water Flashcards

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1
Q

Name the 7 important properties of water, which makes it useful

A
  • cohesive
  • high specific heat capacity
  • large latent heat of evaporation
  • a good solvent so allows ionic compounds to separate = good for chemical reactions and good for transport
  • transparent= making water a good habitat
  • lower density when ice
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2
Q

Why does water have a high specific heat capacity?

A

Water molecules are attracted to the positive and negative poles of other water molecules (hydrogen bonding), so they stick together = takes more energy to separate them = high bp

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3
Q

What is the definition of latent heat of vaporisation?

A

heat taken in by a liquid in order to transform it into a vapour

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4
Q

What is the definition of cohesion?

A

the tendency of molecules to stick together

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5
Q

What is the definition of surface tension?

A

Surface tension is the cohesion of the molecules on the surface of a fluid to occupy the least possible volume

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6
Q

Describe the cohesion and surface tension in water

A

Due to hydrogen bonding, water has large cohesive forces. This allows columns of water to move through the xylem of plants and through blood vessels in animals

Water has a high surface tension because hydrogen bonds among water molecules resist stretching or breaking the surface. Water molecules are more strongly cohesive to each other than they are to air. Good for small organisms like pond scaters

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7
Q

Name and explain the properties that help aquatic organisms survive

A
  • ice has a lower density than water = water doesn’t freeze from the bottom, it freezes from the top so aquatic animals will not freeze and can still move. Also, the ice can provide insulation for the aquatic animals
  • High specific heat capacity = water rarely fluctuates in temperature , so organisms will not freeze or be warmed to death
  • solvent = organisms can easily absorbed dissolved components.
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8
Q

In terms of the chemical structure of water, explain why water is such a good transport medium

A

Polar molecule = dissolve ionic substances

cohesive due to easily forming hydrogen bonds with other water molecules = flows nicely

solvent

liquid at room temperature.

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9
Q

Water has a high latent heat of vaporisation. Why is this useful?

A

because so much energy is needed to evaporated water (due to strong hydrogen bonds),as water leaves the surface from which it is evaporating and removes a lot of heat with it. You feel this as a cooling effect on your skin.

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10
Q

Why are new nucleotides only added in a 5 to 3 direction during dna synthesis? (4 marks)

A

DNA polymerase is the enyzme that joins adjacent nucleotides together

its specific

DNA polymerase only complementary to the 3 end of strand.

5 end and 3 end are different shapes.

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11
Q

Give two features of DNA and explain how each one is important in the semi-conservative replication of DNA? (2 marks, 3 possible answers)

A

1- Weak hydrogen bonds between bases allow two strands to unzip

2- 2 strands exists, both of them can act as template for replication

3- Complementary base pairing, this allows accurate replication

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12
Q

why may a gene contain more than the necessary amount of bases it needs

A

because there are regions of the gene that are non-coding

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13
Q

What inorganic ions and where are they found?

A

An inorganic ion is an ion that does not contain carbon

occur in solution in the cytoplasm and body fluids of organisms, some in high concentration and others in very low concentrations

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14
Q

Describe the role of iron ions in haemoglobin

A
  • an important part of haemoglobin
  • Fe2+ binds to the oxygen in haemoglobin
  • when bound to oxygen it temporarily becomes fe 3+
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15
Q

Describe the role of sodium ions in terms of glucose and amino acids

A

A molecule of glucose or an amino acid can be transported into a cell alongside sodium ions = co-transport

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16
Q

Describe the role of phosphate ions

A

DNA, RNA and ATP all contain phosphate groups

bonds between phosphate groups store energy in ATP

DNA and RNA allow nucleotides to join up to form the polynucleotides

17
Q

why is a SINGLE strand of DNA a better storage molecule than RNA

A

RNA contains a hydroxyl group so it can easily be hydrolysed

18
Q

Why is a stain used for microscopes

A

to distinguish organelles

19
Q

During interphase in eukaryotic cells, DNA replication takes place. Explain why one strand of DNA replicates continuously, whereas the opposite strand replicates discontinuously

A
20
Q

What is the enzyme used for the hydrolysis of ATP and what is the enzyme used for the condensation reactions of ATP?

A

Hydrolysis = ATP hydrolase

Condensation = ATP synthase

21
Q

What is end production inhibition and describe it

A

The end product is acting as an inhibitor (allosteric effector) to the enzyme at the beginning of the biochemical pathway

The attachment slows the reaction time, preventing enz-sub complexes forming

As the concentration of the product decreases, the product then is released from the enzyme and the reactions begin again

It is non- competitive and reversible

22
Q

Why is enzyme inhibition important

A

important in regulating metabolic pathways.

23
Q

explain five properties that makes water important for organisms

A
  1. A metabolite in condensation/hydrolysis/ photosynthesis/respiration;
  2. A solvent so (metabolic) reactions can occur OR A solvent so allowing transport of substances;
  3. High heat capacity so buffers changes in temperature; For ‘buffer’ accept ‘resist’.
  4. Large latent heat of vaporisation so provides a cooling effect (through evaporation);
  5. Cohesion (between water molecules) so supports columns of water (in plants); For

‘6. Cohesion (between water molecules) so produces surface tension supporting (small) organisms;

  • ice floating so maintaining aquatic habitat beneath
  • water transparent so allowing light penetration for photosynthesis