In prokaryotes, chromatophores are

• specialized granules responsible for colouration of cells

• structures responsbile for organizing the shape of the organism

• inclusion bodies lying free inside the cells for canying out various metabolic activities

• internal membrane systems that may become extensive and complex in photosynthetic bacteria

What are Singer and Nicolson known for?

• One-gene-one-enzyme hypothesis

• Plasma membrane modifications

• Fluid-mosaic model of plasma membrane

• Structure of DNA

Cell theory was proposed by

• a botanist

• a zoologist

• a botanist and a zoologist

• a psychologist

In a 50 gm living tissue, what would be the amount of water

• 15- 25 gm

• 25 - 30 gm

• 35- 45 gm

• 70- 90 gm

The outermost limiting layer of mycoplasma is made up of

• cell wall

• cell membrane

• mucilaginous sheath

• slime layer

Specific proteins responsible for the flow of materials and information into the cell are called

• membrane receptors

• carrier proteins

• integral proteins

• none of these

Assertion : Nucleus is the controlling centre of a cell.

Reason : Pores in the nuclear envelop regulate the flow of materials in and out of the nucleus.

• If both assertion and reason are true and reason is the correct explanation of assertion

• If both assertion and reason are true but reason is not the correct explanation of assertion

• If assertion is true but reason is false

• If both assertion and reason are false

• Virchow

• Hooke

• Leeuwenhoek

• Brown

Which of the following is responsible for the mechanical support, protein synthesis and enzyme transport?

• Cell membrane

• Mitochondria

• Dictyosome

• Endoplasmic reticulum

Many cells function properly and divide mitotically even though they do not have

• plasma membrane

• cytoskeleton

• mitochondria

• plastids