Biological molecules Flashcards
State properties of water
- metabolite
- solvent
- H bonds
- High specific heat capacity
- High latent heat of vaporisation
- liquid water denser than ice
How is water a metabolite
Used in hydrolysis, made in condensation
How is water a solvent
Polar molecule, dissolves solutes for transport/ reactions
what does hydrogen bonding in water allow
Allows cohesion for transpiration and pond-skater habitat
Role of high specific heat capacity in water
Acts as a buffer to temperature change
Role of high latent heat of vaporisation of water
Reduction of body temperature via sweating
Role of liquid water denser being than ice
Aquatic habitats protected under floating ice
Define monomer
Individual molecules that can make up a polymer
Define polymer
Long chain of many individual monomers that have been bonded together in a repeating pattern via condensation reactions
What are condensation reactions
Occur when two molecules combine to form a more complex molecule with the removal of water
What are hydrolysis reactions
Occur when larger molecules are broken down into smaller molecules with the addition of water
What type of bonds join monomers together
Covalent
What type of molecules are joined by H bonds
- polar molecules
- stabilises larger structures
What are monosaccharides
Are the simplest carbohydrates, being sweet tasting, soluble and full of C-H bonds for energy storage
What are isomers
Molecules with the same formula but different atom arrangement in space
- example: alpha and beta glucose
What are disaccharides
Formed when two monomers react in a condensation reaction, forming a glycosidic bond
What monomers make maltose
a Glucose + a Glucose
What monomers make lactose
a Glucose + B Galactose
What monomers make sucrose
a Glucose + Fructose
What makes cellobiose
B Glucose + B Glucose
What is the 1 non-reducing sugar
Sucrose
What are the 2 reducing sugars
Maltose and lactose
What test is used to qualitatively test the presence of reducing and non- reducing sugars
Benedict’s solution
What will Benedict’s test look like for reducing sugars
- heating with Benedict’s solution changes colour from blue to green, yellow, or orange-red
- reducing sugars reduce Cu^2+ to Cu forming copper (I) oxide precipitate
Why can’t you use Benedict’s to directly test for non- reducing sugars
- non-reducing sugars can’t reduce Benedict’s until the glycosidic bond is hydrolysed
How do you carry out Benedict’s test on non- reducing sugars
- Boil with HCl to break into monosaccharides (reducing sugars)
- Cool and add sodium hydrogen carbonate to neutralise
- Test with Benedict’s and look for the same colour change as before
How can the concentration of reducing sugars be quantitatively measured
Colorimeter
How do you carry out colorimetry
- Centrifuge separates ppt and unreacted Benedict’s
- Supernatant placed in a cuvette and into colorimeter with red filter
- Transmission of light measured, using zero reading with water
what does high transmission/low absorbance mean
high amount of reducing sugars
what does low transmission/ high absorbance mean
low amount of reducing sugars
what’s a calibration curve
uses a series of known concentrations and transmissions used to estimate the concentration of sample sugars
what can reducing sugar concentration also be measured with
reagent test strips
how are reagent strips used
- strip dipped into the sample solution and the colour is compared to a calibration card, showing how colour relates to sugar concentration
give an example of what reagent test strips can be used for
urine testing for sugar in diabetics
what’s starch
a plant-based energy storage molecule made of two types of alpha glucose polymers: amylose and amylopectin
what are the properties of starch and why
- insoluble - no effect on water potential
- compact granules - take up little space
- branching - multiple sites for rapid hydrolysis
- large molecule - many glucose for respiration
what are the two types of starch
- amylose
- amylopectin
explain structure of amylose
- long chain of a-glucose molecules
- has 1-4 glycosidic bonds
- amylose coils into spiral shape
- hydroxyl groups holding the spiral in place
- hydroxyl group on C 2 situated are on inside of coil, making the molecule less soluble and allowing H bonds to form to maintain the coil’s structure
- no branches