Biological Molecules Flashcards
What bonds are formed in a condensation reaction
Glycosidic bond
Sucrose
Glucose + fructose
Lactose
Glucose + galactose
Maltose
Glucose + glucose
Test for non reducing sugars
Add dilute HCl and heat in water bath then neutralise with sodium hydrogen carbonate
Reducing sugars test
Add Benedicts reagent to sample and heat in water bath
If positive coloured ppt forms
What polysaccharides of alpha glucose make starch
Amylose and Amylopectin
Amylose structure and benefit
Long unbranched chain of a-glucose
Angles if glycosidic bonds give coiled structures like cylinder making it compact making it good for storage as fit more in one space
Amylopectin structure and benefit
Long branched chain of a-glucose
Side branches allow enzymes that break down molecule to reach glycosidic bonds easily meaning glucose can be released quickly
Starch adaption to function
Insoluble in water and doesn’t affect water potentiometer so doesn’t cause water to enter cells by osmosis making it sweep
Good for storage
Glycogen
Has more branches than amylopectin for faster release of glucose which important for animals and very compact for good storage
Cellulose structure and benefit
Made of long unbranched chains of beta glucose, when beta glucose molecules bond they form straight cellulose chains
Cellulose chains linked by hydrogen bonds to form strong fibres called microfibrils. These provide structural support for cells
Structure of triglyceride
One molecule of glycerol with 3 fatty acids attached to it
Type of lipid
Fatty acid structure
Have long tails made of hydrocarbons
Tails aye hydrophobic making it insoluble in water
All fatty acids have same basic structure but hydrocarbon tail varies
Phospholipid structure
One molecule of glycerol with 2 fatty acids and a phosphate group which is hydrophilic
Triglyceride adaptation to function
Used as energy storage molecules, Long hydrocarbon tails of fatty acids contain chemical energy which is released when broken down, contain twice as much energy per gram as carbs
Insoluble so don’t affect water potential, insoluble droplets clump together facing inwards sheilding glycerol hews from water
Phospholipid adaptation to function
Make up bilateral of cell membranes what comes in and out
Heads are hydrophilic and tails hydrophobic so form double layer with heads facing out towards water on either side
Centre of bilayer is hydrophobic so water soluble substances can’t pass through so acting as barrier to those substances
Primary structure of proteins
Sequence of amino acids in the polypeptide chain
Amino acids joined by polymerisation
Secondary structure
Doesn’t remain flat and straight
Hydrogen bonds form between amino acids in chain making it coil into alpha helix or fold into a beta pleated sheet
Twist into 3D structure
Tertiary structure of proteins
More bonds form including hydrogen and ionic bonds.
Ionic bonds between anime group and carboxyl
Disulfide bridges form between two molecules of amino acid cysteine. Sulfur atoms bond together. Forms final 3D structure for proteins made from single polypeptide chain
Quaternary structure of proteins
Way multiple chains assembled together.
For proteins made from more than one polypeptide chain it is the final 3D structure
Carbohydrates
Made from monosaccharides and is polymers
Polymers
Complex molecules composed of long chains of monomers joined together ( monomers are small basic molecular units)
Iodine test
Add iodine dissolved in potassium iodide solution to test sample
If starch present go from browny orange to dark blue/black
