcript:

Recap - You have 5 minutes! What two things must a haemoglobin be efficient at? What animals typically have haemoglobin with a high affinity for oxygen? Why might an animal have haemoglobin with a low affinity for oxygen? What effect would a increase in CO2 have on the association of oxygen with a haemoglobin? Sketch a graph to illustrate this. Sketch a graph comparing a lugworms and a humans oxygen dissociation curve.

Lesson Objectives E – Needed a lot of help to write own method C – wrote a workable method, and got a good set of results. Identified any trends in results. A – Independently planned and carried out the investigation. Scientifically commented on results

Task: To investigate the effect of surface : volume ratio on diffusion rate

Objectives; To calculate surface-area-to-volume ratio (SA:V) To show the effect of surface-area-to-volume ratio on the diffusion rate of hydrochloric acid

Surface area to volume ratio Hint (NB units not given) Surface area to volume ratio Length of edge of a cube Surface area of whole cube Volume of cube (length x width x height) Ratio of surface to volume (surface area / volume)

You need to: Plan an experiment to answer the question Identify factors to control You will be given 1M hydrochloric acid Agar stained with universal indicator Ask for additional equipment! Make a prediction, and justify it Record your results appropriately Analyse and display your results appropriately Interpret your results, making reference to any data or graph.

You will be given; 1M hydrochloric acid Agar stained with universal indicator Ask for additional equipment!

Questions What prediction did you make about the rate of diffusion and the effect of surface-area-to-volume ratio? Identify at least three key factors you controlled in this experiment. Explain the effect of surface-area-to-volume-ratio on the rate of diffusion and how this is important in living organisms using your graph and your scientific knowledge. What are the limitations of this experiment? Should this procedure have a control? If so, what would it be? The volume of a living organism is proportional to the number of cells in its body. Each cell needs oxygen and nutrients and needs to get rid of metabolic waste products such as carbon dioxide. The smallest organisms can absorb nutrients and get rid of waste by diffusion through their outer membranes. Do you think larger organisms can do the same? Why?

Teachers answers Prediction should link the diffusion rate and the increased or reduced surface-area-to-volume ratio. Key factors controlled should include: temperature, shape of the block, size of block, immersion method, volume of acid used, the depth of acid used and the type of agar. A decrease in surface-area-to-volume ratio causes a reduction in the rate of diffusion. In living organisms this is important since larger animals have a smaller SA:V ratio and will be unable to obtain enough nutrients and oxygen by diffusion alone. Difficulty in cutting and measuring accurately. Difficulty in maintaining a constant shape. Eye used to judge exact end point. Blocks may float, effecting immersion. Any sensible suggestion – leave a cube in water, or on a piece of filter paper so you can be sure the change in indicator is due to diffusion of the surrounding solution inwards, not the effect of time on the cubes. Larger organisms would not be able to get all the nutrients they need, or get rid of all their waste products by diffusion as there is not enough surface area for each cell. The rate of diffusion cannot be increased so this will limit the size of the organism unless it has specialised gas exchange surfaces or other mechanisms.

Rate of diffusion effected by? Concentration gradient Area over which diffusion takes place Thickness of exchange surface = (surface area x (difference in concentration)) / length of diffusion path

In order to ensure maximum diffusion, what can we do?

A typical human erythrocyte has a disk diameter of 6–8 µm and a thickness of 2 µm, being much smaller than most other human cells. These cells have a volume of about 90 fL with a surface of about 136 μm2, and can swell up to a sphere shape containing 150 fL, without membrane distension. Adult humans have roughly 2–3 × 1013 (20-30 trillion) red blood cells at any given time, comprising approximately one quarter of the total human body cell number (women have about 4 to 5 million erythrocytes per microliter (cubic millimeter) of blood and men about 5 to 6 million; people living at high altitudes with low oxygen tension will have more). http://en.wikipedia.org/wiki/File:Erytrocyte_deoxy_to_oxy_v0.7.gif