Unit 1.1 Biological compounds Flashcards
What do all organisms need for survival
(b) What is it often called
All organisms need inorganic ions to survive
(b) These inorganic ions are often called
minerals.
Where do inorganic ions occur?
They occur in a solution in the cytoplasm and body fluid of organisms, some in high concentrations and others in very low concentrations
What are micronutrients and give 2 examples
Micronutrients are minerals needed in minute (trace) concentrations e.g. copper and zinc.
What are Macronutrients and give 2 examples
Macronutrients are needed in small concentrations e.g. magnesium and iron.
Name the four key inorganic ions in living organisms
Magnesium ions (Mg2+) Iron ions ( Fe2+) Calcium ions (Ca2+) Phosphate ions (PO4 3-)
What is the biological role for Magnesium in plants
Constituent of chlorophyll and therefore essential for photosynthesis
What is the biological role for Iron in animals
Constituent of haemoglobin, which transports oxygen in red blood cells
What is the biological role for Nitrate
Nitrogen derived from nitrate is needed for making nucleotides, including ATP, DNA and RNA. Nitrogen is also needed for amino acid formation.
What is the biological role for Phosphate in living organisms
Used for making nucleotides, including ATP, DNA and RNA. A constituent of phospholipids found in biological membranes. Hardens bones.
What is the biological role for Calcium in living organisms
Hardens bones and teeth (not strengthen). Also a component of plant cell walls.
What does the term ‘organic’ mean
Molecules that have a high proportion of carbon and hydrogen atoms
What does the term ‘inorganic’ mean
A molecule or ion that has no more than one carbon atom.
Why is water a polar molecule?
Due to the uneven distribution of charge within the molecule - The oxygen end of the molecule is more electronegative than the Hydrogen and the Hydrogen atoms have a positive charge.
What is a dipole
A polar molecule which has a positive and negative charge, separated by a very small distance - uneven distribution of charge
When two water molecules are in close contact, what do the opposing charges do and what do they form?
When two water molecules are in close contact the opposing charges attract each other forming a hydrogen bond.
What does the term ‘Hydrogen bond’ mean
The weak attractive force between a hydrogen atom (with a partial positive charge) and an atom with a partial negative charge, usually oxygen or nitrogen.
Are individual hydrogen bonds weak and what happens when there are many hydrogen bonds (between many water molecules)
Individual hydrogen bonds are weak, but many hydrogen bonds (between many water molecules) form a lattice-like framework which is much stronger.
What is cohesion?
A property of water molecules that creates an attraction between them and causes them to stick together
Name 8 properties of water
1 - Water is a solvent
2 - Water as a transport medium
3 - Chemical reactions take place in water
4 - Water has a high specific heat capacity
5 - Water has a high latent heat of vaporisation
6 - Cohesion
7 - Surface tension
8 - Density
Can ions and other polar molecules dissolve in water?
Yes
Can non-polar molecules such as lipids dissolve in water?
No
Why is water’s high specific heat capacity important for organisms?
Water acts as a temperature buffer, enabling endotherms to resist fluctuations in core temperature and to maintain optimum enzyme activity.
Why is water’s high high latent heat of vaporisation important for organisms?
When water evaporates, it has a cooling effect. This is important in homeostasis; organisms can lose heat though sweating or panting
What does evaporation of water from a surface cause?
Cooling