Carbohydrates, Lipids and Proteins (SR) Flashcards
What are Monomers?
Individual molecules that make up a polymer
What are Polymers?
Long chains
Composed of multiple Monomers
Bonded together in Repeating Pattern
When does a Condensation Reaction Occur?
Occurs when two molecules combine to form a more complex molecule with removal of water
When does a Hydrolysis Reaction Occur?
When larger molecules are broken down into smaller ones with the addition of water
What are Monosaccharides?
Simplest Carbohydrates
Consisting of only one Sugar molecule (Glucose, Fructose & Galactose)
What is Glucose?
A Hexose sugar with 2 Isomers:
α-Glucose
β-Glucose
What are Disaccharides?
Sugars that are composed of two Monosaccharides
Joined together in a condensation reaction
Forming a Glycosidic Bond
What is an example of a polysaccharide and is the main energy store in plants?
Amylopectin (Starch)
Composed of α-Glucose
What is an example of a polysaccharide used for energy store in animals?
Glycogen
Composed of α-Glucose
What is an example of a polysaccharide that is used as a structural component?
Cellulose
Composed of long unbranched chains of β-Glucose
What are the two types of Fatty Acids?
1) Saturated
2) Unsaturated
What is the difference between a Saturated Fatty Acid and an Unsaturated Fatty Acid?
Saturated has no C=C double bonds, as many hydrogens as possible
Unsaturated has at least 1 C=C double bond, therefore contains less Hydrogen, C=C bond causes a kink so can’t be closely packed together, which means it is liquid at room temp
What is a triglyceride molecule?
Formed by joining one molecule of Glycerol to 3 Fatty Acids
Done by 3 Condensation Reactions
Forming Ester Bonds
How do Triglycerides have key roles in Respiration and Energy Storage?
Due to its Insolubility and High Carbon : Hydrogen Ratio
What is the difference between a Phospholipid and a Triglyceride?
Triglyceride has 3 Fatty Acid Chains
Phospholipid has 2 Fatty Acid Chains and a Phosphate molecule
How do the properties of Phospholipids make them great for cell-surface membranes?
Hydrophobic Tails (fatty acids & glycerol) - Non-polar and insoluble in water (inner layer) Hydrophilic Head (Phosphate) - Polar and soluble in water Overall forms Phospholipid Bilayer (outer layer)
What are Amino Acids?
Monomer Units used to make Proteins
How many naturally occurring Amino Acids are there?
20
Only difference is the R Group
What are Dipeptides and how are they formed?
Two amino Acids
Joined together by Condensation Reaction
Forming Peptide Bond
What is a Polypeptide?
Polymer made of many Amino Acids
Joined together by Peptide bonds
What are the 4 Structural Layers (Structures) of Proteins?
1) Primary (1º)
2) Secondary (2º)
3) Tertiary
4) Quaternary
What is the Primary Structure (1º)?
Specific Sequence of Amino Acids in a Polypeptide Chain
Peptide Bonds hold them together
What is the Secondary Structure (2º)?
Curling or Folding of Polypeptide Chain
Into α-helices and β-pleated sheets due to formation of H-Bonds
Hydrogen Bonds (H-Bonds) hold it together
What is the Tertiary Structure?
Overall Specific 3D Shape of a Protein, determined by interactions b/w R groups and properties of R groups
Hydrogen Bonds, Ionic Bonds and Disulphide Bridges hold them together
What is the Quaternary Structure?
Specific 3D shape of a protein determined by the multiple polypeptide chains and/or prosthetic groups bonded together
Hydrogen Bonds, Ionic Bonds and Disulphide Bridges hold them together
How do you test for Reducing Sugars?
Benedict’s Reagent
Reducing Sugar Reduces Cu (II) to Cu (I)
Changes from Blue to Brick Red/Orange ppt formed
What is the test for Starch?
Iodine in Potassium Iodide solution
Sample changes from Brown-Orange to dark Blue/Black if Starch present
How do you test for Non-Reducing Sugars?
Break down into Reducing sugars by heating w/diluted HCl or hydrolyse using Enzymes
Neutralise solution using Sodium Hydrogencarbonate
Continue with Benedict’s Reagent
Brick Red/Orange ppt formed if reducing sugar present
How do you test for Proteins?
Biuret Test
Add Sodium/Potassium Hydroxide to solution containing crushed up/dissolved proteins/food to make solution alkaline
Shake
Add Copper (II) Sulphate Solution
Solution should go from Blue to Purple if Proteins present
How do you test for Lipids?
Emulsion Test
Add Ethanol to test solution and shake for approx 1 min so it dissolves
Add Water to the solution
Any lipid will show as a milky white emulsion, the more lipid there is, the more noticeable the emulsion is
Test can be Improved by adding Sudan III to stain Lipids Red
What are Enzymes?
Biological Catalysts
That speed up Rate of Reaction
Remains Unchanged and re-usable @ end of reaction
How do enzymes work?
They lower the Activation Energy
What was the old theory for Enzyme Action?
Lock and Key
Each substrate is a ‘key’ and only fits to specific ‘lock’ (enzyme)
What is the alternative theory for Enzyme Action?
Induced Fit:
Substrate Induces change in enzyme so that it fits
Enzyme when it contacts, moulds around Substrate
Conformational change so enzyme moulds to fit substrate
What is the Specificity of Enzymes down to?
Due to Tertiary Structure of Active Site
Allowing Complementary binding to Substrates
What types of Reactions do Enzymes Catalyse?
Both Intra- and Extracellular reactions
That determine structures and functions from cellular to whole organism levels
What factors affect Enzyme Activity?
1) pH
2) Temperature
3) Enzyme Concentration
4) Substrate Concentration
5) Competitive & Non-Competitive Inhibitor Conc.
What is Competitive Inhibition?
Inhibition of Enzyme that is Reversible
Can be overcome by increasing amount of Substrate
Irreversible bonding called an Inactivator
Level of Inhibition depends on conc. of Substrates
What is Non-Competitive Inhibition?
When Inhibitor Binds to Allosteric Site Alters Specific shape of Enzymes Tertiary Site (Active Site) Disrupts shape of active sites Substrate can no-longer bind to Enzyme IRREVERSIBLE
