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72 Cards in this Set
- Front
- Back
What are macromolecules?
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- large organic polymers formed from monomers
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By what process are macromolecules formed?
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Polymerisation
(dehydration, condensation) - involves loss of water |
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Macromolecules are broken down by:
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addition of water (hydrolysis)
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What are the 4 classes of macromolecules?
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1. Carbohydrates
2. Lipids 3. Proteins 4. Nucleic Acids |
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Carbohydrates (define)
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- sugars and their polymers
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What do carbohydrates serve as?
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smallest carbohydrates serve as fuel and carbon sources
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What are the monomers of carbohydrates?
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monosaccharides
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Monosaccharides (properties)
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1. Major nutrients for cells (glucose being most common)
2. Can be produced by photosynthetic organisms 3. Stores energy in their chemical bonds (used by cellular respiration -> ATP) 4. Carbon backbone three to seven 5. Structure 6. Can exist in chain or ring 7. Glucose rings have two forms : alpha vs beta |
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Carbon backbone three to seven (monosaccharides)
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3 carbons: triose
5 carbons: pentose (DNA and RNA) 6 carbons: hexose (glucose) |
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Structure of a monosaccharide
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- 1 carbon double bonded to an oxygen (C=O) [carbonyl group]
- Other carbons attached to hydroxyl group (OH) [H-C-OH] |
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Monosaccharide rings (examples)
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glucose, galacose, fructose
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Glucose in ring form (alpha vs beta)
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Alpha-glucose: OH on carbon 1 is below ring
Beta-glucose: OH on carbon 1 is above ring |
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Disaccharides (define)
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- consists of two monosaccharides joined by a glycosidic linkage
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Glycosidic linkage (define)
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covalent bond formed by a condensation reaction
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Examples of disaccharides
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maltose: glucose-glucose (beer/wine)
lactose: galactose-glucose (milk) sucrose: glucose-fructose (sugar) |
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Polysaccharides (define)
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few hundread to tens of thousands of monosaccharides linked together
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What are polysaccharides for?
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Energy storage & structural support
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Types of polysaccharides
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1. Energy storage (alpha-glucose)
2. Structural (beta-glucose) |
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Energy storage polysaccharides (in plants)
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Starch:
- glucose monomers in the alpha-configuration - unbranched - forms a helix (spiral) - found in wheat, corn, and potatoes - most animals have digestive enzymes that can hydrolyse starch |
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Energy storage polysaccharides (in animals)
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glycogen:
- large highly branched glucose polymer - stored in human liver and muscle cells |
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Structural polysaccharides in plants
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Cellulose:
- linear unbranched polymer of glucose in beta configuration - reinforces plant cell walls - cannot be digested by animals (lack the enzyme to break down beta-glycosidic linkages) |
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Structural polysaccharides in insects and crustaceans
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chitin:
- polymer comprised of beta-glucose monomers substituted on carbon 2 with an amino group - building blocks of the cell wall of Fungi - exoskeleton of arthropods |
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Lipids (characteristics)
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- not polymers
- insoluble in water; hydrophobic |
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Types of lipids
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1. Fats (storage)
2. Phospholipids (major component of cell membranes) 3. Steroids: cholesterol, hormones |
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Fats (define)
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Constructed from glycerol and fatty acids
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Glycerol
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a three carbon alcohol
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Fatty acids
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long hydrocarbon (16-18 carbons)
carboxyl group at one end hydrophobic due to hydrocarbon chain see notes |
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Fats can be either:
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saturated or unsaturated
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Saturated fatty acid
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no carbon-carbon double bonds
hydrogen at every possible position straight chains solid at room temperature (butter) |
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Unsaturated fatty acid
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Contains a C=C double bond
causes a "kink" in the hydrocarbon backbone liquid at room temperature (vegetable oil) |
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Formation of fats
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Condensation reaction
formation of ester linkage - 3 fatty acids link to one glycerol (triglycerides) |
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Function of fats
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1. Storage of energy (twice as much energy as polysaccharide)
2, Protects internal organs 3. Prevents heat loss (whales and seals) |
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Phospholipids (structure)
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1 glycerol molecule
2 fatty acids molecules 1 phosphate group (PO4-) 1 hydrophilic group attached to phosphate group |
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Phospholipids (properties)
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hydrophobic and hydrophilic (amphipathic)
