Plant cell organelles Flashcards
How many nucleus’ do plant cells contain and what are they
Usually one but can be more
Contains most genetic material - DNA, RNA, protein
What is the nuclear envelope
Double membrane that surrounds the nucleus
What is the use of nuclear pores
Allows proteins and RNA to move in/out of nucleus
Control what is being transcribed/translated
What is heterochromatin
Inactive chromatin
What is euchromatin
Accessible chromatin that can be transcribed
What does the nucleolus consist of
Material that will make up ribosomes
What occurs at the nucleolus
rRNA synthesis
When are ribosomes inactive
When the two subunits come apart
Where are ribosomes located
Rough ER
Nuclear envelope
Within the cytosol
What occurs at the smooth ER
Lipid synthesis
Carbohydrate metabolism
How does the RNA material reach the rough ER
Rough ER normally attached to the nucleus so comes straight from nucleus to endoplasmic reticulum to be made to a protein
What is the golgi body function
Provides network of vesicles for secretory purposes
Sorts - proteins know where to go, packages for transport
Modifies products from rough ER
What is the golgi body made of
Flattened sacs of cisternae
What occurs at cis face of golgi
Receive vesicles from rough ER
What happens to the transcribed mRNA
Goes to ribosomes to be translated into protein
Proteins sorted to smooth ER, where bud off into vesicles, go where need to/go to cystol for further modficiation
What happens at trans face of golgi
Form vesicles then go where needed
What occurs at the mitochondria
Respiration
Structure of mitochondria
Has double membrane
- inner membrane highly folded - cistae
Gives large SA for for ATP synthesis
Structure of chloroplasts
Double membrane
Thylakoids - membranous sacs stacked to form granum
Own starch grains
Stroma - internal fluid
Where does photosynthesis occur in chloroplast
Grana - light reaction
Where does carbon dioxide fixation occur in chloroplast
Stroma
Examples of plastids
Proplastid Chloroplast Chromoplast Leucoplast Elaioplast Proteinplast Amyloplast
What is the function of a chloroplast
Produce energy
What is the function of a proplastid
Depending on what cell it goes into it develops into different thing
What is the function of a chromoplast
Pigment synthesis and storage
What is the function of a leucoplast
Store variety of energy sources in non-photosynthetic cells
What is the function of a elaioplast
Storage of lipids in e.g. carrots
What is the function of a proteinoplast
Protein storage and site of enzyme activity on these proteins in a lot of cells
What is the function of a amyloplast
Synthesis and storage of starch
What happens if plant lacks statoliths
Plant can’t respond to gravity
Roots end up coiling = agravitropic
What is the peroxisome
Metabolic compartment bound by single membrane
Self replicating but doesnt have own DNA so requires it from nucleus
What is the peroxisome function
Detoxing cell, helps cell survive in toxic environment
Hydrogen peroxide is a metabolic waste product, toxic to cell - peroxisome converts it to water
What is a vacuole
Membrane bound organelles filled with cell sap
Contains fluid often acidic pH, many have toxic/bitter compounds to stop animals eating them
What is the function of the vacuole
Keeps plant upright
Provide turgor pressure - lots of water stored in vacuoles
How does the vacuole link to homeostasis
Regulate the turgidity by regulating amount of water in the cell.
Cell has excessive water: vacuole absorbs the water and then diffuses it out of the cell
Cell lacks water: water from the vacuole gets passed back into the cell - maintaining turgidity
How does the cytoskeleton benefit the plant cell
Vesicles from ER and golgi travel along ‘monorails’ provided by cytoskeleton
Growth in particular direction
Involved in positioning organelles e.g. chloroplasts where most light
Plasma membrane function
Mediates subtance transport in/put cell using transmembrane protiens
Coordinates synthesis and assembly of cellulose microfibrils
Relays hormonal and environmental signalling factors
What is the plasmodesmata function
Provides mechanism of symplastic (within cell) communication
What is the plasmodesmata
Channels that link cells cytoplasms through cell wall (across middle lamella)
