test 11/2/15 Flashcards
who was Robert Hooke and how did he discover cells
he was the first person to use a light microscope in 1665 and he discovered cells by looking at a piece of cork under a LM and it made him think of tiny cell chambers like the cell
cell theory- 3 different facts-
- all living things are made up of cells
- cells are the basic unit of structure and function in living things
- new cells are produced from existing cells
tell the difference between eukaryotes and prokarotes
-eukaryotes have a nucleus and prokaryotes don’t
what is the cell membrane
it regulates what enters and leaves the cell and also provides support and protection
what is the lipid bilayer
it is a double layered sheet around the cell membrane. it gives all the cell membranes a strong, flexible structure that forms a strong barrier between the cell and its surroundings
what is the main function of the cell wall
it is to provide support and protection for the cell
what is concentration of a solution
it is the mass of solute in a given volume of a solution or mass/volume.
ex. 3g per liter
what is diffusion
when particles move to an area where they are less concentrated from a more concentrated area
what is equilibrium
when the concentration of the solute is the same throughout a system
why don’t substances require the cell to use energy when they diffuse across membranes
bc diffusion depends upon random particle movements
what is osmosis
its the diffusion of water through a selectively permeable membrane
what does permeable mean
means water is allowed to pass through it
what does impermeable mean
means water is not allowed to pass through it
what does isotonic mean
same strength
what does hypertonic mean
above strength
what does hypotonic mean
below strength
what is osmotic pressure
osmosis pressure exerts a pressure known as osmotic pressure on the hypertonic side of a selectively permeable membrane
what happens during facilitated diffusion
molecules such as glucose can not be diffused across the cell membrane on its on so it has to move through protein channels instead
what is active transport
it requires energy
the cell must sometimes move materials in the opposite direction against concentration
what is endocytosis
the process of taking materials into the cell by means of pockets
what is phagocytosis
cell eating
what is pinocytosis
pockets that form along a cell membrane that fill with liquid and pinch off to form vacuoles along the cells
what is exocytosis
fuses with the cell membrane and forces all the contents out of the cell
what are unicellular organisms
single celled organisms
include both prokaryotes and eukaryotes
what are multicellular organisms
made up of many cells that work together
what are the levels of organization in an multicellular organism
cells, tissues, organs, organ system
what are organs
many groups of tissues that work together
what are organ systems
a group of organs that work together
what are cels in multicellular organisms specialized to do
to perform particular functions within the organism
what do multicellular organisms have
have cell specialization and play different rolls for each type of cell
who was anton van leewenhoek
he was the first person to ever use a microscope in the 1600 to study nature
