BIOLOGICAL DRAWING OF BANANA (CROSS SECTION)

In the past practical papers, there used to be a question asking candidates to draw a cross section (or transverse section) of a banana. The following figures should help.

Real Specimen

Biological Drawing of a Cross Section of a Banana
NOTE:
During that time, food tests were also conducted on the banana slice. What type of food nutrients do you think are present in it?

MONOCOT LEAF

The following figures show transverse sections of monocot leaves.

NOTICE HOW THE STOMATA ARE DISTRIBUTED (COMPARED TO DICOT LEAVES)?
YOU CAN ALSO SEE STOMATA ON THE UPPER SURFACE, RIGHT?
EVER WONDER WHY?
(TRY TO FIGURE OUT WHY?)

XEROPHYTE, MESOPHYTE AND HYDROPHYTE

XEROPHYTE
Plants that live in conditions where water is scare (for example in the desert)

MESOPHYTE
Land plants living in environment with moderate amount of moisture.

HYDROPHYTE
A plant adapted to grow in water.

Transverse Section of a Mesophyte Leaf

Transverse Section of a Xerophyte Leaf

Transverse Section of a Hydrophyte Leaf

Notice the adaptations of the Xerophyte and the Hydrophyte leaves?

• Xerophyte leaf needs to conserve as much water as possible so it tends to curl so as not to expose the stomata. So the stomata is hidden inside the curl inner side of the leaf. Apart from this, it has a very thick waxy cuticle and some may even have leaf hairs. Generally leaves of the xerophyte are succulent to store water as much as possible.
• Hydrophyte leaf needs to be able to float so that it can trap as much light energy from the sun as possible. To enable it to float the leaf has unusually large intercellular air spaces for storing air which in turn provides BUOYANCY. Apart from this, the stomata can be found on the upper surface (unlike the mesophyte - the stomata are found on the lower surface of the leaf).
  

ONION BULB

DO YOU KNOW THAT AN ONION BULB ACTUALLY CONSISTS OF LEAVES (SCALE LEAVES)?

DO YOU KNOW THAT AN ONION PLANT IS AN EXAMPLE OF A MONOCOT?
NOTE: BE AWARE THAT THERE MAY BE QUESTIONS IN THE PRACTICAL PAPER ASKING YOU TO MAKE A FULLY LABELLED DRAWING OF AN ONION BULB. NOTE THE LEAVES AND THE STEM TISSUE.
FOOD TEST MAY ALSO BE ASKED AND DO NOT BE SURPRISE THAT AN ONION BULB CONTAINS REDUCING SUGAR!!! (NOTE: WHEN COOKING ONION, THE DARK BROWN CARAMEL IS ACTUALLY THE SUGAR!!!)


The following figure shows how an onion bulb is to be drawn (Longitudinal Section!!!)

CHLOROPLAST

CHLOROPLAST AS CAN BE SEEN UNDER A MICROSCOPE

A FIGURE SHOWING THE INTERNAL STRUCTURE OF A CHLOROPLAST

NOTE: CHLOROPLAST - SITE WHERE PHOTOSYNTHESIS TAKES PLACE