1.1- Biological Compounds Flashcards
What are organic molecules?
molecules that have a high proportion of carbon and hydrogen atoms
What are inorganic molecules?
a molecule or ion that has no more than one carbon atom
What is an example of an organic compound?
Glucose C6 H12 O6
What are examples of inorganic molecules?
carbon dioxide CO2
water H2O
What are micronutrients? Give examples
minerals needed in minute concentrations
e.g. copper, zinc
What are macronutrients? Give examples
minerals that are needed in small concentrations
e.g. magnesium, iron
What are the main macronutrients?
magnesium
iron
nitrate
phosphate
calcium
What is the biological role of magnesium?
constituent of chlorophyll and therefore essential for photosynthesis
What is the biological role of iron?
constituent of haemoglobin, which transports oxygen in red blood cells
What is the biological role of nitrate?
needed for making nucleotides, including ATP, DNA, RNA
also needed for amino acids formation
What is the biological role of phosphate?
used for making nucleotides
a constituent of phospholipids found in biological membranes
it hardens bones
What is the biological role of calcium?
Hardens bones and teeth
component of plant cell walls
What is the ionic symbol of phosphate?
PO4 (3-)
Why is water a polar molecule?
because of the uneven distribution of charge- the oxygen end has a partial negative side, whereas the hydrogen end has a partial positive side
What does dipole mean?
a polar molecule which has a positive and negative charge which is separated by a very small distance
What type of bond is attracting water molecules together?
hydrogen bonds
What are hydrogen bonds
the force of attraction between a hydrogen atom- partially positive charge
and an oxygen atom- partially negative side
Individually hydrogen bonds are weak and can be easily broken
but together, it requires a lot of energy to break
What are the properties of water?
solvent
high specific heat capacity
cohesion
surface tension
high latent heat of vaporisation
density
How is water a solvent?
substances can dissolve in it because it is charged due to the positive and negative parts of the molecule
What is high specific heat capacity?
large amounts of energy is needed to raise the temperature of water
What is high latent heat of vaporisation?
due to cohesion between the water molecules, large amounts of energy is needed to change water from a liquid to a vapour state
What is surface tension?
cohesions taking place between the junction of water and air
it allows the surface of water to act like a habitat
What is cohesion?
the attraction between water molecules due to the hydrogen bonds which allows water to be transported
(xylem vessels)
What is density of water?
water has a maximum density at 4 degrees
ice is less dense than water because when water freezes it expands making the hydrogen bonds further away from each other
What are carbohydrates?
organic compounds which contain carbon, hydrogen and oxygen atoms
What are sugars?
they can dissolve in water to form a sweet solution
What is the general formula for monosaccharides?
(CH2O)n
What is the function of a triose? (3 carbon atoms)
important in metabolism
intermediates in respiration and photosynthesis
What is a pentose? (5 carbon atoms)
constituents of nucleotides
e.g deoxyribose in DNA, ribose in RNA, ATP, ADP
What is a hexose? (6 carbon atoms)
Glucose
main source of energy in respiration
carbon bonds are broken to release energy, which is transferred to make ATP
What are isomers?
compounds that have the same molecular formula but different structural formula
What are glucose’s isomers?
alpha glucose
beta glucose
What is the difference between alpha and beta glucose?
in alpha glucose the hydroxyl group on carbon 1 (OH) lies below the plane of the ring
whereas in beta glucose the hydroxyl group lies above the plane of the ring
How do you detect a reducing sugar?
Benedict’s and heat test
blue- brick red
How do you detect a non-reducing sugar?
it must be hydrolysed by boiling in dilute hydrochloric acid
the acid must be neutralised with dilute sodium hydroxide before testing with Benedict’s reagent
What are disaccharides?
two monosaccharides formed together by glycosidic bonds
How is maltose formed?
2 glucose molecules
How is sucrose formed?
glucose and fructose
How is lactose formed?
glucose and galactose
What is a condensation reaction?
a type of reaction that joins two molecules together with the formation of a glycosidic bond involving the elimination of water
What are polysaccharides?
polymers consisting of many monosaccharides joined together in a long chain
What are known as storage polysaccharides?
starch
glycogen
What are known as structural polysaccharides?
cellulose
chitin
What is starch?
Starch stores energy in plants in the form of glucose
made up of alpha glucose molecules, added one at a time by a condensation reaction
What are the two types of starch polysaccharides?
amylose
amylopectin
What is amylose?
polysaccharide component of starch
it is a long unbranched chained of glucose molecules joined by 1-4 glycosidic bonds
due to this, it is coiled forming hydrogen bonds between the glucose molecules
What is amylopectin?
polysaccharide component of starch
branched and is made up of glucose molecules joined by 1-4 and 1-6 glycosidic bonds
due to the presence of many side branches it is rapidly digested by enzymes therefore energy is released quickly
How do you test for starch?
iodine
brown- blue/black
What is glycogen?
main energy storage molecule in animals
formed from many molecules of alpha glucose joined together by 1-4 and 1-6 glycosidic bonds
What is the difference between glycogen and amylopectin?
