Plastids Flashcards
Define plastids
membrane bound organelles found in the cells of plants, algae and some euk.
What is the primary role of the cholroplasts?
photosynthesis
Name 5 parts of the chloroplasts
Outer and inner membrane
stroma
grana
stroma lamellae
Name three things that the chloroplasts can help synthesis?
fatty acids
lipids
purines and pyrimidines
What are proplastids?
Where are they present and what do they do?
Precursor to other plastids
Present in young meristematic regions
where they divide to keep pace cell division to ensure continuity
Where Elaioplast found?
Are these rare?
What do these store?
Found in cells surrounding a captivity where pollen develops
These are rare
Store mostly sterol esters
What are amyloplasts ?
starch storing plastids in non-green tissues such as storage organs
What are leucoplasts?
Colourless plastids involved in oil and lipid synthesis and surrounded by ER membrane
Plastids are not found in ____?
Plastids are not found in prokaryotes
What is the range of the sizes of a plastids?
89kb to 400 kb
Plastids contain multiple copies of the genome. Up to how many?
150
All plasmids share a number of key features. What are they?
Enclosed by an envelope
Reproduced by division
Contains a reduced genome, a singular circular chromosome of double stranded DNA
90% of chloroplasts proteins are encoded by what?
And how are these proteins directed to the chloroplast?
nuclear genes
Directed to chloroplast by N-terminal transit peptides
Is photosynthesis energy efficient?
No only 4.5%
Describe the energy cycle
Solar energy reacts with 2H2O to release o2 in the photosynthesis light reaction to produce 4H+ and 4e
Then combustion and respiration reactions reproduce the water
4H+ + 4e + o2 produces Ch2O in the photosynthesis dark reaction
