biology - chapter 2 Flashcards
cells
cell theory
all things are made up of one or more cells
cells are the basic unit of life
cells can only come from other cells
prokaryote
a cell that doesn’t contain a nucleus or other membrane-bound organelles
eukaryote
a cell that contains a nucleus and other organelles, each surrounded by a thin membrane
example of a prokaryote
e.coli
organelle
a cell structure that performs a specific function for the cell
name all of the organelles common to plant and animal cells
cytoplasm, cell membrane, nucleus, nucleolus, mitochondria, endoplasmic reticulum, golgi bodies, vacuoles
cytoplasm
mostly water, but also contains other substances.
jelly-like (although sometimes liquid) substance holding all the organelles in the cell.
cell membrane
a flexible double-layered membrane functioning to support the cell and allow some substances to enter and some not.
semi-permeable.
nucleus
spherical structure containing genetic information and instructs the cell
DNA
the material in the nucleus of a cell that contains all fo the cell’s genetic information
mitchondria
convert energy for the cell (powerhouse)
active tissues have more mitochondria
endoplasmic reticulum
network of tubes and pockets that transport materials like proteins through the cell
controls hormones in the brain
controls contraction in the muscles
golgi bodies
collect and process materials for export out of the cell
also make mucus
any tissue with a lot of mucus = many golgi bodies
vacuoles
a single layer of membrane enclosing fluid in a sac
containing substances
removes stuff out of the cell
maintaining pressure
organelles only in plant cells
cell wall
central vacuole
chloroplasts
cell wall
rigid but porous structure made of cellulose protecting the outside of the cell from physical injury
central vacuole
full of water which keeps the pressure correct and the cells plump and firm
asexual reproduction
the process of producing offspring from only one parent; genetically identical to the parent
sexual reproduction
the process of producing offspring by the fusion of two gametes; genetic information from each parent
gametes
parental cells that contain only half of the DNA usually found in a cell. they join with another cell to create a new organism!!
why do cells not just get bigger instead of multiplying?
the bigger a cell is, the longer diffusion takes, and all organelles in a cell need certain chemicals so they cant take too long to get there
diffusion
a transport mechanism for moving chemicals into and out of the cell from an area of higher concentration to an area of lower concentration
concentration
the amount of a substance in a given volume of solution
osmosis
the movement of a fluid, usually water, across a membrane toward an area of high solute concentration