Science B4, C4

Here are some quick notes to help you with some of the easy basics

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  • Created by: Sonal
  • Created on: 30-12-12 20:04

Cell Structure and Function- Animal

Nucleus- Contains DNA, DNA contains the instructions for making proteins, e.g the enzymes used in the chemical reactions of respiration and photosynthesis

Cytoplasm- Gel like substance where proteins like enzymes are made, some enzyme controlled take place here like anaerobic respiration 

Cell Membrane- Holds the cell together & controls what goes in/out, it lets gases, water pass but is a barrier to chemicals

Mitochondria- These are where the enzymes needed for the reactions of aerobic respiration are found and where the reactions take place

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Cell Structure and Function- Plant

Rigid Cell Wall- It is made of cellulose and supports the cell and strengthens it

Vacuole- It contains sap which is a weak solution of sugar and salts

Chloroplasts- These are where the reactions for photosynthesis takes place. They contain a green substance called chlorophyll and the enzymes needed for photosynthesis 

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Equations for Biology

Aerobic respiration- Glucose+Oxygen = Carbon Dioxide+Water 

   - C(6)H(12)O(6)+6O(2) = 6CO(2)+6H(2)O

Anaerobic respiration- Glucose = Lactic Acid (Energy)

     - Glucose = Ethanol+Carbon Dioxide (Energy)

Photosynthesis- Carbon Dioxide+Water = Glucose+Oxygen

- 6CO(2)+6H(2)O = C(6)H(12)O+6O(2)

Brackets- small number at the bottom

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Diffusion, Osmosis, Active Transport

Diffusion is the passive overall movement of particles from a region of their higher concentration to a region of their lower concentration

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

Active Transport is the overall movement of chemicals across a cell membrane from a region of lower concentration to a region of higher concentration using energy released by respiration

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Elements when heated are...

Some elements have a specific colour when heated:

Lithium (Li) is a red flame

Sodium (Na) is a yellow/ orange flame

Potassium (K) is a lilac flame

Calcium (Ca) is a orangey/red flame

Copper (Cu) is a green flame

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Line Spectrum

Each element gives a characteristic line spectrum

When heated the electrons in atoms release energy as light

Different elements emit different wavelengths of light due to the element having different electron arrangement

This means line spectrums can be used to identify elements using a spectroscopy

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Group 1

Group 1 elements are called the alkali metals

As you go down the group the reactivity increases

This is because to gain a full outer shell it has to lose an electron (ion)

If the electron is closer to the nucleus then it is harder to lose it whereas the further away the easier to lose an electron

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Group 7

Group 7 elements are called the halogens

As you go down the group the reactivity decreases

This is because to have a full outer shell it has to gain an electron (ion)

If the shell needed to gain an electron is nearer to the nucleus it is easier gain an electron whereas the further away the additional electrons are attracted less strongly

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Ions

Ions are made when atoms lose or gain electrons

When group 1 elements lose electrons they form positive ions as there are now more protons then electrons

When group 7 elements gain electrons they form negative ions as there are now more electrons than protons

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Chemical Equations

(s) - Solid

(l) - Liquid

(g) - Gas

(aq) - Aqueous (dissolved in water)

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Halogens

Chlorine- Green/ Yellow- Gas

Bromine- Orange/ Brown- Liquid

Iodine- Grey/ Black- Solid

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