Educational worksheet on chromosomes, genes, and DNA with illustrations and fill-in-the-blank questions.

Here is the completed Task 1 with explanations for each answer:

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Chromosomes Section:

1. Chromosomes are found inside the _nucleus_ of a cell.
→ *Explanation:* In eukaryotic cells (like human cells), chromosomes are located within the nucleus, which acts as the control center of the cell.

2. There are _23_ pairs of chromosomes in every human body cell.
→ *Explanation:* Humans have 46 chromosomes total, organized into 23 homologous pairs — one set inherited from each parent.

3. One of each pair of chromosomes comes from each _parent_.
→ *Explanation:* During sexual reproduction, the mother contributes 23 chromosomes via the egg, and the father contributes 23 via the sperm, forming 23 pairs in the offspring.

4. Chromosomes are made up of long lengths of _DNA_.
→ *Explanation:* Chromosomes are structures composed of DNA tightly coiled around proteins called histones. DNA carries the genetic instructions.

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Genes Section:

5. A gene is a short section of a _chromosome_.
→ *Explanation:* Genes are specific segments of DNA located on chromosomes that code for particular proteins or functional RNA molecules.

6. Each gene _codes_ for a different _characteristic_.
→ *Explanation:* A gene contains the instructions to build a protein, which influences a trait or characteristic (e.g., eye color, enzyme production).

7. Genes work in _pairs_. There are different versions of each gene, one is often _dominant_ over the others.
→ *Explanation:* Since chromosomes come in pairs, so do genes. Each gene has two alleles (versions) — one from each parent. The dominant allele masks the effect of the recessive one when they differ.

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DNA Section:

8. DNA is short for _deoxyribonucleic acid_.
→ *Explanation:* This is the full chemical name for DNA — DeoxyriboNucleic Acid.

9. It is a long chain _molecule_ that is made up of a combination of _4_ DNA bases.
→ *Explanation:* DNA is a macromolecule (polymer) composed of nucleotides. Each nucleotide contains one of four nitrogenous bases: Adenine (A), Thymine (T), Cytosine (C), Guanine (G).

10. DNA has a special structure called a _double helix_.
→ *Explanation:* The double helix is the twisted ladder-like structure of DNA, discovered by Watson and Crick, where two strands wind around each other, held together by base pairing (A-T, C-G).

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✔ Final Completed Answers:

| Section | Sentence | Answer |
|--------------|--------------------------------------------------------------------------|----------------------------|
| Chromosomes | Chromosomes are found inside the ________ of a cell. | nucleus |
| | There are ________ pairs of chromosomes in every human body cell. | 23 |
| | One of each pair of chromosomes comes from each ________. | parent |
| | Chromosomes are made up of long lengths of ________. | DNA |
| Genes | A gene is a short section of a ________. | chromosome |
| | Each gene ________ for a different ________. | codes / characteristic |
| | Genes work in ________. There are different versions of each gene, one is often ________ over the others. | pairs / dominant |
| DNA | DNA is short for ________ ________. | deoxyribonucleic acid |
| | It is a long chain ________ that is made up of a combination of ________ DNA bases. | molecule / 4 |
| | DNA has a special structure called a ________ ________. | double helix |

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This task reinforces the hierarchical relationship:
DNA → genes → chromosomes → nucleus

Let me know if you’d like a diagram or further explanation!