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37 terms

Biology chapter 6

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cell theory
the generalization that all living things are composed of cells, and that cells are the basic unit of structure and function of living things.
micrograph
photograph of the view through a microscope
plasma membrane
thin outer boundary which defines the boundary of the cell and regulates the traffic of chemicals between the cells and its surroundings.
nucleus
houses the cells genetic material in the form of DNA
cytoplasm
entire region of the cell between the nucleus and the plasma membrane
cell wall
protects the plant cell and maintains its shape *only plant cells have a cell wall.
prokaryotic cell
lacks a nucleus and most other organelles ex. bacteria
eukaryotic cell
has a nucleus surrounded by its own membrane, and has other internal organelles bounded by membranes. ex. plants, fungi, prosists, and animal
hydrophilic
loves water.
hydrophobic
doesnt like water, doesnt interact with water
phospholipid bilayer
"sandwich" of molecules which surround the organelle wall.
fatty acid tails = HYDROPHOBIC
...
PROTEINS embedded in the phospholipid bilayer.
...
diffusion
the net movement of the particles of a substance from where they are concentrated to where they are less concentrated.
equilibrium
or balance
selectively permeable membrane
allows some substances to cross the membrane more easily then others and blocks the passage of some substances altogether. this is PASSIVE TRANSPORT.
passive transport
diffusion across a membrane, because no energy is needed to do this. *high concentration to low concentration
facilitated diffusion
transport proteins provide a pathway for certain molecules to pass. (facilitate = to help)
osmosis
passive transport over a selectively permeable membrane
hypertonic
a solution with higher concentration
hypotonic
a solution that is said to have lower concentration
isotonic
solutions in which the concentrations of the solute are equal are said to be isotonic.
active transport
a process when a cell expands energy to move molecules or ions across a membrane. during active transport a specific protein pumps a solute across a membrane, usually the opposite direction in which diffusion travels. LOW CONCENTRATION --> HIGH CONCENTRATION
vesicles
larger particles are packages in vesicles in order to move through the membrane.
exocytosis
exiting the products from the cell by fusing with the plasma membrane and spilling its contents out of the cell.
endocytosis
reverse process of exocytosis, takes material into a cell within vesicles that bud inward from the plasma membrane
nuclear envelope
surrounds the nucleus in a pair of membranes, substances made in the nucleus move into the cell's cytoplasm through tiny holes or pores in the nuclear envelope.
nucleous
contains the parts that make up organelles called ribosomes.
ribosomes
proteins are constructed in a cell by ribosomes, "workers"
endoplasmic reticulum
within the cytoplasm of a cell is an extensive network of membranes, produces and enormous amount of molecules. main manufacturing and transportation facilities in the celll factory.
rough ER
has ribosomes lined on the outside of the membrane., ribosomes produce proteins, also produce proteins which are packaged in vesicles.
smooth ER
lack ribosomes but builds lipid molecules.
the golgi apparatus
an organelle that modify, stores, and routes proteins and other chemical products to their next destinations.
vavuoles
in the cytoplasm which are large membrane-bound sacs, they store undigested nutrients.
Lysosomes
membrane bound sacs which contain digestive enzymes that can break down such macromolecules as proteins, nucleic acids and polysaccharides.
mitochondria
they are in eukaryotic cells, and sites where cellular respiration occurs. In this process it releases energy from sugars and certain other organic molecules and then uses it in the formation of another organic molecule called ATP.
ATP (adenosine triphosate)
the main energy source that cells use for most of their work.