CBSE Class 10 Science HOTs Heredity And Evolution

Question. The phenomenon where individuals of a species exhibit differences in characteristics are called:
(a) Adaptation
(b) Evolution
(c) Variation
(d) All of these

Answer: C

Question. Recessive genes can be expressed only in
(a) homozygous condition
(b) heterozygous condition
(b) Both of the above conditions
(d) None of the above conditions

Answer: A

Question. Which part of the DNA provides information for a protein?
(a) Chromosome
(b) Mitochondria
(b) RNA
(d) Gene

Answer: D

Question. Which chromosomes do not play any role in the determination of the sex of an individual?
(a) Autosomes
(b) Metacentric chromosomes
(b) Acrocentric chromosomes
(d) None of the above

Answer: A

Question. When a new plant is formed as a result of cross-pollination from different varieties of a plant, the newly formed plant is called:
(a) Dominant plant
(b) Mutant plant
(b) Hybrid plant
(d) All of these

Answer: A

Question. Germinal variations are those variations which
(a) are inheritable
(b) affect only somatic cells
(b) are not inheritable
(d) None of the above

Answer: A

Question. Which of the following can be inherited from parents to offspring?
(a) Swimming technique
(b) Big nose
(b) Sculpted body
(d) All of the above

Answer: B

Question. The genotype of the offspring formed from the cross depicted as Tt x tt will be
(a) TT and tt
(b) Tt and tt
(b) Only tt
(d) Only TT

Answer: B

Question. In humans, the sex Chromosomes comprises one pair of the total of 23 pairs of chromosomes. The other 22 pairs of chromosome are called:
(a) autosomes
(b) chromosomes
(b) meiosis
(d) all of these

Answer: A

Question. What, according to Mendel, was responsible for the inheritance of specific traits?
(a) Genes
(b) Factors
(b) Chromosomes
(d) DNA

Answer: B

Question. The maleness of a child is determined by 
(a) the X-chromosome in the zygote.
(b) the Y-chromosome in zygote.
(b) the cytoplasm of germ cell which determines the sex.
(d) sex is determined by chance.

Answer: B

Question. A pea plant with round and green seeds (RRyy) is crossed with another pea plant with wrinkled and yellow seeds (rrYY). What would be the nature of seeds in the first generation (F1 generation).
(a) Round green
(b) Wrinkled green
(b) Wrinkled yellow
(d) Round yellow

Answer: D

Question. Which one of the following strongly indicates that bird and dinosaurs are closely related?
(a) They both have feathers
(b) They both respire
(c) They both reproduce
(d) They both have eyes

Answer: A

Question. Formation of 2 independent species due to genetic drift, geographical isolation, natural selection is specifically referred as–
(a) Evolution
(b) Classification
(c) Speciation
(d) Reproduction

Answer: C

Question. There is an inbuilt tendency of variation during reproduction because of–
(i) Errors in DNA copying
(ii) Sexual reproduction
(a) only (i) (b) only (ii)
(c) both (i) and (ii) (d) none of them

Answer: B

Question. Wild cabbage is being cultivated for thousands of years and humans have generated broccoli, cauliflower, kala etc. from it. This is an example of
(a) Natural selection
(b) Genetic drift
(c) Geographic isolation
(d) Artificial selection

Answer: D

Question. If A and B have n characteristics common while A and C have n/2 characteristics common, then which of the two organisms are more closely related?
(a) A and C
(b) A and B
(c) Characteristics need to be known
(d) None of these

Answer: C

Question. If we breed a group of squirrels and surgically remove their tails, then amongst the progeny of these tailless squirrels–
(a) All have no tail
(b) All have a tail
(c) Some of them have tails
(d) Cannot be determined.

