2.2 Biological molecules Flashcards
what is a condensation reaction
reaction that occurs when two molecules are joined together with the removal of water
What is a hydrolysis reaction?
Reaction that occurs when a molecule is split into two smaller molecules with the addition of water
What is a covalent bond?
when 2 non metals share a pair of electrons
What is a monomer?
A small molecule which binds to many other identical molecules to form a polymer
what is a polymer?
a large molecule made from many smaller molecules called monomers
what are the 3 types of molecules?
carbohydrates, proteins, nucleic acids
what is a monomer of a carbohydrate called
monosaccharide
what is an example of a monosaccharide
glucose
what is a polymer of a carbohydrate called
polysaccharide
example of polysaccharide
starch, glycogen, cellulose
what is a monomer of a protein called
amino acid
what is a polymer of proteins called
polypeptide
what is a monomer of a nucleic acid called
nucleotide
what is a polymer of a nucleic acid called
DNA and RNA
what are carbohydrates
a group of molecules containing C, H and O
what are the three main groups of carbohydrates
monosaccharides, disaccharides, polysaccharides
what are the properties of monosaccharides
sweet, soluble in water and insoluble in non-polar solvents
what is alpha glucose and beta glucose
an energy source
how is the displayed formula of alpha glucose different to beta glucose
In alpha glucose, on carbon 1 the hydroxyl group is below the ring structure and hydrogen is above. In beta glucose, on carbon 1 the hydroxyl group is above the ring structure and they hydrogen is below the ring structure
how is ribose different to glucose
it is a pentose sugar rather than a hexose sugar. It found in RNA and is not an energy source
when dissolved in a solution, how do triose and tetrose sugars exist
straight chains
when dissolved in a solution, how do pentose and hexose sugars tend to exist
In a ring or cyclic structure
What is an isomer?
molecules with the same molecular formula but different structures
what are examples of dissacharides
maltose, sucrose, lactose
what are the properties of dissacharides
sweet and soluble in water and insoluble in non-polar solvents
What are the reducing sugars?
maltose and lactose
what are the non-reducing sugars
sucrose
What is a glycosidic bond?
A bond formed between two monosaccharides by a condensation reaction
How is a dissacharide formed?
Two monosaccharides join in condensation reaction forming a 1-4 glycosidic bond between the two hydroxyl groups and give off water
how is a disaccharide broken
hydrolysis of the glycosidic bond with addition of water
how are polysaccharides formed
a series of condensation reactions, water is given off each time a glycosidic bond is formed
what are polysaccharides made of one type of monosaccharide called
homopolysaccharide
where is starch found in plant cells
starch granules
what is amylose
a series of alpha glucose monomers joined by glycosidic bonds between carbons 1 and 4
what structure is amylose and what does it present
it forms a spiral shape and it presents a hydrophobic external surface
what is amylopectin
series of alpha glucose monomers which are joined by glycosidic bonds between carbon 1 and 4 as well as carbon 1 and 6
what is the structure of amylopectin
coils into a spiral shape with branches emerging from the spiral
what is the function of starch
energy store in plants
what are the two parts of starch
amylose and amylopectin
why is the branch structure of amylopectin important
it allows more alpha glucose molecules to be broken off when its needed for respiration
What is the structure of starch
coiled into double helix so its compact, held by hydrogen bonds, OH groups stored inside
why are OH groups stored on the inside of starch
so they aren’t soluble and don’t affect the water potential
what enzyme breaks 1-4 glycosidic bonds
amylase
what enzyme breaks 1-6 glycosidic bonds
glycosidase
where is glycogen found
glycogen granules in animals
structure of glycogen
similar to amylopectin but more branched. 1–4 and 1–6 glycosidic bonds. coiled
what is glycogen
energy store in animals
why is glycogen more branched than amylopectin
animals are more metabolically active and need more glucose for energy for respiration. As its more branched, easy access for enzymes to hydrolyse bonds to obtain alpha glucose
what is an advantage of a coiled structure
its more compact so more can be stored
what is starch and glycogen made of
alpha glucose
Where is cellulose found?
plant cell walls
what is cellulose made of
beta glucose
what are the bonds in cellulose
glycosidic bond on carbons 1-4. Every other beta glucose monomer, it rotates by 180* as on carbon 4 the OH group is below the ring structure and on carbon 1 the OH group is above the ring structure
what happens as a result of rotations
it causes hydrogen bonding between the oxygens which gives the chain additional strength and stops it from spiralling. OH group on carbon 2 sticks out which causes hydrogen bonding to form between chains
what forms microfibrils
60-70 chains of cellulose
what forms macrofibrils
up to 400 microfibrils
what do macrofibrils do
criss-cross for extra strength for the cell wall
function of cellulose
to have strength and support the whole plant
why is there space between macrofibrils
so water and mineral ions can pass in and out
advantage of cell wall being strong
prevents plant cells from bursting when they’re turgid
what are the substances that make the cell wall waterproof
cutin and Suberin
what are some other structural polysaccharides
bacterial cell walls and exoskeletons