Biological Molecules Part 1 Flashcards
What is a monomer
Smaller units from which larger molecules are made
What is a polymer
Molecule made from a large number of monomers joined together
What is a condensation reaction
Joins two molecules together with the formation of a chemical bond and involves the elimination of a molecule of water
What is a hydrolysis reaction
Breaks a chemical bond between two molecules, involves the addition of water
What bond forms between the condensation of two monosaccharides
Glycosidic bond
Glucose + Glucose
Maltose
Glucose + Fructose
Sucrose
Glucose + Galactose
Lactose
What is amylose
1,4 glycosidic bonds
What is amylopectin
1,6d and 1,4 glycosidic bonds
Branched and more terminal ends
Describe the structure and function of starch/ glycogen
Insoluble- doesn’t effect water potential
Helical/ coiled - compact
Large molecules- cannot leave cell
Branched- faster enzyme action
Polymer of alpha glucose, joined by glycosidic bond- provides glucose for respiration
What is the difference between glycogen and starch
Glycogen has more 1,6 bonds- humans have higher metabolic and respiration rate
Describe the structure of cellulose
Polymer of beta glucose
Long and straight chains
Become linked together by many hydrogen bonds to form fibrils
Cellulose chains run parallel to each other
Each other beta glucose is inverted and chains off beta glucose are stacked on top of each other
Collective strength
Explain the difference between starch and cellulose
Alpha, beta
Position of hydrogen and hydroxyl groups on carbon atom 1 inverted
Cellulose is made up of B-glucose (monomers) and glycogen is made up of a-glucose (monomers);
Cellulose molecule has straight chain and glycogen is branched;
Cellulose molecule has straight chain and glycogen is coiled: glycogen has 1,4- and 1,6- glycosidic bonds and cellulose has only 1,4- glycosidic bonds;
Ignore ref. to H bonds / microfibrils
Suggest how glycogen acts as a source of of energy
Hydrolysed to glucose
Glucose used in repsiration
What is the chemical test for starch
Iodine
Turns blue-black
What is the test for reducing sugars
Add food sample, add Benedict’s, heat in water bath
Turns red
What is the test for non-reducing sugars
Heat with Add HCl and neutralise
Benedict’s
Heat
Red
Why should you use a colorimeter
Standardises Method
Provides a quantitive result
To minimise human error
Suggest a method to measure the quantity of reducing sugar
Filter and dry the precipitate
Find mass/ weight
What is soluble starch
Partially hydrolysed starch into shorter chains of alpha glucose
Helps to reduce the size of the starch polymer
What allows cellulose to form straight , strong fibres in biological tissues
Alternating glycosidic bonds that form on opposite sides of the chain
Due to the position of -oh and -h groups in beta glucose
What are the two types of lipids
Triglycerides
Phospholipids
How are triglycerides formed
Condensation
Between one glycerol molecules and three fatty acids
Ester bond
Loos of 3 water molecules
Difference between saturated and unsaturated
Saturated- no double bonds between carbon atoms
Usually solid at room temperature
What is the difference between phospholipids and triglycerides
In phospholipids, one of the fatty acids in substituted by a phosphate-containing group
What chemical test is use do test for lipids
Emulsion
Add ethanol and shake and water
Milky-white emulsion formed
What are the properties of triglycerides
Source of energy
Waterproofing
Insulation
Protection
What are phospholipids for
Cell membranes
What is the group represented by COOH
Carboxyl
The scientist expressed their results as percentage of lipid in plasma membrane by mass. Plain how they would find these results
Divide mass of each lipid by total mass of all lipids (in that type of cell)
Multiply answer by 100
What is needed to break down fat stores
Water
Why are saturated fats solid at room temeprature
Straight unlinked hydrocarbon chain
Molecules stack/ less able to flow around each other
Why are triglycerides metabolised
Synthesis of new plasma membranes
Converted to other fatty acids (energy storage )
Respired - to genate energy
Converted to transport fat-soluble substances (vitamins)
Describe the strucuture of a protein
Primary- linear sequence of amino acids - peptide bonds
Secondary - alpha helix, beta pleated- hydrogen bonds between amine and carboxyl
Tertiary - disulfide bridge, ionic, hydrogen between r-groups
Quaternary - two or more polypeptide chains held together by hydrogen bonds
What is the tests for proteins
Purple/ mauve
Blue if negative
Give the structure of collagen
3 indetical polypeptide chains
Triple helix
Glycine- smaller
Collective strength of hydrogen bonds
Explain how a substrate is broken down by the enzyme
-induced model causes active site (of enzyme) to change shape
-binding to form an enzyme-substrate complex
-lowing of activation energy
-conformational/ shape change
-breaking of bonds in substrate
-products no longer fit the active site and so are released
How does temperature effect enzyme activity
Low- low- too little kinetic energy, few collision
High- high- successful
Higher- denatured- breaking bond sin tertiary, change in active site, no longer fits
How does substrate concentration affect enzyme activity
Low- low
High- higher
At high- plateaus all active site share occupied
Enzyme conc in now limiting factor
What is a competitive inhibitor
Molecule simila rot substrate
Bind to as
Compete with enzyme activity site
Redu availability
Increasing substrate concentration reduce effect
What is a non-competitive inhibitor
Attached dot allosteric site - other than active site
Alter shape
Substrate no longer fits and present e-s complexes formed
