L1.5 - Eukaryotic Cells Flashcards
(20 cards)
What is the structure of ribosomes?
4
tiny organelles made of RNA + protein
consist of 1 large + 1 small sub-unit
not always attached to ER, many found floating in cytoplasm
have no membrane
What is the function of ribosomes?
1
Site of protein synthesis
What is the structure of the nucleus and nucleolus?
4
jelly like matrix
spherical
Nuclear envelope - double membrane
Nucleolus - smaller sphere inside
What is the function of the nucleus and nucleolus?
3
produces RNA to make ribosomes (nucleolus)
Site of DNA replication + transcript (making mRNA)
Contains genetic code for each cell
What is the structure of the endoplasmic reticulum (ER)?
2
Folded membranes (cisternae)
RER has ribosomes lining the cisternae
What is the function of the endoplasmic reticulum (ER)?
2
RER - involved in protein synthesis
SER - Involved in the synthesis + storage of lipids
What is the structure of the golgi apparatus?
2
Folded membranes making cisternae
Secretary vesicles pinch off from cisternae
What is the function of the golgi apparatus?
4
package proteins for secretion
secrete carbs
transport + store lipids
form lysosomes
What is the structure of lysosomes?
1
membrane bound vesicles secreted by golgi apparatus containing ‘hydrolytic enzymes’
What is the function of lysosomes?
2
Secrete digestive enzymes outside the cell
breaks down ingested material or worn out organelles or destroys cells when they die
What is the structure of mitochondria?
3
Double membrane
Inner membrane called cristae
a matrix - contains ribosomes, own DNA + enzymes for respiration
What is the structure of chloroplasts?
4
Double membrane, forming an envelope
Has a colourless mixture called stomata (contains enzymes for photosynthesis)
has thylakoids floating in stomata
have genetic information + ribosomes
What is the function of chloroplasts?
1
Site of photosynthesis
What is the structure of the cell wall?
2
Plants - Made of microfibrils of the cellulose polymer
Fungi - Made of chitin, a nitrogen-containing polysaccharide
What is the function of the cell wall?
3
provides structural support to plant
stops plant bursting when water moves in by osmosis
involved in transport of water into and throughout the plant
What is the structure of the cell vacuole?
3
liquid filled space surrounded by a membrane (membrane called a tonoplast)
many are small (called vesicles)
all cells have one, plants have a large one
What is the function of the cell vacuole?
4
storage (sugars + amino acids)
isolate substances which may be harmful to the rest of the cell
help maintain cell turgidity
Pigments may colour petals to attract pollinators
What is the function of the mitochondria?
2
Site of aerobic respiration to produce ATP
DNA to code for enzymes needed in respiration
What is the structure of plasma membrane?
2
In all cells
Had a phospholipid bilayer - molecules embed within + attached on the outside
What is the function of plasma membrane?
1
Controls the entrance + exit of molecules
