Class 12 Anthropology Important Chapter 1 Cell Biology

Class 12 Anthropology Important Chapter 1 Cell Biology Solutions English Medium As Per The New Syllabus to each chapter is provided in the list so that you can easily browse through different chapters ASSEB Class 12 Anthropology Important Solutions in English and select need one. AHSEC Class 12 Anthropology Additional Notes Download PDF. HS 2nd Year Anthropology Additional Solutions.

Class 12 Anthropology Important Chapter 1 Cell Biology

Also, you can read the NCERT book online in these sections Solutions by Expert Teachers as per Central Board of Secondary Education (CBSE) Book guidelines. ASSEB Class 12 Anthropology Additional Question Answer are part of All Subject Solutions. Here we have given HS 2nd Year Anthropology Important Solutions English Medium for All Chapters, You can practice these here.

Cell Biology

Chapter: 1

IMPORTANT QUESTION AND ANSWER

Answer the Following Questions:

1. What is the basic unit of life?

Ans: Cell.

2. How many chromosomes are there in a normal human cell?

Ans: 46.

3. What is a cell? Mention its two main types.

Ans: A cell is the basic structural and functional unit of life. It is the smallest unit capable of independent existence and self-replication.

Types:

(i) Somatic cells – form the body tissues and organs.

(ii) Germ cells – involved in reproduction (sperm and ovum).

4. What are chromosomes? Write their chemical composition.

Ans: Chromosomes are thread-like structures in the nucleus that carry genetic material. They become visible during cell division.

Composition: DNA, histone and non-histone proteins, and a small amount of RNA.

5. Describe the structure of DNA.

Ans: DNA is a double-stranded helical molecule. Each strand is made of nucleotides, Which include:

(i) A deoxyribose sugar.

(ii) A phosphate group.

(iii) A nitrogenous base (A, T, G, C).

Base pairing occurs as A–T and G–C.

6. What is the role of mitochondria?

Ans: Mitochondria are called the “powerhouse of the cell.” They produce ATP (energy) through cellular respiration. They also help in metabolism and apoptosis (programmed cell death).

7. What is crossing over? Why is it important?

Ans: Crossing over is the exchange of genetic material between homologous chromosomes during Prophase I of meiosis.

Importance:

(i) Introduces genetic variation.

(ii) Helps in recombination of traits.

8. What is the role of the Golgi apparatus?

Ans: The Golgi body modifies, sorts, and packages proteins and lipids for transport. It is involved in the formation of lysosomes and secretion.

9. Mention the components of a nucleotide.

Ans: A nucleotide is the building block of DNA and RNA.

It consists of:

(i) A nitrogenous base (A, T/U, G, C).

(ii) A pentose sugar (ribose or deoxyribose).

(iii) A phosphate group.

10. Mention the roles of ribosomes in the cell.

Ans: (i) Ribosomes are the site of protein synthesis.

(ii) They read mRNA and help join amino acids into proteins.

(iii) They may be free-floating or attached to the rough endoplasmic reticulum.

11. What are stem cells? Mention their significance.

Ans: Stem cells are undifferentiated cells that can divide and develop into various cell types.

Significance:

(i) Useful in regenerative medicine.

(ii) Help in repairing damaged tissues.

12. Write the functions of the cell membrane.

Ans: (i) It encloses cell contents and provides shape.

(ii) Controls movement of substances in and out of the cell (selectively permeable).

13. Name the different types of RNA and mention one function of each.

Ans: (i) mRNA – Carries genetic code from DNA to ribosome.

(ii) tRNA – Brings amino acids during protein synthesis.

(iii) rRNA – Forms the structural and functional part of ribosomes.

14. What are the main events of metaphase in mitosis?

Ans: (i) Chromosomes align at the equatorial plate.

(ii) Spindle fibers attach to centromeres.

(iii) Nuclear envelope is completely disintegrated.

15. Write a short note on cell theory?

Ans: Cell theory is one of the fundamental principles of biology that explains the structure and function of all living organisms. It was first proposed by Matthias Schleiden (a botanist) and Theodor Schwann (a zoologist) in the 1830s. According to their theory, all living organisms are composed of one or more cells, and the cell is the basic unit of structure and function in all living beings. Later, in 1855, Rudolf Virchow added an important statement to the theory — “Omnis cellula e cellula”, meaning that all cells arise from pre-existing cells. Thus, the modern cell theory includes three main points: (i) All living organisms are made up of cells, (ii) The cell is the basic structural and functional unit of life, and (iii) New cells are formed only by the division of pre-existing cells. This theory laid the foundation for modern biology by emphasizing the role of cells in growth, reproduction, and heredity.