Biochemsitry Introduction Flashcards
What are atoms
Building blocks of all matter
What are elements
A pure substance which cannot be broken down into a simpler substance by a chemical reaction and only contains 1 type of atom
How many elements are in the periodic table
100
Which 4 elements make up 96% of body mass
Oxygen, carbon, hydrogen and nitrogen
Describe the basic structure of an atom
Positively charged protons and neutral charged neutrons in the nucleus surrounded by electron shell containing negatively charged electrons
How are electrons organised in the atom ‘cloud’
Into electron shells and sub shells which can accommodate a specific number of electrons e.g. 1st shell= 2 electrons, 2nd= 8 and 3rd=18 etc.
When is an atom most stable
When it’s outermost shell or sub shell is completely full of electrons
In what two ways are electrons shared
Shared with another atom in a covalent bond or given/received from another atom in an ionic bond
What is an ion
An atom that has its charge altered by losing or gaining an electron (ionisation)
What are negatively charged ions
Anions (gained electrons)
What are positively charged ions
Cation (lost electrons)
What is a molecule
Two or more atoms chemically joined together
What is a compound
A molecule composed of atoms from two or more different elements
What is the difference between organic and inorganic compounds
Organic contains carbon
How do chemical bonds form
Via electron activity such as donating or taking electrons
What is ionic bond formation dependent on
Electronegativity/ attraction of an atom for electrons
How is the electronegativity of an element portrayed on the periodic table
Increasing electronegativity from bottom to top and left to right
When do ionic bonds form
When the difference in electronegativity between 2 atoms is very high >1.7
Describe the formation of an ionic bond
The atom with the highest electronegativity pulls one ore more electron away from the other atom and becomes negatively charged (anion) while the other atom becomes positively charged (cation) forming an ionic bond due to attraction between + and -
Describe how covalent bonds form
Electrons are shared with another atom to fill shells, a covalent bond is formed for each pair of shared electrons
What are the two main types of covalent bond
Polar and non polar
What is a polar covalent bond
A bond which one part of the molecule is more charged than the other as electrons are not shared equally, forming hydrophilic molecules
What are non polar covalent bonds
A bond which the charges of each molecule are equal as the electrons are equally shared. Atoms from the same element are non polar covalent
Which is the strongest bond
Covalent
What is a redox reaction
If one molecule is oxidised the other is reduced
Which molecule one of the best electron acceptors that accepts electrons when we generate large amounts of ATP
Oxygen
When are redox reactions key
During long duration exercise when ATP turnover is high
What is the most common redox reaction in energy metabolism
NAD+ gains 2 electrons from H+ to form NADH (reversible)
What is a reduction reaction
Gaining electrons
What is an oxidation reaction
Losing electrons
