atoms, molecules
_______ & ________ from the environment are necessary to build new molecules.
carbon
_____________ is used to build biological molecules such as carbohydrates, proteins, lipids, and nucleic acids.
storage, cell
carbon is used in ____________ compounds and ______ formation in all organisms.
nitrogen
_____________ is used to build proteins and nucleic acids.
phosphorus
______________ is used to build nucleic acids and certain lipids.
hydrolysis, dehydration, monomers
______________ and _____________ synthesis are used to cleave and form covalent bonds between _____________.
polymers
structure and function of ______________ are derived from the way their monomers are assembled.
nucleotide
in nucleic acids, biological information is encoded in sequences of ____________ monomers.
five, phosphate, nitrogen
each nucleotide has structural components: a ______-carbon sugar (deoxyribose or ribose), a ___________, and a ___________ base (adenine, thymine, guanine, cytosine, or uracil).
dna, rna
_______ and ______ differ in structure and function.
order, polypeptide, shape
in proteins, the specific _________ of amino acids in a ___________ (primary structure) determines the overall ________ of the protein.
directionality, amino, carboxyl
amino acids have _____________, with an ________ (NH2) terminus and a __________ (COOH) terminus.
hydrophilic, hydrophobic, ionic
the R group of an amino acid can be categorized by chemical properties (______________, ______________, or _______),
structure
the interactions of R groups determine ____________ and function of that region of the protein.
carbohydrates
complex __________________ comprise sugar monomers whose structures determine the properties and functions of the molecules.
lipids
_________ are nonpolar macromolecules.
saturation
differences in _________________ determine the structure and function of lipids
phospholipids, polar
_________________ contain polar regions that interact with other _________ molecules, such as water, and with nonpolar regions that are often hydrophobic.
subcomponents
directionality of the _________________ influences structure and function of the polymer.
covalent, carboxyl
proteins comprise linear chains of amino acids, connected by the formation of ________________ bonds at the ___________ terminus of the growing peptide chain.
amino
proteins have primary structure determined by the sequence order of their constituent ________ acids.
folding, alpha, beta
proteins have secondary structure that arises through local ___________ of the amino acid chain into elements such as _______-helices and ______-sheets.
three, free
proteins have tertiary structure that is the overall ________-dimensional shape of the protein and often minimizes _______ energy.
polypeptide
proteins have quaternary structure that arises from interactions between multiple ____________ units.
carbohydrates
__________________ comprise linear chains of sugar monomers connected by covalent bonds.
polymers
carbohydrate ______________ may be linear or branched.
ribosomes
________________ comprise ribosomal RNA (rRNA) and protein.
smooth, rough
endoplasmic reticulum (ER) occurs in two forms—_________ and _________.
rough
____________ ER is associated with membrane-bound ribosomes.
rough
_________ ER compartmentalizes the cell.
smooth
_________ ER functions include detoxification and lipid synthesis.
golgi
the ________ complex is a membrane-bound structure that consists of a series of flattened membrane sacs
golgi
functions of the _________ include the correct folding and chemical modification of newly synthesized proteins.
mitochondria, smooth
_______________ have a double membrane. The outer membrane is _______________, but the inner membrane is highly convoluted, forming folds.
lysosomes, enzymes
_______________ are membrane-enclosed sacs that contain hydrolytic _____________.
vacuole, plants
a ___________ is a membrane-bound sac that plays many and differing roles. In __________, a specialized large vacuole serves multiple functions.
chloroplasts, double
_____________ are specialized organelles that are found in photosynthetic algae and plants, and have a ________ outer membrane.
function
organelles and subcellular structures, and the interactions among them, support cellular ________.
mechanical, protein, intracellular
endoplasmic reticulum provides ____________ support, carries out _________ synthesis on membrane-bound ribosomes, and plays a role in ____________ transport.
metabolic
mitochondrial double membrane provides compartments for different ____________ reactions.
enzymes, digestion, recycling
lysosomes contain hydrolytic _________, which are important in intracellular ____________, the ___________ of a cell’s organic materials, and programmed cell death (apoptosis).
increases, atp
the folding of the inner membrane __________ the surface area, which allows for more _____ to be synthesized.
thylakoids, stroma
within the chloroplast are __________ and the _________.
grana
thylakoids are organized in stacks, called _______.
pigments, proteins
membranes contain chlorophyll _________ and electron transport _________ that comprise the photosystems.
dependent
the light-______________ reactions of photosynthesis occur in the grana.
stroma
the _________ is the fluid within the inner chloroplast membrane and outside of the thylakoid.
stroma
the carbon fixation (calvin-cycle) reactions of photosynthesis occur in the _________.
