ATP – adenosine triphosphate. All cells need energy to carry out their processes. ATP is the main source of energy in all cells.

What is it made of? 1x adenine (nitrogen containing base) Ribose – 5 carbon sugar. 3x phosphate groups in a chain.

Why is ATP the main source of energy? Bonds between 3 phosphate groups are unstable and have a LOW ACTIVATION energy to break them apart. When they break apart they release lots of energy.

ATP + H2O  ADP + Pi + ENERGY The last (terminal) phosphate is usually the one to be removed. TIP: Tri = 3 Di = 2 The reaction. ATP + H2O  ADP + Pi + ENERGY Adenosine diphosphate Inorganic phosphate (that is lost from ATP) Adenosine triphosphate Water is used to break apart this reaction, is it a hydrolysis or condensation reaction?

ATP + H2O  ADP + Pi + ENERGY How to form ATP. The reaction is actually reversible. The enzyme ATP synthase is needed to make ATP. The reaction. ATP + H2O  ADP + Pi + ENERGY Inorganic phosphate (that is lost from ATP) Adenosine diphosphate Adenosine triphosphate Water is released to form ATP, is it a hydrolysis or condensation reaction?

ATP – immediate energy source. Because it is so unstable and quick to release energy, ATP is not a good energy store. Instead it is an immediate energy source. Why is ATP an immediate energy soure: ATP energy is released rapidly Energy released in a single step To unstable to be a store Energy transferred directly to the reaction that needs it.

Where is ATP made and used? ATP is made in the mitochondria of cells. Uses: Movement - ATP provides energy for muscle contraction. (Muscle cells have loads of mitochondria. Metabolic processes – provides energy to build big molecules. Active transport – to move particles against a concentration gradient. Secretion of molecules. To activate molecules in reactions (make reactions happen).

Water and its functions.

Water = H2O Hydrogen x 2 Oxygen x 1

As a complete molecule, water has no charge, it is neutral…. But look closer and the different parts of small amounts of charge, this makes water dipolar (“two charges”).. Dipolar water molecule. Oxygen = slightly negative. hydrogen= slightly positive.

The opposite charges attract and form hydrogen bonds. This allows water to “stick together” (look at the droplets below). Drawn like this!

Latent heat of vaporisation – energy to evaporate 1 gram of water. All the hydrogen bonds between each water molecule means lots of energy is needed to separate them and allow them to evaporate. To turn water to a gas all the hydrogen bonds must break first! This is why the latent heat of vaporisation is so high. Sweat is mainly water. Sweating cools you down as loads of energy is removed from the body to make the sweat evaporate. .

Specific heat capacity of water – energy required to heat a 1kg of water by 1 degrees Celsius. All the hydrogen bonds between each water molecule means lots of energy is needed to warm up water. This means water stays at a relatively constant temperature, even on hot and cold days. This protects aquatic animals from sudden changes in their environment.

Surface tension. The hydrogen bonds connecting water means it can act like a skin. Small insects can walk on it.

Water sticks together because of hydrogen bonds – this is called cohesion. Cohesive forces allow water to be pulled (sucked) up a straw or the xylem of a plant.

Other uses of water. Solvent – water dissolves other molecules. Metabolism – chemical reactions take place in an aqueous medium (water) Metabolism – water used to break down molecules (hydrolysis). Water is used in reactions (photosynthesis).