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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

gene expression

the process by which the information within a gene becomes a useful product

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)

housekeeping genes

not subject to regulation during cell differentiation.


expressed in all cells


ex) ribosomal protein, RNA Polymerase



cell-type specific genes

turned on in a particular cell-type and turned off in other cell-types



cytology

study of cell structure and function

what do all cells have in common & why?

DNA, set of 20 amino acids, macromolecule subunits


evolved from the same ancestor

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)

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

resolving power

ability to clearly separate two objects (higher RP means you can see more detail)

light microscope



best resolving power (0.2micrometers/200nm)



electron microscope


transmission


scanning

2nm resolving power


t- electrons go through, can see inside cells


s- electrons bounce off, see surface of cells

contrast

difference between subject and background

prokaryotes

no nucleus (bacteria & archaea)


DNA and very few organelles

cytoplasm

`

material inside cell surrounding nucleus within the cell membrane

eukaryotes

have a true nucleus


have membrane enclosed organelles

nucleus

information storage in cell


enclosed by two membranes (nuclear envelope)


contains dna in chromosomes

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)

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

endoplasmic reticulum

where most materials designed for export are made


enlarged in cells specialized for protein secretion



golgi apparatus

modifies and packages molecules from ER

lysosomes

small, irregularly shaped


where intracellular digestion occurs



peroxisomes

small membrance enclosed


provide a safe environment for reactions to occur


hydrogen peroxide inactivates toxic molecules



Features of the chemistry of cells

based on organic carbon compounds


reactions occur in aqueous environments


complex


tightly regulated


coordinated by large, polymeric molecules

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



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





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

proteins and their features

peptide bonds between amino acids to form polypeptide chains


sequence is important as side chains determine function

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

ionic bonds

donate and accept electrons


create electrically charged ions


create salts (high water solubility)



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



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

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

photosynthesis

plants take in inorganic molecules and produce organic molecules using the sun's energy


ligh energy + co2 + h2o -> sugar + o2 + heat

respiration

break down of sugars to release energy through controlled oxidation reactions

oxidation

loss of electrons


can involve addition of oxygen atoms (lower energy state)


decrease CH bonds

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



delta G negative

energetically favorable


reaction can be spontaneous

delta G positive

energetically unfavorable


reaction cant be spontaneous

free energy change depends on

energy stored in each molecule and their concentrations

standard free energy change depends on

energy stored in each molecule

peptide bond

bond between amino group and carboxyl group of an amino acid, releasing h2o (condensation reaction)

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

active site

very specific binding site


where enzyme binds to substrate and catalysis occurs


contains a few amino acids


usually polar or charged



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

enzyme characteristics

highly specific


affected by temperature and pH

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

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

feedback inhibition

negative regulation - product made late in pathway inhibits enzyme acting earlier in the pathway

phosphorylation

phosphate group attachment to a protein that results in conformational change

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

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

saturated fatty acid

no double bonds/no bends


all c's contain maximum number of H's

conformations

shapes that a molecule can have. ex) proteins determined by noncovalent interactions between parts of the macromolecule

chaperone protein

helper protein that is needed to aid in folding of certain proteins

anabolic reaction

larger molecule is made from smaller ones


ex)condensation reaction that build polymers from monomers

disulfide bond

covalent bond between two S-H groups from cysteine side chains. Can be intra or intermolecular and serve to protect proteins

proteomics

study of all proteins in a cell, study of protein structures and folding, how it relates to a proteins function, comparison between proteins