Biological Molecules Flashcards
What molecules make up carbohydrates
Carbon
Hydrogen
Oxygen
What are 3 properties of monosaccharides
Soluble in water
Sweet taste
Form crystals
Name the sugar that has three carbons
Triose
What is the difference between alpha and beta glucose
Beta glucose’s right OH group on carbon 1 is above the plane of the ring
Alpha glucose’s right OH group on carbon 1 is below the plane of the ring
What is an isomer
A molecule that has the same chemical atoms but there arrangement is different
Glucose contains many bonds - what does this mean it can store lot of
Stores energy in its covalent bonds
Explain the structure of alpha glucose
Forms hydrogen bonds with H/OH groups of water so Is SOLUBLE
- can be easily transported around the organism in the plasma or phloem
- bonds contain energy
- molecules broken down to release energy
- join together via condensation reaction
Name three disaccharides
Maltose
Sucrose
Lactose
Name three monosaccharides
Glucose
Fructose
Galactose
How are two disaccharides bonded
Covalently bonded together
Contains glycosidic bonds
What three atoms is there in a glycosidic bond
Two carbon and one oxygen
What happens during hydrolysis of a disaccharide
The OH bond in water breaks- one of the C-O bonds in the glycosidic bond breaks- the h atoms bonds to the o atom and the OH from water bonds to the carbon
What happens when two glucose molecules bond together
React to from maltose
Condensation reaction
Produces water
Glycosidic bond forms
What catalysed the hydrolysis of maltose
Maltase
Similarities between lactose and maltose
Both contain glucose
Contain two 5 C rings
Both have 1-4 glycosidic bond
Differences between lactose and maltose
Lactose contains beta glucose
Maltose has alpha glucose
L has beta glycosidic bond
M has alpha glycosidic bond
What is starch made from
Two different polysaccharides:
Coiled amylose
Coiled and branched amylopectin
Where is the glycosidic bond in amylose
Below the plane of the ring
What type of bond is amylose
Alpha 1-4 glycosidic bond
What type of bond does amylopectin have
Alpha 1-4 and alpha 1-6 glycosidic
What type of bond In glycogen
Alpha 1-4 and alpha 1-6 glycosidic bond
How is glycogen different to amylopectin
There is more branching points in glycogen than there is in amylopectin
Why does glycogen have branched
So it can be rapidly hydrolysed by enzymes
Name three properties of glycogen
Insoluble
Compact
Energy dense
Starch v glycogen
Where is it found
S- stores as grains- glucose store in PLANTS
G- sorted as granules- ANIMALS
Starch v glycogen
Name of the monomer that forms the polymer
S-Alpha glucose
G- alpha glucose
Starch v glycogen
Name of the bond
Starch- amylose- alpha 1-4 glycosidic bond
-amylopectin- alpha 1-4 1-6 glycosidic bond
Glycogen- alpha 1-4 and 1-6 glycosidic bond
What is the stored alpha glucose used for
Respiration
How do the structures and properties of glycogen and starch relate to their function
- compact can store lots of energy (stored in a small volume)
- metabolically inactive: don’t take part in metabolic reactions
- insoluble in water
- chain molecules- glucose held in chain and is hydrolysed or built up by enzymes
- amylopectin and glycogen are branched
Why is it that animals have a faster metabolic rate
Have significantly more branching points
What are two structural properties of cellulose
High tensile strength and insoluble
What is the function of cellulose
To give strength to resist osmotic pressure
what type of glucose does Celulose have
Beta glucose
Name of the bond in Celulose
Beta 1–4 Glycosidic bond
How are the Glycocidic bonds in Celulose formed
Alternate beta glucose molecules rotate 180° which makes long straight chains
What do you cellulose molecules joined together to form
Microfibrils which are cross-linked by hydrogen bonds
What type of molecule is a lipid
They are macromolecules not polymers
What atoms make up lipids
Carbon hydrogen and oxygen
Less oxygen to carbon atom more hydrogen per carbon atom (than in carbohydrates)
How are triglyceride and phospholipid molecules Similar
Contain a glycerol molecule attached to fatty acid chains
What is the purpose of triglycerides
And energy storage and source can be hydrolysed to generate ATP
Insolation e.g. Blubber in Wales
Protection a vital organs
What is the function of a phospholipid
To make plasma membrane
What is the purpose of sterols
Some hormones are made from sterols
What are triglycerides compose from
One molecule of glycerol linked to 3 fatty acid’s
Describe the structure of fatty acid chain
A carboxylic acid group at one end and long hydrocarbon chain with between 12 to 20 carbon is in it
What are the two types of fatty acid’s
Saturated and unsaturated
What does unsaturated mean
What effect does this have
There is a double bond
Puts a kink in the molecule and the molecules can’t pack as closely together
Describe the structure of glycerol
OH
Explain how the fatty acids join to the glycerol
Each hydroxyl group in the glycerol joins with the carboxyl group on the fatty acid
What happens when a triglyceride forms
Condensation reaction
Three Ester bonds are made
As are three molecules of water
How are lipids respired to make ATP
Lipids are hydrolysed into fatty acids and glycerol
These are then respired to give ATP
What is metabolic water
The water that is produce when glycerol and fatty acids respire
Explain the structure of phospholipid
A glycerol
2 fatty acids
A phosphate group
Which part of the phospholipid is hydrophobic and hydrophilic
Phosphate group is hydrophilic
Fatty acids are hydrophobic
What does surfactants
When the phosphate head tuck into the water and the fatty acid tails sticking out of the water - they sit on the water surface
What is a bilayer
Form structures based on a two layered sheet formation
Name an example of a steroid alcohol
Cholesterol
Describe the structure of cholesterol
Four carbon based ring structure
What is the job of cholesterol
Regulates the fluidity and maintains the stability of the membrane
Where does cholesterol sit
Between the hydrophobic fatty acids tails of the phospholipids
What else is made from cholesterol
Hormones
Can cholesterol pass through the bilayer
Yes they diffuse through
What does a qualitative test do
Tests for the presence or absence of a particular biological molecule
Disadvantage of a qualitative test
Does not tell you the concentration of a particular biological molecule
What is the test for starch
Iodine solution
Black/blue
Test for reducing sugar
Benedicts solution
(Must be shaken and heated)
Red- present
Blue- not
Test for non reducing sugar
Boil with HCL
Neutralise with sodium carbonate
Repeat benedicts test
Red-present
Blue-not
Test for protein
Biuret reagent
Shake
Lilac - proteins
Test for lipids
Emulsion test Crush sample add ethanol Shake Pour into water
Lipid is present- cloudy white emulsion
What is a colorimeter
A device that shines a beam of light through a sample
A photoelectric cell then picks up the light that has passed through
The sample is placed in a cuvette the between the light and the cell
The more sugar present…
The more copper surface used up
Less light absorbed
More transmitted
How can a colorimeter be calibrated
Using a red filter
Zero colorimeter using distilled water or Unreacted benedicts
