Tissues: Class 9 Study Guide
A tissue is a group of similar cells that work together to do one job.
In multicellular organisms, cells that look alike and do the same job form a tissue. Different tissues combine into organs, and organs into organ systems.
Plants have meristematic tissue, whose cells keep dividing at growing points, and permanent tissue, whose cells have stopped dividing.
Plant tissues
| Tissue | Type | Job |
|---|---|---|
| Apical meristem | Meristematic | Growth in length at tips |
| Parenchyma | Simple permanent | Stores food; photosynthesis in chlorenchyma |
| Collenchyma | Simple permanent | Flexible support |
| Sclerenchyma | Simple permanent | Hard, dead support |
| Xylem | Complex permanent | Carries water and minerals up |
| Phloem | Complex permanent | Carries food in both directions |
Animal tissues
Epithelial tissue covers and lines surfaces, such as skin and the gut. Connective tissue joins and supports, and includes blood, bone, cartilage, tendons (muscle to bone), ligaments (bone to bone) and fat. Muscular tissue contracts to cause movement: striated (voluntary), smooth (involuntary) and cardiac (heart). Nervous tissue is made of neurons that carry messages.
Cover, join, move or signal.
Epithelial, connective, muscular, nervous.
Skin, blood, heart, brain.
For example the neuron.
Why are tissues useful?
Division of labour makes complex bodies possible. Xylem and phloem let a tree reach great heights. Muscles let animals run, and nerves let them react quickly. When we are cut, epithelial cells and blood help the wound to close.
Worked examples and common mistakes
Example: Which tissue connects bone to bone? Ligament. Example: Which tissue carries water in a plant? Xylem. Common mistakes: mixing up xylem and phloem, and mixing up tendon and ligament. Remember: tendons join muscle to bone, ligaments join bone to bone.
Check your understanding: model answers
1. Phloem. 2. Striated (skeletal), smooth and cardiac. 3. It carries messages as electrical signals.
✨ Key Takeaways
- A tissue is a group of similar cells with one job.
- Plants have meristematic and permanent tissues.
- Xylem carries water and phloem carries food.
- Animals have epithelial, connective, muscular and nervous tissue.
💬 Questions for Discussion & Reflection
- Which plant tissue carries food?
- Name the three kinds of muscle.
- What does a neuron do?
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