Water, ATP and inorganic ions Flashcards
How do water molecules bond together?
The slight negative charge on the oxygen atom makes it attract the slightly positive hydrogen atom of another water molecule forming a hydrogen bond. The numerous hydrogen bonds in water make it a very stable structure.
Explain the property of water, metabolite and the examples of its biological importance?
A reactant in many metabolic reactions or a product of metabolic reactions.
It is used to break the bonds that hold biological molecules together in hydrolysis reactions and is released during condensation reactions.
Explain how water is a solvent and the examples of its biological importance?
Because water is polar, the positive end of a water molecule will be attracted to the negative ion and the negative end of a water molecule will be attracted to the positive ion, this allows the substance to dissolve.
- Transport of dissolved substances, like carbon dioxide, in the blood plasma in animals.
-Transport of dissolved mineral ions in the xylem and dissolved sucrose in the phloem in plants.
-Enzymes can also dissolve in the cytoplasm of cells, allowing metabolic reactions to take place. Reactions happen faster in solution.
Explain the high specific heat capacity of water and the examples of its biological importance?
A lot of heat energy is required to raise the temperature of water. The energy is used to weaken or break the many hydrogen bonds between water molecules, so water can gain or lose lots of heat energy without changing temperature so it acts as a buffer, preventing rapid changes in temperature.
This means aquatic environments are very temperature-stable and protects aquatic and marine organisms from sudden environmental changes. Water inside organisms also remains at a stable temperature helping them maintain a constant core body temperature, this is important so that enzymes can work properly.
Explain the large latent heat of vaporisation of water and the examples of its biological importance?
It takes a lot of energy to break the hydrogen bonds between water molecules to allow them to become gas. Lots of heat energy is absorbed by the hydrogen bonds before they break which allows small amounts of water to have a large cooling effect with little loss of water through evaporation.
E.g. sweating, panting, evaporation of water into leaf air spaces in transpiration.
Explain the strong cohesion between water molecules and the examples of its biological importance?
Cohesion is the ability of water molecules to stick together. This is due to the polarity of water and its ability to attract to other water molecules by forming hydrogen bonds.
Cohesion allows continuous colums of water to travel up xylem vessels in plants efficiently during transpiration.
It also produces surface tension where liquid water meets air which can support small organisms (Pond skaters).
What is ATP and what is its structure?
ATP(adenosine triphosphate) is the immediate source of energy in cells, the energy released from glucose in respiration is used to make ATP.
ATP is made from the base adenine, combined with a ribose sugar and three phosphate groups
How is a molecule of ATP formed?
Formed from ribose, three phosphate groups and adenine. Adenosine diphosphate (ADP) has an inorganic phosphate added during a condensation reaction catalysed by ATP synthase.
How is ATP hydrolysed?
This reaction occurs to release the energy stored in ATP. ATP is broken down by a hydrolysis reaction into ADP and an inorganic phosphate. This reaction is catalysed by ATP hydrolase.
Properties that make ATP a suitable and useful source of immediate energy-It releases energy in small amounts.
Because of this no energy is wasted, compared to glucose, which releases large amounts of energy and lots is wasted as heat energy.
Properties that make ATP a suitable and useful source of immediate energy-A single bond is hydrolysed in one step.
It releases energy rapidly, so is an immediate energy source, compared to glucose, where several bonds need to be broken, which takes longer.
Properties that make ATP a suitable and useful source of immediate energy-An inorganic phosphate released can be used to phosphorylate other substances.
It makes another compound more reactive, it lowers the activation energy needed for a reaction to take place. Whereas glucose does not contain phosphate so can’t.
Properties that make ATP a suitable and useful source of immediate energy-It can be regenerated easily.
ATP can be reformed from ADP and an inorganic phosphate in respiration and photosynthesis. Whereas animals have to consume glucose and their food and plants must carry out photosynthesis.
Properties that make ATP a suitable and useful source of immediate energy-ATP is small and soluble.
It is easily transported around the cell in the cytoplasm. This is similar to glucose, which can also be transported easily around the cell in the cytoplasm.
Properties that make ATP a suitable and useful source of immediate energy-ATP can’t leave the cell.
It means there always is a constant supply of ATP or ADP and an inorganic phosphate in order to make ATP, compared to glucose, which can leave the cell and therefore can run out.
