Kerala SSLC Biology Chapter 6 Questions Unravelling Genetic Mysteries English Medium
Question 1.
The scientist who has laid the foundation of Genetics
a. Carl Linnaeus
b. Gregor Johann Mendel
c. James Watson
d. Charles Darwin
Answer:
b. Gregor Johann Mendel
Question 2.
The different forms of genes that control the trait,
a. Chromosome
b. Allele
c. Nucleotide
d. Nucleus
Answer:
c. Allele
Question 3.
The genetic constitution of females,
a. 44 + XX
b. 44 + XY
c. 43 + XX
d. 43 + XY
Answer:
a. 44 + XX
Question 4.
The sugar seen in DNA.
a. Ribose
b. Ribosome
c. Ribulose
d. Deoxyribose sugar
Answer:
d. Deoxyribose sugar
Question 5.
Fill up the blanks by observing the relationship between the first pair.
a. DNA: Two strands RNA: …………………..
b. Associated with ribosome: rRNA
Carry amino acids to the ribosome: …………………..
c. TT: tall
tt: …………………..
Answer:
a. Single strand
b. tRNA
c. Dwarf
Question 6.
Find the odd one out, note down the common features of others.
a. TTRR, TtRr, TTRr, ttrr
b. A-T, G-C, T-A, U-A
c. Adenine, Thymine, Guanine, Uracil
Answer:
a. ttrr
Others are tall plant with round seed
b. U-A
Others are nitrogen base pairs in DNA.
c. Thymine
Others are nitrogen bases seen in RNA.
Question 7.
Select the statements related to RNA from the given statements.
a. Has two strands
b. Ribose sugar is seen
c. Do not participate directly in protein synthesis
d. The nitrogen bases are Adenine, Uracil, Cytosine, Guanine
Answer:
b, d
Question 8.
Given below is the illustration showing how sex determination is taking place in human beings.
b. What are the inferences you arrive at from this illustration?
Answer:
a. i. 44 + XX
ii. 44 + XY
iii. 44 + XX
iv. 44 + XY
b. The male and female ratio will be 1:1. The XY chromosomes of the father determine whether the child is male or female.
Question 9.
The stages related to action of gene is given below. Arrange them in correct order.
a. mRNA reaches the ribosome.
b. mRNA reaches outside the nucleus.
c. Protein is synthesized.
d. tRNA carries amino acids to the ribosome.
e. mRNA forms from DNA.
f. Based on the information in mRNA amino acids are added.
Answer:
e, b, a, d, f, c
Question 10.
Observe the illustration and answer the questions given below.
a. Name the illustration.
b. What is its importance?
Answer:
a. Crossing over
b. As a result of this, part of a DNA crosses over to become the part of another DNA. This causes a difference in the distribution of genes. When these chromosomes are transferred to the next generation, it causes the expression of new characters in offspring.
Question 11.
Select the correct statements.
a. 46 chromosomes are seen in humans.
b. 23 pairs of autosomes are found in humans.
c. Genetic constitution of male is 44 + XY.
d. Sex chromosomes are of two types.
e. Genetic constitution of female is 46 + XX.
Answer:
a, c, d
Question 12.
Observe the illustration related to hybridization of two types of pea plants and answer the following questions.
a. Which are the characters expressed in first-generation?
b. Which are the hidden characters in this experiment?
c. Write the possible expression of different characters in next generation.
Answer:
a. Round seed, white flower
b. Flat seed, red flower
c. Round seed, white flower Round seed, red flower Flat seed, white flower Flat seed, red flower.
Question 13.
Given below is the illustration of a cross conducted between red-flowered and white-flowered pea plants. Complete it suitably.
a. First-generation
b. Write down the ratio of pea plants with different characters in the second generation.
Answer:
b. 3 red flowers: 1 white flower
Question 14.
Complete the given illustration of a nucleotide molecule.
Answer:
a. Sugar molecule
b. Phosphate
Question 15.
Complete the flow chart showing gene action.
Answer:
a. mRNA reaches outside the nucleus.
b. mRNA reaches ribosomes.
c. Based on the information in mRNA amino acids are added.
Question 16.
Complete the table suitably.
Answer:
Question 17.
Observe the illustration and answer the questions given below.
a. What is the dominant and recessive characters in the first generation?
b. If the plants obtained in first-generation is self-pollinated, what are the characters appear in the second generation? In which ratio.
c. Redraw the illustration using letters.
