Question

Define active and passive transport. What is diffusion? and is it active or passive? What is osmosis? Active or passive?

What is bulk transport? and what are the two types?

What are the effects of isotonic, hypertonic, and hypotonic solutions on plant and animal cells?

How do cells “talk” to each other?

Answer 1

Ans)

Active transport is the process of passage of molecules from a low concentration gradient to higher concentration gradient and requires energy or ATP.

Passive transport is the process of passage of molecules across a membrane and does not require energy.

Diffusion is the movement of particles from higher concentration gradient to a lower concentration gradient.

Diffusion does not utilise energy ans is passive.

Osmosis is the movement of solute particles from a lower concentration gradient to a higher concentration gradient across a Semi permeable membrane. Osmosis is passive, requires no energy.

Bulk transport is the movement or transport of larger molecules such as proteins and polysaccharides inwards or outwards from the cell.

2 types are -

Endocytosis - macromolecules move into the cell their an invagination of the cell.

Exocytosis - macromolecules are transport out of the cell.

Isotonic solution - since the concentration gradient inside the cell and across the cell is same there is no net movement of molecules and cell maintains is shape and structure

Hypotonic solution - the cell absorbs water by osmosis until the concentration gradient is equal inside and outside the cell. The plant cell becomes turgid.

Hypertonic solution.

The plant cell loses molecules across the cell until the pressure within the cell and outside the cell match. The cell shrinks because the protoplasm of the plant cell detaches causing gaps between the cells.

In animal cells placed in Hypotonic solution the cell swells up and bursts due to increased pressure inside of the cell. Since animal cells do not possess cell wall they do not become turgid like plant cells. Plant cells do not burst.

In hypertonic solutions animals cells shrink due to outward movement of water molecules.

And in isotonic solution the cell shows no changes.

Cells talk or communicate via chemical signals.

These chemical signals are in the form of certain inflammatory mediators or hormones or neurotransmitters. These chemical signalling compounds bind to their specific receptors to elicit responses.