IGCSE Biology Paper-3: Specimen Questions with Answers 335 - 336 of 358
Passage
Fig. shows a diagram of a cross-section of a dicotyledonous leaf, as seen using a light microscope.
Question 335 (4 of 4 Based on Passage)
Edit
Write in Short
Short Answer▾Describe two ways in which tissue A is adapted for maximum photosynthesis.
Explanation
Palisade Cells
- The palisade cells are the main site of photosynthesis, as they have many more chloroplasts than spongy mesophylls.
- Large Vacuole: Restricts chloroplasts to a layer near the outside of the cell where they can be reached by light more easily.
- Cylindrical Arrangement: They are arranged at right angles to the upper epidermis, reducing the number of light-absorbing cross walls preventing light from reaching the chloroplasts. This also allows long-narrow air spaces between them, providing a large surface area for gaseous exchange.
- Movement of chloroplasts: Proteins can move the chloroplasts within cells to absorb maximum light.
- Thin cell walls: to allow gases to easily diffuse through them.
Question 336
Write in Short
Short Answer▾The development of a new human life involves different stages.
These stages are labelled by the letters P to V.
The stages are not in the correct order.
P formation of a zygote
Q implantation
R fertilization
S formation of an embryo
T release of an egg cell
U development of a fetus
V birth
Put the seven stages in the correct order.
Write the letters in the spaces in the flow chart to show the correct order.
Explanation
