Write the scientific name of the fruit-fly. Why did Morgan prefer to work with fruit-flies for his experiments? State any three reasons. - Biology


Write the scientific name of the fruit-fly. Why did Morgan prefer to work with fruit-flies for his experiments? State any three reasons.



The scientific name of fruit fly is Drosophila melanogaster. Morgan preferred to work with fruit fly for his experiments because

(i) It is simple and convenient to breed under laboratory conditions throughout the year.

(ii) Its generation time is only 10–12 days.

(iii) It breeds quickly and prolifically and so produces large progeny after each mating.

(iv) Its contrasting features are easily observable.

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2013-2014 (March) All India Set 1

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If only one 'X' chromosome is found in a female person, which of the following symptoms she will show?

  1. epicanthal skin fold
  2. webbing of neck
  3. small testis and absence of spermatogenesis
  4. presence of simian crease on the palm

What will be the phenotype of progeny, if a carrier haemophilic female marries a normal male?

(a) Why are thalassemia and haemophilia categorized as Mendelian disorders? Write the symptoms of these diseases. Explain their pattern of inheritance in humans.

(b) Write the genotypes of the normal parents producing a haemophilic son.

Give an example of an autosomal recessive trait in humans. Explain its pattern of inheritance with the help of a cross.

In which of the following disorders number of chromosomes present is 47?
(A) Turner’s syndrome
(B) Cushing’s syndrome
(C) Acquired Immuno - Deficiency Syndrome
(D) Down’s syndrome

Name the disorder caused by under secretion of thyroxine in children

During a medical investigation, an infant was found to possess an extra  chromosome-21. Describe the symptoms the child is likely to develop later in the life.

The genotype of a person withTumer's syndrome will be:
(i)   44+XXY
(ii)  44+XYY
(iii) 44+XO
(iv) 44+XXYY

State any two symptoms of Down’s syndrome.

Attempt any TWO of the following: 

‘The gene for sickle cell anaemia in homozygous condition is lethal and produces sickle cell trait in heterozygous carrier’. Explain. 

In human beings 45 chromosomes/single X/XO abnormality causes ______.

Webbed neck is characteristic of ______ syndrome.

What is the reason for the 21st trisomy?

What are the different characters that develop due to Klinefelter's syndrome?

Mention the symptoms of Phenylketonuria.

A male rabbit of genotype 'AABBDDEE' is crossed with a female rabbit of genotype 'aabbddee' to produce F1 hybrid offspring. How many genetically different gametes can be produced by this F1 hybrid?

Read the following statements and select the correct option.

i. Genetic disorders are broadly categorised as, Mendelian disorders and chromosomal disorders.

ii. Mendelian disorders are caused due to absence or excess of one or more chromosomes or their abnormal arrangement.

iii. Chromosomal disorders are mainly caused due to alteration or mutation in the gene.

Match the Column I and Column II and select the correct option.

  List-I   List-II
i. Holandric genes a. Pleiotropy
ii. Multiple effects of a single gene b. Hypertrichosis
iii. Skin colour in man c. Multiple Alleles
iv. ABO Blood types d. Polygenic inheritance

The correct answer is

Feminised males have ______ chromosomes.

Identify I and II in the given diagram of chromosome.

Thalassemia and sickle cell anaemia are caused due to a problem in globin molecule synthesis. Identify the correct statement from the following.

Identify the genetic disorder m which an individual has an overall masculine development, gynaecomastia and is sterile.

Following list indicates various genetic diseases. Identify the diseases that are not caused due to single gene defect.

Huntington's chorea, alkaptonuria, Sickle cell anaemia, Down syndrome, thalassemia, Taysachs disease, Turner syndrome, cystic fibrosis, haemophi Lia, Klinefelter syndrome, albinism

Identify the option that correctly represents the number of chromosomes in Down syndrome.

Sickel-cell anaemia is an example of ______.

It is well known that Queen Victoria of England was a carrier for haemophilia. Since this is an X-linked disease, it can be predicted that ______.

The person with Turner’s syndrome has ______.

Down’s syndrome is due to ______.

Select the disease which is caused by recessive autosomal genes when present in homozygous conditions.

Read the following and answer from given below:

Turner's syndrome is an example of monosomy. It is formed by the union of an allosome-free egg and a normal 'X' containing sperm or a normal egg and an allosome-free sperm. The individual has 2n = 45 chromosomes (44 + X0) instead of 46. Such individuals are sterile females who have rudimentary ovaries, underdeveloped breasts, small uterus, short stature, webbed neck, and abnormal intelligence. They may not menstruate or ovulate. This disorder can be treated by giving female sex hormones to women from the age of puberty to make them develop breasts and have menstruation. This makes them feel more normal.

The number of Barr bodies present in a female with Turner's syndrome is ______

Which of the following is called as Royal disease?

Clotting of blood is to ______.

The practice of analyzing inheritance patterns in human beings is called ______

The technique exployed in human genetic counselling is:

Fused ear lobes appear in the progeny due to an autosomal recessive gene. Work out the genotypes of number in the given pedigree.


Which of the folowing is a correct match?

Lipoprotein lipase deficiency (LPLD)is a genetic disorder in which a person has a defective gene for lipase. This leads to high triglycerides, stomach pain, and fat deposits under the skin. It may eventually affect the liver, pancreas and may also cause diabetes. The disorder occurs if a child acquires defective genes from both parents (autosomal recessive). ERT (enzyme replacement treatment) is one of the treatments offered to patients with LPLD.

    1. What procedure is followed in ERT?
    2. What could be one possible drawback of ERT?
  1. How can LPLD be treated using Biotechnology? Elaborate.

What is the genotype of Turner's Syndrome?

Mention any one symptom of Turner's syndrome.

Describe Turner's syndrome.


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