10th Science Book Back Answers Unit 18 – Heredity:

Samacheer Kalvi 10th Standard Science Book Back Questions with Answers PDF uploaded and the same is given below. Class-tenth candidates and those preparing for TNPSC exams can check the New Science Book Back Question and Answers PDF below.  Samacheer Kalvi Class 10th Std Science Book Back Answers Biology Unit 18 – Heredity Solutions are available below. Complete solutions for all 23 Units’ book back questions with a solutions guide uploaded and available on our site. Check the complete Samacheer Kalvi 10th Science Unit 18 Answers below:

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

Samacheer Kalvi 10th Science Book Subject One Mark, Two Mark Guide questions and answers are below. Check Science Book Back Questions with Answers. Take the printout and use it for exam purposes.

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10th Science – Biology

Unit 18: 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 is_______.
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 characters (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 a 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.

Other Important links for 10th Science Book Answers Solutions:

For the 10th Standard Science Unit 19 book back question and answers solutions PDF, check the link – Samacheer kalvi 10th Science Unit 19 – Origin And Evolution Of Life

Click here for the complete Samacheer Kalvi 10th Science Book Back Solution Guide PDF – 10th Science Book Back Solutions