2: cell structures Flashcards
what is an organelle?
a sub-cellular structure that has one or more jobs to perform in the cell
what a cell membrane?
a very thin layer of protein and fat
what is the purpose of the cell membrane?
- controls what enters and leaves the cell
- separates the contents of the cell from the environment
what is a cell wall?
a structural layer made of cellulose, just outside the cell membrane
what does the cell wall do?
- provides support
- gives a definite shape
- prevents cell from bursting
what is a cytoplasm?
a clear jelly made up of water
what is the purpose of the cytoplasm?
place where metabolic reactions take place
what are vacuoles?
a fluid filled space
what is the purpose of the vacuole?
- contains cell sap
- storage of substances
- storage of waste products
what is the nucleus?
the largest organelle
what does the nucleus do?
- contains the genetic material which makes up genes on chromosomes
- protein synthesis, mitosis, cell activities
list the properties of the nucleus
- surrounded by nuclear envelope perforated by nuclear pores
- contains chromatin
- contains nucleolus
what do the nuclear pores of the nuclear envelope do?
allows and controls exchange between nucleus and cytoplasm
what is the chromatin?
long, thin, loosely coiled packs of DNA that condense to make chromosomes
what is the nucleolus?
the nucleolus is a spherical structure found in the nucleus whose primary function is to produce ribosomes
what is the endoplasmic reticulum (ER)?
interconnected tubes and flattened sacs that begin at the nucleus and wind through the cytoplasm
what is the main difference between rough ER and smooth ER?
rough ER is covered with many ribosomes
what is the golgi body?
vesicles that have broken off from the ER and have joined together
what does the golgi body do?
it collects, processes, and sorts molecules
what does RER do?
transports and modifies proteins