Skip to main content

The fundamental unit of life | class 9 science NCERT solutions

Chapter - 5

NCERT Class 9th solutions
Page 59

Ans1.
Robert hooke discovered cells in 1665 while examining a thin slice of cork through a self designed microscope. He saw that the cork resembled the structure of a honeycomb. The small boxes in the comb are called cells.

Ans2.
A cell is capable of independently carrying out all the necessary activities of life. So, they are called structural and functional unit of life.

Page 61

Ans1.
Carbon dioxide moves by diffusion and water move by osmosis through cell membrane.

Ans2.
It is called selectively permeable membrane because it allows the entry and exit of some substances, not all.

Page 63

Ans1. ((Pending))

Page 65

Ans1.
The two organelles which have their own genetic material are -
1) Mitochondria
2) Plastids

Ans2.
The cell will not be able to revive and lysosomes will digest it.

Ans3.
When the cell gets damaged, lysosomes may burst and the enzymes digest their own cell. Therefore, lysosomes are known as suicide bags.

Ans4.
The proteins are synthesized in the ribosomes that are also known as protein factories.


                                    by      www.advguruji.blogspot.com
Labels:

Comments

Post a Comment

Popular posts from this blog

Age problems (for practice) | class 10 mathematics | advguruji | Physics Advocate

Linear Equations Q1. Ten years ago, father was twelve times as old as his son and ten years hence, he will be twice as old as his son will be. Find their present ages. Ans. Present age of father = 34 years          Present age of son = 12 years Q2. Three years ago, Priya's mother was six times older than her. Four years from now, Priya's mother will be one year older than thrice her age. Find the present age of Priya and her mother. Ans.  Present age of Priya = 8 years       Present age of mother = 33 years Q3. Five years ago, Rakesh was five times younger than his mother. Ten years from now, his age will be half of his mother's age. Find the present age of Rakesh and his mother. Ans. Present age of Rakesh = 10 years      Present age of mother = 30 years Q4.           (equation in one variable) A  is elder to  B  by two years. A's father  F  is twice as old as  A .  ...
1 comment
Read more

Multiple Choice Questions (MCQs) on fluid mechanics class 11 : Physics advocate/advguruji

Best of Luck Q1. Hairs of shaving brush cling together when it is removed from water due to- (a) force of attraction between hair (b) surface tension (c) viscosity of water (d) characteristic property of hair Q2. Coatings used on raincoat are waterproof because they - (a) increases angle of contact (b) decreases angle of contact (c) does not alters angle of contact (d) forms a smooth surface Q3. A body measures 5 N in air and 2 N when put in water. The buoyant force is- (a) 7 N (b) 9 N (c) 3 N (d) None of these Q4. A hole is made at the bottom of the tank filled with water (density = 1000 kg/m³). If the total pressure at the bottom of the tank is three atmospheres (1 atmosphere = 10⁵ N/m²), then the velocity of efflux is nearest to- (a) 20 m/s (b) 10√2 m/s (c) 20√2 m/s (d) √500 m/s Q5. When the temperature is increased the angle of contact of a liquid? (a) increases (b) decreases (c) remains the same (d) first increases and then decreases Q6. The surface tension of a soap solution is 2...
1 comment
Read more

Problems on acceleration due to gravity and variation of acceleration due to gravity, class 11 | Physics Advocate

Q1. Calculate the percentage decrease in the weight of a body when it is taken to a height of 40 km above the Earth's surface. Radius of Earth = 6,400 km Ans. 1.25% Q2. Calculate the depth below the surface of Earth where the acceleration due to gravity is 25% of its value at the Earth's surface. Take, radius of Earth = 6,400 km. Ans. 4.8 × 10⁶ m Q3. A body weighs 100N on Earth's surface. Calculate the gravitational force on the body at a height equal to one-fourth the radius of Earth. Ans. 64 N Q4. Calculate the percentage decrease in weight of a body when taken to a tunnel 38.4 km below the Earth's surface. Ans. 0.6% Q5. Calculate the height from the Earth's surface at which the acceleration due to gravity becomes 75% compared at Earth's surface. Take, radius of Earth = 6,400 km. Ans. 990 km ---------------------------------------------------------------------------------------------- EXTRA QUESTIONS Q6. Find the percentage increase in acceleration due to grav...
Post a Comment
Read more