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Cell: The Unit of Life
What is a centromere? How does the position of centromere form the bas...

What is a centromere? How does the posit | Class 11 Biology Chapter Cell: The Unit of Life, Cell: The Unit of Life NCERT Solutions

Welcome to the NCERT Solutions for Class 11 Biology - Chapter Cell: The Unit of Life. This page offers a step-by-step solution to the specific question from Exercise 1, Question 14: . With detailed answers and explanations for each chapter, students can strengthen their understanding and prepare confidently for exams. Ideal for CBSE and other board students, this resource will simplify your study experience.

Question 14:

What is a centromere? How does the position of centromere form the basis of classification of chromosomes. Support your answer with a diagram showing the position of centromere on different types of chromosomes.

Answer:

Centromere is a constriction present on the chromosomes where the chromatids are held together.

Chromosomes are divided into four types based on the position of the centromere.

(i) Metacentric chromosome

The chromosomes in which the centromere is present in the middle and divides the chromosome into two equal arms is known as a metacentric chromosome. During anaphase, they appear V-Shaped.

Metacentric chromosome

(ii) Sub-metacentric chromosome

The chromosome in which the centromere is slightly away from the middle region is known as a sub-metacentric chromosome. In this, one arm is slightly longer than the other. During anaphase, they appear L-Shaped.

Sub-metacentric chromosome

(iii) Acrocentric chromosome

The chromosome in which the centromere is located close to one of the terminal ends is known as an acrocentric chromosome. In this, one arm is extremely long and the other is extremely short. During anaphase, they appear J-Shaped.

Acrocentric chromosome

(iv) Telocentric chromosome

The chromosome in which the centromere is located at one of the terminal ends is known as a telocentric chromosome. During anaphase, they appear i-Shaped.

Telocentric chromosome

Other Questions of Chapter Cell: The Unit of Life

Which of the following is correct:
(a) Cells of all living organisms have a nucleus.
(b) Both animal and plant cells have a well defined cell wall.
(c) In prokaryotes, there are no membrane bound organelles.
(d) Cells are formed de novo from abiotic materials.

Write the functions of the following
a. Centromere
b. Cell wall
c. Smooth ER
d. Golgi Apparatus
e. Centrioles

The genomic content of the nucleus is constant for a given species where as the extra chromosomal DNA is found to be variable among the
members of a population. Explain.

What are the characteristics of prokaryotic cells?

Describe the structure of the following with the help of labelled diagrams.
(i) Nucleus
(ii) Centrosome

Is extra genomic DNA present in prokaryotes and eukaryotes? If yes, indicate their location in both the types of organisms.

How do neutral solutes move across the plasma membrane? Can the polar molecules also move across it in the same way? If not, then how are these transported across the membrane?

Which of the following is not correct?
(a) Robert Brown discovered the cell.
(b) Schleiden and Schwann formulated the cell theory.
(c) Virchow explained that cells are formed from pre-existing cells.
(d) A unicellular organism carries out its life activities within a single cell.

What are nuclear pores? State their function.

New cells generate from (a) bacterial fermentation (b) regeneration of old cells (c) pre-existing cells (d) abiotic materials

Popular questions of class 11 Biology

Q: Describe briefly the four major groups of Protozoa.

Q: Why are living organisms classified?

Q: State two economically important uses of: (a) Heterotrophic bacteria (b) Archaebacteria

Q: What is the difference between direct and indirect development?

Define a taxon. Give some examples of taxa at different hierarchical levels.

Q: Describe the important properties of enzymes.

What are the steps involved in formation of a root nodule?

Q: Illustrate the taxonomical hierarchy with suitable examples of a plant and an animal.

Q: How is a key helpful in the identification and classification of an organism?

Q: What is stomatal apparatus? Explain the structure of stomata with a labelled diagram.

Recently Viewed Questions of Class 11 Biology

Name the pathological condition when uncontrolled cell division occurs.

Aquatic animals generally are ammonotelic in nature where as terrestual forms are not. Comment.

Name the cells/tissues in human body which
a. exhibit ameboid movement
b. exhibit ciliary movement

Q: How is the study of plant anatomy useful to us?

How do you distinguish between a skeletal muscle and a cardiac muscle?

Q: Explain the term thecodont and diphyodont.

Why earthworm is called the friend of farmer?

Q: Draw the labelled diagram of the following:
(i) Gram seed
(ii) V.S. of maize seed

Mitosis results in producing two cells which are similar to each other. What would be the consequence if each of the following irregularities
occur during mitosis?
a. Nuclear membrane fails to disintegrate
b. Duplication of DNA does not occur
c. Centromeres do not divide
d. Cytokinesis does not occur.

Q: Discuss with your teacher about
(i) haploid insects and lower plants where cell-division occurs, and
(ii) some haploid cells in higher plants where cell-division does not occur.

Study Tips for Answering NCERT Questions:

NCERT questions are designed to test your understanding of the concepts and theories discussed in the chapter. Here are some tips to help you answer NCERT questions effectively:

Read the question carefully and focus on the core concept being asked.
Reference examples and data from the chapter when answering questions about Cell: The Unit of Life.
Review previous year question papers to get an idea of how such questions may be framed in exams.
Practice answering questions within the time limit to improve your speed and accuracy.
Discuss your answers with your teachers or peers to get feedback and improve your understanding.

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