Cells Exam 9/29 Flashcards
microscope
a tool used to magnify small objects
electron microscopes
microscope that forms an image by focusing beams of electrons onto a specimen
scanning electron microscope
a type of electron microscope used to build up 3D images of the surface of a specimen
transmission electron microscope
an electron microscope that studies the internal structure of cells and takes 2D images
prokaryotes
cells that lack a nucleus and other membrane bound organelles
nuclear membrane
the double membrane that surrounds the nucleus and controls what comes in and out of it
eukaryote
cells that contain a nucleus and membrane bound organelles
nucleus
the distinct central organelle that contains the cell’s genetic material (DNA)
ribosomes
organelles that manufacture proteins
mitochondria
the organelle that converts fuel particles into usable energy (ATP)
cell membrane
the thin membrane the surrounds the cytoplasm of a cell
cell wall
a rigid layer of nonliving material that surrounds the cells of plants and some other organisms
channel proteins
integral membrane proteins that form channels or pores in the cell membrane to facilitate the passage of ions or molecules
diffusion
the tendency for molecules to spread out evenly into the available space
osmosis
the diffusion of water across a selectively permeable membrane
active transport
the movement of particles across a cell membrane into a region of higher concentration which requires energy
endocytosis
the process by which a cell surrounds an object in the outside environment in a portion of the plasma membrane
exocytosis
the excretion of materials at the plasma membrane
homeostasis
the regulation of the internal environment of a cell or organism to maintain conditions suitable for life
cell theory
one of the fundamental ideas of modern biology
principles of cell theory
all living cells are composed of one or more cells
cells are the basic unit of structure and organization of all living organisms
cells arise only from previously existing cells, with cells passing copies of their genetic material onto their daughter cells
examples of prokaryotic organisms
bacteria and virus cells
examples of eukaryotic organisms
human, plant, and animal cells
Ribosomes are made of a ______ and _______ section.
Small and large
What is the cell membrane responsible for?
Homeostasis
Additional energy is not required for _______.
Diffusion
Electron microscopes can only be used on ______ cells.
Dead
