Plant Tissues, Organs & Systems Flashcards
What is the process by which water travels up xylem from the roots to the leaves?
Water travels up xylem to replace the water lost due to transpiration
Transpiration is essential for maintaining water levels in plants.
Define transpiration in plants.
Transpiration is the loss of water vapour from plant leaves by evaporation at the surfaces of mesophyll cells followed by diffusion through the stomata
It is a critical process for water regulation in plants.
What role does lignin play in xylem?
Lignin strengthens the plant and causes xylem cells to die, forming hollow tubes for water transport
This adaptation helps the plant withstand water pressure.
How do xylem cells facilitate water movement?
Xylem cells become hollow and join end-to-end to form a continuous tube for water and mineral ions
This structure is crucial for efficient water transport.
In which direction does water movement occur in xylem?
Water movement in xylem only takes place from roots to leaves
This is different from phloem, where movement occurs in different directions.
What is the effect of high air movement on transpiration rate?
Higher air movement increases transpiration rate by removing water vapour from around the leaf, enhancing the concentration gradient
This leads to greater water loss from the plant.
How does high humidity affect transpiration?
High humidity decreases the transpiration rate due to a weaker concentration gradient when air is saturated with water vapour
Less water is lost in such conditions.
What happens to guard cells at high light intensity?
Guard cells become turgid and the stomata open, allowing increased water loss
This is a response to the environmental conditions.
How does temperature influence the rate of transpiration?
Higher temperatures increase the transpiration rate because particles have more kinetic energy
This results in faster evaporation of water.
Fill in the blank: Transpiration is the loss of water vapour from _______.
plant leaves
What controls the opening and closing of stomata?
Guard cells
Guard cells regulate gas exchange and water loss in plants.
What is the primary role of stomata?
Control gas exchange and water loss
Stomata are predominantly located on the underside of leaves.
What happens to guard cells when they are turgid?
Stomata open
This allows air to circulate but increases water loss via transpiration.
What transports dissolved sugars in plants?
Phloem tissue
The movement of food molecules through phloem is called translocation.
What is translocation?
Movement of food molecules through phloem tissue
It involves the transport of dissolved sugars from leaves to other parts of the plant.
What occurs when guard cells lose water and become flaccid?
Stomata close
This reduces water loss via transpiration.
Where are stomata predominantly found in plants?
Underside of the leaf
This location helps reduce transpiration due to cooler and shaded conditions.
What is the function of root hair cells?
Efficient uptake of water and mineral ions
Root hair cells utilize osmosis and active transport.
What adaptation do root hair cells have to increase absorption?
High surface area to volume ratio
This increases the rate of absorption of water and minerals.
What is moved by xylem tissue?
Water and mineral ions
The process is called transpiration, and it flows one way from roots to leaves.
What is the direction of flow in phloem?
All directions
Phloem transports sucrose and amino acids.
List the types of plant tissues.
- Epidermal tissues
- Palisade mesophyll
- Spongy mesophyll
- Xylem
- Phloem
- Meristem tissue
Meristem tissue is found at the growing tips of shoots and roots.
What is the function of the waxy cuticle on a leaf?
Prevents water from evaporating
It serves as a protective layer on top of the leaf.
What is the role of the palisade mesophyll?
Absorb light for photosynthesis
It contains column-shaped cells packed with chloroplasts.
What do air spaces in the spongy mesophyll do?
Increase surface area for gas diffusion
They mainly facilitate the diffusion of carbon dioxide.
What is the function of the lower epidermis in leaves?
Contains guard cells and stomata
This structure is crucial for gas exchange.
What is the significance of the vascular bundle in leaves?
Transport substances to and from the leaf
It contains both xylem and phloem.
What adaptation allows leaves to maximize light absorption?
Palisade layer at the top of the leaf
This positioning allows chloroplasts to receive direct light.
True or False: The epidermis of a leaf is thick and opaque.
False
The epidermis is thin and transparent to allow light penetration.
Fill in the blank: The __________ transports water into the leaf.
[Xylem]
Xylem is essential for providing water needed for photosynthesis.
What is the primary function of chlorophyll in leaves?
Absorb light energy for photosynthesis
Chlorophyll is crucial for converting light energy into chemical energy.
What is the role of stomata during the day?
Open for gas exchange
They close at night to conserve water.
What feature of leaves allows for efficient transport of water and carbohydrates?
Network of veins
This structure connects various parts of the leaf and the plant.
What is the main product of photosynthesis transported by phloem?
Sucrose and amino acids
These substances are vital for plant nutrition and energy.