Answer: B

Question. Fossils helps
(a) To study evolution
(b) To understand climatic conditions in past
(c) For a hierarchy of organisms (classification)
(d) They help in all the above

Answer: D

Question. Organism A recently came into existence while B was formed millions of years ago.
What does this indicate?
(i) A is more efficient than B
(ii) A is more complex than B
(a) Only (i) (b) Only (ii)
(c) Both (i) and (ii)
(d) Either (i) or (ii)

Answer: C

Question. Which of the following can be called a characteristic?
(a) Plants can photosynthesise
(b) We have 2 eyes
(c) Mango tree is multicellular
(d) All of these

Answer: D

Question. The number of pairs of sex chromosomes in the zygote of humans is:
(a) 1
(b) 2
(b) 3
(d) 4

Answer: A

Question. In humans, sex determination is controlled by
(a) allosomes
(b) autosomes
(b) temperature
(d) All of the above

Answer: A

Question. Which of the following statements is incorrect?
(a) Gene is a sequence of nucleotides.
(b) During the process of gene expression, DNA is first copied into RNA.
(b) Genes can acquire mutations in their sequence.
(d) Genes cannot acquire mutations in their sequence.

Answer: C

Question. The sex of the child depends on the chromosomes present in the
(a) egg of the female
(b) sperm of the male
(b) Both (a) and (b)
(d) None of these

Answer: B

Question. A cross between a tall plant (TT) and short pea plant (tt) resulted in progeny that were all tall plants because: 
(a) tallness is the dominant trait.
(b) shortness is the dominant trait.
(b) tallness is the recessive trait.
(d) height of pea plant is not governed by gene ‘T’ or ‘t’.

Answer: A

Question. Which of the following is an example of genetic variation?
(a) One person has a scar but his friend does not.
(b) One person is older than the other.
(b) Reeta eats meat but her sister Geeta is a vegetarian.
(d) Two children have different eye colour.

Answer: D

Question. When a gene exists in more than one form, the different forms are terms as
(a) alleles
(b) heterozygotes
(b) genotypes
(d) homozygotes

Answer: A

Question. In human males all the chromosomes are paired perfectly except one. These unpaired chromosomes are:
(i) Large chromosome
(ii) Small chromosome
(iii) Y-chromosome
(iv) X-chromosome
(a) (i), (ii)
(b) (iii) only
(c) (iii), (iv)
(d) (ii), (iv)

Answer: C

Important Questions for NCERT Class 10 Science Herediry and Evolution

Very Short Answer type Questions :

Question. What happened when Mendel crossed two traits of a character in a pea plants?
Answer: Only dominant trait appeared in F₁

Question. Who provided experimental evidence to support theory of origin of life from inanimate matter?
Answer: Miller and Urey

Question. Why are asexually reproducing organisms capable of showing hereditary features?
Answer: Asexual reproduction tends to preserve the similarities among all the individuals belonging to a give line of descent. Therefore, asexually reproducing organisms are capable of showing hereditary features.

Question. If the sperm bearing Y-chromosome fertilizes the egg, the child born will not be entirely like his father. Why is it so?
Answer: It is so because the other sex chromosome, ie the X-chromosome will also have its effects and other autosomes of the egg will also show their characteristics.

Question. A normal pea plant bearing colored flowers suddenly start producing white flowers. What could be the possible cause?
Answer:The appearance of white flowers is due to mutation.

Question. Mention any two recessive traits of garden pea.
Answer: Dwarf (height of plant), wrinkled seed

Question. Write the characteristics on the basis of which duck-biled platypus is considered as a link between reptiles and mammals.
Answer: The characteristic resembling reptiles is laying of eggs and the characteristics resembling mammals is presence of mammary glands.

Question. What will be the percentage of ab gametes produced by AaBb parent?
Answer: 25 percent

Question. Mendel crossed a pure white recessive pea plant with a dominant pure red flowered plant. What will be the first generation of hybrids?
Answer: All red

Question. Name the chemicals which were essential for origin of life.
Answer: Proteins and nucleic acid

Question. Why males are called heterogametic?
Answer: Because they have dissimilar sex chromosomes.

Question. What is the percentage possibility a couple of having daughters?
Answer: 50 percent

Question. Name 2 organisms in which sex determination is regulated by environmental factors.
Answer: Turtle, lizard 

Short Answer Type Questions :

Question. How one is change adopted to perform different functions? Give one example.
Answer: In evolution, one change occurred initially is used to perform other functions. For example, feathers were evolved for warmth, later they were adapted for flight.

