Basic molecules in biochemistry Flashcards
What are biomolecules composed of?
bulk and trace elements
what are bulk elements?
those that are present most in the mammalian boday
What are trace elements?
elements that are found in smaller quantities in the mammalian body
Name the 10 bulk elements
carbon, nitrogen, oxygen, hydrogen, potassium, phosphorus, calcium, sodium, chlorine, sulpher
Name the 6 trace elements
iodine, magnesium, copper, zinc, selenium, iron,
What element do all biomolecules contain?
carbon
What does carbon from compounds with in order to create biomolecules?
other bulk elements
Why do elements form bonds with each other?
to make their outer shells more stable
How any electrons are needed in a stable 1st shell?
2
How many electrons are needed in subsequent electron shells in order for the element to be stable?
8
What is a single covalent bond?
where two elements join and share a single electron
give an example of a single covalent bond in a molecule
Hydrogen is H2, has one electron in it’s outer shell so bonds with another hydrogen atom so both outer shells are full
Define covalent bond
chemical bond that involves the sharing of electron pairs between atoms
What is a double covalent bond?
bond formed when 2 electrons are shared between the elements that are bonded.
Give an example of a double covalent bond
oxygen is 02, has 6 electrons in its outer shell, shares two electrons in order to fill outer shell.
What are macromolecules?
The major constituents (components) of a cell
Define polymer
molecules made from multiple units of smaller molecules
What is the molecular weight of a polymer?
above 5000g per mol.
What are the main macromolecules?
proteins, nucleic acids and polysaccarides
what are monomers?
single unit molecules
what is the molecular weight of a monomer?
500g per mol or less
What can macromolecules be further assembled into?
supramolecular complexes
what do supramolecular complexes form?
functional units
give an example of a functional unit
ribosome
What are ribosomes?
small cytoplasmic granules found in all cells
Where can ribosomes be found?
in the cytoplasm of the cell or on the rough endoplasmic reticulum (RER)
What do ribosomes contain?
RNA and protien
What are ribosomes involved with?
protein synthesis
What is catabolism?
the breakdown of molecules which releases energy
what is anabolism?
the formation of molecules which uses energy
What happens during the reduction of a molecule?
addition of an electon/electrons
What charge do electrons have?
negative
describe the stages of catabolism
food and energy stores are broken down into metabolic intermediates and CO2, this releases energy. The energy that is produced is used to convert NAD+ into NADH and H+. NADH and H+ are converted back into NAD+. The energy from this is used to create water and ATP.
What does ATP stand for?
adenosine triphosphate
What is ATP known as?
the energy currency of the cell
What is ATP made up of?
nitrogenous base (adenine) and a pentose sugar (ribose) and a tri phosphate group
Where is the energy stored in ATP?
between the phosphate groups
What happens to the ATP molecule when the phosphate bonds are broken?
ATP is converted into ADP with a phosphate molecule seperate and energy is released
What does ADP stand for?
adenosine diphosphate
How much of an animals body is made up of water?
approx 60%
What does water do within the body?
acts as a solvent for solutes, a substrate in some reactions and as a lubricant and cushion
Define substrate in terms of a chemical reaction
the subsatnce on which an enzyme acts
what is a polar molecule?
one where there is an excess of electrons either positively or negatively
Why is water a polar molecule?
has a negatively charged oxygen atom and two positively charged hydrogen atoms
What makes water a highly interacting molecule?
its polarity and the hydrogen bonds between molecules
What characteristic means that substances that are polar can dissolve in water?
they are hydrophillic
give examples of polar molecules
Cl- Na+ and K+
What substances are non polar
Lipids
What are the main charateristics of lipids in relation to water?
they are hydrophobic and do not disolve in water
What is ionisation?
the process in which a molecule becomes and ion
What is an ion?
a charged particle, either positive or negative
What happens to acids in water?
ionise to produce H+ ions
how do strong acids behave in water?
become completely ionised
what happens to weak acids and bases in water?
they are partially ionised
what is pH?
the way in which the concentration of H+ is quantified
How can the concerntration of hydrogen be written in reguards to pH?
pH= log10[h+]
What solutions are said to be neutral?
solutions with H+ equal to 10 to the power -7
what solutions are said to be acidic?
solutions with H+ greater than 10 to the -7
what solutions are said to be basic?
solutions with H+ less than 10 to the -7
Why is pH important in biochemistry?
it affects the structure and function of biomolecules
What can the pH of body fluids (e.g. blood, urine) be used as?
a diagnostic tool
What is blood pH normally?
7.4
What does acidosis describe?
The condition when blood pH falls below 7.35
What does alkalosis describe?
the condition where blood pH rises above 7.45
What sort of ion donors are acids?
positive ions
what can positive ions also be known as?
protons
What do bases act as during ionisation?
proton acceptors
what is a conjugate acid base pair?
an acid and a base which differ only by the presance or absence of a proton
what does pKa show?
a constant, the point at which equal concentrations of the acid and base form of a conjugate acid pair exist
What is a buffering region in relation to pKa?
the area in which the addition of more base or acid will have minimal effect on the pH of the solution.
What is the buffer region important for?
maintaining a constant pH of the body
What can conjugate pairs act as?
buffers
How can pH be maintained within a safe range in the body?
by having conjugate pairs that act as buffers by neutralising acids and bases added to the body
What three buffer systems are their in the body?
phosphate buffer systems, carbonic-acid buffer systems and protein buffer systems
What 3 molecules do protein buffer systems include?
haemoglobin, amino acids and plasma protiens.
How is the bicarbonate from the carbonic-acid bicarbonate system stored?
sodium bicarbonate
