BM - Monomers + Polymers Flashcards
Describe the processes of condensation and hydrolysis reactions and explain their importance in the formation and breakdown of biological molecules.
[6 marks]
- Condensation: Joins monomers by forming covalent bonds and releases a molecule of water (e.g., peptide bond in proteins, glycosidic bond in carbohydrates).
- Hydrolysis: Breaks polymers into monomers by adding water (e.g., digestion of starch into glucose).
- Importance: Allows synthesis of macromolecules essential for structure and function (e.g., enzymes, DNA).
- Enables digestion and energy release during metabolism.
Compare and contrast alpha-glucose and beta-glucose, and explain how their structures relate to their functions in polysaccharides.
Differences:
* Alpha-glucose: -OH group below carbon 1.
* Beta-glucose: -OH group above carbon 1.
Functions:
* Alpha-glucose forms starch and glycogen (energy storage, easily hydrolyzed).
* Beta-glucose forms cellulose (straight chains, hydrogen bonding, structural support in plant cell walls).
Explain how the structure of starch and glycogen relates to their roles in energy storage.
Starch:
* Composed of amylose (unbranched, compact) and amylopectin (branched, fast energy release).
* Insoluble, preventing osmotic effects in cells.
Glycogen:
* Highly branched, allowing rapid hydrolysis for energy release in animals.
* Compact for efficient storage.
Describe the structure of cellulose and explain how it is adapted for its function.
4 points
Structure:
* Made of beta-glucose molecules linked by 1,4-glycosidic bonds.
* Straight, unbranched chains.
* Chains linked by hydrogen bonds to form strong microfibrils.
Function:
* Provides strength for structural support in plant cell walls.
Explain the role of monomers such as glucose, amino acids, and nucleotides in the synthesis of polymers.
Glucose: Forms polysaccharides like starch, glycogen, and cellulose.
Amino acids: Link via peptide bonds to form polypeptides (proteins).
Nucleotides: Join via phosphodiester bonds to form nucleic acids (DNA and RNA).
Significance: Essential for cellular structure, metabolism, and genetic information.
Explain the similarities and differences between starch, glycogen, and cellulose.
Similarities:
* All polysaccharides formed from glucose monomers.
Differences:
* Starch: Alpha-glucose, energy storage in plants, amylose and amylopectin.
* Glycogen: Alpha-glucose, highly branched, energy storage in animals.
* Cellulose: Beta-glucose, straight chains, structural support in plants.
Explain how the structure of polysaccharides affects their rate of hydrolysis and their role in living organisms.
Structure:
* Starch and glycogen: Branched structure allows rapid hydrolysis.
* Cellulose: Straight, unbranched chains resist hydrolysis, providing strength.
Role:
* Starch and glycogen for energy storage and release.
* Cellulose for structural integrity in plants.
Describe the chemical reactions involved in the conversion of polymers to monomers and monomers to polymers.
Give two named examples of polymers and their associated monomers to
illustrate your answer.
- A condensation reaction joins monomers together and forms a (chemical) bond and releases water
- A hydrolysis reaction breaks the (chemical) bond between monomers and uses water
- Amino Acids –> Polypeptide/Protein/Enzyme/Antibody
- Nucleotides –> Polynucleotide/DNA/RNA
- Alpha Glucose –> Starch/Glycogen
- Beta Glucose –> Cellulose
What is a monomer?
A small repeating unit from which polymers are made from
Describe how you would test a piece of food for the presence of lipid.
Dissolve in Ethanol then add water
shake and if lipid present there will be a white emulsion.
Messenger RNA (mRNA) is used during translation to form polypeptides.
Describe how mRNA is produced in the nucleus of a cell.
5 marks
- Helicase brekas H bonds between bases which unwinds the DNA
- One strand acts as a template
- Freefloating RNA nucleutides are attrated to the complimentary base pairs.
- RNA polymerase joins RNA nucleotides together
- Pre mrna is spliced to remove introns
Describe the structure of proteins.
5 marks
- Proteins are polymers of amino acids joined together by peptide bonds via condensation reactions
- The primary structure is the order of amino acids in the peptide
- Secondary structure is the folding of the polypeptide chain due to hydrogen bonding into an alpha helix or a beta pleated sheet.
- Tertiary structure is the 3-D folding due to hydrogen/ionic and disulphide bonds
- quarternary structure which is when the protein has two or more polypeptide chains joined together.
Describe how proteins are digested in the human gut.
4 marks
- Hydrolysis of peptide bonds;
- Endopeptidases break polypeptides into smaller peptide chains;
- Exopeptidases remove terminal amino acids;
- Dipeptidases hydrolyse / break down dipeptides into amino acid
Name the type of reaction that joins monosaccharides together.
Condensation (reaction)
Some cells lining the bronchi of the lungs secrete large amounts of mucus. Mucus contains protein.
Name one organelle that you would expect to find in large numbers in a mucus-secreting cell and describe its role in the production of mucus.
Golgi (apparatus)
Package / process proteins;
