test 1 (ch. 1,2,4,11) Flashcards
what are cells
small, membrane enclosed units
what are solitary cells
the simplest forms of life
what are multicellular cells
communities of cells derived by growth and division from a single cell
life requirements
- use energy and produce
- interact with the environment
- reproduce by themselves
cell theory
- all organisms are made from cells
- cells are the smallest unit of life
- all cells produced from there cells
carbohydrates: monomer and polymer
monosaccharide and polysaccharide
proteins: monomer and polymer
amino acid and polypeptide
lipids: monomer and polymer
fatty acid, glycerol and lipid
nucleic acids: monomer and polymer
nucleotide and nucleic acid
function of nucleic acids
genetic information carried in DNA molecules
function of proteins
determines cell appearance and behavior
what is central dogma
relationship between DNA, RNA, and proteins make self-replication possible
mutations can change the nucleotide sequence
for better (favored) or worse (eliminated), or neutral (tolerated)
what are the types of mutations
substitutions, deletions, insertion, inversersions
what do genes provide
instructions for the cells form, its function, and its complex behavior
escherichia coli
how cells replicate DNA; decoding genetic instructions
saccharomyes cerevisiae
budding yeast; basic mechanism of eukaryotic cells cell division cycle
arabidosis thaliana
small weeds that grows indoors and reproduces quickly
drosophila melanogaster
foundation of classical genetics
caenorhabitis elegans
clockwork development with exactly 959 body cells; apoptosis (programmed cell death)
zebrafish
vertebrae studies; transparent for first two weeks of life
mouse models
mammalian genetics, cell biology
human cells
human cells in vitro, clinical studies, and medical databases
cells are chemical systems that what
obey physical and chemical laws
what are the most common elements in living organisms
carbon, hydrogen, oxygen, and nitrogen
how many electrons can fit in each shell within an atom
innermost shell can hold up to two, the second shell can hold up to eight, the third shell can hold up to 18
what do valence electrons determine
how an atom interacts with other atoms
what are the two type of bonds
covalent (sharing) and ionic (transferring)
types of covalent bonds
single and double
which bonds allow the molecule to rotate freely
single bond
which bonds allow the molecule to be shorter and stronger, but less flexible
double bonds
electrons are shared unequally, and they will vary in electronegativity strength
polar covalent bonds
how do ionic bonds form
by the gain and loss of electrons
what is an ion
an atom or molecule that has a charge to it because of the loss or gain of electrons
will an ion with a negative charge be attracted to another negative or a positive ion
positive
what does a hydrogen bonding form between
hydrogen atom and another atom; taking part in a separate covalent bond
are hydrogen bonds strong or weak
they are individually weak
when H+ is dissolved in water which on releases it and which one accepts it
acids release and bases accept
how many bonds can a carbon atom form
four bonds
what are chemical groups
atoms or clusters of atoms that are covalently bonded to carbon backbone
what can carbohydrates be used for
energy source, structural materials, and signaling & recognition
all amino acids have what
an amino group, carboxyl group, and side chain attached to their a-carbon atom
what are some of the amino acids
asparagine, glutamine, serine, tyrosine, alanine, etc
what is ATP
energy currency of the cell
what does ATP do
energizes many molecules by phosphate group transfers
ATP is synthesized by what
ADP and inorganic phosphate and it releases energy when it is hydrolyzed back to ADP and inorganic phosphate
what are amino acids linked together by
covalent peptide bonds formed by dehydration reactions
what is denaturing
physically unfolding the proteins
amino acids are linked together by _______ _______ ______, which are formed by a ________ ________
covalent peptide bonds, dehydration reaction
shape of protein is specified by _______ _______ ________
amino acid sequence
backbone and side chain atoms are bonded with ______ bonds
noncovalent
the 3 typed of noncovalent bonds in backbones and side chains are
electrostatic, hydrogen, van der waals
which noncovalent reaction is between fully charged or polar atoms
electrostatic
which noncovalent bond is between atoms in short distances, which have fluctuating electrical charges
