ATP and water Flashcards
What is the role of ATP and what is it used in
- produces required energy for organisms to stay alive
. Anabolic reactions - building of larger molecules from smaller ones
. To move substances across the cell membrane (active transport) - In animals energy is required for:
. muscle contraction - coordination movement at the whole-organism level
. conduction of nerve impulses and cell processes
What is ATP
Adenosine triphosphate
known as the universal energy currency
How is ATP beneficial?
- The hydrolysis of ATP can be carried out quickly and easily whenever energy is required by action of one enzyme ATPase
- A useful quantity of energy is released from the hydrolysis of one ATP molecule - this reduces waste but also gives the cell control
- ATP is relatively stable at cellular PH levels
what is the structure of ATP
- It is a phosphorylated nucleotide
-Adenosine (A nucleotide) can be combined with 1,2 or 3 phosphate groups
. AMP - Adenosine monophosphate
. ADP - Adenosine diphosphate - ATP contains a pentose group (Ribose)
- adenine base (ribose+adenine = adenosine overall)
- 3 phosphate groups
what does the phosphate groups do and what do they look like in ATP
- The phosphate groups coil due to the negative oxygen molecules
- The phosphates have 4 oxygen atoms and one phosphate in the middle
the south oxygen has a double bond
What is more stable ADP or ATP and why
ADP is more stable because its has a lower energy potential due to the removal of a phosphate
Explain the hydrolysis of ATP
- ATP is hydrolysed to ADP by a hydrolysis reaction water is added.
- An inorganic phosphate group is catalysed by the enzyme ATP hydrolase (ATPase)
. removal of the first phosphate group from ATP releases 30.8kjmol-1 forming ADP
. The second releases the same amount and forms AMP
The inorganic phosphate released via hydrolysis of ATP can be used to phosphorylate other compounds making them more reactive
Explain ATP synthesis
- ATP is formed when ADP is bonded with an inorganic phosphate (pi) group by the enzyme ATP synthase
- This is an energy requiring reaction which can come from food/light
- Water released as a waste molecule (ATP synthesis is a condensation reaction)
What is the structure of water
one oxygen is covalently bonded to two hydrogen atoms /
Water is a dipole as it has an unevenly distributed charge as oxygen attracts more electrons than hydrogen meaning oxygen is slightly negative and hydrogen is slightly positive
(sometimes shown by a delta sign)
Hydrogen bonds from between adjacent water molecules due to the slight negative oxygens and positive hydrogens as they will now attract
What are the properties of water
- An excellent solvent
- A relatively high specific heat capacity
- A relatively high latent heat of vaporisation
- Water has a high surface tension and cohesion
- Acts as a reagent
Why is water a excellent solvent
- Water is a polar molecule so many substances will dissolve in it
- Because it is dipolar the positive oxygen will attract negatively charged ions and the negative hydrogen will attract positively charged ions
- Hydrophobic and non polar molecules cannot dissolve
This allows substances to be transported efficiently (e.g. in the blood or the xylem) and chemical reactions to occur.
why does water have a high specific heat capacity
what is specific heat capacity
and why is it advantageous
Amount of thermal energy needed to raise 1kg of a substance by 1 degrees
- large amount of energy needed to break the many hydrogen bonds between water molecules
- Takes a lot of thermal energy meaning the temperature of water doesn’t fluctuate and remain relatively stable
stabilising is important so enzymes don’t denature because internal temps of plants and animals will stay constant in different temps
Why does water have a relatively high latent heat vaporisation
and why is it advantageous
- Lots of energy is needed to convert waters liquid state into a gaseous state due to the hydrogen bonds need lots of energy needed to break them to turn water into gas
- This is good for organisms as water is a significant cooling as energy is needed to evaporate it (e.g. when sweating thermal energy will be used to evaporate the sweat so it will be removing alot of heat cooling us)
How is water a strong cohesion
and why is this and advantage
Cohesion is the term used to describe water sticking together by hydrogen bonds
It is advantageous because :
- due to water molecules sticking together it is a continuous column of water up the xylem meaning its easier to draw up than individual molecules
- Cohesion also provides surface tension in water meaning small invertebrate’s can live on top of the surface of the water providing a habitat away from predators
