cell structure Flashcards
what does prokaryotic mean? give an example
“before nucleus” e.g. bacterial cells, they have no membrane bound organelles
what does eukaryotic mean?
“true nucleus” e.g. animal, plant and fungal cells, they have membrane bound organelles
describe the stages of protein synthesis
1) proeins synthesied on the ribosomes bound to the ER
2) pass into the cisternae and packaged onto the transport vesicles
3) vesicles conataining the newly synthesied proteins move towards the golgi apparatus via the transport function of the cyroskeleton
4) the vesicles fuse with the golgi apparatus and the proteins enter
5) proteins are structually modified before leaving the golgi in vesicles
6) secretory vesicles carry proteins to be secreted from the cell, they move towards then fuse with the plasma membrane releasing their contents by exocytosis
give the features and functions of the vacuole
surrounded by membrane called the tonoplast & contains cell sap. Uses- important when studying osmosis in plants
describe plasma membrane and its function
made mainly of proteins and lipids its the surface of animal cells in the inside of plant cells- regulates the movement of substances in and out of the cell, also has receptor molecules on it which allow it to respond to chemicals like hormones
describe a cell wall and its funtion
rigid structure that surrounds plant cells mainly made of cellulose- supports plant cells
describle flagella or undulipodia & function
found in eukaryotic cells with cilla, longer and differnt function made of microtubles, in prokaryotic cells known as flagella, any human cell with an undulipodia like flagellum is a spermatozan- whip like movement
Cilla & function
eukaryotic cells, cilla found in grater numbers, cilla can be mobile or stationary - mobile has a rhythmic motion to produce a current in surrounding fluid, cilliated cells line the trachea to move mucus, in fallopian tubes. Stationary- one cillum used as a sensory purpose can also be used for signally purposes.
cytoskeleton & functions
network of fibers necessary for the shape of a cell holds organelles in place, contorls cell movement and the movement of organelles within the cells
THREE COMPONENTS
give the 3 components of the cytoskeleton function
1- microfilaments- contractile fibers made from the protien actin, responsible for cell movement & cell contraction during cytokenesis
2- microtubules- globular tubular proteins polymerise to form scaffold like structure determining shape. Act like tracts for organelles spindle fibres are made of microtubules
3- intermediate fibers- give mechanical strength to the cell & help maintain their integrity
nucleus & function
double membrane bound organelle, has nuclear pores for exchange of large molecules with cytolpasm, nucleoplasm conatins chromatin - control of cell and cell division
mitochondria & funtion
double membrane, spherical or rod shaped, about 1000 in a typical cell, cristae increase the SA for reactions to take place
ribosomes & function
70s in prokryotes and 80s in eukayotes (70s in chloroplasts and mitochondria), very small, made of equal parts protein and RNA, can from polyribosomes - site of protein synthesis
rER &; function
ribosomes, continuous with plasma membrane, phospolipd membrane- increase surface area for chemical reactions, transport proteins, cell shape
sER & function
phospholipid membrane, continuous with nucleus and plasma membrane- lumen more tubluar, cell shape, increase SA for chemical reactions
