Practice Questions
1.State what a vascular bundle contains
Xylem and Phloem
2. Describe 3 adaptations of xylem
Any 3 of the following
| Structural part of Xylem | Adaptation |
|---|---|
| Hollow tubes (no end walls / no cytoplasm) | Allows water to flow freely from root to leaf. |
| Lignin in cell walls | Strengthens the tubes and prevents them collapsing under pressure. Helps waterproof the vessels. |
| Thick walls | Give support to the plant, helping keep it upright. |
| One-way flow | Water and minerals move upwards only — from roots to leaves. |
3. Describe 3 adaptations of phloem
Any 3 of the following
| Structural part of Phloem | Adaptation |
|---|---|
| Sieve tube elements | Long cells joined end to end to form tubes for transport. Have sieve plates (holes at ends) that allow sugars to flow. |
| Companion cells | Each sieve tube has a companion cell beside it. Contain lots of mitochondria to provide energy for active transport of sugars. |
| Cells are alive | Unlike xylem, phloem vessels are living cells, necessary for active transport. |
| Bidirectional flow | Sugars can move up or down the plant to where they are needed (e.g. growing regions or storage organs). |
Factors affecting the rate of photosynthesis
Measuring & calculating rates of photosynthesis
Inverse square law and photosynthesis
Economics of enhancing the conditions in greenhouses
Investigating the effect of light intensity on the rate of photosynthesis
Data analysis and nervous system
The effect of a factor on human reaction time
Controlling blood glucose concentration
Regulating water and nitrogen levels in the body.
Hormones and human reproduction
Using hormones to treat infertility
Control and coordination in plants using hormones
Investigating the effect of light or gravity on the growth of newly germinated seedlings