•
following questions in brief.
1.
List the (main) factors that determine the shape of a cell.
Distinguish between unicellular and multicellular organisms. Give two examples
of each.
2.
3.
Give reasons for the following:
(a) The cell is called the structural and functional unit of life.
(b) Plant cells are more rigid than the animal cells.
4.
Which cell organelle is known as the 'Powerhouse of the cell'? Why is it so
called?
5.
Name the cell organelles responsible for imparting colour to the leaves and
fruits of a plant.
6.
What are cilia and flagella? Write one similarity and one dissimilarity betwee
the two of them.
Answers
Answer:
1)The main factors that determine the shape of the cell are cytoskeletal proteins, cell membrane in animal cell and cell wall in plant cells. Other factors include Ψw , concentration of solutes etc
unicellular organisms are single celled organisms.but multicellular organisms have more than one cell.
the unicellular organisms do various activities on its own but multicellular organisms depend on other cells to perform various activities.
unicellular organisms include eukaryotes and prokaryotes but multicellular organisms include eukaryotic cells only.
3)
a)Cell is known as structural and functional unit of life because living organism is the formed of cell and all the physiological, biochemical, genetic and metabolic function take place inside the cell. It is the smallest functional unit which can exist independently.
b) because plant cell contain cell wall
4) mictrocondria is known as power house of cell because it releases ATP
5) colour of leave is due to choloroplast while colour of fruit is due to chromoplast
6)Similarities include:
Cilia and flagella are both auxiliary parts of living cells.
They can both be used for movement
Differences include:
1.Flagella are longer in size while cilia are shorter.
2.Cilia contributes in the prevention of dust accumulation in breathing tubes by simply creating a thin layer of mucous in the tube while the flagella mainly uses sperm cells to move and propel.
3.Cilia are present in multi-cellular organisms and help in moving fluids past an immobile cell while the flagella are mainly found in gametes