Biological molecules (water) 2.1.2 Flashcards

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1
Q

Organic molecules

A
  • Contain hydrogen and carbon
  • Either macromolecules (Molecules containing a large number of atoms) or small molecules
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2
Q

Polymers and monomers

A

Polymers are a chain of repeating units (monomers) joined togther by covalent bonds and formed through a condensation reaction. Monomers are molecules that are covalently bonded to eachpther to form a polymer.

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3
Q

What are the biomolecules?

A

Lipids, nucleic acids, carbohydrates and proteins.

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4
Q

How many bonds can the elements carbon, nitrogen, oxygen and hydrogen form?

A
  • carbon atoms can form 4 bonds
  • nitrogen atoms can form 3 bonds
    -Oxygen can form 2 bonds
    -Hydrogen forms 1 bond
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5
Q

Important cations

A
  • Sodium ion (Na +) necessary for nerve impulse transmission and kidney function.
  • Potassium ion (K+) nerve impulse transmission and stomatal opening.
  • Calcium ion (Ca 2+) nerve impulse transmission and muscle contraction
  • Hydrogen ion (H+ aka a proton) catalysis of reactions and pH determinations
  • Ammonium ion (NH4) production of nitrate ions by bacteria
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6
Q

Important anions

A
  • Chloride (Cl-) balances charge of sodium and potassium ions in cells
  • Hydroxide (OH-) catalysis of reactions and pH determinations
  • Nitrate (NO3-) nitrogen supply to plants for amino acids and protein production.
  • Phosphate (H2PO4-) cell membrane formation, nucleic acid and ATP formation, bone formation.
  • Hydrogen carbonate (HCO3-) maintainence of blood pH
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7
Q

The living composition of a cell

A

70% water, (about)1% inorganic substances, 29% organic polymers and macromolecules, 0-1% organic monomers and other organic molecules.

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8
Q

what is an ion?

A

An atom or molecule in which the total number of electrons are not equal to the number of protons.

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9
Q

Carbohydrates

A

Polymer = Polysaccarides
Name of bond between polymers = Glycosidic bond
Monomer = Monosaccarides
Elements = C, H, O

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10
Q

Fats/Lipids

A

Polymer = Triglycerides
Name of bond between polymers = Ester bond
Monomer = 3 fatty acids + glycerol
Elements = C, H, O

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11
Q

Proteins

A

Polymer = Polypeptide
Name of bond between polymers = Peptide bond
Monomer = Amino acids
Elements = C, H, N, O, S

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12
Q

Nucleic acids

A

Polymer = Polynucleotides
Name of bond between polymers = Phosphodiester bond
Monomer = Nucleotides
Elements = C, H, O, N, P

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13
Q

Elements in carbohydrates, fats, proteins and nucleic acids

A

CHO
CHO
CHNOS
CHONP

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14
Q

Hydrolysis

A
  • All polymers are broken down/hydrolysed into their respective monomers by the addition of water to break the covalent bond.
  • A catabolic/exothermic reaction so releases energy.
    -(look at diagram on powerpoint)
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15
Q

Condensation reaction

A
  • All monomers are joined condensed into their respective polymers by the removal of water to form a covalent bond.
  • An anobolic reaction (endothermic) requires an input of energy.
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16
Q

The water molecule

A
  • An oxygen atom bonded to 2 hydrogen
  • Oxygen is delta negative (s-) whereas oxygen is delta positive (s+)
  • It’s a polar molecule as theres an uneven distribution of charge
  • Hydrogen bonds are weak
  • Hydrogen bonding gives water it’s unique characteristics.
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17
Q

Characteristics of water

A
  • Has an unusually high BP
    -A small molecule much lighter than carbon dioxide and water.
  • A liquid at room temp due to the hydrogen bonds
  • When water turns into ice it becomes less dense.
  • ## As water is cooled below 4 degrees the hydrogen bonds fix in the positions of the polar molecules slightly further apart then the average distance in the liquid state.
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18
Q

Important functional groups in biological molecules

A

These are all polar (hydrophyllic)
- Hydroxyl (many in carbohydrates)
- carbonyl
- carboxylic acids (present in amino and fatty acids)
- amino
- Sulfhydryl (involved in protein structure)
- Ester
- Phosphate
Except for:
- methyl/hydrocarbon(non polar/hydrophobic)

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19
Q

Solvent properties of water

A
  • Ionic substances can dissolve in water because a shell of orientated water molecules is formed around each ion.
  • Polar substances e.g. simple sugars can dissolve in water due to hydrogen bonding between polar group in their molecules.
20
Q

Water is polar

A
  • Known as the universal solvent as it dissolves more substances than any other liquid
  • Forms a shell around ions and makes H bonds with polar solutes

Biological importance:
1. Water is the medium for chemical reactions to take place.

