Chapter 1 Fundamental Unit Of Life

Question 1

What is cell?

Answer 1

Structural and functional unit of life.

Question 2

What is cell theory and who proposed it?

Answer 2

Cell theory states that every living organism is made up of cells. Schleiden and schwann together put forward the cell theory.

Question 3

Smallest and largest cells?

Answer 3

S - mycoplasma

L - ostrich egg

Question 4

What is the outer covering of plant and animal cell? Also tell double and membraneless organelles.

Answer 4

Plant - cell wall + cellulose

Animal - cell membrane ( protein +lipid)

Double - mitochondria, nucleus

Less - centrosome, ribosome

Question 5

What is a selectively permeable membrane?

Answer 5

If a membrane permits specific solute particles with solvent freely.

Question 6

What is diffusion and osmosis?

Answer 6

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

Osmosis is a special type of diffusion In which solvent moves from higher to lower concentration through spm.

Question 7

What is isotonic, hypotonic and hypertonic solutions?

Answer 7

Iso - if the medium has exactly the same water concentration as the cell.

Hypo - if the medium surrounding the cell has higher concentration than the cell.

Hyper - if the medium has lower concentration or the cell has higher concentration than the medium.

Question 8

Differentiate between prokaryotic and eukaryotic type of cells.

Answer 8

Pro - 1 primitive nucleus

2 single chromosome

3 70s ribosome

4 membrane bounded cell organelles absent
Ex - bacteria, cynobacteria.

Euk - 1 advanced nucleus
2 more than one chromosome
3 80s ribosome
4 membrane bounded cell organelles present

Question 9

Differentiate between plant and animal cell

Answer 9

Plant- 1 cell wall present

2 lysosomes absent

3 central vacuole

4 plastid - present

Animal - 1 cell wall absent

2 lysosomes present

3 periphery vacuoles( not central)

4 plastid absent

2

Question 10

What is the function of cell wall in plants?

Answer 10

Outer covering of plants. It provides mechanical support and rigid shape of the cell.

Question 11

What is nucleus? Nucleoplasm and nucleolus?

Answer 11

Nucleus controls all cellular activities of the cell. It’s called brain of the cell.

Nucleoplasm is the dense sap present inside the nuclear envelope

Nucleolus is one or more round body present in the nucleoplasm.

Question 12

What is chromatin fibre, chromosomes and genes?

Answer 12

Chromatin fibre is a network of dark staining fibre in the nucleus.

When chromatin condenses during cell division, it forms rod like structures called chromosome. Chromosomes contain genetic information in the form of dna.

Functional segment of dna is called gene.

Question 13

Function of er?

Answer 13

Rer helps in protein synthesis.

Ser helps in lipid synthesis.

It gives internal support to cytoplasm.

Question 14

Function of golgi body?

Answer 14

Material synthesised near er is packaged and dispatched by golgi body.

Complex sugar are broken down to simple by gogli body

It is also involved in the formation of lysosomes.

Question 15

Function of lysosomes?

Answer 15

Lysosomes -

Keep the cell clean by digesting any foreign material.

If the cell gets damaged lysosomes may digest the whole cell.

Question 16

Function of mitochondria? And why it is called the powerhouse of the cell?

Answer 16

Mitochondria produces energy in the form of atp.

Mitochondria are able to make their own protein due the presence of their own dna.

Question 17

Write a note on plastids.

Answer 17

Only present in plant.

Chromoplast ( type of plastid) contains chlorophyll which gives green colour to plant.

Leucoplast ( type of colorless plastid) stores oils starch etc.

Plastid have their own dna

Question 18

What are vacuoles?

Answer 18

Vacuoles are the storage sac of the cell.

They contain many important materials like amino acid, sugar etc.