Plant Structure and Function worksheet focusing on root anatomy, featuring a labeled diagram of a dicot root and related comprehension questions.
Diagram of a dicot root cross-section with labeled parts including cortex, phloem, epidermis, endodermis, and xylem, accompanied by a multiple-choice labeling exercise and true/false statements about root structure and function.
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Show Answer Key & Explanations
Step-by-step solution for: Plants and Their Parts | Primary 3 Science - Geniebook
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Show Answer Key & Explanations
Step-by-step solution for: Plants and Their Parts | Primary 3 Science - Geniebook
Let's solve this step-by-step based on the diagram and questions provided in the worksheet.
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The image shows a cross-section of a dicot root. We are given these terms to use:
- cortex
- phloem
- epidermis
- endodermis
- xylem
We need to label the numbered parts (1–5) in the diagram.
#### Understanding the structure of a dicot root (from outer to inner):
1. Epidermis – the outermost layer of cells; protects the root and has root hairs.
2. Cortex – lies beneath the epidermis; made of parenchyma cells; stores food and transports water.
3. Endodermis – a single layer of cells surrounding the vascular cylinder; regulates movement of substances into the vascular tissue.
4. Vascular Cylinder (Stele) – contains xylem and phloem:
- Xylem – usually in a star-like pattern (often 4 or more arms), transports water and minerals upward.
- Phloem – located between the arms of xylem, transports organic nutrients.
In a typical dicot root:
- The xylem is arranged in a star shape (often with 4 or more points).
- The phloem is located in the spaces between the xylem arms.
- The cortex is large and surrounds the stele.
- The endodermis is just inside the cortex.
- The epidermis is the outermost layer.
Now, let’s label each number:
1. Epidermis – outermost layer; may have root hairs.
2. Cortex – beneath epidermis; large region of parenchyma cells.
3. Endodermis – thin layer separating cortex from vascular cylinder.
4. Xylem – the dark, star-shaped structures in the center.
5. Phloem – the lighter areas between the xylem arms.
> ✔ So the labels are:
>
> 1. Epidermis
> 2. Cortex
> 3. Endodermis
> 4. Xylem
> 5. Phloem
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Now, evaluate each statement:
6. A root hair is a small extension of an epidermal, or outermost, cell layer of a dicot root.
✔ True – Root hairs are extensions of epidermal cells that increase surface area for absorption.
7. Layers of parenchyma cells make up the cortex of a dicot root and the central pith of a monocot root.
✔ True – Cortex in dicots and pith in monocots are both made of parenchyma cells.
8. Outside the endodermis is a tissue called the pericycle that develops vertical roots.
✘ False – The pericycle is *inside* the endodermis, not outside. It gives rise to lateral (branch) roots.
9. Vascular cambium cells found at the center of a root grow more xylem and phloem cells that increase the size of the root.
✘ False – Vascular cambium is not typically present in roots of most plants (especially herbaceous ones). In secondary growth, it forms in stems and roots of woody plants, but it's not located at the center. The vascular cambium is between xylem and phloem, and it produces secondary xylem and phloem. Also, in roots, the vascular cambium arises from the pericycle and vascular tissues, not the center. But the key issue: it's not "at the center" — so false.
10. Behind the root tip are cell-producing growth tissues called the root cap.
✘ False – The root cap protects the apical meristem. The apical meristem is the cell-producing tissue. The root cap is *behind* the tip, but it's not the growth tissue — it's protective. The apical meristem is the actual growth tissue.
11. The difference between roots and stems lies in the way they transport water.
✘ False – Both roots and stems use xylem to transport water. The main differences lie in structure and function (e.g., roots absorb water, stems support and conduct), but transport mechanism is the same. So this is false.
12. Primary growth in a stem occurs in the apical meristem.
✔ True – Primary growth (lengthening of the plant) occurs in the apical meristems at the tips of roots and stems.