Question. The theory of evolution of species by natural selection was given by
(a) Mendel
(b) Darwin
(c) Lamarck
(d) Weismann

Answer : B

Question. What is the difference between genetic drift and change due to natural selection?
(a) Genetic drift does not require the presence of variation.
(b) Genetic drift never occurs in nature, natural selection does.
(c) Genetic drift does not involve competition between members of a species.
(d) There is no difference.

Answer : C

Question. Which of the follow in giscontrolledbygenes ?
(a) Eye colour
(b) Height
(c) Hair colour
(d) All of these

Answer: D

Question. If you were to sample garden pea plants in Mendel’s garden, which of the following statements would hold?
(a) Round seeds were more abundant than wrinkled seeds.
(b) Wrinkled seeds were more abundant than round seeds.
(b) Both round and wrinkled seeds were equally abundant.
(d) Answer depends on the time of day when sampling is done.

Answer: A

Question. According to Mendel, the genotypic ratio of F2 generation in a monohybrid cross is
(a) 3 : 1
(b) 9 : 3 : 3 : 1
(b) 1 : 1
(d) 1 : 2 : 1

Answer: D

Question. In human males, all the chromosomes are paired perfectly except one. This/these unpaired chromosome is/are 
(i) large chromosome
(ii) small chromosome
(iii) Y-chromosome
(iv) X-chromosome
(a) (i) and (ii)
(b) (iii) only
(b) (iii) and (iv)
(d) (ii) and (iv)

Answer: C

Question. In peas, a pure tall (TT) is crossed with a pure short plant(tt). The ratio of pure tall plants to pure short plants in F2 generation is:
(a) 1:3
(b) 3:1
(b) 1:1
(d) 2:1

Answer: C

Question. The process where characteristics are transmitted from parent to offsprings is called:
(a) Variation
(b) Heredity
(b) Gene
(d) Allele

Answer: B

Question. What determines the differences between the progeny and parents?
(a) Inheritance
(b) Heritage
(b) Genetics
(d) Variation

Answer: D

Question. From the list given below select the character which can be acquired but not inherited. 
(a) Colour of eye
(b) Colour of skin
(b) Size of body
(d) Nature of hair

Answer: C

Question. The discipline of Biology that deals with the study of inheritance is
(a) Cytology
(b) Evolution
(b) Genetics
(d) Morphology

Answer: C

Question. Which of the following statements is not true with respect to variations?
(a) All variations in a species have equal chances of survival.
(b) Change in genetic composition results in variation.
(b) Selection of variants by environmental factors forms the basis of evolutionary processes.
(d) Variation is minimum in asexual reproduction.

Answer: A

Question. A Mendelian experiment consisted of breeding tall pea plants bearing violet flowers with short pea plants bearing white flowers. The progeny all bore violet flowers but almost half of them were short. This suggests that the genetic make-up of the tall parent can be depicted as:
(a) TTWW
(b) TTww
(b) TtWW
(d) TtWw

Answer: C

Question. The terms ‘genotype’ and ‘phenotype’ were coined by
(a) Darwin
(b) Bateson
(b) Johannsen
(d) Mendel

Answer: C

Question. A zygote which has an X-chromosome inherited from the father will develop into a 
(a) boy
(b) girl
(b) X-chromosome does not determine the sex of child
(d) either boy or girl

Answer: B

Question. If Mendel would have carried out cross pollination of a pea plant having tt trait with pea plant having Tt trait then the F1 Progeny plants would have been?
(a) Two dwarf and Two tall plant
(b) One dwarf and three tall plant
(b) All Tall
(d) All dwarf

Answer: A

Question. Dominant alleles are expressed exclusively in a heterozygote, while recessive traits are expressed only if the organism is …………..for the recessive allele.
(a) homozygous
(b) heterozygous
(b) normal
(d) none of these

Answer: A

Question. A group of laboratory mice having tails are bred together and their progeny is studied. The progeny had tails. However, the scientist removed the tails surgically and again bred them for four successive generations. In your opinion, what would be the nature of the new progeny?
(a) All mice born will have tails.
(b) All mice born will have no tails.
(b) The ratio of tailless to the tailed mice will be 1 : 3.
(d) The ratio of tailless to the tailed mice will be 1 : 4.

