Plastid (include Chloroplast) Flashcards
plastid
membrane-bound organelles in cells (plant, algae etc)
example in plastid
chloroplast - predominant type in leaves and other aerial tissues
thylakoid
interconnected and closed continuum
thylakoid - contain
granum disks and multiple (stack) and stroma lamella
granum
spiral formation
budding of each side
chloroplast synthesises
purine and pyrimidine
FA and lipids
isoprenoids
isoprenoids
plant hormones (GA)
abscisic acid
strigolactones
haem
Haem
Tetrapyrrole
for cytochrome, peroxidase, catalase
reduction of nitrile and sulphate
nitrogen fixation - conversion of inorganic N
types of plastids
proplastid chromoplast amyloplast leucoplast elaioplast
proplastid
precursor of all plastids found in young meristematic region
divide at pace with cell division - continuity
chromoplast
non-photosynthetic , crystalline/needle structure
amyloplast
starch-storing - non-green tissue
e.g. potato tubers
leucoplast
involved in oil and lipid synthesis - plastoglobuli
varies in appearance and often surrounded by ER membrane
plastoglobuli
electron dense particles
elaioplast
had rounded and angular lipid bodies - store sterol esters
found elaioplast
cell surrounding tapetum - develops pollen
tapetum
anther cavity
needle shape chromoplast
in birds of paradise flowers
chromoplast contain
carotenoid e.g. carotene, xanthophyll for colour
GA - plant hormone
gibberellic acid
tapetum
anther cavity
size and no. plastids
5-8μm long and 3-4μm thick
correlation of size and number of plastid
increase in size = decreases number of plastid
Arabidopsis mesophyll
around 120
87 hypothetical proteins encoded
features of plastid
has internal membrane structure
reduced genome
translation
reproduced by division
translation - protein synthesis uses
prokaryotic-like ribosomes
primary endosymbiotic event
form red algae, glaucocystophytes and green algae(land plants)
endosymbiosis
ancestral host cell engulf cyanobacterium
gene is lost in nucleus - leakiness in chloroplast - divide and burst
DNA goes to nucleus
engulfing cyanobacterium
its membrane and double membrane present but one of them gets lost
after DNA enters nucleus during endosymbiosis
integrates to nucleogenomes and new proteins are produced
translation of mRNA in cytoplasm with chaperone and target sequence at end terminus
N-terminal transit peptides
able to tell protein destination to and after going to chloroplast
tic-toc complex
translocon
tic- translocon of inner chloroplast membrane
toc - translocon of outer chloroplast membrane
Tim-tom complex
in outer of mitochondria
example of endosymbiosis
algae - chloroplast
able to engulf
example of plastid present in non-plant
large group intracellular
parasite - includes plasmodium falciparum causing malaria
plant plastid size and number
120-160kb
with 60-200 genes
reduced genome
single circular DNA
size - 89kb to 400kb
organised in polycistronic transcriptional unit
contain multiple copies of genome (<150)
gymnosperms
only plastid that divide paternally - inherited
