Cell unit 2 Flashcards
differentiate rough er and smooth er
rough er:
-> ribosomes/ribophorins are present
-> cisternae mainly
->protein synthesis
-> continouous with the nuclear membrane
smooth er:
-> ribosomes absent
-> tubules mainly
-> lipid/glycogen metabolism
->lipid synthesis
-> in animal cells, lipid like steroidal hormone synthesis
what are ribophorins
these are glycoproteins that help in attaching ribosomes to rer
whatis sarcoplasmic reticulum
present in skeletal/mucles cells of human
-storage of ca++ and energy rich cpds for mucle contraction
-smooth er
functions of er
*Mechanical support
*Formation membrane of lysosomes, GB, NM and microbodies
*Precursor of secretory material to Golgi body.
*Detoxification- SER
*Cellular metabolism
*Intracellular transport
*Protein synthesis- RER
*Lipid Synthesis- SER
-lab of the cell
*synthesis of lipoproteins and glycogen.
* help in the scretion of materials
formation of cell memrname
what are golgi in plants called
lipochondria
c/a dictyosome
what is zone of ecxclusion
there are no organelles present in the region around the golgi apparatus called zone of exclusion or golgi ground. this is because it is involved in constant transport of substances b/w er and golgi bodies
function of golgi
involved in the glycosylation of of lipids and proteins
->formationof lysosomes
-> formation of acrosome during spermiogenesis
->cell pllate: phragmoplast formation
-> synthesis of cell wall ( pectin,mannans)
->formation of lubricants in the root cap of hydrophytes for penetration into the soil
how are lysosomes made
membrane-er
materials inside- golgi
who maintains the hydrolases inside the lysosome
-> lysosome containing a number of acid hydrolases
that are active under acidic condition, which is
maintained by an H+ ATPase in the membranee
Membrane of lysosome has an active H+ pump mechanism which produce acidic pH
in lumen of lysosome.
why are lysosomes polymorphic
Lysosomes are polymorphic cell organelle. Because, lysosomes have different
physiological forms.
Lysosomes are abundantly found in phagocytic cells.
what are the types of lysosomes
(a) Primary Lysosomes or storage granules - These lysosomes store enzyme Acid
Hydrolases in the inactive form. These are newly formed lysosome.
(b) Digestive vacuoles or Heterophagosomes - These lysosome formed by the fusion of
primary lysosomes and phagosomes. These are secondary Lysosomes.
(c) Residual bodies :– Lysosomes containing undigested material are called residual
bodies. These may be eliminated by exocytosis.
(d) Autophagic Lysosomes or autophagosomes :– Lysosomes containing cell organelles
to be digested are known as Autophagosomes.
functions of lysosomes
(a)
Intracellular digestion :-
Heterophagy :– This is digestion of foreign materials received in cell by
phagocytosis and pinocytosis.
Autophagy :– Digestion of old or dead cell organelles. Autophagy also takes
place during starvation of cell.
(b) Extracellular digestion :– During osteogenesis, lysosomes of osteoclast
(bone eating cells) dissolve unwanted part of bones.
Extracellular digestion also occurs by fungal lysosomes.
(c) Cellular digestion/Autolysis/Autodissolution :– Sometimes all lysosomes of a cell
burst to dissolve the cell completely, it is Autolysis. That’s why lysosome called as
suicidal bags of cell.
Old cells, unwanted organs of embryo or larva are destroyed by autolysis.
e.g. :- Cathepsin enzyme of lysosome digests the tail of tadpole larva of frog during
metamorphosis.
where is anthocyanins found
Water soluble pigment anthocyanin,anthoxanthin is found in cell sap/vacuole.
mitochondria is endosymbiont explain
euakryote engulfs a prokaryote for energy, eukaryote gives food and prokaryote makes energy. This evolved into mitochondria/plastid
Mitochondria called as semi autonomous cell organelles because
they have protein synthesis machinery (self synthesized some
proteins and depend on nucleus for remaining proteins)
*Protein synthesis machinery
*Ribosomes (70s)
*RNA
*DNA
*Enzymes
Type of DNA (ds circular DNA, G-C rich).
*Type of Ribosome (70s).
*Divided by binary fission.
differentiate between chloroplasts,chromoplasts and leucoplasts
cholroophyll
-> pigments and lamellar strcutures present
-> pigments= chlorophyl and carotenoids
-> presnet in green plarts
chromoplasts
-> pigments and lamellar tstrcutures absen
-> pigments= carotenoids and xanthophylls
-> found in pericarp and fruits/petals
leucoplasts
-> pigments /lamellar strcutures absent
-> no pigments
-> found in storage parts of plant
