Cells and Tissues Worksheet | Assignments Anatomy | Docsity - Free Printable

You've uploaded a page from a biology textbook or workbook titled “CELLS AND TISSUES”, and it includes an Overview section with numbered questions to answer. The answers have already been filled in by hand (or typed) on the worksheet. Your request is to solve the problem and explain the solution — meaning, you want a clear explanation of *why* each answer is correct.

Here’s a detailed breakdown and explanation for each question:

---

1–4. Name the four elements that make up the bulk of living matter.

✔ Answers:
1. Hydrogen
2. Carbon
3. Oxygen
4. Nitrogen

🔹 Explanation:
These four elements — H, C, O, N — are known as the CHON elements and together constitute about 96% of the mass of living organisms. They form the backbone of all biological molecules:
- Carbon forms the skeleton of organic molecules.
- Hydrogen and Oxygen are key components of water and organic compounds.
- Nitrogen is essential for amino acids (proteins) and nucleic acids (DNA/RNA).

---

5. Name the single most abundant material or substance in living matter.

✔ Answer: Oxygen

🔹 Explanation:
While water (H₂O) is the most abundant *compound*, the question asks for the most abundant material or substance — interpreted here as element. In terms of mass percentage in the human body, oxygen is the most abundant element (~65% by mass), mostly because it’s a major component of water and organic molecules like proteins, carbohydrates, and fats.

> 💡 Note: If the question meant “compound,” the answer would be water. But since the previous questions asked for *elements*, and oxygen is listed here as the answer, we interpret this as asking for the most abundant *element*.

---

6. Name the trace element most important for making bones hard.

✔ Answer: Calcium

🔹 Explanation:
Calcium (Ca) is not a *trace* element in the strictest sense (it’s a major mineral), but in many educational contexts, especially at the high school level, it’s sometimes grouped with minerals needed in small amounts for specific functions. Calcium is essential for bone and teeth formation, providing rigidity through hydroxyapatite crystals. While phosphorus is also critical, calcium is the primary element associated with bone hardness.

> ⚠️ Technically, “trace elements” are those needed in very small amounts (e.g., iron, zinc, copper). Calcium is a *macromineral*. But given the context and common curriculum usage, calcium is the expected answer here.

---

7. Name the element, found in small amounts in the body, that is needed to make hemoglobin for oxygen transport.

✔ Answer: Iron

🔹 Explanation:
Iron (Fe) is a trace element required for the synthesis of hemoglobin, the oxygen-carrying protein in red blood cells. Each hemoglobin molecule contains four iron atoms, which bind oxygen in the lungs and release it in tissues. Without iron, oxygen transport is severely impaired, leading to anemia.

---

8–12. Although there are many specific “jobs” that certain cells are able to do, name five functions common to all cells.

✔ Answers:
8. Reproduction
9. Metabolism
10. Excretion
11. Growth
12. Responds to Stimuli

🔹 Explanation:
All living cells — whether bacterial, plant, or animal — must perform these basic life functions to survive and maintain homeostasis:

1. Reproduction – Cells divide (via mitosis or binary fission) to create new cells for growth, repair, or reproduction of the organism.
2. Metabolism – All cells carry out chemical reactions to obtain and use energy (e.g., cellular respiration, protein synthesis).
3. Excretion – Cells remove waste products (like CO₂, urea) to prevent toxicity.
4. Growth – Cells increase in size or number through synthesis of new cellular components.
5. Responds to Stimuli – Cells detect and react to changes in their environment (e.g., nerve cells respond to signals, muscle cells contract when stimulated).

> 🧬 These five functions align with the characteristics of life: organization, growth, reproduction, response to stimuli, metabolism, and homeostasis.

---

## ✔ Final Summary:

| Question | Answer | Reason |
|----------|------------------|--------|
| 1 | Hydrogen | One of the CHON elements; vital in water and organic molecules |
| 2 | Carbon | Backbone of all organic molecules |
| 3 | Oxygen | Most abundant element by mass in body; part of water and biomolecules |
| 4 | Nitrogen | Essential for proteins and nucleic acids |
| 5 | Oxygen | Most abundant *element* in living matter by mass |
| 6 | Calcium | Key mineral for bone hardness (hydroxyapatite) |
| 7 | Iron | Required for hemoglobin to bind and transport oxygen |
| 8 | Reproduction | All cells can divide to produce more cells |
| 9 | Metabolism | Chemical processes to sustain life |
| 10 | Excretion | Removal of metabolic wastes |
| 11 | Growth | Increase in cell size or number |
| 12 | Responds to Stimuli | Ability to react to environmental changes |

---

📌 Note for Learners: This worksheet reinforces foundational concepts in cell biology — understanding the elemental composition of life and the universal functions of cells. These concepts are crucial for studying tissues, organs, and systems later on.

Let me know if you’d like diagrams, mnemonics, or practice questions to reinforce this!