Additional Science OCR GCSE

Revision bullet points

HideShow resource information
  • Created by: stephanie
  • Created on: 03-05-10 18:41

B4 - Homeostasis

Homeostasis :- Means mantaining a constant internal environment.

Negative feedback counteracts change keeping your internal environment the same.

Diffusion is the movement of particles from a region with high concentration to a region with a lower concentration.

Osmosis is the overall movement of water from a dilute to a more concentrated solution through a partially permeable membrane.

A partially permeable membrane only lets certain substances pass through it.

Enzymes are very specific proteins which speed up chemical reactions in cells.

Vasodilation occurs when body temperature is too hot, this is when blood vessels close to the skin surface increase in diameter.

Vasoconstriction occurs when body temperature is too cold, this is when blood vessels close to the skin surface decrease in diameter.

1 of 6

C4 - Chemical Patterns (card 1)

Atoms consist of the nucleus in the centre and electrons moving around it.

Proton = Mass 1 , Charge = +1, Neutron = Mass 1, Charge = 0 Electron = Mass 0.0005 , Charge = -1

Number of proton equal the number of electrons in an atom, if some electrons are added or taken away then it becomes on ion.

Chalkboard with description of periodic table notation for nitrogen. There is a square with three values in it. Top has atomic number, center has element symbol, and bottom has atomic mass value. The atomic number equals number of protons and also the number of electrons in a neutral atom. Atomic mass equals the mass of the entire atom. (http://www.chem4kids.com/files/elements/art/007_symbol.gif)

2 of 6

C4 - Chemical Patterns (card 2)

Electron Shell Rule:

1st shell =2 electons ,

2nd shell=8 electrons

3rd shell =8 electrons ...etc

Group 1 of the periodic table = alkali metals - become more reactive as you go down the table

Group 7 of the periodic table = Halogens - become less reactive as you go down the table

3 of 6

P4 - Explaining Motion

speed = distance /time or (http://gcsemaths.org.uk/blog/wp-content/uploads/speed_distance_time_triangle.png)

momentum = mass x velocity

change of momentum = resultant force x time for which force acts

change in energy = work done

work done = force x distance

kinetic energy = 1/2 x mass x velocity

4 of 6

P4 - Explaining Motion

(http://www.racemath.info/graphics/graphs/graph_vel.gif)

5 of 6

P4 - Explaining Motion

(http://www.antonine-education.co.uk/Physics_AS/Module_2/Topic_1/Graph_2.gif)

6 of 6

Comments

stephanie

When you print these, it loses the graphs and images for some reason so i copied and pasted into a word document to print these out

ivie

thanks this really helped refresh my memory. 2 hours before Science exam wish me luck!!

Gamze

this is really goood! thnksss

Similar Science resources:

See all Science resources »See all Physics resources »