Samcheer Kalvi 10th Science Unit 18 – Heredity Book Back Answers:

TN Samacheer Kalvi 10th Standard New Science Book Back 1 Mark and 2 Mark Question & Answers Guide PDF uploaded and available below. Class 10 New Syllabus 2021 to 2022 Book Back Solutions available for both English and Tamil Mediums. Samacheer Kalvi 10th Science Unit 18 – Heredity Book Back Answers/solutions are provided on this page.

TN 10th Std Science Book Portion consists of  23 Units. Tamilnadu Class 10th Std Science consists of Physics Units 1 to 6, Chemistry Units 7 to 11, Biology Units 12 to 22, and Unit 23 – Visual Communication. Check Unit wise and Full Samacheer Kalvi 10th Science Book Back Questions and Answers/Answer Key Guide PDF format for Free Download.

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10th Samacheer Kalvi Science Book Back Solutions:

Samacheer Kalvi 10th Books Science Subject 1 Mark and 2 Mark Solutions 2022 PDF for reduced syllabus available below. Check Physics, Chemistry, and Biology questions for English and Tamil Medium. Click the Download option to download Book Back 1 Mark questions and answers/Answers Key. Take the printout and use it for exam purposes.

10th Science Unit 18 – Book Back 
Heredity

I. Choose the best answer:

1. According to Mendel alleles have the following character
a) Pair of genes                     b) Responsible for character
c) Production of gametes    d) Recessive factors
Ans : (b) Responsible for character

2. 9 : 3 : 3 : 1 ratio is due to
a) Segregation                            b) Crossing over
c) Independent assortment     d) Recessiveness
Ans : (c) Independent assortment

3. The region of the chromosome where the spindle fibers get attached during cell division
a) Chromomere   b) Centrosome   c) Centromere   d) Chromonema
Ans : (c) Centromere

4. The centromere is found at the center of the chromosome.
a) Telocentric b) Metacentric c) Sub-metacentric d) Acrocentric
Ans : (b) Metacentric

5. The units form the backbone of the DNA.
a) 5 carbon sugar   b) Phosphate   c) Nitrogenous bases   d) Sugar phosphate
Ans : (d) Sugar phosphate

6. Okasaki fragments are joined together.
a) Helicase   b) DNA polymerase   c) RNA primer   d) DNA ligase
Ans : (d) DNA ligase

7. The number of chromosomes found in human beings are.
a) 22 pairs of autosomes and 1 pair of allosomes    b) 22 autosomes and 1 allosome
c) 46 autosomes    d) 46 pairs of autosomes and 1 pair of allosomes
Ans : (a) 22 pairs of autosomes and 1 pair of allosomes.

8. The loss of one or more chromosomes in ploidy is called.
a) Tetraploidy b) Aneuploidy c) Euploidy d) polyploidy
Ans : (b) Aneuploidy

II. Fill in the blanks

1. The pairs of contrasting character (traits) of Mendel are called.  Ans: Allele or allelomorphs

2. Physical expression of a gene is called Ans : Phenotype

3. The thin thread-like structures found in the nucleus of each cell are called.  Ans: Chromosomes

4. DNA consists of two chains. Ans: Polynucleotide
5. An inheritable change in the amount or the structure of a gene or a chromosome is called.  Ans: Mutation

III. True or False (Correct the Statement if it is false)

1. A typical Mendelian dihybrid ratio of F2 generation is 3:1.
Ans: False. A typical Mendelian dihybrid ratio of F2 generation is 9 : 3: 3: 1.

2. A recessive factor is altered by the presence of a dominant factor.
Ans: False. A recessive factor is masked by the presence of a dominant factor.

3. Each gamete has only one allele of a gene. Ans: True.

4. Hybrid is an offspring from a cross between genetically different parents. Ans: True.

5. Some of the chromosomes have an elongated knob-like appendage known as telomere.
Ans: False. Some of the chromosomes have an elongated knob-like appendage known as Satellite.

6. New nucleotides are added and a new complementary strand of DNA is formed with the help of the enzyme DNA polymerase.
Ans: True

7. Down’s syndrome is a genetic condition with 45 chromosomes.
Ans: False. Down’s syndrome is a genetic condition with 47 chromosomes.

IV. Match the following:

Question:

Answer:
1. (c) 22 pairs of chromosome
2. (d) 2n
3. (e) 23rd pair of chromosome
4. (a) Trisomy 21
5. (b) 9 : 3 : 3 : 1.

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