Thyroid Gland - Hormones and their functions

Thyroid gland is a bilobed, butterfly-shaped organ which is the largest endocrine gland in the body. The medical term for thyroid gland is "glandula thyreoidea". It secretes three hormones: T3 hormone, T4 hormone and Calcitonin. 

• Weight: 20-60 grams
• Size: 2-inches long

Wharton described the Thyroid gland for the first time.

Who was Mendel and why he selected garden pea for breeding experiments?

Gregor Mendel is know as the Father of Genetics who has postulated three Laws of Inheritance - Law of Dominance, Law of Segregation and Law of Independent Assortment.

In this article we will study about:

• Who was Gregor John Mendel - Father of Genetics?
• 7 traits studied by Mendel
• Reasons for selecting garden pea (Pisum sativum) for breeding experiments

ICSE 2018: The diagram given below represents a stage during cell division. [mitosis]

ICSE 2018:

Q. The diagram given below represents a stage during cell division. [5 marks] 

Study the same and answer the questions that follow:

(i) Identify whether it is a plant cell or an animal cell. Give a reason in support of your answer. 

(ii) Name the stage depicted in the diagram. What is unique feature observed in this stage? 

(iii) Name the type of cell division that occurs during: 

1. Replacement of old leaves by new ones. 

2. Formation of gametes. 

(iv)  What is the stage that comes before the stage shown in the diagram?

(v) Draw a neat, labelled diagram of the stage mentioned in (iv) above keeping the chromosome number constant

Solution:

ICSE 2019 - SOLVED Class 10 Biology Question Paper

SOLVED Class-10 Biology Question Paper - ICSE 2019

The Science Paper-3 (BIOLOGY) carried total of 80 marks and was divided into two sections, each carrying 40 marks. 

From Section-I, all questions had to be answered whereas from Section-II, any 4 questions could be attempted.

Total time given to solve the paper was 2 hours. 

General Instructions:

• Answers to this paper must be written on the paper provided separately. 
• You will not be allowed to write during the first 15 minutes. 
• This time is to be spent in reading the question paper. 
• The time given at the head of the paper is the time allowed for writing the answers.

Light and Dark Adaptation in Human Eye

Have you ever noticed: 

• When we enter a dark room from outside, immediately the things inside the room do not appear clear. Why?

• Why do we experience dazzling effect, when we come out of cinema hall after noon show?

Have you experienced above mentioned scenarios and wondered why does it happen? How does our eyes adapt to these situations?

If yes, then this article on "Light and Dark adaptation of Human Eye" will help to answer your curiosity.

ICSE 2019: Given below is an experimental set-up to demonstrate a particular tropic movement in germinating seeds.

ICSE 2019:

Q. Given below is an experimental set-up to demonstrate a particular tropic movement in germinating seeds. Study the diagram and answer the questions that follow: [5 marks]

 (i)  Label the parts 1 and 2.

(ii) Name the tropic movement shown by part 1.

(iii) Part 1 is affected by two stimuli. Name them. Which one of the two is stronger?

(iv) What is thigmotropism? Give one example.

(v) What is meant by ‘positive’ and ‘negative’ tropic movements in plants?

Solution:

ICSE 2019: Given below is a diagram representing a stage during mitotic cell division (Animal Cell).

ICSE 2019:

Q. Given below is a diagram representing a stage during mitotic cell division. Study the diagram and answer the following questions. [5 marks]

(i) Identify the stage by giving a suitable reason.

(ii) Is it a plant or an animal cell? Give a reason to support your answer.

(iii) Draw a neat, labelled diagram of the stage which follows the one shown in the

diagram.

(iv) How many chromosomes will each daughter cell have after the completion of the

above division?

(v) Name the four nitrogenous bases.

Solution: 

ICSE 2019: Study the picture given below and answer the following questions: Identify the type of pollution

ICSE 2019:

Q. Study the picture given below and answer the following questions: [5 marks]

(i) Identify the type of pollution.

(ii) Name one pollutant that causes the above pollution.

(iii) Mention the impact of this pollution on human health.

(iv) State one measure to control this pollution.

(v) What is a ‘pollutant’? Explain the term.

Solution: 

ICSE 2019: Given below is an apparatus which was set up to investigate a physiological process in plants.

ICSE 2019:

Q. Given below is an apparatus which was set up to investigate a physiological process in plants. The set-up was placed in bright sunlight. Answer the questions that follow: [5 marks]

(i) Name the process being studied. Define the process.

(ii) Why was the pot enclosed in a rubber sheet?

(iii) Mention two external factors which can accelerate the above process.

(iv) List two adaptations in plants to reduce the above process.

(v) Draw a neat, labelled diagram of a stomatal apparatus.

Solution: 

ICSE 2019: The diagram given below represents a system in the human body.

ICSE 2019:

Q. The diagram given below represents a system in the human body. Study the diagram and answer the following questions: [5 marks]

(i) Identify the system.

(ii) Label the parts marked 5 and 6.

(iii) Name the two hormones secreted by 1.

(iv) Mention the number and the name of the part involved in fertilisation and implantation from the above diagram.

(v) Mention the surgical methods of contraception in

1. Human males    2. Human females

Solution: 

ICSE 2019: In Mendel's experiments, tall pea plants (T) are dominant over dwarf pea plants (t)

ICSE 2019:

Q. In Mendel's experiments, tall pea plants (T) are dominant over dwarf pea plants (t). [5 marks]

(i) What is the phenotype and genotype of the F1 generation if a homozygous tall plant is

crossed with a homozygous dwarf plant?

(ii) Draw a Punnett square board to show the gametes and offspring when both parents

are heterozygous for tallness.

(iii) What is the phenotypic ratio and genotypic ratio of the above cross in (ii)?

(iv) State Mendel’s Law of Dominance.

(v) What is a dihybrid cross?

Solution: 

ICSE 2019: The diagram given below represents an endocrine gland in the human body.

ICSE 2019:

The diagram given below represents an endocrine gland in the human body. Study the diagram and answer the following questions: [5 marks]

(i) Identify the endocrine gland. Where is it located?

(ii) Why is the above gland referred to as the ‘master gland’?

(iii) Name the hormone which in deficiency causes diabetes insipidus. How does this

disorder differ from diabetes mellitus?

(iv) Explain the term ‘hormone’. What is the role of tropic hormones in the human body?

(v) Which lobe of the above gland secretes

1. Oxytocin    2. ACTH    3. Growth hormone

Solution: