20 Apr 2022

Samacheer Kalvi 9th Science Book Back Unit 7 Term 2

Samacheer Kalvi 9th Term II Science Book Back Question and Answers – Unit 7:

Samacheer Kalvi 9th Standard New Science Book Back 1 Mark and 2 Mark Question & Answers PDF uploaded and available below. Class 9 New Syllabus 2021 to 2022 Book Back Question & Answer solutions available for both English and Tamil Medium. Class 9 Science Book Term 2 Unit 7 – Organization of Tissues Answers/Solutions are provided on this page. 9th Std Science Book is of Term 1st, 2nd, 3rd, and consists of 9 Units in each Term. All 9 Units of Term 1st, 2nd, 3rd Science Book Back One, and Two Mark Solutions are given below.

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Samacheer Kalvi 9th Science Book Back Unit 7 Term 2 Solutions Guide PDF:

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Term – 2

Unit – 7

Organization of Tissues

Section – A

I a. Match the following:

1. Sclereids                a) Chlorenchyma

2. Chloroplast           b) Sclerenchyma

3. Simple tissue        c) Collenchyma

4. Companion cell    d) Xylem

5. Trqachieds             e) Phloem

Ans: 1-b; 2-a; 3-c; 4-e; 5-d

I b. Match the contents of Column I, II and III

Column I Column II Column III
1. Columnar Epithelium a. Absorption A. Anchoring of muscle
2. Bones b. Axon B. Dendrites
3. Neurons c. Body framework C. Secretion
4. Areolar Tissue d. Ground substance D. Ciliated
5. Tongue e. Trachea E. Fibroblasts
6. Epithelium f. Striated muscle F. Visceral tissue

Ans: 1-e-D ; 2-c-A ; 3-b- B ; 4-d- E; 5-f-F ; 6- a-C

II. Choose the correct answer:

1. A meristematic tissue consist of
a) Immature cells which are in a state of division and growth
b) Mature cells
c) Non-living cells
d) Sclerenchyma cells

2. The tissue composed of living thin walled polyhedral cell is
a) Parenchyma
b) Collenchyma
c) Sclerenchyma
d) None of above

3.The fibres consist of
a) Parenchyma
b) Sclerenchyma
c) Collenchyma
d) None of above

4. Chlorenchyma is known to develop in the
a) cytoplasm of chlorella
b) mycelium of a green mould such as aspergillus
c) Spore capsule of moss
d) pollen tube of pinus.

5. Companion cells are closely associated with
a) sieve elements
b) vessel elements
c) trichomes
d) guard cells

6. Which of the following is a complex tissue.
a) parenchyma
b) collenchymas
c) xylem
d) sclerenchyma

7. Aerenchyma is found in
a) epiphytes
b) hydrophytes
c) halophytes
d) xerophytes

8. Two long bones of the hand are dislocated in a person who met with an accident. Which among the following may be the possible reason?
a) Tendon injury
b) break of skeletal muscle
c) ligament tear
d) rupture of areolar tissue

9. Unstriated muscles are found in
a) blood vessels
b) gastrointestinal tract
c) urinary bladder
d) all of these

10. Which of the following is not found in a neuron?
a) sarcolemma
b) dendrite
c) neurolemma
d) axon

11. Long, unbranched multinucleated cells are
a) striated muscle cells
b) smooth muscles
c) cardiac muscles
d) none of the above

12. White fibres of connective tissue are made up of
a) Elastin
b) Reticular fibres
c) Collagen
d) Myosin

13. Brush bordered epithelium is found in
a) stomach
b) small intestine
c) fallopian tube
d) trachea

14. Smooth muscles occur in
a) Uterus
b) Artery
c) Vein
d) all of the above

15. Which muscles are involuntary?
i) striated muscles; ii) smooth muscles; iii) cardiac muscles; iv) skeletal muscles
a) (i) and (ii)
b) (ii) and (iii)
c) (iii) and (iv)
d) (i) and (iv)