  1. Cells are 70% water
  2. Water acts as a transport medium e.g. in blood, phloem and xylem.
  3. Water is a reactant in some reactions e.g. hydrolysis.
21
Q

High specific heat capacity of water

A
  • This is high in water due to the presence of hydrogen bonds

Biological importance
1. Stable temperature for enzyme controlled reactions

  1. Both eukaryotic and prokaryotic cells less prone to damage from change in temp
  2. Aquatic organisms have a stable environemnt.
  3. Thermoregulation for organisms
22
Q

High latent heat of vaporisation for water

A
  • High due to hydrogen bonds

Biological importance
1. water as a coolant (sweating, panting, transpiration)

  1. water is a liquid over large range of temperatures.
23
Q

High specific heat capacity of water

A
  • High due to hydrogen bonds
  • Stable temp for enzyme reactions
  • Eukaryotic and Prokaryotic cells less prone to changes in environment.
  • Thermoregulation is facilitated for organisms to keep their temp constant.
24
Q

Which type of bond holds the delta negative oxygen and delta positive hydrogen together between water molecules?

A

Hydrogen bond

25
Q

Specific latent of vapourisation (Liquid to gas)

A
  • sweat evapourates off skin
  • panting in animals
  • transpiration stream keeps plants cool in hot weather.
26
Q

Cohesive forces in water

A
  • The forces of attraction between molecules, high for water due to hydrogen bonds

Biological importance:
1. Allows for transpiration stream so water can move up great heights in a tree.

27
Q

Surface tension

A
  • When the surface of a liquid resists external forces, it is formed on water due to strong cohesive forces due to hydrogen bonds.

Biological importance:
1. Habitat for insects e.g. pond skaters

28
Q

What is surface tension?

A

the cohesion of the molecules on the surface of a fluid to occupy the least possible volume.

29
Q

Which type of bond holds the oxygen and hydrogen together within a water molecule?

A

Covalent bonds

30
Q

What is the name for the substances that are dissolved in a liquid and the name of the liquid that other molecules are dissolved in?

A

Solvent and solute

31
Q

What are polar molecules?

A

Any molecule with an uneven distribution of charge across it.

32
Q

Molecules that are attracted to water and molecules that are repelled by water

A

Hydrophillic and hydrophobic

33
Q

What term describes the structure than forms when water freezes into ice?

A

Lattice

34
Q

What is the name for water molecules hydrogen bonding to other water molecules?

A

Cohesion

35
Q

Density of ice and water

A
  • In ice each water molecule is hydrogen bonded to a maximum of 4 other water molecules.
  • The crystal structure formed requires water molecules to move further away from eachother therefore there are fewer molecules in a given space than in liquid water so this makes ice less dense than water.
  • The highest density of water is at 4 degrees as ice melts this cold dense water sinks below the water underneath and creates currents which move nutrents around.

Biological importance
1. Ice insulates ponds by providing a cover so water remains liquid underneath so aquatic organisims can survive.

  1. Forms a habitat for terrestial organisms on the surface of ice
36
Q

Adhesion in water

A
  • The attraction between different molecules this allows for capillary effect e.g. between water and glass

Biological importance
1. Water movement in transpiration stream is enabled by attraction to xylem walls

37
Q

It is transparent

A

Light will penetrate to reach aquatic plants and algae for photosynthesis

38
Q

Sex cells (gametes) can be suspended in it

A

Sperm can reach eggs for internal and external fertilisation

39
Q

Equal density

A

Creates buoyancy for aquatic organisms

40
Q

High latent heat of fusion

A

Contents of cells and aquatic environments are slow to freeze in the winter

41
Q

Polar covalent bonds are characterised by

A

An unequal sharing of electrons between two atoms in a molecule

42
Q

How does water arrange around dissolved glucose?

A

Slightly charged parts of water molecules are attracted to the opposite slightly charged regions of a glucose molecule.

43
Q

What is the name for water molecules hydrogen bonding to other water molecules? It is this property that makes small water droplets join into fewer larger droplets. It is also the property of water that maintains a continuous column of water through a plant to enable water transport through the xylem

A

Cohesion

44
Q

What are the 4 roles of water in the specification?

A

Coolant, solvent, transport medium and habitat.

45
Q

What is the name for water molecules hydrogen bonding to different types of molecule? It is this property that makes the meniscus when water is hydrogen bonding to the molecules that make the walls of the tube (or container) it is in

A

Adhesion

46
Q

Which property of water allows it to act as a skeleton (called a hydrostatic skeleton), allows organisms to push against it to move (e.g. fish swimming), and allows hearts to push water around rather than squashing it?

A

It is incompressible