Answer:
a. Dominant character – Tall Recessive character – Dwarf
b. 3 Tall: 1 Dwarf
Question 18.
Analyze the illustration based on the self-pollination of first-generation.
a. Complete the illustration.
b. Offsprings of second generation. In which ratio?
Answer:
a. 1 – T
2-t
3 – TT
4 – Tt
5 – Tt
6 – tt
b. 3 tall: 1 Dwarf
Question 19.
A pea plant with genetic constitution TtRr (Tall plant producing round seed) was subjected to self-pollination. The genetic constitution of some of the progenies obtained are given below. Write the expressed character of the given progenies based on their genetic constitution.
a. TTRr
b. ttRr
c. ttrr
d. Ttrr
Answer:
a. TTRr – Tall plant producing round seed
b. ttRr – Dwarf plant producing round seed.
c. ttrr – Dwarf plant producing wrinkled seed
d. Ttrr – Tall plant producing wrinkled seed
Question 20.
The note prepared by Shahana on Mendel’s inferences during the classroom analysis of Mendel’s hybridization experiment in pea plants, based on a single trait is given below. Analyse the statements in the note and correct those that are wrong ones.
a. A trait is controlled by a specific factor.
b. A character is expressed and the other remains hidden in the first generation.
c. The character that remains hidden in the first generation does not appear in the second generation.
d. The ratio of characters in the second generation is 3:1.
Answer:
a. One trait is controlled by the combination of two factors.
c. The character that remains hidden in the first generation appears in the second generation.
Question 21.
Complete the flowchart illustrating the location of gene by using the information given in the box:
Answer:
Question 22.
Observe the illustration given below and answer the questions.
a. Identify the dominant character.
b. How does the parental plant with green-colored seed and the plant in the first generation differ in their alleles?
c. Describe alleles.
Answer:
a. Green
b. Alleles in parental plant-QG Allele in the first generation – Gg
c. Different forms of a gene.
Question 23.
Observe the nucleotide strands given below and answer the questions. ‘
a. Identify the strand that is found in DNA only.
b. Identify the strand that can be found in both DNA and RNA.
c. What is a nucleotide?
Answer:
a. B
b. A
c. A unit of sugar, phosphate, and nitrogen base/ Component of nucleic acid.
Question 24.
Given below is an illustration regarding sex determination. Observe the illustration and answer the questions.
a. Complete A, B, C in the illustration.
b. What is the possibility of the formation of a male child or a female child? Explain.
Answer:
a.
A. 44 + XY
B. 22 + X
C. 22 + Y
b. Equal chance. The number of male gametes with X chromosome and those with Y chromosome are equal. Egg with the X chromosome has equal chance to combine with sperm having Y chromosome and those having X chromosome.
Question 25.
Given below is a placard exhibited in a school rally organised ‘Against Racism ’.
It is not racial difference that makes the skin colour different; This is an adaptation to live under the sun.
a. How will you explain the difference in skin colour of people living in different parts of the world?
b. What attitude should be adopted by a scientifically enlightened society towards the idea in the placard? Substantiate.
Answer:
a. Melanin, a pigment protein imparts colour to skin.
It is due to the difference in gene function.
b. Skin colour is an adaptation to live under the sun.
- Races among mankind are only cultural.
- Scientifically, all men are of the same race.
- Consider all men as equal, without any racial difference.
Question 26.
‘Gene itself is allele; allele itself is gene Substantiate your answer.
Answer:
Statement is partly correct. Each character is controlled by pair factors called genes. Different forms of a gene are called alleles. Generally, a gene has two alleles. Alleles can be of the same types (TT) or of different types (Tt). If the alleles are of different types, only one trait represented by any one of the alleles get expressed.
Question 27.
In the hybridization experiment conducted by Mendel on the basis of two contrasting traits of the character height in pea plant
a. In the first generation, tall plants are expressed. No dwarf plant is seen in the first generation.
b. The dwarf plants were expressed in second generation. Give explanation.
Answer:
a. When plants that differ in a pair of contrasting traits are hybridized, only one trait is expressed while the other remains hidden in the offsprings of the first generation. The expressed trait is called dominant trait and the hidden trait is called recessive trait.
b. During gamete formation the factors that determine height segregate without getting mixed. This is the reason for the expression of the dwarf plants in second generation.
Kerala SSLC Biology Chapter Wise Questions and Answers