Answer: A

Question. _______ is the observable set of characteristics of an organism.
(a) Phenotype
(b) Genes
(b) DNA
(d) All of these

Answer: A

Question. Humans have two different sex chromosomes, X and Y. Based on Mendel’s laws, a male offspring will inherit which combination of chromosomes?
(a) Both the X chromosomes from one of its parents.
(b) Both the Y chromosomes from one of its parents.
(b) Combination of X chromosomes from either of its parents.
(d) Combination of X and Y chromosome from either of its parents.

Answer: D

Question. When a cross is made between two parents with respect to a single character, it is called a
(a) dihybrid cross
(b) monohybrid cross
(b) trihybrid cross
(d) None of these

Answer: B

Question. Select the group which shares maximum number of common characters.
(a) Two individuals of a species
(b) Two species of a genus
(b) Two genera of a family
(d) Two genera of two families

Answer: A

Question. The number of pairs of sex chromosomes in the zygote of a human being is
(a) 2
(b) 3
(c) 1
(d) 4

Answer : C

Question. Human offspring’s sex is determined
(а) through father’s sex chromosomes.
(b) through mother’s sex chromosomes.
(c) by hormones.
(d) by enzymes.

Answer : A

Question. A man with blood group A marries a woman having blood group O. What will be the blood group of the child?
(a) O only
(b) A only
(c) AB
(d) Equal chance of acquiring blood group A or blood group O.

Answer : D

Question. Some dinosaurs had feathers although they could not fly but birds have feathers that help them to fly. In the context of evolution this means that
(a) reptiles have evolved from birds
(b) there is no evolutionary connection between reptiles and birds
(c) feathers are homologous structures in both the organisms
(d) birds have evolved from reptiles.

Answer : D

Question. Which one of the following pairs are homologous organs?
(a) Forelimbs of a bird and wings of a bat.
(b) Wings of a bird and wings of a butterfly.
(c) Pectoral fins of a fish and forelimbs of a horse.
(d) Wings of a bat and wings of a cockroach.

Answer : A

Question. Those organs which have the same basic structure but different functions are called
(a) Vestigial organs
(b) Analogous organs
(c) Homologous organs
(d) None of these

Answer : C

Question. The process by which new species develop from the existing species is known as
(a) Evolution
(b) Natural selection
(c) Artificial selection
(d) Speciation

Answer : D

Question. Which of the following is the ancestor of ‘Broccoli’?
(a) Cabbage
(b) Cauliflower
(c) Wild cabbage
(d) Kale

Answer : C

True and False :

Question. Variation decreases the chances of survival of an organism in a changing environment.
Answer: False

Question. Genes controls the development of inherited characterstics such as hair colour, skin colour, etc. 
Answer: True

Question. Acquired variations in somatic traits are not passed from generation to generation. 
Answer: True

Question. Human height is a trait which shows variations. 
Answer: True

Question. The theory of origin of life on earth proposed by haldane was confirmed by Stanley L. Miller and Harold C Urey. 
Answer: True

Assertion and Reasoning Based Questions :

Question. Assertion: If the weight of the beetle is reduced because of starvation, that will not change the DNA of the germ cells.
Reason:Acquired traits are not inherited.
(a) If both assertion and reason are true and reason is the correct explanation of assertion.
(b) If both assertion and reason are true, but reason is not the correct explanation of assertion.
(c) If assertion is true, but reason is false.
(d) If assertion is false, but reason is true.

Answer: A

Question. Assertion: Dominant allele is an allele whose phenotype expresses even in the presence of another allele of that gene.
Reason: It is represented by a capital letter, e.g. T.
(a) If both assertion and reason are true and reason is the correct explanation of assertion.
(b) If both assertion and reason are true, but reason is not the correct explanation of assertion.
(c) If assertion is true, but reason is false.
(d) If assertion is false, but reason is true.

Answer: B

Question. Assertion: Mendel was successful in his hybridisation experiments.
Reason: Garden pea proved as an ideal experimental material.
(a) If both assertion and reason are true and reason is the correct explanation of assertion.
(b) If both assertion and reason are true, but reason is not the correct explanation of assertion.
(c) If assertion is true, but reason is false.
(d) If assertion is false, but reason is true.

