Tissues are grouped together to perform a combined function. Such a structure, consisting of many different kinds of plant tissue, but with a combined main function, is known as an ORGAN , e.g. a leaf.
Assessment
LO 1: Scientific investigations:
The learner will be able to act confidently on curiosity about natural phenomena, and to investigate relationships and solve problems in scientific, technological and environmental contexts.
This is evident when the learner:
- conducts investigations and collects data;
- evaluates data and communicates findings.
LO 2: Constructing Science Knowledge:
The learner will know and be able to interpret and apply scientific, technological and environmental knowledge.
This is evident when the learner:
- recalls meaningful information;
- categorises information;
- interprets information;
2.4 applies knowledge.
Memorandum
PLANT CELL
- It consists of a framework containing a special liquid – PROTOPLASM – with a variety of structures suspended in it.
Assignment 3
- Control the light quantity carefully with the condensor/
- Focus carefully up and down when busy with the maximum enlargement.
- Colouring: with iodine solution for better self definition starch grains will also colour.
Activity
Assignment 1
- Sketch of the plant cell:
| LabelNumber | Function |
| 1. | Photosynthesis occurs here |
| 2. | Controls all cell activity |
| 3. | Membrane enclosing the vacuole; vacuole stores moisture and colourants |
| 4. | Moisture, colourants |
| 5. | Respiration, produces energy |
| 6. | External protective and strengthening membrane |
| 7. | Controls entry and exit of substances |
| 8. | Medium in which reactions occur and in which the organelles are suspended |
Assignment 2:
THE NUCLEUS
| Function | |
| 1. | Controls molecules in the nucleus |
| 2. | Stores genetic material; bears heriditary characteristics |
| 3. | Contains nuclear material, communicates with the rest of the cell |
| 4. | Special structures and moisture |
Assignment 3
- Plants PHOTOSYNTHESISE and RESPIRE. The two organelles that are involved are the CHLOROPLAST and the MITOCHONDRION .
- Studying this aspect of natural science remains important right through to matric.
CHLOROPLASTS
Contain the colour pigment chlorophyll;
Accommodate photosynthesis;
Enclosed by a double membrane;
Contains stroma of liquid and grana – stacked hollow disks (thylacoids) that are suspended in it. Grana are attached to other flat membranes (lamellae).
MITOCHONDRIA
accommodate the ENERGY-providing process of RESPIRATION;
also enclosed by a double membrane;
a fold/ridge of the inner membrane is called a crista (cristae);
the matrix is the liquid inside the mitochondrion.
- All the organelles that might occur are not discussed in Grade 9, but those that are mentioned will indicate some of the differences between typical plant and typical animal cells.
| Explanation |
| Absent in animal cells; maintans form and provides sturdiness in plant cells, as plants have no supporting skeletons. |
| Small or absent in the case of animal cells; it provides storage and also adds to the sturdiness of the plant cell. |
| Animal cells have no PLASTIDS. |
| Plant cells have a fixed shape determined by the cell wall – animal cells come in many shapes. |
- Perhaps you have realised that plant cells are unique. In nature, though, there is endless variation in the shape and characteristics of plant cells. Such variation of form is referred to as DIFFERENTIATION , the variation in function that accompanies it is referred to as SPECIALISATION . Both of these terms are of importance in the biological study of cells.
- When cells are grouped together, we have to do with the next level of organisation, namely TISSUES . Tissuea are cells that are grouped together to execute a specific task.
- This, for example, provides for cells that only serve to conduct water through the plant – the xylem.
- Tissues are also grouped together to perform a combined function. Such a structure, consisting of many different kinds of plant tissue, but with a combined main function, is known as an ORGAN .