Exam 1 - 1) UNIVERSAL FEATURES OF ALL CELLS: a. All cells...

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Unformatted text preview: 1) UNIVERSAL FEATURES OF ALL CELLS: a. All cells come from pre-existing cells b. Cells are the minimum functional unit of life c. All cells are surrounded by a plasma membrane containing transport proteins d. All cells require free energy to drive reactions and create order e. All cells store their hereditary info in DNA f. All cells transcribe DNA into RNA g. mRNA is translated into protein on ribosomes in all cells h. All cells use proteins to catalyze reactions: enzyme. Some RNA also act as catalysts 2) PROKARYOTE a. Has no nucleus or organelles b. Eubacteria and archaea (live in extreme environment) are prokaryotes 3) EUKARYOTE a. Organelles are membrane-bound: compartmentation b. Large structures are not organelle (compose of polysaccharides): i. cell wall ii. ribosomes iii. plasma membrane iv. cytosol : aqueous gel surrounding the organelles v. cytoskeleton : network of protein fibers supports eukaryotic cell shape 4) BONDING: a. Covalent bonds i. Sharing electrons with another atom ii. Strongest bond iii. Nonpolar (C-H or C-C) 1. Electrons are attracted almost equally to both atoms 2. Hydrophobic a. Nonpolar molecules do not mix well with water, and do not form hydrogen bonds iv. Polar (O-H, C-O, N-H) 1. Unequal sharing of electrons 2. Hydrophilic b. 4 types of Noncovalent bonds : result in a single native conformation i. Ionic bonds (electrostatic attractions): 2 nd strongest bond 1. Transfer of an electron from one atom to the other 2. Weak in aqueous solution 3. Ions can cluster around charged groups in macromolecules ii. Hydrogen bonds: 3 rd strongest bond 1. Partial positively charged H atom with partial negatively charged N or O 2. Only occur in molecules with polar bonds 3. Water can form up to 4 H-bonds with other water iii. Van der Waals: weakest bond 1. Cause by unequal electron distribution: temporary dipole iv. Hydrophobic forces: 3.5 strongest - strength between hydrogen and ionic bond 1. Association of nonpolar molecules to avoid interacting with water 2. Exclusion: driving force of nonpolar molecule from water a. NONPOLAR MOLECULES DO NOT ATTRACT TO EACH OTHER! 3. Push nonpolar side chain groups into the core of the protein, away from water 5) TYPES OF MACROMOLECULES (monomers covalently linked) a. Amino acids: proteins (polypeptides) i. 20 different amino acids in proteins 1. Side chain determines the polarity: acidic, basic, hydrophobic or polar ii. Only L-amino optical isomers are found in proteins (CCW) iii. Amino acids are linked by peptide bonds iv. Only the alpha carbon can do free rotation b. Sugars: polysaccharides (carbohydrates) c. Nucleotides: nucleic acids (DNA, RNA) d. Fatty acids & lipids: membranes and lipids i. Fatty acids are amphipathic that possess hydrophobic tail and hydrophilic head regions ii. If hydrophobic hydrocarbon chain contains a double bond , itll bend the chain a.k.a Unsaturated (oils) iii. Saturated fatty acids w/ no double bond iv. Triacylglycerol- 3 fatty acids joined to glycerol and is used for energy storage...
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This note was uploaded on 12/05/2009 for the course BIO 341 taught by Professor Noris during the Fall '09 term at Rhode Island.

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Exam 1 - 1) UNIVERSAL FEATURES OF ALL CELLS: a. All cells...

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