Chemical Elements & Biological Compounds Flashcards
What are other names for inorganic ions
- electrolytes
- minerals
Why do living organisms need a variety of inorganic ions to survive?
- muscle contraction
- nervous coordination
- maintaining water potential in cells and blood
What are the two main types of nutrients (inorganic ions)
Describe the importance of magnesium in plants and mammals
Plants:
-An important constituent of chlorophyll and is therefore essential for photosynthesis.
- plants without magnesium in their soil cannot make chlorophyll and so the leaves are yellow, a condition known as chlorosis.
- growth is often stunted from lack of glucose
Mammals:
- need magnesium for their bones
Describe the importance of iron in the human body
- A constituent of haemoglobin, which transports oxygen in red blood cells
- A lack of iron in the diet can lead to anaemia
Describe the importance of phosphate ions
- Are used for making nucleotides, including ATP and are a constituent of phospholipids, found in biological membranes
Describe the importance of calcium ions
An important structural component of bones and teeth in mammals and is a component of plant cell walls providing strength
Why is water classed as a dipole?
It has a positively charged end (hydrogen) and a negatively charged end (oxygen). A molecule with separated charges is polar (these charges are very small)
Describe water’s properties as a solvent
- because water molecules are dipoles, they attract charged particles
- these dissolve in water; chemical reactions take place in solution
- water acts as a transport medium
Water as a solvent, its effect on plants and animals:
Plants: - water transports minerals in the xylem -water transports sucrose and amino acids in the phloem Animals: - plasma transports dissolved substances
Waters properties as a metabolite
- water is used in many biochemical reactions as a reactant Hydrolysis: Maltose + water ---> glucose + glucose Condensation: Glucose + glucose ---> maltose + water
Why is water said to have a high specific heat capacity?
A large amount of energy is needed to raise 1g of water by 1 degree
- hydrogen bonds restrict their movement
- resisting an increase in kinetic energy
- prevents large fluctuations in temperature
Waters high specific heat capacity and it’s affect in plants and animals
Plants & animals:
- keeps aquatic habitats stable so organisms do not have to adapt to extremes in temperature
- allows enzymes to work efficiently
Why is water said to have a high latent heat of vaporisation
A lot of heat energy is needed to change it from a liquid to a vapour
Waters high latent heat of vaporisation and its affects in plants and animals
Plants:
Heat is used to vaporise water from a leafs surface
Animals:
Water is used to vaporise sweet from the surface of the skin and as the water evaporates the body cools
What is cohesion?
- Water molecules attract each other forming hydrogen bonds
- individually the bonds are weak but because there are many of them the molecules stick together in a lattice
How is cohesion useful in plants?
It allows columns of water to be drawn up xylem vessels in plants
How is surface tension created?
- cohesion between water molecules at the surface produces surface tension
How can surface tension be useful for some animals:
The body of an insect (e.g a pond skater) is supported
What temperature does water have its maximum density?
4 degrees
Why does ice float on water?
Ice is less dense than water because hydrogen bonds hold the molecule further apart than they are in a liquid. So ice floats in water.
Why is waters density important for organisms?
- it’s a good insulator and prevents large bodies of water loosing heat and freezing completely
- so organisms beneath can survive
Why is waters transparency an important property?
- it lets aquatic plants photosynthesise effectively
