Plastids Flashcards
What is the plastids general membrane structure?
Double layered membrane (envelope)
Name a few functions of a Plastid
- Photosynthesis (energy production / carbon fixation)
- Pigment biosynthesis (chlorophylls / carotenoids)
- Starch biosynthesis (carbohydrate storage)
- Fatty acid biosynthesis (membrane biogenesis / oils)
- Amino acid biosynthesis (protein synthesis )
- Nucleic acid biosynthesis (DNA/RNA)
- nitrogen assimilation (nitrate reduction)
What are the different plastid types?
- Proplastid
- Chloroplast
- Etioplast
- Amyloplast
- Leucoplast
- Chromoplast
Which plastid is not developed from the Proplastid?
Etioplast
In what cell do you usually find the Chloroplast? And what kind of ribosome do they contain?
Mainly in leaf mesophyll cells
Ribosome - 70S
Chloroplasts play a vital role in the conversion of nitrate into ammonium & glutamine (amino acid). What is this process called?
Nitrogen assimilation
In what plastid does fatty acid synthesis occur?
In the chloroplasts
Etioplasts works in special environments - which?
In dark environments
Etioplasts conversion:
Protochlorophyllide do rapidly convert back to Chlorophyllide by POR when exposed to light.
Give an example of when this occurs.
Example, grass that has been covered up (dark) and later is exposed to light (grass rapidly gets the green colour back)
What is the Amyloplasts major function?
Store starch
Where do you usually find Amyloplasts?
Seeds & roots
Leucoplasts are involved in the synthesis of …?
Monoterpenes
Where do you usually find Leucoplasts?
In leaf & steams (ex citrus peel)
Chromoplasts are yellow/orange plastids. They contain large amount of …?
Carotenoids (responsible for many colours in fruit & vegetables)
Half of the amino acids (essentials) are synthesised in … (which plastid)?
Chloroplasts
