Biology ICSE Class 7 Important Questions Chapter 1 Basic Biology
Extra Questions
Question 1.
Who developed the first simple microscope ?
Answer:
Anton Van Leeuwenhoek.
Question 2.
Name few unicellular organisms.
Answer:
Bacteria, Amoeba, Paramecium and Chlamydomonas.
Question 3.
Name some shapes of cells with example.
Answer:
- Irregular shape – Example : Amoeba
- Oval shape – Example : Chlamydomonas.
- Oblong shape – Example Paramecium
- Elongated – Example : Muscle cells
- Thread like – Example : Nerve cells
Question 4.
What is cell biology ?
Answer:
The study of cells is called cell biology.
Question 5.
Write few differences between cell wall and cell membrane.
Answer:
Cell wall :
- It is the outermost, thick, protective layer of a cell.
- It is found only in bacterial and plant cell.
- It is non-living and permeable.
Cell membrane :
- It is the outer covering of the protoplasm in a cell.
- It is found in plant and animal cells.
- It is living and semi- permeable.
Question 6.
Who coined the term ‘nucleus’ ?
Answer:
Robert Brown
Question 7.
What are the main components of a typical cell ?
Answer:
(i) Cell membrane
(ii) Protoplasm – It has two parts :
(a) Nucleus
(b) Cytoplasm – It contains various cell organelles.
Question 8.
Write the number of chromosomes present in –
(i) human beings
(ii) onion
(iii) rice
(iv) dogs
Answer:
(i) 46
(ii) 16
(iii) 24
(iv) 60
Question 9.
Name the kind of plastid present in –
(a) Green leaves
Answer:
Chloroplasts
(b) Fruits and petals of flowers
Answer:
Chromoplasts
(c) Potato and ginger
Answer:
Leucoplasts
Question 10.
What is the importance of cell division ?
Answer:
- Growth
- Reproduction
- Repair and replacement of old and worn-out cells.
Question 11.
Fill in the blanks.
1. Organisms which are made up of a single cell are called …………. organisms.
Answer:
Organisms which are made up of a single cell are called unicellular organisms.
2. Muscles cells are …………. and contractile.
Answer:
Muscles cells are elongated and contractile.
3. The jelly-like fluid that surrounds the nucleus of a cell is called ………….
Answer:
The jelly-like fluid that surrounds the nucleus of a cell is called cytoplasm.
4. ………….. membrane is a selectively permeable membrane.
Answer:
Plasma membrane is a selectively permeable membrane.
5. The ………….. contains a network of thread-like structures called chromatin network.
Answer:
The nucleoplasm contains a network of thread-like structures called chromatin network.
6. Golgi bodies are also called ………….
Answer:
Golgi bodies are also called dictyosomes.
7. A plant cell gets shape and support from its ………….
Answer:
A plant cell gets shape and support from its cell wall.
8. In a plant cell food is manufactured in …………
Answer:
In a plant cell, food is manufactured in chloroplast
9. give colour to flowers and fruits.
Answer:
Chromoplasts give colour to flowers and fruits.
10. Fluid-filled cell organelles that are usually larger in a plant cell than in an animal cell are called
Answer:
Fluid-filled cell organelles to are usually larger in a plant cell than in an animal cell are called vacuoles.
Practice Question 1.
The cells in a potato tuber do not have chloroplasts. How would you identify its cells as plant cells by observing them under a microscope ?
Answer:
Take a potato tubes and cut it into small pieces using sharp blade cut a small thin transparent layer from potato tuber. Place it on a drop of water on a clean glass slide and add a drop of iodine. After covering it with coverslip. We will observe thick walled polygonal cells under microscope. Presence of outer cell wall indicate that these are plant cells. Presence of cell wall is a characteristic feature of plants only.
Practice Question 2.
Draw fig. structure of nucleus
Answer:
ICSE Class 7 Biology Important Questions