Unit 15 Inheritance Short Questions

Q.1 Define Genetics.
Q.2 Define Inheritance.
Q.3 What are traits? Write two human traits.
Q.4 What are Genes?
Q.5 What are homologous chromosomes? OR / What are Homologous chromosomes? How many of these exist in man?
Q.6 How is chromatin/ chromosome made up of?
Q.7 What is nucleosome?
Q.8 Define Double helix.
Q.9 Define DNA replication.
Q.10 What is the purpose of DNA replication?
Q.11 How does DNA work?
Q.12 Differentiate between transcription and translation
Q.13 Define a Gene. Write symbols of Genes for any two traits.
Q.14 Define Allele.
Q.15 Define Locus.
Q.16 What is genotype? Describe its Types.
Q.17 Define Albinism
Q.18 Differentiate between dominant alleles and recessive allele.
Q.19 What features should be present in an organism used for genetic experiments?
Q.20 Differentiate between monohybrid cross and dihybrid cross. OR Define monohybrid
and dihybrid cross.
Q.21 What is meant by Pi, Fq and F2 generations?
Q.22 Define Law of Segregation.
Q.23 Define Mendel’s Law of independent assortment.
Q.24 Define co-dominance. Give an example.
Q.25 Define incomplete dominance. Give example.
Q.26 Define variation. Give sources of variations.
Q.27 Define Gene flow.
Q.28 Describe types of variations with examples.
Q.29 Define Organic or Biological Evolution.
Q.30 What processes are involved in Organic evolution.
Q.31 What is anti-evolution or theory of special creation?
Q.32 Define Natural selection.
Q.33 Define Artificial selection/sélective breeding
Q.34 Differentiate between breeds and varieties or cultivars.
Q.35 Define genotype and phenotype.
Q.36 What is template strand?
Q.37 Define Punnett Square?
Q.38 What will be Genotype of plants produced as a result of cross between two plants having Genotype Rr?
Q.1 Define Genetics.
Answer:
It is a branch of biology which deals with the study of inheritance.
Q.2 Define Inheritance.
Answer:
Inheritance means the transmission of characteristics from parents to offspring.
Q.3 What are traits? Write two human traits.
Answer:
Characters which are transmitted from parents to offspring are called traits. In man, height, eye colour etc are examples of traits and are inheritable.
Q.4 What are Genes?
Answer:
Genes are segments of DNA. Each specific gene contains instructions for the synthesis of specific protein.
Q.5 What are homologous chromosomes? OR / What are Homologous chromosomes? How many of these exist in man?
Answer:
The body cells have constant number of paired chromosomes. The two chromosomes of a pair are called as homologous chromosomes. For example, in human body cells, there are 23pairs of homologous chromosomes for a total of 46 chromosomes.
Q.6 How is chromatin/ chromosome made up of?
Answer:
Chromatin or chromosome is made up of DNA and protein.
Q.7 What is nucleosome?
Answer:
In chromatin, DNA wraps around histone proteins and form round structure called as nucleosome. DNA is also present between nucleosomes. In this way, nucleosomes and DNA between them look like beads on string.
Q.8 Define Double helix.
Answer:
DNA consists of two polynucleotide strands which are coiled around each other in the form of Double helix. There is phosphate-sugar backbone on outside, while nitrogenous bases are on inside of double helix.
Q.9 Define DNA replication.
Answer:
It is a process in which one parental DNA is divided into two genetically identical daughter DNA molecules.
Q.10 What is the purpose of DNA replication?
Answer:
DNA replication is done to make the copies of chromatids of chromosomes.
Q.11 How does DNA work?
Answer:
DNA is genetic material. It performs its role by giving instructions for the synthesis of specific proteins. Some proteins perform structural role while others act as enzymes to control all bio-chemical reactions of cells.
Q.12 Differentiate between transcription and translation
Answer:
i. Transcription
It is a process in which specific sequence of DNA nucleotides is copied in the form of messenger RNA (MRNA).
ii. Translation
The mRNA carries the sequence of its nucleotides to ribosomes. Ribosomes read this sequence and joins specific amino acids, according to it proteins are synthesized.
Q.13 Define a Gene. Write symbols of Genes for any two traits.
Answer:
Definition
Particular segment of DNA that contains instructions for synthesis of particular protein is called as gene.
OR
Particular sequence of nucleotides that contains instructions for synthesis of particular protein is called as gene. Symbols of Genes The trait of round seeds (controlled by allele R) was dominant over wrinkled (controlled by. allele r) seeds. Similarly yellow seed (controlled by Y) was dominant over green (controlled by y).
Q.14 Define Allele.
Answer:
Genes occur in pairs on homologous chromosomes. Each member of gene pair is called as allele. The alternative forms of a gene are called as alleles e.g. ‘A’ and ‘a’ are two alternative forms of a gene or ‘B’ and ‘b’ are two another alternative forms of a gene.
Q.15 Define Locus.
Answer:
Location or position of gene on chromosome is called as its locus.
Q.16 What is genotype? Describe its Types.
Answer:
The specific combinations of genes in an individual is known as genotype. It has two types
i.e. Homozygous and. Heterozygous
(i) Homozygous Genotypes.
The genotype in which gene pair contains two identical alleles (AA,aa) is called as homozygous
genotype.
(ii) Heterozygous genotype
The genotype in which gene pair contains two different alleles (Aa) is called as heterozygous
genotype.
Q.17 Define Albinism
Answer:
It is a condition in which normal body pigments are absent.
