Please select a subject first
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Given below are two statements labelled as Assertion (A) and Reason (R).
Assertion (A): Proteins are found to have two different types of secondary structures viz alpha-helix and beta-pleated sheet structure.
Reason (R): The secondary structure of proteins is stabilized by hydrogen bonding.
Select the most appropriate answer from the options given below:
Concept: Structure of Proteins
Account for the following:
There are 5 OH groups in glucose
Concept: Structures of Glucose
Account for the following:
Glucose is a reducing sugar
Concept: Classification of Carbohydrates
Account for the following:
What happens when D – glucose is treated with the following reagents
Bromine water
Concept: Structures of Glucose
Account for the following:
What happens when D – glucose is treated with the following reagents
HNO3
Concept: Structures of Glucose
Read the passage carefully and answer the questions that follow:
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Strengthening the Foundation: Chargaff Formulates His "Rules" Many people believe that James Watson and Francis Crick discovered DNA in the 1950s. In reality, this is not the case. Rather, DNA was first identified in the late 1860s by Swiss chemist Friedrich Miescher. Then, in the decades following Miescher's discovery, other scientists- notably, Phoebus Levene and Erwin Chargaff- carried out a series of research efforts that revealed additional details about the DNA molecule, including its primary chemical components and the ways in which they joined with one another. Without the scientific foundation provided by these pioneers, Watson and Crick may never have reached their groundbreaking conclusion of 1953: that the DNA molecule exists in the form of a three-dimensional double helix. |
Answer the following questions:
- A segment of DNA has 100 adenine and 150 cytosine bases. What is the total number of nucleotides present in this segment of DNA?
- A sample of hair and blood was found at two sites. Scientists claim that the samples belong to same species. How did the scientists arrive at this conclusion?
- The sample of a virus was tested and it was found to contain 20% adenine, 20% thymine, 20% guanine and the rest cytosine. Is the genetic material of this virus (a) DNA-double helix (b) DNA-single helix (c) RNA? What do you infer from this data?
OR
How can Chargaff’s rule be used to infer that the genetic material of an organism is double-helix or single-helix?
Concept: Structure of Nucleic Acids
Why tryptophan is an essential amino acid?
Concept: Biomolecules in the Cell > Proteins >> Amino Acids
An α-helix is a structural feature of ______.
Concept: Structure of Proteins
Proteins are polymers of ______.
Concept: Structure of Proteins
When D-glucose reacts with HI, it forms ______.
Concept: Structures of Glucose
Assertion (A): Proteins are polymers of α-amino acids connected by a peptide bond.
Reason (R): A tetrapeptide contains 4 amino acids linked by 4 peptide bonds.
Concept: Structure of Proteins
Which of the following statements is not true about glucose?
Concept: Preparation of Glucose
Assertion (A): Vitamin C cannot be stored in our body.
Reason (R): Vitamin C is fat soluble and is excreted from the body in urine.
Concept: Classification of Vitamins
β-pleated sheet structure in proteins refers to ______.
Concept: Structure of Proteins
The vitamins which can be stored in our body are ______.
Concept: Classification of Vitamins
DNA fingerprinting is used to determine paternity of an individual. Which property of DNA helps in the procedure?
Concept: Structure of Nucleic Acids
What structural change will occur when a native protein is subjected to change in pH?
Concept: Denaturation of Proteins
When sucrose is hydrolysed the optical rotation values are measured using a polarimeter and are given in the following table:
| S. No. | Time (hours) | Specific Rotation |
| 1 | 0 | + 66.5° |
| 2 | ∞ | - 39.9° |
- Account for the two specific rotation values.
- What is the specific name given to sucrose based on the above observation?
- One of the products formed during the hydrolysis of sucrose is a glucose, that reacts with hydroxylamine to give compound A. Identify compound A.
Concept: Classification of Carbohydrates >> Disaccharides
Which of the following is a natural polymer ? Buna-S, Proteins, PVC
Concept: Types of Polymerisation Reactions - Addition Polymerisation or Chain Growth Polymerisation
Write the name of monomers used for getting the following polymers : Bakelite
Concept: Classification of Polymers> Based on Structure
