Write the functions of the following
(a) Centromere (b) Cell wall
(c) Smooth ER (d) Golgi apparatus
(e) Centrioles
(a) Centromere – It is required for proper chromosome segregation. The centromere consists of two sister chromatids. It is also necessary at the point chromosome attaches to the spindle apparatus during mitosis and meiosis.
(b) Cell wall – Cell wall helps in providing a definite shape to the cell and also protects protoplasm against any mechanical injury, /.c., damage and infection. It also helps in cell-to-cell interaction and provides barrier to undesirable macromolecules and attack of pathogens.
(c) Smooth ER – It acts as a major site for the synthesis of lipid and also helps in synthesis of steroidal hormone in animal cells.
(d) Golgi apparatus –
(i) It is involved in the formation of lysosomes, vesicles that contain proteins and remains within the cell.
(ii)It performs the function of packaging material.
(iii)It acts as an important site for the formation of glycoproteins and glycolipids.
(iv)It helps in the production of complex
carbohydrates other than glycogen and starch. .
(v) It helps in the formation of cell wall.
(e) Centrioles- Centrioles help in cell division by forming microtubule – organising centrer (MTOCS). It also, form the basal body of cilia and flagella of the cells.
Give the biochemical composition of plasma membrane. How are lipid molecules arranged in the membrane?
The genomic content of the nucleus is constant for a given species where as the extra chromosomal DNA is found to be variable among the members of a population. Explain.
Are the different types of plastids interchangable? If yes, give examples where they are getting converted from one type to another.
Structure and function are correctable in living organisms. Can you justify this by taking plasma membrane as an example?
Are the different types of plastids interchangable? If yes, give examples where they are getting converted from one type to another.
Is there a species specific or region specific type of plastids? Flow does one distinguish one from the other?
Discuss briefly the role of nucleolus in the cells actively involved in protein synthesis.
Write the functions of the following
(a) Centromere (b) Cell wall
(c) Smooth ER (d) Golgi apparatus
(e) Centrioles
Is extra genomic DNA present in prokaryotes and eukaryotes? If yes, indicate their location in both the types of organisms.
Eukaryotic cells have organelles which may
(a) not be bound by a membrane
(b) bound by a single membrane
(c) bound by a double membrane
Group the various sub-cellular organelles into these three categories.
Briefly give the contributions of the following scientists in formulating the cell theory.
(a) Rudolf Virchow
(b) Schleiden and Schwann
Differentiate between Rough Endoplasmic Reticulum (RER) and Smooth Endoplasmic Reticulum (SER).