Organization in plants TOPIC 2 Flashcards
What is an organelle
a structure within a cell
Give two examples of a cell
palisade cell
root hair cell
Give two examples of a tissue
Meristem tissue
Vascular tissue
Give two examples of an organ
Flower
Leaf
Give two examples of an organ system
shoots
roots
Give two examples of an organism
Plant
Tree
What is A
Waxy cuticle
What is B
upper epidermis
What is C
Chloroplasts
What is D
Vacuole
What is E
Xylem vein
What is F
Phloem vein
What is G
Lower epidermis
What is H
Waxy cuticle
What is I
Air channel
What is J
Stoma
What is K
Guard cells
What is L
Spongy Mesophyll
What is M
Palisade Mesophyll
What is the function of the waxy cuticle
To help prevent water loss through evaporation
What is the function of the upper epidermis
To allow light through to the chloroplasts
What is the function of the spongy mesophyll
To increase rate of gas exchange
What is the function of the chloroplasts
To perform photosynthesis
What is the function of the guard cells
To take in or lose water by osmosis to open or close the stomata
What is the function of the palisade mesophyll
The cells contain lots of chloroplasts to carry out photosynthesis
What is the function of the phloem vein
To transport dissolved sugars up and down the plant
What is the function of the stomata
To let gases diffuse in and out of the leaf
What is the function of the xylem vein
To transport water and mineral ions up the plant
How do plants produce glucose
By the process of photosynthesis
What is glucose needed for in plants
respiration
Are the cells living or dead in the xylem
dead
Are the cells living or dead in the phloem
living
What is the structure of cells in the xylem
Hallow cells
Strengthened by lignin
What are the contents of cells in the phloem
Cytoplasm and cell sap
What is the arrangement of the cells like in the xylem
joined end to end
What is the arrangement of the cells like in the phloem
Elongated
What is the direction of transport like in the xylem
from root hair cells in the roots to the stem and leaves
What is the direction of transport like in the phloem
up and down the plant
What are the substances transported in the xylem
water and mineral ions
What are the substances transported in the phloem
dissolved sugars
What is the key process involved in the xylem
Transpiration
What is the key process involved in the phloem
Translocation
What gas diffuse into the leaf through the stomata
Carbon dioxide
What gases diffuse out of the leaf through the stomata
Water vapour
Oxygen
Describe what happens to the guard cells when the stomata open
Guard cells absorb water through osmosis, becoming turgid, causing the stoma to widen and open.
Describe what happens to the guard cells when the stomata close
Guard cells lose water through osmosis, becoming flaccid, causing the stoma to narrow and close
How do the roots take up water from the soil
By osmosis
What are the specialized cells that absorb water from the soil
Root hair cells
What drives the transpiration stream
the loss of water vapour
What makes transpiration quicker
increased air temperatures
increased light intensity
increased air movement
low humidity
Describe the transpiration stream
The roots absorb water through root hair cells by osmosis. The water and minerals travel up the xylem to the leaves. Water turns into water vapour by evaporation and is lost through the stomata. More water is absorbed replacing the water that was lost.
Why does increase in temperature speed up the transpiration stream
- The temperature goes up
- Kinetic energy of the water vapour goes up
- Faster diffusion and transpiration
Why does increase in air movement speed up the transpiration stream
- Water vapour outside the left gets blown away
- The concentration gradient between the inside and outside of the leaf is maintained
- More diffusion and transpiration
Why does increase in light intensity speed up the transpiration stream
- More light means more photosynthesis
- This means more stomata open to let CO2 diffuse in
- This increases diffusion and transpiration
Why does low humidity speed up the transpiration stream
- Low humidity = less water vapour molecules outside the leaf
- This maintains the concentration gradient
- Causing water vapour molecules to diffuse faster and transpiration to be quicker
What is the equation for photosynthesis
Carbon dioxide + water –> glucose + oxygen
In the roots where do you find the root hair cell
In the epidermis layer
Why do roots have root hair cells
To increase the surface area and therefore make the process of osmosis quicker
How is the root hair cell adapted
- It is large to make a larger surface area for more osmosis
- It’s outer epidermal layer is one cell think for a short osmosis pathway
Where does the phloem tissue transport dissolved sugars from
The sources, which are the leaves, once photosynthesis has occured
Where are the dissolved sugar transported to by the phloem
To the sinks, which is the rest of the plant
What is translocation
The movement of dissolved sugars (food) through the phloem tissue
How can cell sap move from one phloem cell to another
Because the cells have walls with pores between them
What is the sugar transported by the phloem used for
Respiration or converted into starch for storage
What does a potometer do
A potometer can be used to investigate the rate of transpiration in plants
What are the two types of potometers
- Mass potometer
- Bubble potometer
Why do potometers not provide an accurate value for the amount of water traspired
Because some of the water taken up by the roots will be used in photosynthesis or to provide turgor
How does a weight potometer work
- Apparatus & plant are weighed & then left
- When reweighed the amount of water lost can be calculated
Why is a bubble potometer set up underwater
To prevent the entry of any unwanted air bubbles
In a bubble potometer why is the junction between the shoot and potometer sealed
To prevent any air leaks
What does meristem tissue do in plants
It allows the plant to grow by changing into different plant cells
How is the palisaded mesophyll adapted
It is at the top of the leaf for maximized light absorption and contains lots of chloroplasts, which contain chlorophyll which is what absorbs the light for photosynthesis
Define transpiration
The loss of water vapour through the stomata by diffusion
What is the transpiration stream
The constant stream of water absorbed, transported up the xylem to the leaves and out of the stomata
What two forces moves water up the xylem
- Adhesive forces
- Cohesive forces
What is adhesion
Adhesion is the attraction between each water molecule and the xylem vessle walls
What is cohesion
Cohesion is the attraction among (between) the water molecules, it holds the water together
What vein is A in the cross-section of the stem
Phloem
What vein is B in the cross-section of the stem
Xylem
What vein is A in the cross-section of the root
Xylem
What vein is B in the cross-section of the root
Phloem