Recall how to carry out a simple experiment to determine the energy content in a food sample

Food

Weight of Food (g)

Temperature of Food from Start

Temperature of Food From Ending

Popcorn

0.18

28

29

Crouton

0.55

27

31

Noodle

1.25

25

36

Bread

0.86

28

31

 

 

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Popcorn:

20g x (29-28) x 4.2 = 84

84/0.18 = 466.7J

Crouton:

20g x (31-27) x 4.2 = 336

336/0.55 = 1110.7J

Noodle:

20g x (36-25) x 4.2 = 924

924/1.25 = 739.2J

Bread:

20g x (31-28) x 4.2 = 252

252/0.86 = 293.0J

 

2.23 Balanced Diet

understand that a balanced diet shound include appropriate proportions of carbohydrates, protiens lipid, vitamins, minerals water, and dietary fibre

  • A balanced diet includes : Carbohydrates, protiens, lipid, vitamins, minerals & dietary fibre
  • On the other side of Balanced Diet, is life style  - age, gender and activity 
  • Each sides have to match ( from above )

2.15c Concentration gradients and cells

Understand the factors that affect the rate of movement of substances into and out of cells to include the effects of surface area to volume ratio, temperature and concentration gradient

  • If you increase the concentration, there would be many more glucouse moleclues around the cell.
  • The frequency which they collide and enter would be greater than the lower concentration gradient


2.15b Temperature and Diffusion

Understand the factors that affect the rate of movement of substances into and out of cells to include the effects of surface area to volume ratio, temperature and concentration gradient

  • Temperature = average kinetic energy of the molecules. 
  • If you increase the temperature it increases the average kinectic energy. 
  • The higher teh kinetic energy the faster the molecules move

 

2.15a Surface area and Diffusion

Understand the factors that affect the rate of movement of substances in to and out of cells to include the effects of surface area to volume ratio, temperature and concentration gradient

  • in a cell the volume is measured to 1 unit and the surface area is measured to 2 units, which makes the ratio 2: 1 
  • Molecules are able to diffuse in to the cell. 
  • If you increase the surface area but keep the volume the same (by folding the surface) as this has much more surface for it to diffuse in to the cell. 
  • By increasing surface area it increases movement of substances

2.14 Turgid Plant Cell

Understand the importance in plants of turgids cells as a means of support
  • The wall pressure in a turgid cell provides the plant with suppose so that the plant seedling has sufficient water in the soil and as along as the rate of transpiration is not too high the plant will remain strong
  • If the plant experience high rate of water loss the volume of the cytoplasm will decrease. This will conclude to loss of support.

 

 

2.13b Osmosis in animal cells

Understand that movement of substances into and out of cells can be by diffusion, osmosis and active transport
  • Definition of Osmosis is movement of water from a dilute solution to a concentrated solution
  • When a animal cells is in a dilute solution - the name is hypotonic
  • When a animals cell is in a solution where cytoplasym and external solution is equal - the name is isotonic
  • When a animal cell is in a concentrated solution - the name is hypertonic
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2.13a Diffusion in cells

Understand that movement of substances into and out of cells can be by diffusion, osmosis and active transport
  • Diffusion is a movement of molecules of high concentration to a regent of a low concentration 
  • Movement of molecules is passive - so you don't add energy
  • An example of diffusion is movement of oxygen in to a respiring animal cell 
  • The same cell can carry out respiration, producing a high concentration of carbon dioxide inside the cell diffusing into a low concentration outside the cell

2.12 Definitions of diffusion, osmosis and active transport

Recall simple definitions of diffusion, osmosis and active transport
  • These are the three ways that substances move in or out of cells
  • Diffusion is when molecules move from a regent of their high concentration to a regent of their low concentration
  • Osmosis is the movement of water
  • The rule of osmosis is water will move form dilute solution to the concentration solution through a membrane
  • Active transport occurs when special carrir proteins on the surface of a cell pick up particles from one side of the membrane and the transport them to the other side.
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