List the four major classes of biological macromolecules in all known life forms.
Carbohydrates, Lipids, Proteins, Nucleic acids
Describe the construction and deconstruction of biological polymers
Polymers ("many part") are made from monomers ("one part")
Put together by condensation by removing water = dehydration Taken apart by adding water = hydrolysis
Explain how organic polymers contribute to biological diversity.
Organisms use 40-50 common monomers
There are many combinations of those in long linear sequences
Describe the distinguishing characteristics of carbohydrates and explain how they are classified.
Chemical characteristics:
Polyhydroxylated (1C:2H:1O) aldehydes, ketones, alcohols & acids
Very polar while carrying appreciable energy
Provide carbon skeletons for biosynthesis
Classification:
Number of carbon atoms per monomer (triose, tetrose, pentose,
Distinguish significant monosaccharides and disaccharides.
Mono-: a single sugar unit
Glucose: A hexose
Import for energy, raw material for biosynthesis Found in ring form
Ribose and deoxyribose are the pentoses of nucleic acid
Di-: two monosaccharides with a glycosidic linkage
Maltose = two glucoses
Lactose = gl
Identify a glycosidic linkage and describe how it is formed.
Glycosidic linkages form between hydroxyl groups
Water is removed, one O atom link sugars
Describe the structure and functions of polysaccharides.
Storage Polysaccharides
Starch
Helical 1-4 linked glucose polymers, may be branched
Energy storage in plants
Hydrolysed using amylase Glycogen
Highly branched glucose polymers
Energy storage in liver and muscle
Structural Polysaccharides
Cellulose: very l
Distinguish the glycosidic linkages found in starch and cellulose and explain why the difference is biologically important.
Starch: glucose in alpha rings; 1-4 linkages digestible by us Cellulose: glucose in beta rings; 1-4 linkages not digestible by us
Describe what distinguishes lipids from other major classes of macromolecules.
Does not include polymers"; but fatty acids are made from 2C units Generally hydrophobic; except for steroid hormones
Mostly hydrocarbon
Generally small
Describe the building-block molecules, unique properties, and biological importance of fats, phospholipids, and steroids.
Fats
Glycerol + 3 fatty acids with ester linkages = triacylglycerol Saturated (with H): no double bonds, straight, solid
Unsaturated: double bonds, kinked, liquid
Ester linkages are largely hidden; whole molecule is nonpolar Functions: Stores > twices as
Describe the characteristics that distinguish proteins from the other major classes of macromolecules and explain the biologically important functions of this group
Composed of 20 amino acids; the most structurally diverse Functions:
Structural support (collagen)
Transport of other substances (hemoglobin)
Signaling (insulin)
Movement (myosin and actin)
Defense (antibodies)
Catalysts (enzymes)
Differentiate polypeptide and protein.
Polypeptide = a chain of amino acids
Protein = folded, trimmed, combined, modified (finished), functional
List the four major components of an amino acid. Explain how amino acids may be grouped according to the physical and chemical properties of the side chains.
Components: amino, carboxyl, H, R (variable) group
Side chain classes: nonpolar, polar, acidic, basic
Identify a peptide bond and explain how it is formed.
Peptide bond links amino and carboxyl groups on adjacent amino acids In a structure: N-C w/double bonded O
Amide bond is formed by dehydration
Explain what determines protein conformation and why it is important.
Amino acid sequence mainly determines conformation
Matching shapes determine interactions between molecules Substrate-enzyme
Hormone-receptor protein
Antibiotic-target protein
Define primary structure and describe how it may be deduced in the laboratory.
Primary structure = amino acid sequence
Determination (Sanger, 1958)
Cut with sequence-specific proteases, characterize fragments Identify the amino- and carboxy-terminal amino acids
Describe the two types of secondary protein structure. Explain the role of hydrogen bonds in maintaining the structure.
? helix: coil stabilized by H-bonds between every fourth amino acid
? pleated sheet
Parallel straight stretches of amino acids, carbonyls staggered Carbonyls H-bond with aligned strand
Define tertiary structure and list the stabilizing interactions.