Answer: A

Question. Assertion: Dominant allele is an allele whose phenotype expresses even in the presence of another allele of that gene.
(a) If both assertion and reason are true and reason is the correct explanation of assertion.
(b) If both assertion and reason are true, but reason is not the correct explanation of assertion.
(c) If assertion is true, but reason is false.
(d) If assertion is false, but reason is true.

Answer: B

Question. Assertion: The sex of the children will be determined by chromosome received from the father.
Reason: A human male has one X and one Y chromosome.
(a) If both assertion and reason are true and reason is the correct explanation of assertion.
(b) If both assertion and reason are true, but reason is not the correct explanation of assertion.
(c) If assertion is true, but reason is false.
(d) If assertion is false, but reason is true.

Answer: A

Question. Assertion: Chromosomes are capable of self-reproduction and maintaining morphological and physiological properties through successive generations.
Reason:Chromosomes are capable of self-reproduction and maintaining morphological and physiological properties through successive generations.
(a) If both assertion and reason are true and reason is the correct explanation of assertion.
(b) If both assertion and reason are true, but reason is not the correct explanation of assertion.
(c) If assertion is true, but reason is false.
(d) If assertion is false, but reason is true.

Answer: A

Very Short Answer type Questions :

Question. Define genetic drift.
Answer: The change in the frequency of certain genes in a population over generations.

Question. What is a gene? 
Answer: Gene is the unit of inheritance. It is the part of a chromosome which controls the appearance of a set of hereditary characters.

Question. Give one characteristic to show that birds are closely related to dinosaurs.
Answer: Presence of feathers on birds.

Question. What is Heredity?
Answer: It refers to the transmission of characters or traits from the parent to their offspring.

Question. Where are genes located? 
Answer: Genes are located on DNA present in chromosomes.

Question. A Mendelian experiment consisted of breeding pea plants bearing violet flowers with pea plants bearing white flowers. What will be the result in F1 progeny?
Answer: All plants in Fj generation will bear violet flowers.

Question. What is DNA? 
Answer: Deoxyribonucleic Acid (DNA) is a molecule which carry the hereditary characters or traits in a coded form from one generation to the next in all the organisms.

Question. Name any two organisms which are now extinct and are studied from their fossils.
Answer: Ammonite, trilobite, knightia and Rajasaurus. 

Question. Define vanation. 
Answer: Variation is defined as the differences in the characters or traits among the individuals of a species.

Question. Where did life originate on earth?
Answer: Life originated in the sea water.

Short Answer Type Questions :

Question. (i) State the observation of Mendel on self-pollination of first generation plants.
(ii) Which is a small section of DNA that is the genetic code for a characteristic?
Answer: (i) Mendel cross-breed peas with 7 pairs of pure-breed traits. Firstgeneration (F1) progeny only showed the dominant traits, but recessive traits reappeared in the self-pollinated secondgeneration (F2) plants in a 3:1 ratio of dominant to recessive traits.
(ii) A gene is a small section of DNA which is the genetic code for a characteristic.

Question. Here are the three possible genotypes for hair length in cats.
Complete the table below, Remember short hair is dominant. 

Answer: 

Question. How is the equal genetic contribution of male and female parents ensured in the progeny? 
Answer: Human beings contain 23 pairs of chromosomes-22 pairs are autosomes and one pair sex chromosomes. During meiosis
process gametes are formed in sex cells where the chromosome number is halved(n). At the time of fertilisation when male gamete fuses with female gamete the diploid number (2n) is restored back in zygote. Thus half of the chromosomes come from father and other half from mother. In this way meiosis process ensures equal genetic contribution of male and female parents in the progeny.

Question. Why are human beings who look so different from each other in terms of size, colour and looks said to belong to the same species?
Answer: Human beings belong to a same species called Homo sapiens. Based on the study of fossils, molecular phylogeny involving DNA sequence though human beings, who look so different from each other in terms of size, colour and looks belong to a single species. The study of fossils suggests that they have originated in Africa. Gradually their number increases and they spread throughout the whole continent, some also migrate to other parts of the world. The geographical and climatic variations in different regionslead to variations in their genes as a result their colour, looks, size also varies.

