edexcel as biology there are three units: unit 1: lifestyle, transport, genes and health (40% as 20%...
TRANSCRIPT
![Page 1: Edexcel AS Biology There are three units: Unit 1: Lifestyle, Transport, Genes and Health (40% AS 20% GCE) Exam: Jan 2013 Unit 2: Development, Plants and](https://reader035.vdocuments.us/reader035/viewer/2022070408/56649e6a5503460f94b67488/html5/thumbnails/1.jpg)
Edexcel AS BiologyThere are three units:
Unit 1: Lifestyle, Transport, Genes and Health (40% AS 20% GCE)Exam: Jan 2013
Unit 2: Development, Plants and the Environment (40% AS 20% GCE)
Exam: June 2013
Unit 3: Practical Biology and Research Skills (20% AS 10% GCE)1500 - 2000 words report on into a biological topic – June
2013
![Page 2: Edexcel AS Biology There are three units: Unit 1: Lifestyle, Transport, Genes and Health (40% AS 20% GCE) Exam: Jan 2013 Unit 2: Development, Plants and](https://reader035.vdocuments.us/reader035/viewer/2022070408/56649e6a5503460f94b67488/html5/thumbnails/2.jpg)
Edexcel A2 BiologyThere are three units:
Unit 4: The Natural Environment and Species Survival (40% A2 20% GCE) Exam: Jan 2013
Unit 5: Energy, Exercise and Coordination (40% A2 20% GCE)Exam: June 2013
Unit 6: Practical Biology and Research Skills (20% A2 10% GCE)Students will complete a written report of an experimental
investigation
![Page 3: Edexcel AS Biology There are three units: Unit 1: Lifestyle, Transport, Genes and Health (40% AS 20% GCE) Exam: Jan 2013 Unit 2: Development, Plants and](https://reader035.vdocuments.us/reader035/viewer/2022070408/56649e6a5503460f94b67488/html5/thumbnails/3.jpg)
What is involved.....
Skills: practical skills, fact learning, application of knowledge, mathematical skills, independent investigations- planning, implementing and writing up scientific reports, research papers.
Topics: human biology, environmental biology, plant biology, immunology, genetics.
Requirements: you need to be prepared to do lots of independent research and self study.
![Page 4: Edexcel AS Biology There are three units: Unit 1: Lifestyle, Transport, Genes and Health (40% AS 20% GCE) Exam: Jan 2013 Unit 2: Development, Plants and](https://reader035.vdocuments.us/reader035/viewer/2022070408/56649e6a5503460f94b67488/html5/thumbnails/4.jpg)
Membranes
![Page 5: Edexcel AS Biology There are three units: Unit 1: Lifestyle, Transport, Genes and Health (40% AS 20% GCE) Exam: Jan 2013 Unit 2: Development, Plants and](https://reader035.vdocuments.us/reader035/viewer/2022070408/56649e6a5503460f94b67488/html5/thumbnails/5.jpg)
Why do cells need membranes?
• Control entry and exit of substances
• Keep things in! Contain the cell contents and organelles;
compartmentalise individual cell processes
• Communication with external environment
• Site of chemical reactions
• Allows cell to change shape
• Transport and packaging within a cell
![Page 6: Edexcel AS Biology There are three units: Unit 1: Lifestyle, Transport, Genes and Health (40% AS 20% GCE) Exam: Jan 2013 Unit 2: Development, Plants and](https://reader035.vdocuments.us/reader035/viewer/2022070408/56649e6a5503460f94b67488/html5/thumbnails/6.jpg)
What are cell membranes made of?
Mostly LIPIDS ...... And so is impenetrable to water
soluble substances
Some PROTEINS .These allow water-soluble substances and
other molecules to pass across.
![Page 7: Edexcel AS Biology There are three units: Unit 1: Lifestyle, Transport, Genes and Health (40% AS 20% GCE) Exam: Jan 2013 Unit 2: Development, Plants and](https://reader035.vdocuments.us/reader035/viewer/2022070408/56649e6a5503460f94b67488/html5/thumbnails/7.jpg)
3 main types of lipid
- Phospholipids – most abundant
- Cholesterol - helps to stabilise the membrane by partial immobilising of the fatty acid chains
- Glycolipids - involved in cell to cell recognition and communication
Membrane Structure
![Page 8: Edexcel AS Biology There are three units: Unit 1: Lifestyle, Transport, Genes and Health (40% AS 20% GCE) Exam: Jan 2013 Unit 2: Development, Plants and](https://reader035.vdocuments.us/reader035/viewer/2022070408/56649e6a5503460f94b67488/html5/thumbnails/8.jpg)
PhospholipidsLipids formed when 2 fatty acids, a phosphate group and glycerol are joined together.
![Page 9: Edexcel AS Biology There are three units: Unit 1: Lifestyle, Transport, Genes and Health (40% AS 20% GCE) Exam: Jan 2013 Unit 2: Development, Plants and](https://reader035.vdocuments.us/reader035/viewer/2022070408/56649e6a5503460f94b67488/html5/thumbnails/9.jpg)
Hydro – waterPhillic – loves
Hydro – waterPhobic – hates
Due to the negative charges on the phosphate group
The long hydrocarbon chains do not have any charged groups
![Page 10: Edexcel AS Biology There are three units: Unit 1: Lifestyle, Transport, Genes and Health (40% AS 20% GCE) Exam: Jan 2013 Unit 2: Development, Plants and](https://reader035.vdocuments.us/reader035/viewer/2022070408/56649e6a5503460f94b67488/html5/thumbnails/10.jpg)
Fatty acid tails- Hates water
Phosphate head- Likes water so turned towards water
![Page 11: Edexcel AS Biology There are three units: Unit 1: Lifestyle, Transport, Genes and Health (40% AS 20% GCE) Exam: Jan 2013 Unit 2: Development, Plants and](https://reader035.vdocuments.us/reader035/viewer/2022070408/56649e6a5503460f94b67488/html5/thumbnails/11.jpg)
This is the basic structure that forms all cell membranes.
In water phospholipids tend to form into a double layer with the phosphate ‘heads’ in the water and the fatty acid ‘tails’ away from it.
![Page 12: Edexcel AS Biology There are three units: Unit 1: Lifestyle, Transport, Genes and Health (40% AS 20% GCE) Exam: Jan 2013 Unit 2: Development, Plants and](https://reader035.vdocuments.us/reader035/viewer/2022070408/56649e6a5503460f94b67488/html5/thumbnails/12.jpg)
The fluid mosaic model of the plasma membrane:
The proteins and phospholipids can move in the layer. Small molecules can move in and out of the membrane.
![Page 13: Edexcel AS Biology There are three units: Unit 1: Lifestyle, Transport, Genes and Health (40% AS 20% GCE) Exam: Jan 2013 Unit 2: Development, Plants and](https://reader035.vdocuments.us/reader035/viewer/2022070408/56649e6a5503460f94b67488/html5/thumbnails/13.jpg)
The fluid mosaic model of the plasma membrane:
Temperature affects the fluidity of the membrane.
HOW?
To be investigated......
![Page 14: Edexcel AS Biology There are three units: Unit 1: Lifestyle, Transport, Genes and Health (40% AS 20% GCE) Exam: Jan 2013 Unit 2: Development, Plants and](https://reader035.vdocuments.us/reader035/viewer/2022070408/56649e6a5503460f94b67488/html5/thumbnails/14.jpg)
Findings…
As the temperature increases the % absorbency increases as more pigments are released from the vacuole into the surrounding water. The more pigment, the greater the light absorbed.