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58 Cards in this Set
- Front
- Back
evolution |
the way living species gradually change over time and adapt to their environment in more complex ways ex) selection for mutations in DNA over time allowed for differences in the various types of cells we see today |
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gene expression |
the process by which the information within a gene becomes a useful product |
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cell differentiation |
cell becomes a specialized cell-type occurs through differences in gene expression (gene expression is sometimes turned on or off depending on the specialized cell) |
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housekeeping genes |
not subject to regulation during cell differentiation. expressed in all cells ex) ribosomal protein, RNA Polymerase |
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cell-type specific genes |
turned on in a particular cell-type and turned off in other cell-types |
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cytology |
study of cell structure and function |
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what do all cells have in common & why? |
DNA, set of 20 amino acids, macromolecule subunits evolved from the same ancestor |
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in what ways do cells differ & why? |
size, structure, function, chemical requirements mutations in DNA and selections for certain changes have gradually resulted in the differences between cells we see today (evolution, yo) |
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Cell Theory - what and who? |
1) all organisms consist of one or more cells 2) cells exist from preexisting cells 3) cells are the basic unit of structure for all organisms Schleiden and Schwann |
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resolving power |
ability to clearly separate two objects (higher RP means you can see more detail)
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light microscope |
best resolving power (0.2micrometers/200nm) |
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electron microscope transmission scanning |
2nm resolving power t- electrons go through, can see inside cells s- electrons bounce off, see surface of cells |
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contrast |
difference between subject and background |
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prokaryotes |
no nucleus (bacteria & archaea) DNA and very few organelles |
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cytoplasm
` |
material inside cell surrounding nucleus within the cell membrane |
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eukaryotes |
have a true nucleus have membrane enclosed organelles |
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nucleus |
information storage in cell enclosed by two membranes (nuclear envelope) contains dna in chromosomes |
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mitochondria |
generate usable energy from food to power cell harness energy from oxidized food molecules to produce ATP - fuels cell functions double membrane have their own dna thought to have evolved from an engulfed bacteria - evidence: mitochondrial dna more similar to bacterial dna than eukaryotic dna (no introns) |
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chloroplasts |
large & green only found in plant and algae cells have internal sacs of membranes containing chlorophyll carry out photosynthesis - convert energy from sun to make sugar, release oxygen have their own dna thought to have evolved from an engulfed bacteria |
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endoplasmic reticulum |
where most materials designed for export are made enlarged in cells specialized for protein secretion |
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golgi apparatus |
modifies and packages molecules from ER |
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lysosomes |
small, irregularly shaped where intracellular digestion occurs |
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peroxisomes |
small membrance enclosed provide a safe environment for reactions to occur hydrogen peroxide inactivates toxic molecules |
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Features of the chemistry of cells |
based on organic carbon compounds reactions occur in aqueous environments complex tightly regulated coordinated by large, polymeric molecules |
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Properties of Water |
high surface tension high boiling point universal solvent - polar dissolves ionic and polar bonds by forming spheres of hydration around hydrophilic molecules |
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Polysaccharides and their features |
monosaccharides held together by condensation reactions sugars used for energy, polysaccharides store sugars structural units (ex: cellulose, chitin) cell recognition - sugars on surface of cells attached to glycoproteins and glycolipids |
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lipids and their features |
amphipathic (contain both hydrophobic and hydrophilic regions) Triacylglycerols - 3 fatty acids covalently bonded to a glycerol via condensation reaction phospholipids - 2 fatty acids and a phosphate group |
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proteins and their features |
peptide bonds between amino acids to form polypeptide chains sequence is important as side chains determine function |
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covalent bonds - polar/nonpolar? |
electrons are shared and have a particular geometry characterized by bond angles polar - electrons are shared unequally nonpolar - electrons shared equally presence of water makes covalent bonds stronger |
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ionic bonds |
donate and accept electrons create electrically charged ions create salts (high water solubility) |
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hydrogen bonds |
occur between molecules not atoms weak and short lasting bonds, but when networked together allow water to have high boiling point and high surface tension not limited to water |
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Nature of noncovalent interactions |
1)ionic- charged groups on polymer esp protein 2)hydrogen bonds - two halves of DNA 3)hydrophobic interactions allow binding to different molecules allow for stable conformations |
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1st law of thermodynamics 2nd law of thermodynamics |
energy can be converted to different forms but not created or destroyed entropy only increases in an isolated system, spontaneous processes lead to more entropy |
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photosynthesis |
plants take in inorganic molecules and produce organic molecules using the sun's energy ligh energy + co2 + h2o -> sugar + o2 + heat |
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respiration |
break down of sugars to release energy through controlled oxidation reactions |
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oxidation |
loss of electrons can involve addition of oxygen atoms (lower energy state) decrease CH bonds |
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reduction |
gain of electrons for organic molecules usually involves addition of a proton with electron (-H covalent bond) can involve addition of hydrogen atoms (higher energy state) increase CH bonds |
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delta G negative |
energetically favorable reaction can be spontaneous |
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delta G positive |
energetically unfavorable reaction cant be spontaneous |
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free energy change depends on |
energy stored in each molecule and their concentrations |
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standard free energy change depends on |
energy stored in each molecule |
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peptide bond |
bond between amino group and carboxyl group of an amino acid, releasing h2o (condensation reaction) |
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primary secondary tertiary quaternary structures |
-order of amino acids -protein folding locally (alpha helix, beta sheet held together by h bonds between n-h and c=o groups), dont involve bonds with side chains -3-d structure, global folding (noncovalent interactions between side chains) -arrangement in multi subunit complexes - complete structure of a protein composed of more than one polypeptide chain |
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active site |
very specific binding site where enzyme binds to substrate and catalysis occurs contains a few amino acids usually polar or charged |
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enzyme functions |
bring reactants in close vicinity lower activation energy stabilize transition state * They DONT change the equillibrium or overall free energy of a reaction. They can cause reaction to get to equilibrium more quickly |
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enzyme characteristics |
highly specific affected by temperature and pH |
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Vmax |
the fastest rate at which an enzyme can work less influenced by how well substrate binds all available active sites are occupied by substrate at this point |
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Km |
concentration at which enzyme is working at half saturation point how fast an enzyme works at low concentration of substrate low km=higher binding affinity to substrate |
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feedback inhibition |
negative regulation - product made late in pathway inhibits enzyme acting earlier in the pathway |
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phosphorylation |
phosphate group attachment to a protein that results in conformational change |
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enzymes regulated by |
1) amount of substrate and products 2) amount of enzyme 3) allosteric regulation - conformational changes resulting in binding site/active site changes due to enzyme bonding to effectors 4) covalent modification - chemical group attached to enzyme or removed from it |
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confocal microscope |
takes an image of a plane through an object. uses fluorensence to see object 3d picture resulting from multiple images of multiple planes through the object |
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saturated fatty acid |
no double bonds/no bends all c's contain maximum number of H's |
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conformations |
shapes that a molecule can have. ex) proteins determined by noncovalent interactions between parts of the macromolecule |
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chaperone protein |
helper protein that is needed to aid in folding of certain proteins
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anabolic reaction |
larger molecule is made from smaller ones ex)condensation reaction that build polymers from monomers |
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disulfide bond |
covalent bond between two S-H groups from cysteine side chains. Can be intra or intermolecular and serve to protect proteins |
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proteomics |
study of all proteins in a cell, study of protein structures and folding, how it relates to a proteins function, comparison between proteins |