16. Nerve cell does not contain
a) Axon
b) Nerve endings
c) Tendons
d) Bendrites

17. Tendon connects
a) Cartilage with muscles
b) Bone with muscles
c) Ligament with muscles
d) Bone with bone.

18. In a certain type of cell division the diploid number of chromosome is reduced to half. This kind of division occurs in
a) Testis
b) Ovary
c) Both ovary and testis
d) All body cells

III. Fill in the blanks:

  1. The complex tissues are made up of more than one type of cells and these work together as a
  2. Sclerenchyma tissues provide mechanical support to
  3. Parenchyma, Collenchyma, Sclerenchyma are simple type of
  4. Xylem and phloem are complex
  5. Epithelial cells with cilia are found in trachea, bronchioles and kidney tubules of our
  6. Lining of small intestine is made up of columnar epithelium
  7. The two types of skeletal connective tissues are cartilage and bone
  8. Humans have 46 Their sperms and eggs will have 23 chromosomes each.
  9. During paring of chromosomes in meiosis, the homologous chromosomes come to lie side by side.

IV. State whether True or False. If False, write the correct statement:

1. Epithelial tissues is protective tissue in animal body
Ans: False –Compound epithelium is protective tissue in animal body.

2. Epithelial layer does not allow regulation of materials between body and external environment
Ans:False – Epithelium is involved in absorption and elimination of waste.

3. Bone and cartilage are two types of areolar connective connective tissues.
Ans:False – Bone and cartilage are two types of skeletal connective tissues.

4. Striated and non-striated tissues are types of epithelial tissue
Ans: False – Striated and non-striated tissues are types of muscles.

5. As growth occurs in an individual the skin cells divide only to replace such cells that are lost from the surface.
Ans: False – Cell division tales place for growth and to replace dead cells.

6. Parenchyma is a simple tissue. – True

7. Phloem is made up of  Tracheids
Ans: False – Philoem is made up of sieve elements, companion cells and philoem parenchyma.

8. Vessels are found in collenchymas
Ans: False – Vessels are found in xylem.

Section – B

I. Short Questions & answer:

1. Give two types of Sclerenchyma.
Sclerenchyma cells are grouped into (i) fibres and (ii) sclereids.

2. Name the components of xylem and phloem.
Xylen is composed of different kinds of elements.
They are
(i) Xylem tracleids
(ii) Xylem fibres
(iii) Xylem vessels and
(iv) Xylem parenchyma.

Phloem consists of the following elements
(i) Sieve elements
(ii) Companion cells
(iii) Phloem fibres and
(iv) Phloem parcnchyma.

3. Name the tissue that connects muscle to bone in humans.

4. Name the tissue that stores fat in our body.
Adipose tissue

5. Name the connective tissue with a fluid matrix.

6. Name the tissue present in the brain.
Nervous tissue

II. Short Answer Questions:

1. What are intercalary meristems? How do they differ from other meristems?
Intercalary meristem lies between the region of permanent tissues It is part of primary meristern which is detached due to formation of intermittent permanent tissues. It is found either at the base of leaf eg. pinus or at the base of internodes e.g. grasses.

2. How would you differentiate between meristematic and permanent tissue?
Meristems are actively dividing tissues of the plant, that are responsible for primary (elongation) and secondary growth (thickness) of the plant. Permanent tissues are those in which growth has stopped either completely or for the time being. At times, they become mareistematic partially or wholly. Permanent tissues are of two types namely (i) simple tissues and (ii) complex tissues.

3. What is complex tissue? Name the various kinds of complex tissues.
Complex tissues are made up of more than one type of cells that work together as a unit. Complex tissues consist of parenchyma and sclerenchyma cells. However, collenchymatous cells are not present in such tissues. Common example are xylem and phloem.

4. Differentiate fibres from sclereids.
Fibres are elongated sclerenchymatous cells, usually with pointed ends. Their walls are lignified. Fibres are abundantly found in many plants. Sclereids are widely distributed in plant body. They are usually broad and they may occur in single or in groups. Sclereids are isodiametric, with lignified walls. Pits are prominent and seen along the walls. Lumen is filled with wall materials. Sclereids are also common in fruits and seeds.

