Chapter 4 - Cells: The Working Units of Life Flashcards
of the following, which is enclosed in a membrane, and has the greatest amount of internal surface area? nucleus endoplasmic reticulum mitchondria chloroplast ribosome
Endoplasmic reticulum
what would be found at the top of a centrifugation gradient?
ATP molecules
Prokaryotes
are surrounded by a cell membrane
proteins are synthesized by _____ and the carbohydrates are added in the _____.
the rough endoplasmic reticulum and golgi apparatus
T/F
DNA in the nucleus is packaged with several proteins
True
Organelles that is involved in energy-transfer conversation
chloroplasts
the presence of ____ means that substances must pass through, rather than between, the epithelial cells that form the lining of the small intestine
tight junctions
how do biological membranes serve cells?
by being responsible for selective permeability, compartmentalization, interactions with other cells, and the surrounding environment
phospholipid bilayer
prevents free passage of most materials across a membrane
what does the movement of specific substances into or out of a cell often require
specific transporter proteins
how does oxygen enter cells?
by simple diffusion
how does glucose enter cells?
by facilitated diffusion relying on the participation of “transporter” proteins
primary and secondary active transports move solutes in which way
against their concentration gradients
what is required for primary active transport
direct ATP hydrolysis EX Na+K+ATPase
energy moving “down” gradients provides energy transfers that drives
secondary active transport
“saturation” of transport refers to what
solute movements that require transporter proteins, and occurs when all of these proteins are actively transporting their appropriate solute
ribosomes
sites of protein synthesis, where the information encoded by nucleic acids directs the sequential linking of amino acids to form proteins
cytoskeleton
collective name for filaments made up on polymers of monomer subunits that play roles in cell division or in maintaining the shapes of cells
mitochondria
the powerhouse of the cell
centrioles
are associated with nuclear division and formation of cells
cell membrane
separates the cell from its environment and regulates traffic of materials into and out of the cell
rough endoplasmic reticulum
the site of much protein synthesis, which occurs on ribosomes on its surface
cell wall
in a plant cell
supports the cell
ribosomes
assemble proteins
smooth endoplasmic reticulum
proteins and other molecules are chemically modified
chloroplasts
harvest the energy of sunlight to produce sugar
golgi
processes and packages proteins
concentrates, packages, and sorts proteins before they are sent to their cellular or extracellular destinations
adds some carbs to pro
some polysaccharides for the plant cell wall are synthesized
vacuoles
occur in many eukaryotic cells, but particularly those of plants and fungi
storage and structure reproduction and catabolism
microtubules
long, hollow, unbranched cylinders that form rigid internal skeleton for some cells or cell regions
act as a framework along which motor proteins can move structure within the cell
tight junctions
prevent substances from moving through spaces between cells EX: the epithelium of the urinary bladder contains tight junctions to prevent urine from leaking out into the body
Desmosomes
hold adjacent cells together with stable protein connections, but materials can still move around in the extracellular matrix
gap junctions
channels that run between membrane pores in adjacent cells, allowing substances to pass between ells.
