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39 terms

Chapter 6: cell structure and function

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active transport
the movement of materials through a cell membrane using energy
ATP
(adenosine triphosphate) main energy source that cells use for most of their work
cell
(biology) the basic structural and functional unit of all organisms
cell theory
idea that all living things are composed of cells, cells are the basic units of structure and function in living things, and new cells are produced from existing cells
cell wall
strong layer around the cell membrane in plants, algae, and some bacteria
chloroplast
an organelle found in plant and algae cells where photosynthesis occurs
cilia
short, hair-like structures made of microtubules that enable movement of cells or movement of materials outside a cell
concentration
describes how much solute is present in a solution compared to the amount of solvent
cytology
study of cells
diffusion
process by which molecules tend to move from an area where they are more concentrated to an area where they are less concentrated
endocytosis
process by which a cell takes in a substance by surrounding it with the cell membrane
endoplasmic reticulum
a system of membranes that is found in a cell's cytoplasm and that assists in the production, processing, and transport of proteins and in the production of lipids
equilibrium
When the concentration of a solute is the same throughout a solution
eukaryotic cell
A type of cell with a membrane-enclosed nucleus and membrane-enclosed organelles. Examples of organisms with these cells are protists, plants, fungi, and animals.
exocytosis
the process by which a substance is released from the cell through a vesicle that transports the substance to the cell surface and then fuses with the membrane to let the substance out
facilitated diffusion
movement of specific molecules across cell membranes through carrier proteins
flagella
long, thin, whip-like structures, with a core of microtubules, that enable some cells to move
golgi apparatus
stack of membranes in the cell that modifies, sorts, and packages proteins from the endoplasmic reticulum
hypertonic
describes a solution whose solute concentration is higher than the solute concentration inside a cell; net water flow is going out of a cell
hypotonic
when comparing two solutions, the solution with the lesser concentration of solutes; net water flow is going into a cell
isotonic
having a solute concentration equal to that of another solution; net water flow is in equilibrium
lysosome
membrane-bound sac(organelle) containing digestive enzymes that can break down proteins, nucleic acids, and polysaccharides
membrane
thin layer that separates various cellular structures or organs
microfilament
solid rod of protein, thinner than a microtubule, that enables a cell to move or change shape; found in eukaryotic cells
microtubule
straight, hollow tube of proteins that gives rigidity, shape, and organization to a cell
mitochondria
Powerhouse of the cell, organelle that is the site of ATP (energy) production
nuclear envelope
layer of two membranes that surrounds the nucleus of a cell
nucleolus
The organelle where ribosomes are made, synthesized and partially assembled, located in the nucleus
organelle
specialized structure that performs important cellular functions within a eukaryotic cell (prokaryotic cells have some)
osmosis
diffusion of molecules through a semipermeable membrane from a place of higher concentration to a place of lower concentration until the concentration on both sides is equal
passive transport
transport of a substance across a cell membrane by diffusion
permeable membrane
a membrane that allows for diffusion of certain solutes and water
phospholipid bilayer
two-layer "sandwich" of molecules that surrounds a cell
plasma membrane
thin flexible barrier that regulates what enters and exits the cell; composed of two layers of lipids
prokaryotic cell
A type of cell lacking a membrane-enclosed nucleus and membrane-enclosed organelles; found only in the domains Bacteria and Archaea.
ribosome
small organelle in the cell on which proteins are assembled; made of RNA and protein
selectively permeable
a property of cell membranes that allows some substances to pass through, while others cannot
vacuole
cell organelle that stores materials such as water, salts, proteins, and carbohydrates
vesicle
small membrane-bound sac that functions in moving products into, out of, and within a cell