Tissues in Action · Lesson 11 of 11
Chapter Summary and Practice
“Every tissue returns for one final meeting, and this time everyone knows its function.”
• Connect plant and animal tissues with their functions. • Compare the major tissue types using structural evidence. • Trace how tissues cooperate in transport, growth and movement. • Interpret investigations, graphs and real-life situations. • Identify and correct common tissue misconceptions.
A tree becoming taller, a cut clotting, a knee bending and a hand withdrawing from heat may seem like unrelated events. This chapter shows that all of them depend on specialised groups of cells. The final task is to connect each structure with its function and then explain how different tissues cooperate.
At a Glance
Tissues are groups of similar cells that work together. In multicellular organisms, their specialisation creates division of labour. Plant tissues are broadly organised as meristematic and permanent tissues. Animal tissues are grouped as epithelial, connective, muscular and nervous tissues.
| Area | Central idea | Key examples |
|---|---|---|
| Plant growth | Actively dividing meristems add new cells. | Apical, lateral and intercalary meristems |
| Plant protection and support | Permanent tissues are specialised for particular roles. | Epidermis, parenchyma, collenchyma and sclerenchyma |
| Plant transport | Different cell types cooperate in complex tissues. | Xylem and phloem |
| Animal covering | Closely packed cells form surfaces suited to exchange, protection and other functions. | Epithelial tissue |
| Animal connection | The matrix gives connective tissues different properties. | Blood, bone, cartilage, tendon and ligament |
| Movement | Different muscles produce voluntary or involuntary movement. | Skeletal, smooth and cardiac muscle |
| Control | Neurons receive and transmit messages. | Nervous tissue |
| Body framework | Bones, muscles and joints cooperate under nervous control. | Musculoskeletal system |
| Plant regeneration | Some specialised cells can return to division and specialise again. | Totipotency |
Apical meristems increase length, lateral meristems increase girth and intercalary meristems support regrowth from nodes or internode bases. Cells leaving these regions may differentiate into permanent tissues. The epidermis protects; parenchyma stores and may photosynthesise; collenchyma bends without breaking; sclerenchyma supplies hard strength; xylem transports water and minerals; and phloem transports prepared food.
Epithelial tissue covers and lines. Connective tissue binds, supports and transports. Muscular tissue contracts to produce movement. Nervous tissue controls and coordinates through messages. Their functions overlap in real actions: movement needs skeletal muscle, tendons, bones, joints, ligaments, cartilage and nervous control.
| Structural clue | Likely tissue | Reasoning |
|---|---|---|
| Thin, flat cells in one layer | Exchange epithelium | A short pathway permits rapid diffusion. |
| Uneven thickening at cell corners | Collenchyma | The tissue combines support with flexibility. |
| Thick lignified walls in mostly dead cells | Sclerenchyma | The walls provide lasting strength. |
| Tubular, thick-walled pathways | Xylem | Continuous channels conduct water and resist collapse. |
| Fluid matrix | Blood | Cells and dissolved substances can be transported. |
| Branched, rhythmically contracting fibres | Cardiac muscle | The structure suits continuous heart contraction. |
| Long cell with dendrites and an axon | Neuron | The cell receives and carries messages. |
Revise, Reflect, Refine
Quiz
Which statement correctly applies to the lesson “Chapter Summary and Practice”?
Which additional statement also correctly applies to the lesson “Chapter Summary and Practice”?
Which further statement also correctly applies to the lesson “Chapter Summary and Practice”?
Which ability is a stated learning objective of this lesson?
Which topic is directly developed in the lesson “Chapter Summary and Practice”?
Practice Problems
- Meristematic cells divide repeatedly. Which structural features support this ability?
- A plant cannot transport food from its leaves to its roots. Identify the affected tissue and explain your choice.
- Why is the epithelial lining used for gas exchange only one thin layer?
- Distinguish tendons and ligaments.
- Explain why a hinge joint moves mainly in one plane.
- A tree is 25 years old and has 25 annual rings. What relationship does this observation suggest?
- Which meristem increases the diameter of a stem, and where is it located?
- Predict the effects of removing a complete ring of bark and damaging the tissue beneath it.
- A young stem bends during strong wind. Identify the supporting tissue and explain why replacing it with sclerenchyma would change the stem.
- Why can a sugarcane cutting containing a node sprout while a similar piece without a node may fail?
- Explain why “a tissue is always made of only one kind of cell” is not correct.
- Why is living parenchyma less suitable than sclerenchyma for making a tough coconut-husk fibre?
- Correct this statement: meristematic cells occur only at root and shoot tips.
- Which cell generally has the larger vacuole: a plant cell or an animal cell? State the assumption used.
- Give examples showing that a plant tissue can perform more than one function.
Problem
A teak tree has the following age and diameter pairs: (5,4), (10,8), (20,24), (25,28), (30,32) and (40,40), where age is in years and diameter is in centimetres. How should the data be studied?
- 1.Place age on the horizontal axis and stem diameter on the vertical axis.
- 2.Plot each ordered pair accurately.
- 3.Join or compare the plotted points to observe the overall change.
- 4.The diameter generally increases with age, but the amount of increase is not identical in every interval.
- 5.Compare age with the number of annual rings: the listed data give one ring for each year.
- 6.Connect the increase in girth with the activity of the lateral meristem.
Problem
Two sugarcane cuttings differ in whether a node is present. How can the effect of the node be tested fairly?
- 1.Use cuttings from comparable plants and of similar size.
- 2.Change the presence of a node while keeping water, soil, light, temperature and planting depth alike.
- 3.Use the same observation period.
- 4.Record sprouting and growth using the same measurements.
- 5.If pieces with nodes sprout while comparable pieces without nodes do not, the result supports the importance of the growth region at the node.
The Journey Beyond
The ideas can be extended through observation. Tendons can be felt moving above the heel when the toes point up and down. Gardening practices can be connected with meristems and conducting tissues. Leaf surfaces can be compared across dry, moist and aquatic habitats. Dance and physical practices can be analysed by identifying the joints and movements they use.
The Quest Continues…
Plant totipotency raises a further question: could a complete animal be obtained from an animal cell in the same way? Exploring that question requires careful attention to differences between plant and animal development, the conditions cells require and the possible benefits and difficulties of such work.
• A tissue is not necessarily made of only one cell type; complex tissues contain several. • Xylem transports water and minerals, while phloem transports food. • Tendons join muscle to bone, while ligaments join bone to bone. • Joints permit movement, but muscles provide the force. • Meristematic tissue is not restricted to root and shoot tips. • One tissue can contribute to more than one function.
Growth depends on cell division and differentiation. Transport depends on specialised pathways. Movement depends on muscles pulling bones at joints under nervous control. Protection, support and communication all emerge from the same principle: structure is suited to function, and tissues work as coordinated systems.
Previous · Lesson 10
From one cell to an organism: Totipotency
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