cell structure Flashcards
(27 cards)
vacuole fluid
solution of pigments, enzymes, sugars and other organic compounds (incl. some waste products, oxygen, CO2
vacuoles in animal cells
small, temporary e.g. phagocytic vacuoles
vacuoles in plant cells
large, permanent, central
vacuole membrane
tonoplast
vacuole one function
regulate osmotic properties of cell
another function vacuoles example
pigments (which colour flower petals/parts of vegetable) may be located in vacuoles
animal or plant cell more easily seen under light microscope and why
plant cell. usually larger, cell wall outside of cell surface membrane
cell wall
relatively rigid. gives the cell a definite shape. contains fibres of cellulose, a polysaccharide which strengthens the wall.
cell wall a function
prevents cell from bursting (osmotic lysis?) when water enters by osmosis, allowing large pressures to develop inside the cell
cell walls may be
reinforced with extra extra cellulose or with lignin (hard material) for extra strength
cell wall permeability
freely permeable, allowing free movement of molecules and ions through to the cell surface membrane
plant cells linked
plasmodesmata - fine strands of cytoplasm which pass through pore-like structures in cell walls. movement through the pores is thought to be controlled by the structure of the pores.
cell surface membrane another name
plasma membrane
chloroplasts found in
the green parts of the plant, mainly in the leaves
lysosomes structure
spherical sacs, single membrane, no internal structure
lysosomes contain
digestive (hydrolytic) enzymes
lysosomes functions
breakdown of old organelles or even whole cells, digest bacteria in WBC. sometimes released out of cell
ribosomes function
site of protein synthesis
ribosomes found where
on RER, free in cytoplasm
ribosomes made of
RNA and proteins
proteins made by ribosomes on RER:
enter sacs, move through them, can be modified, vesicles can break off which will form Golgi body
Golgi complex
ER vesicles form Golgi body - stack of flattened sacs. -> at the other end Golgi vesicles break off - make lysosomes
Golgi function
collects, processes, sorts molecules (specifically proteins from RER) for transport to another part of the cell or outside of the cell (secretion)
Golgi processing proteins examples
adds sugar to proteins - glycoproteins. removal of first aa (methionine) of proteins to form a functional protein
