3.1 Biological Elements Flashcards
What elements are all living things primarily made from
Carbon, Hydrogen, Oxygen and Nitrogen
When does a covalent bond occur
When two atoms share a pair of electrons.
What is the basic rule of bonding for carbon
Carbon atoms can form 4 bonds with other atoms
What is the basic rule of bonding for nitrogen
Nitrogen atoms can form 3 bonds with other atoms
What is the basic rule of bonding for oxygen
Oxygen atoms can form bonds with 2 other atoms
What is the basic rule of bonding for hydrogen
Hydrogen atoms can only form one bond with another atom
What is an ion
An atom or molecule in which the total number of electrons is not equal to the total number of protons
What is a cation
An atom or molecule that loses one or more electrons and therefore has a net positive charge
What is an anion
An atom or molecule that gains one or more electrons and therefore has a net positive charge
How does an ionic bond form
It forms when one atom in the pair loses an electron and the other atom gains it. These atoms then have opposite charges with the one having lost the electron being positive and the one having gained the electron being negative. These ions are then held together by the attraction of opposite charges.
What is the role of calcium ions (cation)
Nerve impulse transmission, muscle contractions
What is the role of sodium ions (cation)
Nerve impulse transmission, kidney function
What is the role of potassium ions (cation)
Nerve impulse transmission, stomatal opening
What is the role of hydrogen ions (cation)
Catalysis of reactions, pH determination
What is the role of ammonium ions (cation)
Production of nitrate ions by bacteria
What is the role of nitrate ions (anion)
Nitrogen supply to plants
What is the role of hydrogen carbonate ions (anion)
Maintenance of blood pH
What is the role of chloride ions (anion)
Balance positive charge of sodium and potassium ions in cells
What is the role phosphate ions (anion)
Cell membrane formation, nucleic acid and ATP information, bone formation
What is the role of hydroxide ions (anion)
Catalysis of reactions, pH determination
What elements are present in a carbohydrate
Carbon, hydrogen and oxygen, usually in the ratio Cx(H20)x
What elements are present in a lipid
Carbon, hydrogen and oxygen
What elements are present in a protien
Carbon, hydrogen, oxygen, nitrogen and sulfur
What elements are present in a nucleic acid
Carbon, hydrogen, oxygen, nitrogen and phosphorous
What is a polymer
Long chain molecules made by linking up monomers in a repeating pattern
In carbohydrates what are the monomers
Sugars (saccharides)
In protiens what are the monomers
Amino acids
How do the hydrogen bonds in water form
Polar molecules interact with each other as the positive and negative regions of the molecule attract each other and form bonds called hydrogen bonds
What are the characteristics of hydrogen bonds in water
They form in high numbers
Weak interactions which constantly break and reform
Gives water it’s unique characteristics which help to sustain life
What are the characteristics of waters boiling point
Unusually high boiling point
Smaller than CO2 and O2 molecules and are lighter
Liquid at room temp and takes lots of energy to increase the temp and make it gaseous
Becomes less dense in solid state
Why does water become less dense as a solid
Below 4 degrees hydrogen bonds fix the positions of the polar molecules slightly further apart than the average distance in the liquid state.
What structure does freezing water produce
A giant, open, rigid structure, with each every oxygen atom at the centre of a tetrahedral arrangement of hydrogen atoms, resulting in ice being less dense that liquid water, which is why it floats
What are the cohesive properties of water
It moves as one mass because the molecules are attracted to each other. Also water molecules are attracted to other materials
Why is water being a polar molecule vital for life on earth
Water acts as a solvent that many solutes in an organism can be dissolved and many organisms consist largely of water. Water also acts as a medium ofr chemical reactions and also help transport dissolved compounds out of cells