Question. (i) Will all organisms from a cross between two homozygous dominant organisms would have the same phenotype?
(ii) What proportion of offspring from BB v Bb would be BB?
(iii) What proportion of offspring from Cc v Cc would be cc?
(iv) What proportion of offspring from tt v Tt would be tt?
(v) What proportion of offspring from two homozygous recessive organisms would be homozygous recessive?
Answer: (i) True, all organisms from a cross between two homologous dominant organisms would have the same phenotype which would be homozygous dominant.
(ii) 50% of offspring would be BB (homozygous dominant) and the other 50% would be Bb (heterozygous).
(iii) One in four (25%) of offspring would be cc (homozygous recessive). Another 25% would be CC (homozygous dominant) and the final 50% would be Cc (heterozygous).
(iv) 50% of offspring would be tt (homozygous recessive) and the other 50% would be Tt (heterozygous).
(v) All offspring (100%) would be homozygous recessive. Without a dominant gene or genes offspring cannot result in heterozygous or homozygous dominant.

Question. How is the sex of the child determined in human beings? 
Answer: In human beings, there are two types of sex chromosome X and Y; female have XX chromosome whereas male have XY chromosome. Females produce eggs which carry only X chromosomes but males contain half of the sperms with X chromosomes and other half with Y chromosomes. During fertilisation when X carrying sperms fuse with an egg which
contains X chromosome the offsprings will be a female (XX). But when Y bearing sperms fuse with an egg (X) the offspring will be male (XY). Thus the sex of a child is determined by the type of sex chromosome X or Y received by the male gamete.

Question. Outline a project which aims to find the dominant coat colour in dogs.
Answer: Consider a homozygous black coat colour male dog (BB) breed with homozygous white coat colour female dog (bb). In F1 generation all dogs with black coat colour are produced. When these are again bred we get black and white coat colour dogs in F2 generation in the ratio 3 : 1. Thus we can say black colour is dominant over white. 

Question. All the variations in a species do not have equal chances of survival. Why?
Answer: According to 'Survival of the fittest', only the species which can adapt themselves to the environment can survive. Selection of the variants occurs by the different environmental factors. This forms the basis for evolution. Also, when a new change or variation occurs it means that the DNA constitution and the bodily cell apparatus also undergo genetic changes which result in the formation of a new variant. However, this change in the DNA might not be able to survive in the new environment. So, the DNA may get damaged and may stop functioning regularly which will affect the survival of the variant. The variations or the changes that are helpful and help in the evolution of the species will survive while the others will perish.

Question. A study found that children with light coloured eyes are likely to have parents with light-coloured eyes. On this basis can we say anything about whether the light eye colour trait is dominant or recessive?
Why or why not?
Answer: No we cannot say whether the light eye colour trait is dominant or recessive as the child inherits one copy of the trait from father and other from mother and here nature of the trait is not known. The nature can be known from at least three generations but here data is given only for two generations i.e., parents [P] and offsprings [F1].

Question. A man with blood group A marries a woman with blood group O and their daughter has blood group O. Is this information enough to tell you which of the traits blood group A or O is dominant? Why or why not? 
Answer: No, this information is not enough to find out which blood group is dominant. Blood group A can be represented as IAIA or IAIO which is the father’s blood group. Blood group O is represented as IOIO which is the mother’s blood group. The blood group of daughter is also O which might be inherited from her mother or father so it is difficult to assume which blood group is dominant.

Cased Based Questions :

Read the passage carefully and answer the following questions from Gregor Mendel, in 1865, paved the way for the analysis of the underlying genetic basis of traits by setting out to understand the principles of heredity. As per Darwin’s observations, in nearly all populations individuals tend to produce far more offspring than are needed to replace the parents. He also observed that it is very rare for any two individuals to be exactly alike. All the natural variations among individuals lead to natural selection. Individuals born with variations that present an advantage in obtaining resources or mates have greater chances of living and reproducing offspring who would inherit and carry forward the favourable variations. At the same time, individuals with different variations might be less likely to reproduce.

