OLD nutrition in plants (photosynthesis)

Where are chloroplasts located in?

guard cells (least), palisade mesophyll (most), and spongy mesophyll cells. epidermal cells DO NOT HAVE ANY chloroplast

What is the relationship between the structure of the lamina and its function?

if lamina is broad and flat - to absorb maximum light energy, for max rate of photosynthesis. if lamina is thin - to allow carbon dioxide to reach inner cells rapidly and enables light to reach all mesophyll cells…

What do both the network of veins and leaf stalk contain?

Xylem and phloem

What is the function of the leaf blade (lamina)?

Provides a large surface area for absorption of light energy and gaseous exchange.

What is the function of the network of veins in a leaf?

Contains the vascular bundles to transport water, mineral salts, and manufactured food.

What is the function of the leaf stalk (petiole)?

Holds the lamina away from the stem and allows transport to/from the leaf. 2.allows water and mineral salts to be transported to the leaf, and manufactured food away from the leaf

What is the function of the cuticle layer?

Reduces EXCESSIVE water loss due to evaporation and is transparent, allowing light to pass through and enter the leaf, to mesophyll layer.

What is the function of the epidermal cell layer?

Protects the leaf and reduces water loss from evaporation.(and upper epidermis prevents bacteria and fungi form getting in)

What is the function of the thin film of moisture in mesophyll cells?

1. allows water to exit mesophyll cells 2.Allows oxygen and carbon dioxide to dissolve for diffusion in and out of the cells.

What is the function of intercellular air spaces?

Allows diffusion of oxygen, carbon dioxide and water vapor within the leaf. allow diffusion of gases in and out of mesophyll for photosynthesis

What is the function of guard cells?

Controls the opening and closing of the stomata.

stomata opens in the presence of light, tell me what's the gaseous exchange going on here! and what is it for yo

carbon dioxide diffusing in, oxygen diffusing out, for max rate of photosynthesis.

Besides gas exchange, what else diffuses out of the leaf through open stomata?

Water vapor during transpiration.

Why is palisade mesophyll the main site of photosynthesis?

It has the highest number of chloroplasts per cell.

What happens at the palisade mesophyll tissue?

PHOTOSYNTHESIS! its the main site of photosynthesis, more light can be absorbed near the upper leaf surface, thus is more effective in synthesizing glucose (fancy photosynthesis)

What is the function of stomata?

To control the size of the stomatal pore.

What happens to glucose concentration in guard cells in sunlight?

It increases.

How does increased glucose in guard cells affect their water potential?

It lowers the water potential.

appearance guard cells in the presence of sunlight?

more curved, more turgid, stomata opens

why does the stomata close on a sunny day? (include ALL points)

1. excess evaporation of water causes guard cells to become flaccid 2. stomata closes, to prevent excessive water loss by leaf

What happens to stomata when guard cells become flaccid?

They close.

Why do stomata close when guard cells become flaccid?

To prevent excessive water loss.

How does carbon dioxide enter the leaf during the day? (3 steps!)

1. carbon dioxide is used up in the leaf for photosynthesis, so concentration of carbon dioxide is low in leaf. via diffusion, the carbon dioxide diffuses from surrounding air to leaf 2. carbon dioxide dissolves in thin film of moisture on surface of mesophyll cells 3.dissolved carbon dioxide diffuses into leaves

Where does carbon dioxide dissolve before entering mesophyll cells?

In the thin film of moisture on their surface.

What do vascular bundles contain?

Xylem and phloem vessels.

What is the function of xylem?

Transports water and mineral salt ions upwards.

What is the function of phloem?

Transports manufactured food substances.

What is the role of lignin in xylem vessels?

xylem cell walls are thickened with lignin, to increase cell wall strength and support them from collapsing

To where does xylem transport substances?

To the leaves.

What process is involved in xylem transport?

Transpiration pull.

What process is involved in phloem transport?

Translocation.

What is another function of xylem?

Provides mechanical support for the plant.

Where is phloem located in the leaf?

Nearer to the lower surface.

Are xylem cells living or dead?

Dead cells.

Are phloem cells living or dead?

Living cells.

Describe the walls of xylem.

Thicker walls.

Describe the walls of phloem.

Thinner walls.

Describe the lumen size of xylem.

Larger lumen.

Describe the lumen size of phloem.

Smaller lumen.

Are xylem cell walls thickened with lignin?

Yes, they are.

What is the role of lignin in cell walls?

Increases the strength of the cell wall.

What does the companion cell have many of?

Mitochondria.

What does the companion cell provide energy for?

Active transport of food into sieve tubes.

What does the sieve tube cell have?

Only a thin layer of cytoplasm.

what specialisation do sieve tubes have (name 2!), and how does it relates to its function?

sieve tube cell has of a thin layer of cytoplasm, and sieve plates have holes, and this allows rapid flow of manufactured food.

xylems are hollow vessels, made up of only cell wall and no other organelles. it also has no cross walls.

What are xylem's specialisations and its relation to function? (hollow)

this allows water and mineral salt ions to move through xylem with no resistance.

what are the parts of the tissue level structure?

GO AND MEMORISE THE DIAGRAM cuticle, epidermal cell, palisade mesophyll cell, xylem vessel, phloem vessel, spongy mesophyll cell, epidermal cell, cuticle, guard cell, stoma, shimmy shebange go look at the diagram please

What is the layer between xylem and phloem called, and what do they do?

Cambium, they form stem cells, produce new xylem and phloem

What is the function of cambium in plants?

Forms stem cells, similar to bone marrow.

what are sieve tubes made out of?

sieve tubes are made out of sieve tube cells/sieve tube elements, separated by sieve plates