mitochondria
the krebs cycle (citric acid cycle) reactions occur in the matrix of the ______________.
mitochondrial
electron transport and ATP synthesis occur on the inner ______________ membrane.
wastes
organisms have evolved highly efficient strategies to obtain nutrients and eliminate ________.
exchange, surrounding
cells and organisms use specialized __________ surfaces to obtain and release molecules from or into the ____________ environment.
phospholipids
_______________ have both hydrophilic and hydrophobic regions.
hydrophilic
the ____________ phosphate regions of the phospholipids are oriented toward the aqueous external or internal environments.
hydrophobic
the ______________ fatty acid regions of the phospholipids face each other within the interior of the membrane.
embedded
_____________ proteins can be hydrophilic, with charged and polar side groups, or hydrophobic, with nonpolar side groups.
steriods, glycoproteins, glycolipids
cell membranes consist of a structural framework of phospholipid molecules that is embedded with proteins, ___________ (such as cholesterol in eukaryotes), ____________, and ____________ that can flow around the surface of the cell within the membrane.
selective
the structure of cell membranes results in ____________ permeability.
separate
cell membranes __________ the internal environment of the cell from the external environment.
selective
___________ permeability is a direct consequence of membrane structure, as described by the fluid mosaic model.
nonpolar
small _____________ molecules, including N2, O2, and CO2 , freely pass across the membrane.
polar
hydrophilic substances, such as large __________ molecules and ions, move across the membrane through embedded channels and transport proteins.
polar, h2o
_________ uncharged molecules, including ______, pass through the membrane in small amounts.
cell walls
________ _______ provide a structural boundary, as well as a permeability barrier for some substances to the internal environments.
carbohydrates
cell walls of plants, prokaryotes, and fungi are composed of complex ______________.
high, low
passive transport is the net movement of molecules from ____ concentration to ______ concentration without the direct input of metabolic energy.
passive
__________ transport plays a primary role in the import of materials and the export of wastes.
low, high
active transport requires the direct input of energy to move molecules from regions of ____ concentration to regions of ____ concentration.
selective
the ___________ permeability of membranes allows for the formation of concentration gradients of solutes across the membrane.
energy, large
the processes of endocytosis and exocytosis require ________ to move ________ molecules into and out of cells.
exocytosis
in _____________, internal vesicles fuse with the plasma membrane and secrete large macromolecules out of the cell.
endocytosis
in _______________, the cell takes in macromolecules and particulate matter by forming new vesicles derived from the plasma membrane.
diffusion
membrane proteins are required for facilitated ___________ of charged and large polar molecules through a membrane
aquaporins
large quantities of water pass through ______________.
channel
charged ions, including Na+ and K+, require __________ proteins to move through the membrane.
polarized
membranes may become ____________ by movement of ions across a membrane.
active
membrane proteins are necessary for _________ transport.
metabolic, active
____________ energy (such as from ATP) is required for _________ transport of molecules and/ or ions across the membrane and to establish and maintain concentration gradients.
maintenance
the Na+/K+ ATPase contributes to the _________________ of the membrane potential.
external
___________ environments can be hypotonic, hypertonic or isotonic to internal environments of cells.
osmosis
water moves by ____________ from areas of high water potential/low osmolarity/ low solute concentration to areas of low water potential/high osmolarity/high solute concentration.
high, low
______ water potential—>_____ water potential
low, high
______ osmolarity—>_____ osmolarity
low, high
______ solute concentration—>_____ solute concentration
pressure potential
Ψp
solute potential
Ψs
water potential
_______ = Ψs + Ψp
movement
growth and homeostasis are maintained by the constant ___________ of molecules across membranes.
osmoregulation
_________________ maintains water balance and allows organisms to control their internal solute composition/water potential.
solute potential of a solution
Ψs = −iCRT
ionization constant
i
molar constant
c
pressure constant
r (0.0831)
temperature
t (in kelvin (°C + 273))
across
a variety of processes allow for the movement of ions and other molecules __________ membranes, including passive and active transport, endocytosis and exocytosis.
intracellular, enzyme
membranes and membrane-bound organelles in eukaryotic cells compartmentalize ____________ metabolic processes and specific ____________ reactions.
internal
____________ membranes facilitate cellular processes by minimizing competing interactions and by increasing surface areas where reactions can occur.
endosymbiosis
membrane-bound organelles evolved from once free-living prokaryotic cells via ________________.
prokaryotes
__________________ generally lack internal membrane bound organelles but have internal regions with specialized structures and functions.
substrate
the structure of enzymes includes the active site that specifically interacts with ________ molecules.