The basic structure of a leaf
We cannot fully study photosynthesis without knowing more about the structure of a leaf. The leaf is adapted to play a vital role in the process of photosynthesis.
Wide surface area
Mosts green plants have leaves that are broad, flat and exposed to capture as much of the suns energy (sunlight) need for photosynthesis.
Veins
The network of veins in the leaf also carry water from the stems to the leaves. Glucose produced is also sent to the other parts of the plant from the leaves through the veins. Additionally, the veins support and holds the leaf flat to capture sunlight
Pores (holes)
The stomata (tiny holes underneath the leaf) allows air in and out of the leaf. Stomata (single is called stoma) is usually at the bottom surface of the leaf but some plant species have them on the upper surface whiles other have them on both sides.
The stomata closes in the night to retain gases and moisture in the leaf cells, and opens during the day for gaseous exchange to continue.
Below is a close diagram of the leaf structure:
http://www.eschooltoday.com/photosynthesis/structure-of-a-leaf.html
We cannot fully study photosynthesis without knowing more about the structure of a leaf. The leaf is adapted to play a vital role in the process of photosynthesis.
Wide surface area
Mosts green plants have leaves that are broad, flat and exposed to capture as much of the suns energy (sunlight) need for photosynthesis.
Veins
The network of veins in the leaf also carry water from the stems to the leaves. Glucose produced is also sent to the other parts of the plant from the leaves through the veins. Additionally, the veins support and holds the leaf flat to capture sunlight
Pores (holes)
The stomata (tiny holes underneath the leaf) allows air in and out of the leaf. Stomata (single is called stoma) is usually at the bottom surface of the leaf but some plant species have them on the upper surface whiles other have them on both sides.
The stomata closes in the night to retain gases and moisture in the leaf cells, and opens during the day for gaseous exchange to continue.
Below is a close diagram of the leaf structure:
http://www.eschooltoday.com/photosynthesis/structure-of-a-leaf.html
Task 1 Observation and description of the organs of the Allium cepa For this task each pair of students will work with one spring onion, botanical name: Allium cepa . You will work from the visible anatomical scale, to the microscopic tissue scale and into the chemical molecular scale.
You will learn the anatomy of the plant, its specialised cells and tissues and then test for the chemicals that are necessary for life.
Each student is responsible for following instructions, contributing to the tasks and recording their own observations and explanations.
Botanical Drawing of a longitudinal section of a Spring Onion with main organs labelled.
(This is an example of a botanical drawing. In this image the three spring onions each have a flower.)
Longitudinal section of the Allium cepa
Carefully and neatly cut a longitudinal section to reveal the anatomy of the plant.
Draw, identify and label the following organs;
Explain the function of each of these organs in relation to the life process of photosynthesis.
Explain the function of each of these organs in relation to the life process of respiration.
Chemical tests to identify some of the products synthesised by plants.Carbohydrates (sugars and starch) and proteins can be detected by the use of an indicator, which is a chemical that produces a characteristic colour when a particular substance is present.
In this lab, you will test parts of the spring onion for various macro-nutrients, and compare your tests to standards, which are the results of tests that show a positive response for a known substance.
SAFETY: Always wear safety goggles when working with chemicals.
Record your results into your books in a suitable scientific fashion.
You will learn the anatomy of the plant, its specialised cells and tissues and then test for the chemicals that are necessary for life.
Each student is responsible for following instructions, contributing to the tasks and recording their own observations and explanations.
Botanical Drawing of a longitudinal section of a Spring Onion with main organs labelled.
(This is an example of a botanical drawing. In this image the three spring onions each have a flower.)
Longitudinal section of the Allium cepa
Carefully and neatly cut a longitudinal section to reveal the anatomy of the plant.
Draw, identify and label the following organs;
- roots,
- stem,
- leaf bases and
- leaves.
Explain the function of each of these organs in relation to the life process of photosynthesis.
Explain the function of each of these organs in relation to the life process of respiration.
Chemical tests to identify some of the products synthesised by plants.Carbohydrates (sugars and starch) and proteins can be detected by the use of an indicator, which is a chemical that produces a characteristic colour when a particular substance is present.
In this lab, you will test parts of the spring onion for various macro-nutrients, and compare your tests to standards, which are the results of tests that show a positive response for a known substance.
SAFETY: Always wear safety goggles when working with chemicals.
Record your results into your books in a suitable scientific fashion.