cell functions Flashcards
what is the function of the nucleus?
contains the DNA which codes for protein synthesis
what is the function of the nuclear envelope?
seperates the DNA from the cytoplasm
what is the function of the nuclear pore?
allows transport of mRNA out of the nucleus
what is the function of the nucleolus
synthesis of rRNA and ribosomes
what is the structure of ribosomes?
consists of 2 subunits (large and small) made from rRNA and protein
what is the function of ribosomes?
protein synthesis
structure of rough endoplasmic reticulum (RER) ?
forms of flattened sacs (cisternae) which are continuous with the nuclear membrane and may link to the golgi body
What is attached to the RER?
ribosomes
what is the function of the RER?
transports proteins which are synthesised by the ribosomes attached
how is the structure of the smooth endoplasmic reticulum different to the RER?
it does not contain ribosomes
what is the function of the SER?
the synthesis and transport of lipids
what is the structure of the golgi body?
similar the the SER+RER but is more compact
what is the golgi body surrounded by?
vesicles
modifies one, creates two and packages one
what are the 4 functions of the golgi body?
- chemically modifies proteins
- produces lysosomes
- produces glycoproteins
- packages proteins for secretion out of the cell
what sort of membrane does a mitochondria have?
a double membrane
what is the double membrane seperated by?
narrow fluid filled intermembrane space
what does the inner membranes folds form?
cistrae
what is the interior of the mitochondrion called?
the matrix
type of protein
what does the matrix contain?
enzymes
what organelles does the mitochondria contain?
DNA and ribosomes
what is the function of the mitochondria?
the site of aerobic respiration which synthesises ATP
what does the cistrae increase?
the suface area in which part of the respiratory process takes place
what is the structure of vesicles?
small membrane bound organelles
what are the functions of vesicles?
acts as a contractile vacuole to maintain osmotic pressure
structure of the plant vacuole
large membrane bound organelle surrounded by a tonoplast
function of the vacuole
storage of ions and organic molecules
structure of centrioles
consists of 2 hollow cylinders positioned at right angles to eachother
funtion of centrioles?
are used in spindle formation in cell division
structure of lysosome
small vacuoles formed when small portions of the golgi body are pinched off
three functions of lysosomes
- contain and isolate digestive enzymes
- release these enzymes and destroy organelles
- division of material taken into the cell
what sort of membrane does a chloroplast have?
double membrane
what do thykaloids look like ?
flattened sacs
what do many thykaloids form?
granums
what forms between the grana and thykaloids?
lamellae
what is the function of chloroplasts?
site of photosynthesis
what do the thykaloids contain?
chlorophyll
what is the cell wall made of?
cellulose microfibrils in a polysaccharide matrix
3 functions of the cell wall
- freely permeable to water
- prevents osmotic lysis
- provides strength and support
osmotic lysis = the cell wall bursting
structure of the plasmodesmata
a narrow thread of cytoplasm that passses through the cell walls of adjacent plant cells
2 functions of plasmodesmata
- exchange of large organic materials
- allows communication between adjacent cells
