Water Flashcards
What percentage of our body is made up of water?
60-70%
What percentage of our body is made up of water?
60-70%
Describe the structure of a water molecule: (three points)
Is water a polar/dipolar etc molecule?
Explain what is meant by water being a polar/dipolar molecule
What type of bonds are formed between individual water molecules/oxygen and hydrogen atoms?
Water is a dipolar molecule.
The uneven distribution of charge is due to the oxygen atoms being slightly negative and the hydrogen atoms being slightly positive.
Hydrogen bonds are formed inbetween the hydrogen atoms and oxygen atoms. Further bonds are formed between the individual water molecules
What are the factors that result in the five key properties of water? What are the five key properties of water?
The formation of hydrogen bonds and the fact water is a dipolar molecule results in the five key properties of water
- Water is a metabolite
- Water is an important solvent
- Water has a high heat capacity
- Water has a large latent heat of vaporisation
- Water has a strong cohesion between water molecules
What is meant by water being a metabolite? What are some examples of reaction that water is involved in?
Water is a metabolite as it is involved in many reactions. For example photosynthesis (the photolysis of water) and many condensation/hydrolysis reactions
What is meant when it is said water is a solvent?
Water is a good solvent as it has the ability to dissolve many substances
What substances can water readily dissolve?
Gases (oxygen and carbon dioxide)
Wastes (ammonia and urea)
Inorganic ions and small hydrophilic molecules (amino acids, monosaccharides and ATP)
Enzymes whose reactions tale place in solutions
What is the explanation for water being a good solvent?
Polar, or charged molecules, readily dissolve in water due to water being a dipolar molecule. The slightly positively charged ions on the hydrogen atoms attract any negative ion solutes. The slightly negatively charged ions on the oxygen atoms attract any positive ion solutes.
What would polar molecules be described as? Why?
They would be described as hydrophilic. This is because hydrophilic means attracted to water, which is behaviour they exhibit.
What molecules cannot dissolve in water? Example? What are they described as? Why?
(1) Non polar molecules cannot be dissolved in water. (1) An example of a non polar molecule would be lipids. (1) They are described as hydrophobic. (1) This is because hydrophobic things are described as repellent to water.
What molecules cannot be dissolved in water? Example? What would they be described as? Why?
(1) Non polar molecules cannot be dissolved in water. (1) An example of a non polar molecule would be lipids. (1) They are described as hydrophobic. (1) This is because hydrophobic things are described as repellent to water.
In plants, the xylem and phloem act as means of transport for substances:
1. What does the phloem transport around a plant using water?
2. What does the xylem transport around a plant using water?
In plants, the phloem transports sugar molecules that dissolves in the water.
In plants, the xylem transports mineral ions that dissolve in the water
What is meant when water is described to have a “high specific heat capacity”?
This means a lot of energy is required to raise the temperature of water
Why does water have a high specific heat capacity?
In water, the hydrogen bonds between the water molecules need a lot of heat energy to break in order to raise the temperature
Why does water having a high specific heat capacity useful to organisms?
This is useful to organisms because it means the temperature of water remains relatively stable, therefore even if the surround temperature fluctuates a lot, the water should not fluctuate a lot.
Therefore, the internal temperatures of plant and animals should remain relatively constant despite outside temperature, due to the large proportion of the organism being water