van der waals
which noncovalent bond is between H and two electron attracting atoms
hydrogen
when a protein folds, the ____ side chains form hydrogen ions to water, and the ____ side chains are packed into the hydrophobic core region
polar, nonpolar
a proteins backbone to backbone hydrogen bond is between atoms of 2 _____ bonds
peptide
a proteins backbone to side chain hydrogen bond is between atoms of a ______ _____ and an ______ _______
peptide bond, amino acid side chain
a proteins side chain to side chain hydrogen bond is between atoms of two ______ ________ ______ _______
amino acid side chains
protein unfolding is called
denaturation
_____ proteins can guide the folding of a newly synthesized polypeptide chain
chaperone
chaperone proteins can also help form _____ ______
isolation chambers
a backbone model shows ______ ______
overall organization
a ribbon model shows
polypeptide backbone folds
a wire model shows positions of _____ ______ ______ ______
amnio acid side chains
space filling model shows
contour map of surface
_____ are the result of misfiled proteins
prions
a proteins _____ structure involves hydrogen bons
secondary
a proteins _____ structure involves heme and beta polypeptides
tertiary
a proteins _____ structure involves alpha polypeptides
quaternary
_____ _____ is an area of packed globular elements
protein domain
protein domains are made of _____ _____ and ______
alpha helices, beta sheets
elongates and intracellular describes ______ ____
fibrous proteins
_____ is extremely strong and holds tissues together
collagen
_____ forms meshwork and allows recoil
elastin
n-terminus, also called the
amino terminus
c-terminus, also called the
carboxyl terminus
what are cells enclosed by
plasma membrane
each type of protein has a unique amino acid sequence which determines what
its three-dimesional shape and biological activity
what did Hans and Janssen do
make the first microscope by placing two lenses in a tube
what did leeuwenhoek do
he was the first to describe cells and bacteria
what did zernike do
he invented phase-contrast microscope that allows the study of colorless and transparent biological materials
what is ruska do
he develops the electron microscope
what are some membrane functions
- selective diffusion barrier
- excitation and conduction
- electrical insulation
What is the plasma membrane
A protein-studded, fatty film so thin it can’t be seen directly in a light microscope
What is the structure of the plasma membrane
Two ply sheets of lipid molecules about 5nm or 50 atoms thick
eukaryotic cells also contain ______ _____ that enclose intracellular compartments
internal membranes
lipids are arranged in two closely apposed sheets, forming a _____ ______
lipid bilayer
what does a lipid bilayer do
serves as a permeability barrier to most water soluble molecules, while the protein embedded within it carry out the other functions of the membrane
true or false: lipid bilayers are soluble in water
false; although they do dissolve readily in organic solvents such as benzene
each lipid has a _______ head and a ______ tail
hydrophilic (water loving), hydrophobic (water fearing)
the most abundant lipids in cell membranes are the ______
phospholipids
what does amphipathic mean
molecule with both hydrophilic and hydrophobic parts
examples of amphipathic
phospholipids, cholesterol, glycolipids
why do hydrophilic molecules dissolve readily in water
bc they contain either charged groups or uncharged polar groups that can form electrostatic attractions or hydrogen bond with water molecules
why are hydrophobic molecules insoluble in water
bc their atoms are uncharged and nonpolar
what are synthetic bilayers used for
used to study the way lipids move
what does transverse occur
(flip-flop) occurs through the transfer of phospholipid molecule from one bilayer leaflet to the other
what does lateral diffusion occur
occurs through the pairwise exchange of neighboring phospholipid molecule in the same bilayer leaflet
the fluidity of a lipid bilayer depends on what
it composition (closer and more regular the packing of the tails = more viscous and less fluid)(more double bonds = less packed)(shorter tails = less interaction=more fluid)
how many carbon atoms is the most common in hydrocarbon tails of membrane phospholipids
18-20
the fluidity of a cell membrane =
the ease with which its lipid molecules move within the plane of the bilayer
what makes a hydrocarbon tail saturated
