Biological Elements and Water Flashcards
All living things are made primarily from which four key elements?
Carbon (C)
Hydrogen (H)
Oxygen (O)
Nitrogen (N)
In addition to the four key elements all living things are made primarily from, what other two elements play important roles in the biochemistry of cells ?
Phosphorus (P)
Sulphur (S)
Five cations (+ve ions) that play important roles in organisms
Calcium ions (Ca2+)
Sodium ions (Na+)
Potassium ions (K+)
Hydrogen ions (H+)
Ammonium ions (NH4+)
What roles do Calcium ions (Ca2+) play in organisms?
Nerve impulse transmission and muscle contractions.
What roles do Sodium (Na+) play in organisms?
Nerve impulse transmission and kidney function
What roles do Potassium (K+) play in organisms?
Nerve impulse transmission and stomatal opening
What roles do Hydrogen ions (H+) play in organisms?
Catalysis of reactions, proton pump in photosynthesis, pH determination.
What roles do Ammonium ions (NH4+) play in organisms?
Production of nitrate ions
Five anions (-ve ions) that play important roles in organisms
Nitrate ions (NO3-)
Hydrogen carbonate ions (HCO3-)
Chloride ions (Cl-)
Phosphate ions (PO43-)
Hydroxide ions (OH-)
What roles do Nitrate ions (NO3-) play in organisms?
Nitrogen supply to plants for amino acid and protein formation
What roles do Hydrogen carbonate ions (HCO3-) play in organisms?
Maintenance of blood pH
What roles do Chloride ions (Cl-) play in organisms?
Balance positive charge of sodium and potassium ions in cells
What roles do Phosphate ions (PO43-) play in organisms?
Cell membrane formation, nucleic acid and ATP formation, and bone formation
What roles do Hydroxide ions (OH-) play in organisms?
Catalysis of reactions, pH determination
Which elements are found in carbohydrates?
Carbon, hydrogen and oxygen.
Which elements are found in lipids?
Carbon, hydrogen and oxygen.
Which elements are found in proteins?
Carbon, hydrogen, oxygen, nitrogen and sulphur.
Which elements are found in nucleic acids?
Carbon, hydrogen, oxygen, nitrogen and phosphorus.
Define the term ‘polar’ in relation to molecules. Why is this?
Molecules that have regions or negativity and regions of positivity
This is due to how electrons are distributed between elements joined by a covalent bond.
Explain how polar molecules like water interact with each other.
What properties does this give water?
The positive and negative regions of the molecules attract each other and form hydrogen bonds.
These bonds give water its cohesive properties - it moves as one body because the molecules are attracted to each other.
These bonds also give water its adhesive properties - it molecules are attracted to other surfaces.
Explain how the ‘skin’ of surface tension of water enables a pond skater to inhabit the surface of water?
The skin is caused by water molecules are more strongly cohesive to each other than to air, this skin supports the pond skater.
Hydrogen bonds are…
What do they do, in terms of water?
Relatively weak interaction that form and break between the constantly moving water molecules.
There are large numbers of then though, which give water its unique characteristic that are essential for life on Earth.
What are the unique characteristics of water that are essential for life on Earth? (5)
- Unusually high specific heat capacity (boiling point).
- Becomes less dense when it freezes.
- Cohesive properties
- Adhesive properties
- ‘Skin’ of surface tension
Why is it good that water has a high specific heat capacity?
Keeps habitats stable for living things as a lot of energy is needed to change it by a degree.
