organelles and unique features part 1 Flashcards
plant cells
protoplast
cytoplasm
protoplast
pm + cytoplasm + nucleus
cytoplasm
cytosol and other organelles and structures
cytosol
liquid portion of cytoplasm
ctyosol
liquid portion of cytoplasm
subcellular components
- nucleus
- plastids
- mitochondria
- microbodies
- ribosomes
nucleus
- controls cellular activites
- double membrane
- nuclear pores continuous with the ER
- nucleoli
plastids
-chloroplasts,
-chromoplasts,
-leucoplasts
-double membranes
plants can interconvert their plastids
stroma = liquid portion
plastid developmental cycle (slide 14)
- origintel as proplastids
- formed by fission
- in dark = etioplasts
- in light = develop into chloroplasts
- chromoplasts from chloroplasts , but they may develop directly
- roots in dark = leucoplasts develop
proplastids
small and undifferentiated
etioplasts
contain prolamellar bodies
seedlings
proplastids –> etioplasts–> chloroplasts
mitochondria
- double membrane
- inner on folded into cristae
- increases surface area for rxns
- fluid = matrix
- many/cell
- small
- variable in shape
- site of cellular respiration
- require O2, release ATP
microbodies
- single membrane
- spherical with a granular interior
- can have crystalline protein body
- can have enxymes to convert fats into sucrose -gloxysomes
- others are peroxisomes - photorespiration
- both contain catalase to detoxify H2O2
- both are interconvertible
- self replicating
ribosomes
- no membrane
- small particles composed of protein and RNA
- parts made in nucleolus, assembled in cytoplasm
- site of protein synthesis
- free in cytoplasm or on ER or nuclear membrane
- groupd = polyribosomes
- free ribosome produce proteins for cytoplasm
endomembrane system
endoplasmic reticulum
golgi complex
RER
- w/ ribosome
- more flattened
- modifies proteins = produces glycoproteins
SER
- no ribosomes
- tubular
- synthesizes lipids and metabolizes carbohydrates
RER and SER
interconnected
Golgi
- stacks of flattened sacs/cisternae
- single membrane
- packing centre
- synthesize polysaccharides eg. Pectins
- process and secrete glycoproteins from RER
RER and golgi
vesicle from RER fuse with forming face, vesicles pinch off the maturing face, vescicles then travel to wherever contents are required, (formation of a cell plate
central vacuole
-single membrane = tonoplast
-single, large vacuole
can subdivide
-fluid =cell sap
cell sap
high proportion of water, other components are variable, components dependent on age, type, size and location of cell in plant,
- components may form cystals
- sugars, amino acids and organic acids also common
- some contain abundant anthocyanins
- may breakdown/recycle cellular components
- maintains turgor pressure in fully enlarged cells
- aids in cell enlargement and therefore growth when small vacuoles coalesce
cytoskeleton
microtubules
microfilaments
microtubules
- long, cylindrical structures composed of tubulin
- dynamic instabiliy by breaking down and reforming
- invovled with cell wall formation by guiding vesicles
- control orientation of cellulose microfibrils in cell walls
- make up spindle fibers and other critical roles during cell division
microfilaments
- long, spirally arranged chains of actin
- smaller diameter than microtubules
- aid in cytoplasmic streaming and organelle movements
- involved in pollen tube growth
- also associated with microtubules in their functions