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#### Labeling (1–5):
1. Epidermis
2. Cortex
3. Endodermis
4. Xylem
5. Phloem
#### True or False:
6. True
7. True
8. False
9. False
10. False
11. False
12. True
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Let me know if you'd like a visual explanation or a labeled diagram description!
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Part A: Label the parts of the dicot root
The image shows a cross-section of a dicot root. We are given these terms to use:
- cortex
- phloem
- epidermis
- endodermis
- xylem
We need to label the numbered parts (1–5) in the diagram.
#### Understanding the structure of a dicot root (from outer to inner):
1. Epidermis – the outermost layer of cells; protects the root and has root hairs.
2. Cortex – lies beneath the epidermis; made of parenchyma cells; stores food and transports water.
3. Endodermis – a single layer of cells surrounding the vascular cylinder; regulates movement of substances into the vascular tissue.
4. Vascular Cylinder (Stele) – contains xylem and phloem:
- Xylem – usually in a star-like pattern (often 4 or more arms), transports water and minerals upward.
- Phloem – located between the arms of xylem, transports organic nutrients.
In a typical dicot root:
- The xylem is arranged in a star shape (often with 4 or more points).
- The phloem is located in the spaces between the xylem arms.
- The cortex is large and surrounds the stele.
- The endodermis is just inside the cortex.
- The epidermis is the outermost layer.
Now, let’s label each number:
1. Epidermis – outermost layer; may have root hairs.
2. Cortex – beneath epidermis; large region of parenchyma cells.
3. Endodermis – thin layer separating cortex from vascular cylinder.
4. Xylem – the dark, star-shaped structures in the center.
5. Phloem – the lighter areas between the xylem arms.
> ✔ So the labels are:
>
> 1. Epidermis
> 2. Cortex
> 3. Endodermis
> 4. Xylem
> 5. Phloem
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Part B: True or False Questions
Now, evaluate each statement:
6. A root hair is a small extension of an epidermal, or outermost, cell layer of a dicot root.
✔ True – Root hairs are extensions of epidermal cells that increase surface area for absorption.
7. Layers of parenchyma cells make up the cortex of a dicot root and the central pith of a monocot root.
✔ True – Cortex in dicots and pith in monocots are both made of parenchyma cells.
8. Outside the endodermis is a tissue called the pericycle that develops vertical roots.
✘ False – The pericycle is *inside* the endodermis, not outside. It gives rise to lateral (branch) roots.
9. Vascular cambium cells found at the center of a root grow more xylem and phloem cells that increase the size of the root.
✘ False – Vascular cambium is not typically present in roots of most plants (especially herbaceous ones). In secondary growth, it forms in stems and roots of woody plants, but it's not located at the center. The vascular cambium is between xylem and phloem, and it produces secondary xylem and phloem. Also, in roots, the vascular cambium arises from the pericycle and vascular tissues, not the center. But the key issue: it's not "at the center" — so false.
10. Behind the root tip are cell-producing growth tissues called the root cap.
✘ False – The root cap protects the apical meristem. The apical meristem is the cell-producing tissue. The root cap is *behind* the tip, but it's not the growth tissue — it's protective. The apical meristem is the actual growth tissue.
11. The difference between roots and stems lies in the way they transport water.
✘ False – Both roots and stems use xylem to transport water. The main differences lie in structure and function (e.g., roots absorb water, stems support and conduct), but transport mechanism is the same. So this is false.
12. Primary growth in a stem occurs in the apical meristem.
✔ True – Primary growth (lengthening of the plant) occurs in the apical meristems at the tips of roots and stems.
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✔ Final Answers:
#### Labeling (1–5):
1. Epidermis
2. Cortex
3. Endodermis
4. Xylem
5. Phloem
#### True or False:
6. True
7. True
8. False
9. False
10. False
11. False
12. True
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Let me know if you'd like a visual explanation or a labeled diagram description!
Parent Tip: Review the logic above to help your child master the concept of roots stems and leaves worksheet.
