LIMITS TO SIZE: Why are Cells Small Lab?. Why are cells so small? The answer to this question has as...
-
Upload
martina-perkins -
Category
Documents
-
view
221 -
download
0
Transcript of LIMITS TO SIZE: Why are Cells Small Lab?. Why are cells so small? The answer to this question has as...
![Page 1: LIMITS TO SIZE: Why are Cells Small Lab?. Why are cells so small? The answer to this question has as much to do with mathematics as biology. Imagine a.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649ee85503460f94bf8fdc/html5/thumbnails/1.jpg)
LIMITS TO SIZE: Why are Cells Small Lab?
![Page 2: LIMITS TO SIZE: Why are Cells Small Lab?. Why are cells so small? The answer to this question has as much to do with mathematics as biology. Imagine a.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649ee85503460f94bf8fdc/html5/thumbnails/2.jpg)
Why are cells so small?
The answer to this question has as much to do with mathematics as biology. Imagine a cell that is shaped like a cube. As the cell increases, its surface area to volume ratio changes.
![Page 3: LIMITS TO SIZE: Why are Cells Small Lab?. Why are cells so small? The answer to this question has as much to do with mathematics as biology. Imagine a.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649ee85503460f94bf8fdc/html5/thumbnails/3.jpg)
Surface area Surface area is the total area of the
outside surface. For cubes it is expressed in squared units (such as cm2 or m2).
The S.A. of a cell will determine the amount of materials that can be exchanged between the cell and its environment.
Equation: SA = length x width x # of sides
© 2010 Paul Billiet ODWS
![Page 4: LIMITS TO SIZE: Why are Cells Small Lab?. Why are cells so small? The answer to this question has as much to do with mathematics as biology. Imagine a.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649ee85503460f94bf8fdc/html5/thumbnails/4.jpg)
Volume Volume is the amount of space
something occupies. It is expressed in cubic units (such as cm3 or m3).
The volume of a cell will determine the amount of chemical reactions or the metabolism of the cell.
Equation: V= length x width x height
© 2010 Paul Billiet ODWS
![Page 5: LIMITS TO SIZE: Why are Cells Small Lab?. Why are cells so small? The answer to this question has as much to do with mathematics as biology. Imagine a.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649ee85503460f94bf8fdc/html5/thumbnails/5.jpg)
Surface Area to Volume Ratio
Surface Area to Volume Ratio is the comparison of the amount of surface area (what is on the outside) to the volume (what is on the inside)
Cells need to have a large surface area to its volume (hence a high S.A. to V ratio) because wastes need to be able to exit, and nutrients need to be able to enter the cell quickly.
![Page 6: LIMITS TO SIZE: Why are Cells Small Lab?. Why are cells so small? The answer to this question has as much to do with mathematics as biology. Imagine a.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649ee85503460f94bf8fdc/html5/thumbnails/6.jpg)
Growing cells
1cm
2cm
3cm
4cm
5cm
6cm© 2010 Paul Billiet ODWS
![Page 7: LIMITS TO SIZE: Why are Cells Small Lab?. Why are cells so small? The answer to this question has as much to do with mathematics as biology. Imagine a.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649ee85503460f94bf8fdc/html5/thumbnails/7.jpg)
How are surface area and volume affected by growth?
1:11.2:11.5:12:13:16:1
216125642781
2161509654246
654321
SA/V
Volume (cm3)
Surface area (cm2)
Length of side (cm)
© 2010 Paul Billiet ODWS
![Page 8: LIMITS TO SIZE: Why are Cells Small Lab?. Why are cells so small? The answer to this question has as much to do with mathematics as biology. Imagine a.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649ee85503460f94bf8fdc/html5/thumbnails/8.jpg)
Comparing Surface Area and Volume changes
0
100
200
300
400
500
600
700
800
900
1000
0 1 2 3 4 5 6 7 8 9 10
Size / µm
Surface areaVolume
© 2010 Paul Billiet ODWS
(cm)
![Page 9: LIMITS TO SIZE: Why are Cells Small Lab?. Why are cells so small? The answer to this question has as much to do with mathematics as biology. Imagine a.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649ee85503460f94bf8fdc/html5/thumbnails/9.jpg)
Surface Area:Volume Ratio
0
1
2
3
4
5
6
0 1 2 3 4 5 6 7 8 9 10
Size / µm
SA
/V
© 2010 Paul Billiet ODWS
(cm)
![Page 10: LIMITS TO SIZE: Why are Cells Small Lab?. Why are cells so small? The answer to this question has as much to do with mathematics as biology. Imagine a.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649ee85503460f94bf8fdc/html5/thumbnails/10.jpg)
As cells get larger, the S.A.:V gets __________________.smaller
![Page 11: LIMITS TO SIZE: Why are Cells Small Lab?. Why are cells so small? The answer to this question has as much to do with mathematics as biology. Imagine a.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649ee85503460f94bf8fdc/html5/thumbnails/11.jpg)
Since transport of materials in and out of the cell can only happen at the cell’s surface, what problem does this pose?
Bigger cells have a greater volume (meaning a greater metabolism) than smaller cells
BUT bigger cells have a proportionally less surface for exchange.
Diffusion can’t take place as quickly!© 2010 Paul Billiet ODWS
![Page 12: LIMITS TO SIZE: Why are Cells Small Lab?. Why are cells so small? The answer to this question has as much to do with mathematics as biology. Imagine a.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649ee85503460f94bf8fdc/html5/thumbnails/12.jpg)
1. Throw out extensions
Microvilli of small intestine epithelium
Image Credit www.cytochemistry.net/
What are ways to increase surface area while increasing size.
![Page 13: LIMITS TO SIZE: Why are Cells Small Lab?. Why are cells so small? The answer to this question has as much to do with mathematics as biology. Imagine a.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649ee85503460f94bf8fdc/html5/thumbnails/13.jpg)
2. Flatten into a thin film
Chick blastodisc
Image Credits http://anatomia.uw.hu/
![Page 14: LIMITS TO SIZE: Why are Cells Small Lab?. Why are cells so small? The answer to this question has as much to do with mathematics as biology. Imagine a.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649ee85503460f94bf8fdc/html5/thumbnails/14.jpg)
3. Or just divide the cytoplasm into smaller volumes
Early human embryos
Zygote
8-cell Embryo
Image Credit http://www.advancedfertility.com/ Image Credit http://www.rmfcfertility.com/
![Page 15: LIMITS TO SIZE: Why are Cells Small Lab?. Why are cells so small? The answer to this question has as much to do with mathematics as biology. Imagine a.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649ee85503460f94bf8fdc/html5/thumbnails/15.jpg)
Do larger organisms have larger cells or more cells than smaller organisms?
More Cells!!!!
![Page 16: LIMITS TO SIZE: Why are Cells Small Lab?. Why are cells so small? The answer to this question has as much to do with mathematics as biology. Imagine a.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649ee85503460f94bf8fdc/html5/thumbnails/16.jpg)
Multicellular organisms show the same adaptations
Flowering plants have an extensive, branched rooting system to absorb water and minerals
Image Credit http://ecomerge.blogspot.com
![Page 17: LIMITS TO SIZE: Why are Cells Small Lab?. Why are cells so small? The answer to this question has as much to do with mathematics as biology. Imagine a.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649ee85503460f94bf8fdc/html5/thumbnails/17.jpg)
Multicellular organisms show the same adaptations
Mammals have a long small intestine with internal folding to absorb digested food
Image Credit C. Candalh, INSERM