Sequence folds between secondary structures Interactions between R-groups
Hydrophobic side chains fold in for water soluble proteins
Hydrogen bonds Van der Waals interactions stabilize at close range Disulfide bridges form between non-adjacent cysteines
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Using collagen and hemoglobin as examples, describe quaternary protein structure.
Quaternary = more than one amino acid chain bound together Collagen: three helical amino acid chains wound into a triple helix Hemoglobin: 2 alpha + 2 beta chains + 4 hemes
Exemplify the significance of even slight changes in primary structure.
Sickle-cell: one amino acid changed
Changed protein shape, altered cell shape symptoms
Define denaturation and explain how proteins may be denatured
Denaturation of protein = loss of shape and therefore function
By heat, change in pH, organic solvents, polar solutes like urea
Define the protein folding problem
So far, not able to predict protein structure from primary sequence Stages, intermediate structures involved
Describe the role of chaperonins in protein folding.
#NAME?
Define gene in the traditional sense
Segment of DNA that defines the primary structure of a polypeptide
Describe the characteristics that distinguish nucleic acids from the other major groups of macromolecules.
Polymers of 4 nucleotides Order = coded information Complementary strands allow replication
Summarize the functions of nucleic acids.
DNA is a stable, stored form of information giving traits
RNAs are working copies of the information in DNA
Semi-conservative replication allows transmission to offspring
List the major components of a nucleotide, and describe how these monomers are linked to form a nucleic acid.
Nucleotide = nitrogen base+pentose+phosphate
Phosphates link the 3' and 5' carbons on adjacent pentoses
Distinguish pyrimidine and purine nitrogen bases
Pyrimidine bases
One ring Thymine, cytosine, uracil
Purine bases
Two rings Adenine, guanine
Differentiate the three-dimensional structures of DNA and RNA.
DNA:
Double helix
Strands anti-parallel: 3' 5', 5' 3'
Complementary base pairs in center: A-T, G-
RNA:
Mainly single stranded
May fold back on itself and base pair
Explain how the structure of DNA and proteins can be used to document the hereditary background of an organism.
Assume descent with modification and a constant rate of mutation Phyogenetic trees showing relatedness can be constructed
Number of changes is proportional to time since divergence
Extra Fact 1: Structure and function of polymers are derived from the way their monomers are assembled.
Carbohydrates are composed of sugar monomers whose structures and bonding with each other by dehydration synthesis determine the properties and functions of the molecules.
Illustrative examples include: cellulose versus starch.
The nature of the bonding b
Extra Fact 2: Structure and function of polymers are derived from the way their monomers are assembled.
In general, lipids are nonpolar; however, phospholipids exhibit structural properties, with polar regions that interact with other polar molecules such as water, and with nonpolar regions where differences in saturation determine the structure and functio
Extra Fact 3: Directionality influences structure and function of the polymer.
Proteins have an amino (NH2) end and a carboxyl (COOH) end, and consist of a linear sequence of amino acids connected by the formation of peptide bonds by dehydration synthesis between the amino and carboxyl groups of adjacent monomers.
Extra Fact 4: Structure and function of polymers are derived from the way their monomers are assembled.
In proteins, the specific order of amino acids in a polypeptide (primary structure) interacts with the environment to determine the overall shape of the protein, which also involves secondary tertiary and quaternary structure and, thus, its function. The
Extra Fact 5: Directionality influences structure and function of the polymer
Nucleic acids have ends, defined by the 3' and 5' carbons of the sugar in the nucleotide, that determine the direction in which complementary nucleotides are added during DNA synthesis and the direction in which transcription occurs (from 5' to 3').
Extra Fact 6: DNA and RNA molecules have structural similarities and differences that define function.
Both have three components sugar, phosphate and a nitrogenous base which form nucleotide units that are connected by covalent bonds to form a linear molecule with 3' and 5' ends, with the nitrogenous bases perpendicular to the sugar-phosphate backbone. Th
Extra Fact 7: Structure and function of polymers are derived from the way their monomers are assembled.
In nucleic acids, biological information is encoded in sequences of nucleotide monomers. Each nucleotide has structural components: a five-carbon sugar (deoxyribose or ribose), a phosphate and a nitrogen base (adenine, thymine, guanine, cytosine or uracil