1 Flashcards
Scientific theory
Structured explanation to a phenomenon ex. Big bang
“It’s just a theory”
misleading, suggests theory is untested but scientific theories are viewed as tested
Hypothesis
assumed explanation ex. Increased apple consumption decrease’s doctor’s visits
Prediction
outcome if hypothesis is correct “if… then”
Experiment
scientists gather to see if prediction is right
Interpreting Data
help utilize experiment data to answer questions
Falsifiable hypothesis
makes testable predictions, supported by all evidence
Scientific hypothesis
only credible if inherently falsifiable, capable of being tested and proven wrong
Falsifiable and Unfalsifiable examples
Ex.Falsifiable- “all swans are white” Ex.Unfalsifiable- “faith can move mountains” can’t be tested wrong
What prokaryotes and eukaryotes have in common
cell membrane, dna, rna, ribosomes, proteins, cytoplasm
Prokaryotic
relatively simple internal structure, complex chemistry
Eukaryotic
membrane bound organelles and nucleus housing dna, dif shape and function for dif env.
Nucleus
houses dna, rna synthesis site
Golgi apparatus
receives proteins and lipids and ships them
Cytoskeleton
network of protein fibers in eukaryotic, provides structure, organization, support
Protein fibers
microfilaments, intermediate filaments, microtubules
Microtubules
subunit: tubular dimers structure: hollow tube functions: cell shape and support, organelle arrangement, vesicle transport, cell movement, cell division (chromosome seg.), provides structure
Microfilaments
subunit: actin monomers structure: thin helix of actin protein monomers functions: cell shape and support, cell movement (crawling), vesicle transport, muscle contraction, cell division (cytokinesis)
Intermediate filaments
subunit: diverse, cell type specific proteins function: cell shape, structure, and support (animal), dif cells have dif intermediate filaments
Function of Cytoskeleton fibers and cellular processes
provide mechanical strength to cell, link transmembrane and cytoplasmic proteins, anchor centrosomes during mitosis, generate locomotion in cells, interact with myosin to provide force of muscle contraction
Cytoskeleton disruption
leads to disruption of cellular structure and easily damages, can release viruses, cell can’t function w/o
Covalent bond
when two atoms share electrons, single, double, triple refers to electron pairs shared by atoms in bond
Ionic bond
one or more electrons is/are completely transferred from one atom to another, atom gains electrons = - charge, atom loses electrons = +charge, attraction between opposites holds atoms together
Hydrogen bond
common and occurs regularly between water molecules, weak and easily broken, caused by attraction between partial charges on two molecules with polar covalent bonds
Polar covalent bond
one of the atoms in the bond attracts the shared electron more strongly, more electronegative
Nonpolar covalent bond
two atoms in bond share electrons equally, have (nearly) equal electronegative, don’t have partial charges
Electronegative
more electronegative atom = negative partial charge, less electronegative = partial positive charge
Water
bent and highly polar b/c readily forms hydrogen bonds with other water mol, polar mol, and ions, properties: polarity, solvency, cohesion, adhesion, high specific heat, buffering agent, covalent bonds more durable than ionic, readily separates bonds in ions, polar and charged molecules and ions interact readily with water through attractions between opp. Charges (partial and/or full)
Hydrophilic
Readily interacts with water
Hydrophobic
Doesn’t readily interact with water
Amphipathic
Hydrophobic and hydrophilic
Lipids
hydrophobic, nonpolar, functions: stored energy for long time use, provides insulation, building block of many hormones, imp. Constituent of all cellular membranes
Phospholipid
makes up plasma membrane, composed of fatty acid chains attached to a backbone, head (phosphate group) = hydrophilic, fatty acid tails = hydrophobic, arranges themselves in certain pattern b/c properties, form cell membranes
Polar and charged molecules
Doesn’t readily pass across hydrophobic interior
Selective barrier
to get across it has to be hydrophobic or pass through specialized protein in membrane
Fluid Mosaic Model
describes structure of plasma membrane, fluid movement of molecules away from surface
Channels
passive, transports substances only down concentration gradient, doesn’t use energy or bind to substance, less selective
Carriers
transport specific substances both down and against concentration gradient, responsible for facilitated diffusion of sugars, amino acids, nucleosides, transports through intracellular compartments into the extracellular fluid or across cells
Pumps
transporters, transmembrane proteins that actively move ions and/or solutes against a concentration or electrochemical gradient across biological membranes
Facilitated diffusion
doesn’t require ATP for movement of molecules from higher to lower concentration, passive movement of molecules against con., selective process
Primary active transport
directly uses ATP to transport all species of solutes across membrane against concentration gradient
Secondary active transport
transport of solute in direction of increasing electrochemical potential coupled to the facilitated diffusion of second solute in direction of its decreasing electrochemical potential
Electrochemical
gradient of ions or protons (electrochemical gradient) that can move across membrane, determined by diffusion or active transport
Diffusion
movement of molecules from high con. To low con.
Osmosis
movement of water from high con. Of water to low con. Of water
Hypotonic
Higher solute inside, water moves in
Hypertonic
Higher solute outside, water moves out
Isotonic
Equal amounts of solute, water remains consistent
Proteins perform most of the work of living cells
movement (microtubules), defense (antibodies), structure (cytoskeleton), catalysis (enzymes), transport (kinesin), signaling (signal receptor proteins)
Every amino acid has
a central carbon, amino group, carbonyl group, hydrogen, R group (different for different amino acids) 1. Carbonyl group of amino acid react with another amino group to form peptide bond 2. Amino acids can be linked together in a chain to form peptide 3. Every protein is made up of one or more folded-up polypeptides
Primary Structure
sequence of amino acids, determines: how polypeptide folds into final 3D shape, how parts of polypeptides interact with other molecules or ions
Secondary
results from interactions of nearby amino acids, how parts of polypeptide
fold into helices and sheets, stabilized by H-bonding along polypeptide backbone, determined by primary structure
Tertiary
3D folded shape of molecule, determined by: interactions between R groups and surrounding water, interactions between different r groups within polypeptide
Quaternary
results from interactions of polypeptide subunits, covalent and noncovalent interactions can hold polypeptide in protein together
What order do the structures go in?
Primary -> secondary -> tertiary -> quaternary
How are each structures affected by one another?
Each structure affected by primary but primary not affected by any
How are covalent bonds held together?
atoms are sharing electrons
How are ionic bonds held together?
Attractions between full charges
How are hydrogen bonds held together?
Attractions between partial charges, weakest bond because it’s partial charged