glycogen has shorter 1-4 glycosidic bonds
and has more 1-6 branch points
compared to amylopectin
makes glycogen very compact
What is cellulose?
found in cell walls of plants
composed of long, unbranched chains of beta glucose which are joined by 1-4 glycosidic bonds
each alternate beta glucose molecule is rotated 180*
allowing hydrogen bonds to form between adjacent cellulose molecules
Chitin
found in the exoskeleton of arthropods
long chains of beta glucose linked by 1-4 glycosidic bonds
attached with a acetyl group
the cross linked parallel chains form microfibrils
strong, waterproof, lightweight
What are lipids?
biological molecules which are only soluble in organic solvents such as alcohols
(insoluble in water)
non-polar molecule
What are triglycerides?
lipids made of one molecule of glycerol and three fatty acids joined by ester bonds formed in condensation reactions
What are saturated lipids?
no double bonds between neighbouring carbon atoms in the hydrocarbon tail
What are unsaturated lipids?
have at least 1 double bond between neighbouring carbon atoms
How do you test for lipids?
shake the sample with ethanol then add water
positive result clear-cloudy
What are the functions of lipids?
stores energy
source of metabolic water
fat as a bouncy aid
waterproof
insulation, protection
Can saturated fatty acids form a solid?
yes
Can un-saturated fatty acids form a solid?
no, form liquid oils
What are lipoproteins?
lipids and proteins combine together to make lipoproteins
it carries cholesterol and triglycerides to cells in the body
What is LDL?
high in saturated fats build up low-density lipoproteins
it is unhealthy so known as bad cholesterol
What is HDL?
high in unsaturated fats builds up high density lipoproteins
it is protective so known as good cholesterol
What are phospholipids?
made of one glycerol, 2 fatty acids and a phosphate group
the phosphate head gives the molecule an uneven distribution of charge which makes the molecule polar
Are phospholipids hydrophilic or hydrophobic?
both- phospholipid bilayer
when the molecule is placed in water
it will arrange itself into a double layer
the phosphate head is hydrophilic so points outwards
the hydrocarbon tail is hydrophobic so points inwards
the phospholipid bilayer forms the basis of all cell membranes
What are proteins?
as well as carbon, hydrogen and oxygen, it contains nitrogen and sometimes sulfur and phosphorus
polymers made of monomers called amino acids
What is a chain of amino acids called?
polypeptide
What is the basic structure of an amino acid?
attached to a central carbon atom there are:
an amino group
a carboxyl group
a hydrogen atom
r-group
What is a r-group?
a side chain attached to the central carbon which varies for every amino acid, changing the properties of each amino acid
What are essential amino acids?
cannot be synthesised by our bodies, must be provided by our diet
What are non-essential amino acids?
can be synthesised by our bodies
How is a peptide bond formed?
the amino group of 1 amino acid reacts with the carboxyl group of another by a condensation reaction, the water is eliminated and a peptide bond is formed
What are the levels of protein structure?
primary
secondary
tertiary
quaternary
What is the primary structure in a protein?
the sequence of amino acids in a polypeptide chain
it’s determined by DNA, one gene codes for one polypeptide
bond between each amino acid is a peptide bond
What is the secondary structure in a protein?
it’s the shape that the polypeptide chain forms due to hydrogen bonding
hydrogen bonds twist and fold the polypeptide forming an alpha helix or beta pleated sheet
e.g collagen
What is the tertiary structure in a protein?
the alpha helix of a secondary protein structure is further folded and twisted to give a more complex, compact 3D structure
the shape is maintained by disulphide, ionic, covalent, hydrophobic and hydrogen bonds
e.g enzymes
What is the quaternary structure in a protein?
2 or more polypeptide chains in tertiary form
associated with non-protein groups and form large complex molecules like haemoglobin
What can proteins be classified as?
globular
fibrous
What are globular proteins?
have functions such as enzymes, antibodies, hormones
made of different polypeptide group and are compact and folded into 3D spherical molecules
soluble in water
What are fibrous proteins?
perform structural functions
consist of polypeptides in parallel chains with numerous cross linkages to form long fibres
insoluble in water, strong and tough
What is an examples of fibrous protein?
collagen
What is the structure of collagen?
3 polypeptide chains which are wound together to form 3 alpha helices by hydrogen bonds
What is the function of collagen?
gives support and strengthens connective tissue like tendons
Why are triglycerides not considered as polymers?
because glycerol and fatty acids have different structures
What is the difference between collagen and haemoglobin?
c= fibrous protein / h= globular protein
c= 3 polypeptide chains / h= 4 polypeptide chains
c= 3 polypeptide chains the same / h= 2 different types of polypeptide chains
c= secondary protein structure / h= quaternary protein structure
What is meant by the phrase ‘arranged in the same way as the chains in cellulose’?
hydroxyl groups point outwards
link with neighbouring chains via hydrogen bonding to form microfibrils
Give one function of the carbohydrate chains on the glycoprotein?
cell recognition