Question. ______ is simply the generation of diversity and the shaping of the diversity by environmental selection. 
(a) Evolution
(b) Speciation
(c) Heredity
(d) Natural selection

Answer: A

Question. Which one of the following statements is not true? 
(a) Excavating, time-dating, studying fossils, and determining DNA sequences are tools to study evolution.
(b) Variations arising during the process of reproduction cannot be inherited.
(c) Variations in the species may confer survival advantages or merely contribute to the genetic drift.
(d) Classification of organisms is based on tracing evolutionary relationships.

Answer: B

Question. Frequency of certain ________ in a population changes over generations to bring about evolution. C
(a) members
(b) progenies
(b) genes
(d) ideas

Answer: C

Question. VV, Vv and vv are _______, while violet and white are ________. 
(a) genotypes, phenotypes
(b) phenotypes, genotypes
(c) genotypes, genotypes
(d) phenotypes, phenotypes

Answer: A

Question. Which one of the following traits is most likely to pass from one generation to other? 
(a) Artificial hair coloured by a mother during pregnancy.
(b) Acquired skills by a father.
(c) Brown eye colour.
(d) Six fingers in right hand of a person.

Answer: C

Read the passage carefully and answer the following questions from Inheritance is the acquiring of genetic characteristics or traits from parents by their offspring. In humans, both parents equally contribute to the inheritance of traits. In 1860, Gregor Mendel studied the rules of inheritance of traits. He conducted an experiment on pea plants for the same. He cultivated pea plants and observed their pattern of inheritance from one generation to the next generation. This observation resulted in the discovery of three laws of inheritance, famously known as Mendel’s laws of Inheritance.

Question. The two versions of a trait which are brought in by the male and female gametes are situated on : 
(a) copies of the same chromosome.
(b) two different chromosomes.
(c) sex chromosomes.
(d) any chromosomes.

Answer: A

Question. If a round, green seeded pea plant (RRyy) is crossed with wrinkled, yellow seeded pea plant (rrYY), the seeds produced in F1 generation are : 
(a) round and yellow
(b) round and green
(c) wrinkled and green
(d) wrinkled and yellow

Answer: A

Question. ________ is the observable set of characteristics of an organism. 
(a) Phenotype
(b) Genes
(c) DNA
(d) All of these

Answer: A

Question. Select the statements that describe characteristics of genes: 
(A) Genes are specific sequence of bases in a DNA molecule.
(B) A gene does not code for proteins.
(C) In individuals of a given species, a specific gene is located on a particular chromosome.
(D) Each chromosome has only one gene.
(a) (A), (B)
(b) (A), (C)
(c) (A), (D)
(d) (B), (D)

Answer: B

Question. A group of moths some brown and some green lived in a grassland having dry bushes and dry grass. This phenomenon is called: 
(a) Variation
(b) Natural selection
(b) Mutations
(d) None of them

Answer: B

Read the passage carefully and answer the following questions from A genetic disorder is an inherited medical condition. It can be passed from parents to their children. Examples include cystic fibrosis, sickle cell disease and haemophilia. Parents who are heterozygous for these conditions are called carriers. They do not usually have the disorder themselves. This is shown in this Punnett square for cystic fibrosis. An individual who is homozygous (cc) with the recessive allele will develop cystic fibrosis. 

Question. Genetic disorders are: 
(a) Inherited
(b) Acquired
(c) Cannot be determined
(d) None of the above

Answer: A

Question. Which of the following statement is correct in reference to cystic fibrosis? 
(a) Two heterozygous parents (carriers) have a two in four chance of passing it to their children.
(b) Two heterozygous parents (carriers) have a one in four chance of passing it to their children.
(c) Two heterozygous parents (carriers) have a three in four chance of passing it to their children.
(d) Two heterozygous parents (carriers) will surely pass it to their children.

Answer: B

Question. State the probability percentage of children Without cystic fibrosis 
(a) 75%
(b) 25%
(c) 10%
(d) 5%

Answer: A

Question. State the probability percentage of children with cystic fibrosis. 
(a) 75%
(b) 25%
(c) 10%
(d) 5%

Answer: B

Question. State the probability of percentage of children with cystic fibrosis, if the parents are homozygous (cc) with the recessive allele. 
(a) 75%
(b) 25%
(c) 100%
(d) 5%

Answer: C