- fatty acid chains -> hydrophobic - phosphate group -> hydrophilic |
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In water, phospholipids form:
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aggregates, micelles
- hydrophilic head outward, contact with water - hydrophobic chains pointing towards the center, shielding from water |
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In cell membranes, phospholipids form:
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lipid bilayer
- hydrophilic out - hydrophobic tails face each other forms barriers between: - intracellular and extracellular water |
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Steroids (structure)
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carbon skeleton consisting of four fused carbon rings
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Cholesterol (characteristics)
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part of cell membranes
- starting compound for other steroids |
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Proteins (functions)
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1. Structural support
2. Transport 3. Hormonal 4. Movement 5. Defensive 6. Enzymatic THE MDS |
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Protein (monomer)
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amino acids
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Polymers of amino acids are called:
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polypeptides
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Number of different amino acids
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20
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Protein is composed of:
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one or more polypeptides
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Amino acids (structure)
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Four components attached to a central carbon
1. Hydrogen 2. Carboxyl group 3. Amino group 4. R-group of side chain see notes |
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Formation of polypeptides
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forms between two amino acids
- condensation reaction (carboxyl group OH binds with H of NH2 to form water) |
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Linkage between amino acids
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Peptide bond
- covalent - few amino acids to thousands |
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Protein structure
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3D structure of 4 levels
1. Primary structure 2. Secondary 3. Tertiary 4. Quaternary |
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Primary structure of proteins
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Linear sequence of amino acids
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Secondary structure of proteins
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1. alpha-helix (corkscrew to get into cell membranes)
2. beta-pleated sheets (confers strength) [H-bonds between parts of parallel polypeptide proteins] |
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Tertiary structure of proteins
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irregular folds, bends, and contortions
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Quaternary structure of proteins
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Complex of more than one polypeptide
e.g. Hemoglobin (four polypeptides) |
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Nucleic acids (function)
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Stores and transmits hereditary information
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Genes dictate:
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amino acid sequence in proteins
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Gene = ?
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sequence of DNA
- sequence of nucleotides |
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DNA is passed from generation to...
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generation
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What are the types of nucleic acids?
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A. Deoxyribonucleic acid, DNA
B. Ribonucleic acid, RNA |
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Deoxyribonucleic acid (characteristics)
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- chromosomes are comprised of DNA (contains hundred to thousands of genes)
- not directly involved in protein synthesis - directs its own replication |
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Nucleic acids (structure)
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- polymers of monomers, nucleotides
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Nucleotides comprised of:
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1. Nitrogen containing base
2. Pentose sugar 3. Phosphate |
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Nitrogen containing base (types)
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1. Pyrimidines
2. Purines |
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Pyrimidines (define)
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- 6 membered ring of carbon and nitrogen
DNA: Cytosine and Thymine RNA: Cytosine and Uracil CUT PY |
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Purines (define)
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- 5 membered ring fused to a 6 membered ring of carbon and nitrogen
DNA: Adenine and Guanine |
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Sequence of nitrogen bases
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no specific sequence, each gene is unique
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Pentose sugar in nucleic acids
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RNA: Ribose (H-C-OH on carbon 2)
DNA: Deoxyribose (lacks an oxygen atom at carbon 2 - H-C-H) |
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Phosphate in nucleic acids
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Attached to carbon 5 of sugar
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Synthesis of nucleic acid
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Connects sugar of one nucleotide to the phosphate of another nucleotide
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Linkage between nucleic acids
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Phosphodiester bond
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Backbone of nucleic acids
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sugar + phosphate backbone
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Structure of RNA
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single-stranded
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Structure of DNA
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double-stranded
- double helix (Watson and Crick) - Sugar phosphate backbone outside helix - bases inside helix - strands held together by H-bonds |
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Base pairing rules (DNA)
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A-T: 2 H-bonds
G-C: 3 H-bonds |
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Strands of DNA are :
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- complementary
G-C vs A-T during replication, each strand works as a template - anti-parallels |