no double bonds and has a full complement of hydrogen atoms
in animal cells, membrane fluidity is modulated by the inclusion of the sterol ____
cholesterol
why is membrane fluidity important
enables many membrane proteins to diffuse rapidly, cell signaling, ensures membrane molecules are distributed evenly between daughter cells when a cell divides
the golgi membrane contains another family of phospholipid-handling transporters, called _______
flipase
what does flippase do
removes specific phospholipids from the side of the bilayer facing the exterior space and flip them into the monolayer that faces the cytosol
where the cytosolic monolayer face
the cytosol (inside)
where does the noncytosolic monolayer face
either the cell exterior (in case of the plasma membrane) or the interior space (lumen) (outside)
among lipids, those that show the most dramatically lopsided distribution in cell membranes are the ____
glycolipids, (which are located mainly in the plasma membrane, and only in the nonsytosolic half of the bilayer)
membrane assembly
- fatty acid attached to Co-A
- fatty acids bind glycerol 3-phosphate
- inserted in membrane leaflet
- phosphate removed
- polar head attached to glycerol
most membrane functions are carried out by ______
membrane proteins
transporters (protein example and specific function)
Na+ pump - actively pumps Na+ out of the cells and K+ into the cells
ion channels (protein example and specific function)
K+ leak channel - allows K+ ions to leave cells, thereby influencing cell excitability
anchors (protein example and specific function)
integrins - link intracellular actin filaments to extracellular matrix proteins
receptors (protein example and specific function)
platelet-derived growth factor (PDGF) receptor - binds extracellular PDGF and, as a consequence, generates intracellular signals that direct the cell to grow and divide
enzymes (protein example and specific function)
adenylyl cyclase - catalyzes the production of the small intracellular signaling and molecule cyclic AMP in response to extracellular
transmembrane proteins
extends through bilayer and amphipathic
monolayer-associated protein
cytosolic half of membrane and amhipathic a-helix
lipid linked protein
outside the bilayer, ec or cytosolic and anchored by covalently attached lipid
peripheral proteins
attached to other membrane proteins and via weak noncovalent interactions
integral membrane proteins vs peripheral mem proteins
ip: can be released only by disrupting the membrane with detergents
pp: can be released from membrane by gentle extraction
what is the spectrum tetramers made of
linked spectrum dimers and actin molecules link = forming a mesh network
the network from linked spectrum dimers are attached to what
the plasma membrane
single-particle tracking microscopy
label and follow individual or small clusters of molecules
subatomic particles
protons (+), neutrons (no charge), electrons (-)
what is the atomic number
the number of protons in an atom
number of electrons equals what
the atomic number
what are isotopes
atoms of the same element that differ in the number of neutrons (same atomic numbers/different mass numbers)
what are polar covalent bonds
electrons shared unequally (different electronegativites)
electronegativity of elements most to least
oxygen (3.44)
nitrogen (2.55)
carbon (2.2)
hydrogen (3.04)
when blood pH rises, _______ ______ dissociates to form bicarbonate and H+
carbonic acid
when blood pH drops, _______ binds H+ to form carbonic acid
bicarbonate
each carbon atom can form covalent bonds with up to
four atoms
what are chemical groups
atoms or clusters of atoms that are covalently bonded to carbon backbone
what is the macromolecule, bond and other important information of the monomer sugars (monosaccharides)
macromolecule: polysaccharides
bond: glycosidic bonds
info: energy storage, structure
what is the macromolecule, bond and other important information of the monomer fatty acids
macromolecule: phospholipids
bond: ester bond
info: hydrophobic (lipids), amphipathic - phospholipids (hydrophilic head, hydrophobic tails)
what is the macromolecule, bond and other important information of the monomer amino acid
macromolecule:proteins
bond: peptide
info: directional - n terminus (amino acid side) c terminus (carboxyl group side)
what is the macromolecule, bond and other important information of the monomer nucleotide
macromolecule: polysaccharides
bond: glycosidic bonds
info: energy storage, structure
