What controls the entry and exit of molecules in cell?

Q. What controls the entry and exit of molecules in cell?
  1 Nucleus
  2 Ribosomes
  3 DNA
  4 Plasma membrane
  Ans:4
Q. What controls the entry and exit of molecules in cell?
  1 Nucleus
  2 Ribosomes
  3 DNA
  4 Plasma membrane
  Ans:4
Q. Cell membrane is:
  1 Permeable
  2 Selectively permeable
  3 Semipermeable
  4 Impermeable
  Ans:2
Q. Who first observed the plasma membrane?
  1 William Scifriz
  2 Schwann
  3 Palade
  4 None of above
  Ans:1
Q. Plant cells can usually be distinguished because only plant cells possess
  1 Cell walls and mitochondria
  2 Golgi bodies and central vacuoles
  3 Cell walls and central vacuoles
  4 Chromosomes and mitochondria
  Ans:3
Q. The function of a cell wall is
  1 To give definite shape to the cell
  2 To provide mechanical strength and protection to the cell
  3 To prevent the cell from desiccation
  4 All of the above
  Ans:4
Q. Cellular component can be physically separated from each other by
  1 Centrifugation
  2 Radioactive tracers
  3 Microscopy
  4 Chromatography
  Ans:1
Q. The use of which of the following devices has given the modern biologist a better insight into the internal structure of cells
  1 Computer
  2 Electron microscope
  3 Spectrophotometer
  4 Ultracentrifuge
  Ans:2
Q. The smallest size of a cell which can be seen directly by the eye is
  1 One micron
  2 10 Micron
  3 100 Micron
  4 1000 micron
  Ans:3
Q. The cell theory of Schleiden states that
  1 Cells reproduce by mitosis or meiosis
  2 All cells have nuclei
  3 Cells are the ultimate units forming the structure of all plant tissues
  4 Cells arise only from pre-existing cells
  Ans:3