Biological molecules Flashcards
+what is a carbohydrate
molecule contains only C,H,O single unit called monosaccharide, 2 disaccharide and polysaccharide
What is glucose
Alpha and Beta glucose are hexose sugars
-many OH groups so is soluble in water
what is cytosol
fluid part of the cytoplasm
how does glucose bond
condensation reaction between 2 glucose molecules 2 OH groups react forming water and joins molecules by the O
1,4 glyosidic bond
What are the other sugars
fructose + glucose = sucrose
galactose + glucose = lactose
what are the pentose sugars
ribose and deoxyribose
what are the two variations of the polysaccharide starch
amylose, amylopectin
amylose
1,4 glyosidic bonds
bond angles cause a helix shape to form supported by H bonds
compact and less soluble than glucose
amylopectin
1,4 and 1,6 glyosidic
causes branches
more compact
less soluble
1,6 bond every 25 glucose subunits
glycogen
animal storage unit
more branches so more compact and less space required to store it
animals are more metabolically active so neccessary
branching allows for glucose to easily be added to removed
what is hydrolysis
turned stored nutrients into usable energy
water, enzymes used to break down molecules
cellulose
beta glucose
rotates in 180degrees so the OH groups can interact with each other, causes long straight chain molecules
how does cellulose make fibres
cellulose chains make H bonds which form microfibrils many of the microfibrils come together to make microfibrils which come together to make fibres which are strong and insoluble
what is the test for reducing sugars and why
CU(II)SO4-2 has a blue colour when reducing sugar is added to the solution the CU(II)SO4-2 is reducing causing it to change colour from blue to red .
Heat in copper sulphate solution and red ppt should form as a layer depending on reducing sugar conc
Test for non reducing
Boil the solution in HCL to break down the sugars then add an alkali solution to neutralise it. Then do a normal test for reducing sugars red-blue
Disaccharide/ polysaccharide should be broken down into a monosaccharide
What is the test for Starch
Add iodine dissolved in potassium iodide solution should go from yellow/brown to purple/black
What are lipids
C,O,H mainly
fats are solid lipids RTP
oils are lipids that are liquid RTP
What is a triglyceride
1 glycerol group 3 fatty acids, forms ester bonds(esterification)
3 water molecules required to break it down
saturated/unsaturated meaning
sat- no double bonds, all bonds possible by H are made
unsat- double bonds
Phospholipids
modified triglycerides 2 fatty acids 1 glycerol and one phosphate group( many electrons so it is hydrophilic)
What is a sterol
complex alcohols, 4 ring structure with an OH group at the end
amphiphilic
cholesterol
made in liver/ intestines
between phospholipids stops them getting rigid at low temps and fluid at high ones
roles of lipids
hydrophobic barriers
hormone production
electrical insulation
waterproof
roles of triglycerides
long term energy store
cushioning(protects organs)
buoyancy for aquatic animals
what is the test for lipids
ethanol + water shake and positive result is white emulsification
amino acids
same basic structure with differing R groups
types of Amino acid
5 are non essential and are made from other a.a
9 are essential and obtained from what we eat
6 are only needed in early development
Peptide bond
H on one of the Amine groups and and OH of the carboxylic groups bond forming peptide bond and water
what enzyme catalyses the bonding of peptides
peptidyl transferase(in ribosomes)
primary structure of amino acid
sequence of amino acids, directed by DNA. The sequence influences how the chain folds to give it its function and shape.
secondary structure of amino acid
O, H, N atoms interact causing H bonds to form in the chain pulling it into a alpha helix shape, peptide chains forming parallel to each other form H bonds forming a beta pleated sheet
tertiary structure of amino acid
folding of protein into its final shape, causes R groups to interact with each other
hydrophobic/ hydrophilic interactions
H bonds weakest bond
ionic bonds form from opposite charged R groups
disfulide bonds- form between two sulphur atoms
quaternary structure of amino acid
Two or more proteins working together(subunits) same interacts but between subunits
subunits can be different or identical
enzymes have 2 identical subunits
polar/ non polar interactions
proteins fold so that the hydrophilic R groups are pointed outwards toward the aqueous environment
breakdown of peptides
Protease catalyses reverse reaction of peptides, water molecule used to break peptide bond reforming Amine group and COOH
Globular proteins
compact, soluble and spherical
polar R groups are on the outside makes it soluble
solubility is important for functions
insulin
regulation of blood glucose, transported in blood stream so needs to soluble, need to fit on specific receptors so need a specific A,A chain
Conjugated proteins
globular proteins with a non protein component(prosthetic group)
Haem group in the blood made of Fe2+ which can reversibly bind to O2 to move it around the body from lungs to cells
haemoglobin made from 2 alpha and 2 beta units
catalase
enzyme with specific reaction type, quaternary with 4 haem groups, Fe2+ react with hydrogen peroxide(metabolism by-product and speed up its breakdown)
fibrous proteins
long insoluble molecules, many hydrophobic R groups in primary structure. small range of amino acids and repetitive
Elastin
found in elastic fibres, (walls of blood vessels) need to be flexible, return to normal, quaternary protein made of tropoelastin
cross links of covalent bonds
Keratin
hair , skin, nails
large amount of sulphur containing a.a cysteine. forms strong disulphide bridges pending on the amount of bridges the flexibility varies
Collagen
skin, tendons and ligaments. 3 polypeptide chain wound in a rope like structure still flexible
every third a.a is glycine which makes the allows the protein to form packed helix. H bonds between polypeptide chains long quaternary proteins with staggered ends
