Unit 5.5- Plant and Animal Responses Flashcards
(142 cards)
Abiotic components definition:
Components of an ecosystem that are non-living
Alkaloids definition:
Organic, nitrogen-containing bases that have important physiological effects on animals.
Examples of alkaloids:
- Nicotine
- Quinine
- Strychnine
- Morphine
Biotic components definition:
Components of an ecosystem that are living
Pheremone definition:
Any chemical substance released by one living thing, which influences the behaviour or physiology of another living thing.
Tannins definition:
Phenolic compounds, located in a cell vacuole or in surface wax on plants
Tropism definition:
A directional growth response in which the direction of the response is determined by the direction of the external stimulus.
Nastic response definition:
Non-directional and quick response to external stimulus.
What chemicals are used by plants to protect themselves from herbivores?
- Tannins
- Alkaloids
- Pheremones
How do tannins protect plants from herbivores?
- Toxic to microorganisms and larger herbivores
- In leaves they are found in the upper epidermis and make the leaf taste bad
- In roots, they prevent infiltration by pathogenic microorganisms
How do alkaloids protect plants from herbivores?
- Derived from amino acids
- Taste bitter
- Located in growing tops and flowers and peripheral cell layers of stems and roots.
How do pheremones protect plants from herbivores?
Chemical released by plants that can affect the behaviour of physiology of herbivores.
What are examples of types of tropism?
- Phototropism
- Geotropism
- Chemotropism
- Thigmotropism
What is phototropism:
Shoots grow towards the light. This enables them to photosynthesise
What is geotropism?
Roots grow upwards towards the pull of gravity. This anchors them in the soil and helps them to take up water.
What is chemotropism?
On a flower, pollen tubes grow down the style, attracted by chemicals, towards the ovary where fertilisation can take place.
What is thigmotropism?
Shoots of climbing plants, such as ivy, wind around other plants or solid structures to gain support.
Positive tropic response definition:
When a plant responds towards a stimulus
Negative tropic response definition:
When a plant responds away from a stimulus
Example of thigmonastic response:
Venus fly trap closing leaves.
Where are plant hormones produced?
By cells in a variety of tissues in the plant
Examples of plant hormones:
- Cytokinins
- Abscisic acid
- Auxins
- Gibberellins
- Ethene
What do cytokinins do?
- Promote cell division
- Delay leaf senescence
- Overcome apical dominance
- Promote cell expansion
What does abscisic acid do?
- Inhibits seed germination and growth
- Causes stomatal closure when the plant is stressed by low water availability