Q.18 Differentiate between dominant alleles and recessive allele.
Answer:
i. Dominant Allele
In the heterozygous condition, one allele masks or prevents the expression of the other, such allele is called as dominant allele. Dominant alleles are represented by capital letters e.g.
ii. Recessive Allele
The allele which is not expressed is called as recessive allele. Recessive alleles are represented by lower case letters e.g.
Q.19 What features should be present in an organism used for genetic experiments?
Answer:
Organism used in genetic experiments should have following features:
There should be number of different traits that can be studied.
• The organism should have contrasting traits e.g. for the trait of height, there should be only two very different phenotypes i.e. Tallness and dwarfness.
• The organisms (if it is plant) should be self-fertilizing but cross fertilization should also be
possible.
• The organism, should have a short but fast life cycle.
Q.20. Differentiate between monohybrid cross and dihybrid cross. OR Define monohybrid
and dihybrid cross.
Answer:
A cross in which only one trait is studied at a time is called as monohybrid cross e.g. cross between true-breeding round seeded plant and true breeding wrinkled seeded plant. In this case one trait i.e seed shape is under study.
A cross in which two traits are studied at a time is called as dihybrid cross e.g. cross between true breeding round yellow seeded plants and wrinkled green’ seeded plants. In this case, two traits i.e. seed shape and seed colour are under study.
Q.21 What is meant by Pi, Fq and F2 generations?
Answer:
P1 generation
First parental generation is known as P1 generation.
F1 generation
Means first filial. The offspring of Pi generation are called as F, generation.
F2 Generation
Mean’s second filial. The offspring of Fi, generation are called as F2 Generation.
Q.22 Define Law of Segregation.
Answer:
This law states that during gamete formation, the genes (alleles) of each pair segregate from each other and each gamete receives one gene from the pair when the gametes of male and female parents unite, the resulting offspring again gets the genes in pairs.
Q.23 Define Mendel’s Law of independent assortment.
Answer:
This law states that the alleles of a gene pair segregate (get separated and distributed to gametes) independently from the alleles of other gene pairs.
Q.24. Define co-dominance. Give an example.
Answer:
It is a situation in which two different alleles of a gene pair express themselves completely, instead of showing a dominant-recessive relationship. As a result, heterozygous organisms shows a phenotype that is different from both homozygous parents. For example human blood group AB.
Q.25 Define incomplete dominance. Give example.
Answer:
It is a situation in which phenotypic expression of heterozygous organism is intermediate to phenotype expressions shown by both homozygous organisms. Both alleles in heterozygous organisms express this blend (mixture) and neither allele is dominant over the other. For example pink flowered four o’clock plant.
Q.26 Define variation. Give sources of variations.
Answer:
Differences shown by individuals of same species are called variations. Important sources of variations are as following:-
(i) Crossing Over
(ii) Mutation
(iii) Random Fertilization
(iv) Gene flow
Q.27 Define Gene flow.
Answer:
Movement of genes from one population to other population is called gene flow:
Q.28 Describe types of variations with examples.
Answer:
There are two types of variations:
1. Continuous variations
Those variations in which phenotypes show a complete range of measurements from one extreme to other are called as continuous variations.
Height, weight, feet size, intelligence etc. are examples of continuous variations. In every human population, the individuals have a range of heights. No populations can show only two or three distinct heights. Continuous variations are controlled by many genes and are then affected by environmental factors.
2. Discontinuous variations
These are the variations which show distinct phenotypes which can be easily distinguished from each other. The phenotypes of such variations cannot be measured.
Blood groups are good examples of discontinuous variations. In human population, an individual has one of the four distinct blood groups and cannot have in between. Such variations are controlled by alleles of single gene. The environment has little effect on this type of variations
Q.29 Define Organic or Biological Evolution.”
Answer:
Organic or Biological evolution is change in characteristics of population or species of organisms over the course of generations.
The changes in an individual are not considered as evolution because evolution refers to populations, not to the individuals.
Q.30 What processes are involved in Organic evolution.
Answer:
There are two major processes involved in organic evolution.
• Alteration in genetic characteristics (traits) of a type of organisms over time.
• Creation of new types of organisms from a single type.
Q.31 What is anti-evolution or theory of special creation?
Answer:
The anti-evolution idea supports that all living things had been created in their current form only a few thousand years ago. It is also known as theory of special creation.
Q.32 Define Natural selection.
Answer:
Natural selection is process by which the better genetic variations become more common in successive generations of population.
Q.33 Define Artificial selection/sélective breeding
Answer:
Artificial selection (selective breeding) means intentional breeding between individuals for certain traits or combination of traits.
Q.34 Differentiate between breeds and varieties or cultivars.
Answer:
In artificial selection, the bred animals are known as breeds, while bred plants are known as varieties or cultivars.
Q.35 Define genotype and phenotype.
Answer:
Genotype
The specific combination of genes in an individual is known as genotype.
Phenotype
The expression of genotype in the form of trait is known as phenotype.
Q.36. What is template strand?
Ans. The strand of DNA to which new strand is formed called template strand.
Q.37 Define Punnett Square?.
Answer:
It is a diagram used to predict an outcome of a particular cross or breeding experiment. The gametes of both parents having all possible genetic make-up (set-ups) are determined.
Q.38. What will be Genotype of plants produced as a result of cross between two plants having Genotype Rr? 
Answer:
When two heterozygous plants with pink flowers (Rr) are crossed, F2 generation shows phenotypes of red, pink and white flowers in ratio 1:2:1.