Biology Module 3

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  • Created by: 12gambler
  • Created on: 20-09-17 18:03
Diffusion
The movement of molecules from an area of high concentration to an area of low concentration down a concentration gradient
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The rate of diffusion is affected by:
Surface area, thickness of surface and concentration of molecules
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Molecule
2 or more atoms chemically bonded. Eg, water (H20), nitrogen and glucose
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Total surface area= H x W x No of sides x No of boxes
Total volume= H x W x L x No of boxes
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What features does an exchange surface need?
Large surface area so there is space for molecules to pass through (folded walls allow this), Thin, permeable barrier to reduce diffusion distance, Fresh supply of molecules going into cells, Removal of waste molecules going out of cells.
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Organism
An animal or plant, often one that is so small that you cannot see it without using a microscope. Example) Amoeba
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Why do animals need blood systems to supply their cells with oxygen?
The gas exchange surface distance is long so diffusion would be too slow. A blood system allows rapid transport
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Exchange surfaces: A specialised area on an organism that makes it easier for molecules to cross the surface in cells.
Exchange surfaces found in multi-cellular organisms: Villi in the small intestine, Root hair cells in plants, Capillaries and Alveoli in the lungs
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What do all cells need?
Water and minerals, oxygen for respiration, glucose for energy, fats for membranes and proteins for growth and repair
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Amoeba
Single celled microorganisms found in ponds.
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What do all organisms need? water to keep cells hydrated, minerals to aid metabolism, co2, oxygen and ammonia
Oxygen for aerobic respiration, Glucose used as a source of energy, Amino acids to make proteins which are used for growth and repair and Lipids to make cell membranes and as a store of energy
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Gaseous exchange
The exchange of oxygen and carbon dioxide into and out of an organism across the alveoli in the lungs
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Alveoli
Tiny folds of the lung epithelium to increase the surface area. Where gaseous exchange takes place. They are tiny air sacs surrounded by the capillaries
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Bronchi and bronchioles
Smaller airways leading into the lungs
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Diaphragm
A layer of muscles beneath the lungs
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Intercostal muscles
Muscles between the ribs. Contraction of the external intercostal muscles raises the rib cage.
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Trachea
The main airway leading from the back of the mouth to the lungs
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Oxygen and carbon dioxide are the 2 gases involved in gaseous exchange in the lungs
The lungs are adapted for gaseous exchange. they have a large surface area to volume ratio, are moist, have a thin and permeable barrier and a good blood supply
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Breathing in oxygen creates a high concentration of oxygen inside the alveoli and a low concentration in the blood. This creates a steep concentration gradient which causes the oxygen to diffuse across the alveolar wall into the blood
Spirometer- A device for measuring lung capacity
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Tissue
Group of cells that work together to perform a particular function
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Histology
The study of microscopic structures of tissues
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Other cards in this set

Card 2

Front

Surface area, thickness of surface and concentration of molecules

Back

The rate of diffusion is affected by:

Card 3

Front

2 or more atoms chemically bonded. Eg, water (H20), nitrogen and glucose

Back

Preview of the back of card 3

Card 4

Front

Total volume= H x W x L x No of boxes

Back

Preview of the back of card 4

Card 5

Front

Large surface area so there is space for molecules to pass through (folded walls allow this), Thin, permeable barrier to reduce diffusion distance, Fresh supply of molecules going into cells, Removal of waste molecules going out of cells.

Back

Preview of the back of card 5
View more cards

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