Comparison of DNA and RNA structures highlighting their nitrogenous bases and sugar components.

Let's solve both questions step by step.

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Q.3: Label the names of the nitrogenous bases in DNA and RNA

We are given two structures: one for DNA (Deoxyribonucleic acid) and one for RNA (Ribonucleic acid). On each side, there are four nitrogenous bases shown with their letters (A, C, G, T/U), and we need to label them correctly.

#### Nitrogenous Bases in DNA:
- A = Adenine
- C = Cytosine
- G = Guanine
- T = Thymine

#### Nitrogenous Bases in RNA:
- A = Adenine
- C = Cytosine
- G = Guanine
- U = Uracil (replaces Thymine in RNA)

So, fill in the blanks accordingly:

| DNA | RNA |
|-----|-----|
| Adenine | Adenine |
| Cytosine | Cytosine |
| Guanine | Guanine |
| Thymine | Uracil |

> ✔ Answer:
> - DNA: A → Adenine, C → Cytosine, G → Guanine, T → Thymine
> - RNA: A → Adenine, C → Cytosine, G → Guanine, U → Uracil

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Q.4: Fill in the blanks to compare DNA and RNA

We are to complete a table comparing DNA and RNA.

| DNA | RNA |
|-----|-----|
| ➤ A nucleic acid, called deoxyribonucleic acid | ➤ A nucleic acid, called ribonucleic acid |
| ➤ The sugar in DNA is deoxyribose | ➤ The sugar in RNA is ribose |
| ➤ DNA is double stranded | ➤ RNA is single stranded |

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✔ Final Answers:

#### Q.3:
- DNA:
- A → Adenine
- C → Cytosine
- G → Guanine
- T → Thymine
- RNA:
- A → Adenine
- C → Cytosine
- G → Guanine
- U → Uracil

#### Q.4:
| DNA | RNA |
|-----|-----|
| ➤ A nucleic acid, called deoxyribonucleic acid | ➤ A nucleic acid, called ribonucleic acid |
| ➤ The sugar in DNA is deoxyribose | ➤ The sugar in RNA is ribose |
| ➤ DNA is double stranded | ➤ RNA is single stranded |

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🔍 Explanation:

- Nitrogenous Bases:
- Both DNA and RNA have adenine (A), cytosine (C), and guanine (G).
- DNA has thymine (T), while RNA has uracil (U) instead of thymine.
- This is a key difference: T in DNA ↔ U in RNA.

- Sugar Difference:
- DNA has deoxyribose sugar (lacks an oxygen at the 2' carbon).
- RNA has ribose sugar (has a hydroxyl group at the 2' carbon).

- Strandedness:
- DNA is typically double-stranded, forming a double helix.
- RNA is usually single-stranded, though it can fold into complex shapes.

These differences are fundamental to their roles in the cell: DNA stores genetic information, while RNA helps in protein synthesis and gene regulation.

Let me know if you'd like a visual summary or mnemonic!