Biological Molecules Flashcards
what are alpha and beta glucose to each other
Isomers
What’s the main structural difference between Alpha and beta glucose molecules
They differ in the configuration of the hydroxyl group
- Beta Glucose has an OH molecule on top & an H molecule
- Alpha Glucose has an H molecule on top & an OH molecule on he bottom
What do two alpha glucose molecules bond to make
maltose
What does one alpha glucose and a fructose monosaccharide bond
sucrose
What beta glucose and a galactose monosaccharide bond
lactose
what’s the difference between cellulose & starch
- starch is made up of Alpha glucose, cellulose is made up of beta glucose
- starch has branches, cellulose is linear
- starch is a storage molecule, cellulose is a structural molecule
- both have 1-4 glyosidic bonds but starch also has 1-6 glyosidic bonds
what reaction makes bond & what is formed
condensation, forms a water molecule
what reaction breaks bonds & what is used
hydrolysis, uses up a water molecule
what are the similarities between cellulose & starch
- both contain 1-4 glyosidic bonds
- both insoluble
- both broken by hydrolysis
what are the differences between phospholipids and triglycerides
- phospholipid’s contain a phosphate group, 2 fatty acids & a glycerol, whilst triglyceride’s have 3 fatty acids and a glycerol
- phospholipids are part of cell membranes, triglycerides are not part of cell membranes
What has a higher melting point saturated or unsaturated lipids
Saturated
What is the test for lipids
Emulsion test (ethanol)
What’s the test for reducing sugars
Benedicts solution
What are carbohydrates
molecules which consist only of carbon, hydrogen and oxygen
how many carbon atoms in a glucose molecule
six carbon atoms in each molecule
what are polymers
long chains of monomers
give three examples of monomers
- monosaccharides
- amino acids
- nucleotides
what are triglycerides
Triglycerides are lipids made of one molecule of glycerol and three fatty acids joined by ester bonds.
what are phospholipids
In phospholipids, one of the fatty acids of a triglyceride is substituted by a phosphate containing group
describe the results of the Emulsion test
Cloudy-white colour = positive result for lipids
describe results of the benedict’s tests
stays blue = no reducing sugar present
turns brick red colour = reducing sugar present
explain the method of the benedict’s test
heat the sample with benedict’s solution, if it turns red reducing sugars are present. If it stays blue then heat it with dilute hydrochloric acid and then neutralise the solution with sodium hydrogen carbonate and heat it with benedict’s. if it stays blue there are no reducing or non-reducing sugars present
what is the test for proteins
biurets
explain the method of the emulsion test
- Take a test tube and add the sample to be tested and ethanol.
- Shake the test tube thoroughly to dissolve all the lipid in the solution.
- Add water and shake gently.
- A cloudy-white colour indicates the presence of a lipid.
explain the method of the biurets test
- Place the sample to be tested in a test tube and add an equal volume of sodium hydroxide at room temperature.
- Add a few drops of very dilute copper sulphate solution.
- A purple colouration indicates the presence of a peptide bond and hence a protein. A negative result would mean the solution remains blue.
if monosaccharide is the monomer what is the polymer
carbohydrates
if amino acid is the monomer what is the polymer
protein
if nucleotide is the monomer what is the polymer
nucleic acid
explain the primary structure of amino acids
long chains of amino acids joined by peptide bonds, in a specific sequence
explain the secondary structure of amino acids
- alpha helix, the coiled shape is kept by hydrogen bonds
2. beta pleated sheets, hydrogen bonds between the sheets
explain the tertiary structure of amino acids
- ionic bonds, between carboxyl and amino acid groups
- disulphide bridges
- hydrogen bonds
what affects/denatures ionic bonds
Ph
what affects/denatures disulphide bonds
Temperature
what is the purpose of bonds in the tertiary structure
they keep the shape together if the bonds are broken the amino acids denature
Explain the quaternary structure of amino acids
tertiary structures interact forming the quaternary structure. the quaternary structure interacts with extra ionic groups
where is amylase formed
salivary glands
where is maltose formed
small intestine
Explain competitive inhibitors
Prevents the real substrate from binding. They can leave the active site giving the real substrate an opportunity to bind and form an enzyme substrate complex
Explain Non-competitive inhibitors
changes the shape of the active site (denatures) by binding to the allosteric region. Once bound it won’t leave the allosteric region and so permanently denatures the enzyme.
what is the allosteric region
The secondary binding site
explain a substrate concentration graph for both non-competitive and competitive inhibitors
normal enzymes and competitive inhibitors both finish at the same point but the rate of reaction for competitive inhibitors is much slower. non-competitive inhibitors have a slower rate of reaction and a lower final amount of enzyme substrate complexes
Where do hydrogen bonds form
hydrogen bonds form between the carbonyl O of one amino acid and the amino H of another.
what is the optimum temperature for enzymes in the body
37.5*C
what is hydrogen bonding
hydrogen bonding is an attraction between OH groups and positive and negative regions
what does saturated, unsaturated and polyunsaturated mean
saturated= no double bonds unsaturated= one double bond polyunsaturated= multiple double bonds
explain the structure and melting point of saturated molecules
straight chains and high melting points
explain the structure and melting point of unsaturated molecules
bent chains and lower melting point
why do unsaturated fats have low melting points
The “bends” create space which prevents them from packing in tightly meaning they are liquid at room temperature
what’s the difference in bonds between amylose and amylopectin
- amylose only has Alpha 1-4 bonds
2. amylopectin has Alpha 1-4 and 1-6 bonds
what’s the difference in structure between amylose and amylopectin
- amylose is in the shape of a helix
2. amylopectin has branches
what are the similarities between amylose and amylopectin
- both Alpha glucose molecules
- both storage molecules
- both are insoluble
- both have glycosylic bonds
