Chapter 3: Biological molecules Flashcards
anions
*Nitrate - Nitrogen supply to plants and protein formation
*Hydrogen carbonate - maintenance of blood pH
*Chloride - balance sodium and potassium ions in cells
* Phosphate - cell membrane formation, nucleic acid and ATP formation, bone formation
Hydroxide - Catalysts and pH determination
cations
Calcium - Nerve impulses and muscle contraction
Sodium - Nerve impulse transmission and kidney function
Potassium - Nerve impulse transmission and stomatal opening
Hydrogen - catalysis of reactions and pH determination
Ammonia - Production of nitrate ions by bacteria
water
water is important as:
*its a metabolite
*able to do electrolysis
props of water?
*excellent solvent
*High SHC
*High latent heat of vaporisation
*less dense when solid
*high surface tension and cohesion
*acts as a reagent
water (2)
*104.5 bond angle
*covalent bond
*it is a polar molecule as it has charge but is specifically a dipole meaning it has both a slight negative and slight positive charge
*oxygen has the slight negative charge
hydrogen has the slight positive charge
*oppositely charged atoms on each molecule are attracted to eachother and form hydrogen bonds
glucose
*a hexose monosaccharide
*fundamental within carbs
glycosidic bonds
*formed by condensation reaction which produces water
*broken by hydrolisis
alpha-glucose
starch:
*amylose - straight chain therefore only 1-4 glycosidic bonds
*amylopectin - has branches aswell so has 1-4 and 1-6 glycosidic bonds
Glycogen (animals) : like amylopectin but more branched
-amylose is more stable as it can be more compact
carbohydrates
a group of substances used as both energy sources and structural materials in organisms
*carbohydrates - H,O,C element atoms only
monosaccharides
*monosaccharides are simple: galactose, fructose, glucose
* they are bonded together in a condensation reaction to form disaccharides
* bond formed is a glycosidic bond
disaccharides formed from monosaccharides
maltose: 2 x glucose
sucrose: glucose and fructose
lactose: glucose and galactose
What’s the general formula of carbohydrates?
Cx(H2O)y
What’s the bond angle of water?
104.5
Where is the OH group on a glucose which is different to b glucose?
Alpha has OH on bottom on first carbon whereas Beta has OH on top of first carbon.
What reaction is it called when a glycosidic bond is formed?
Condensation reaction and water is released
What type of bond is a glycosidic bond?
Covalent bond
What is starch?
Many alpha glucose molecules joined by glycosidic bonds.
Glucose which is stored in plants is known as starch.
What is amylose?
Is a polysaccharide in starch.
Is formed by alpha glucose molecules and only has 1-4 glycosidic bonds.
Is much more compact as it forms a helix shape.
What is amylopectin?
Is the other polysaccharide of starch.
Contains 1-4 and 1-6 glycosidic bonds.
1-6 glycosidic bonding means amylopectin has branches.
1-6 branch occurs approximately every 25 glucose sub units
What is glycogen?
Is the functionally equivalent storage molecule to starch in animals and fungi.
Forms more branches than amylopectin, therefore is more compact and this is ideal for storage.
What are the key properties of amylopectin and glycogen?
They are insoluble, branched and compact
How is glucose released from starch or glycogen for respiration?
They undergo hydrolysis.
Is catalysed by enzymes.
What is cellulose made from and how?
Cellulose is made from Beta glucose molecules.
Every other beta glucose molecule is inverted so that condensation reactions between the oh groups can occur.
How are cellulose fibres formed from cellulose molecules?
Cellulose molecules form hydrogen bonds with each other to form microfibrils.
Microfibrils join to form macrofibrils.
Macrofibrils combine to produce cellulose fibres.
What do cellulose fibres make?
Cell wall
What are properties of cellulose fibres?
Strong and insoluble
How do you test for reducing sugars? What is the positive test result?
1) place sample in boiling tube. If not liquid, grind it up and mix with water.
2) add equal vol of Benedict’s reagent
3) heat gently in boiling water bath for 5 mins
Blue to brick red
How do you test for non reducing sugars using Benedict’s?
Same as reducing sugars but has to be boiled with dilute HCl first.
How do you test for starch using iodine? What is the positive result?
Dissolve a few drops of iodine solution with potassium iodide.
Yellow to purple/black
What is another way to test for reducing sugars?
Manufactured reagent test strips
What are fats?
Fats are lipids that are solid at room temp
What are oils?
Are lipids that are liquid at room temp
Are lipids polar or non polar?
Non polar and so insoluble in water
What is a triglyceride made from?
A glycerol and three fatty acid tails.
What are the bonds between a glycerol and fatty acid tails called? What is the reaction called?
The bonds are ester bonds and the reaction is called esterification.
What is esterification an example of
A condensation reaction.
How much water is used when triglycerides are broken down? What is the reaction called?
Three water molecules are released.
Hydrolysis
Which of oils and fats are saturated and unsaturated?
Oils - unsaturated
Fats - saturated