5. Mention the most abundant muscular tissue found in our body. State its function.

a. Skeletal muscle: These muscles are attached to the bones and are responsible for the body movements and are called skeletal muscles. They work under our control and are also known as voluntary muscles. The muscle fibres are elongated, non-tapering, cylindrical, unbranched and showing alternating dark and light bands, giving them the striped or striated appearance. These cells posses many nuclei (multinucleate). They occur in the muscles of limbs(biceps and triceps of arms). They undergo rapid contraction.
b. Smooth muscle: These muscles are spindle shaped with broad middle part and tapering ends. There is a single centrally located muscle (uninucleate). These fibrils do not bear any stripes or striations and hence are called non-striated. They are not under the control of our will and so are called involuntary muscles. The walls of the internal organs such as the blood vessels, gastric glands, intestinal villi and urinary bladder contain this type of smooth muscle. Movement of food in the alimentary canal or the contraction and relaxation of blood vessels are involuntary movements.

6. Which tissue is the main component of tendons and ligaments? How do they differ in function?
The fibrobasts and the fibres in the fibrous connective tissue is the principle component of tendons and ligaments.
a) Tendons: They are cord-like, strong structures that join skeletal muscles to bones.
b) Ligaments: They are highly elastic structures. They have great strength and they connect bones to bones.

7. What are the fibres present in the matrix of loose connective tissue?
The matrix consists of collagen fibres, elastin fibres and fibroblast cells.

8. How are collagen fibres organized in dense connective tissues?
Collagen fibres are in parallel bundles. Rows of fibroplasts are present between them.

9. What is skeletal connective tissue? How is it helpful in the functioning of our body
It is solid, rigid and strong, non-flexible skeletal connective tissue. It provides shape and structural framework to the body. Bones support and protect soft tissues and organs.

10. Which tissue is called middleman between tissue cells and blood? Why?
Lymph is the middleman between tissue cells and blood. It is a colourless fluid filtered out of the blood capillaries. It consists of plasma and white blood cells. It mainly helps in the exchange of materials between blood and tissue fluids. So it is called middleman between tissue cells and blood.

11. Why should gametes be produced by meiosis during sexual reproduction?
When gametes are produced by meiosis they have half the number of chromosomes (haploid). When a haploid male gamete and a haploid female gamete fuse during sexual reproduction, the zygote will be a diploid one. It will have the same number of chromosomes as the parent cell. Any abnormality in the number of chromosomes in the zygote will cause disorders.

12. In which stage of mitosis the chromosomes align in an equatorial plate? How?
The duplicated chromosomes arrange on the equatorial plane and form the metaphase plate. Each chromosome gets attached to a spindle fibre by its centromere which is known as the chromosomal fibre. The centromere of each chromosome divides into two, each being associated with a chromatid.

13. Write one point of difference between
a) Bone and cartilage
Bone is solid, rigid, strong and non-flexible. Cartilage is soft, semi-rigid and flexible.
b) Simple and compound epithelial tissue
A simple epithelium is formed of a single layer of cells. A compound epithelium consists of more than one layer of cells.

14. Why is blood considered to be a connective tissue?
The blood and the lymph link different parts of the body. Blood carries nutrients and oxygen to all cells. It transports waste materials to the excretory system. So blood is considered to be connective tissue.

15. Give the sequence of the events occurring during prophase of mitosis.
During this stage chromosomes become short and thick and are clearly visible inside the nucleus. Centrosome splits into two daughter centrioles. They move apart and occupy opposite poles of the cell.. Each centriole is surrounded by radiating rays, termed as aster rays. Spindle fibres appear between the two centrioles. Nuclear membrane and nucleolus disappear gradually.

16. Why is meiosis called reductional division and mitosis as equational division?
Mitosis results in the production of diploid daughter cells with equal distribution of genetic material (DNA). It maintains the diploid (2n) number of chromosomes in daughter cells. So ti is called equational division.
Meiosis is called reduction division because the chromosome number is reduced to haploid (n) from diploid (2n). meiosis produces four daughter cells from a parent cell.

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