B2 Plant s

The leaf is an example of an

Organ

A guard cell is an example of a

Cell

The palisade mesophyll layer is an example of a

Tissue

What name is given to the openings

Stomata

The upper epidermis is _____ so that ___ can pass through it
This means that as much ___ as possible can reach the _____ ___ cells below, and be used in ________

1 transparent
2 light
3 light
4 palisade mesophyll
5 photosynthesis

Which structures help to minimise water loss ( 2 )

- waxy cuticle
- guard cells which can close stomata

If there is plenty of ______ in the leaf, _____ ___ become ____ , which opens the _________
This allows ____ _____ to enter the leaf, but also allows ___ to _______

1 water
2 guard cell s
3 turgid
4 stomata
5 carbon dioxide
6 water
7 escape

What is meristem tissue and where is it found

Meristem tissue is made up of plant stems cells. It's found in the growing parts of the plant such as the tips of shoots and roots

What Are Leave

Site of photosynthesis

Epidermal Tissue

! This covers the whole plant
! Covered with a waxy cuticle to help to reduce water loss by evaporation

Upper Epidermis

Transparent so light can pass through it to the palisade layer

Palisade Mesophyll Tissue

Where most of photosynthesis occurs

Palisade Layer

Lots of little chloroplasts
They are near the top of the leaf where they can get the most light

Spongy Mesophyll

Contains big air spaces to allow gases to diffuse in and out of cells
The air space increase the rate of diffusion of gases

Xylem and phloem

Transport things like water mineral ions and food around the plant
They form a network of vascular bundles which deliver water and other nutrients to the entire leaf / take away glucose produced by photosynthesis

Meristem Tissue

Found at the growing tips of roots and shoots and is able to differentiate into lots of different types of plant cell allowing the plant to grow

Which part of the plant is glucose produced in

Leaves

What do we call the movement of cell sap (a mixture of sugar and water) up and down the plant

Translocation

Phloem cells have _________ in their end walls to allow cell sap to pass along the phloem tube

Pores

What does the xylem transport in a plant

Water

Dissolved mineral ions

How do root hair cells absorb water from the soil

Osmosis

How do root hair cells absorb mineral ions from the soil

Active transport

Which substance are xylem cells reinforced with to make them stronger

Lignin

What is transpiration

The evaporation of water from the leaves

Why does the rate of transpiration increase if the light intensity is increased

The stomata open wider to let more carbon dioxide into the leaf for photosynthesis

Describe The Structure Of Phloem Tubes ( for )

! Made of columns of elongated living cells with small pores in the end walls to allow cell sap to flow through
! They transport food substances made in the leaves for the rest of the plant for immediate use or storage
! The transport goes in both direction
! This process is called translocation

Describe The Structure Of Xylem Tubes ( for )

! Made up of dehid cells joined end to end with no walls between them and a hole down the middle
! They are strengthend with a material called lignin
! They carry water and mineral ions from the roots to the stem and leaves
! The movement of water from the roots through the xylem and out of the leaves is called the transpiration stream

What Is Transpiration Caused By

The evaporation and diffusion of water from a plant s surface

Light Intensity ( tew )

! The brighter the light = greater the transpiration rate
! Stomata begin to close as it get s darker

Tempreture

! The warmer it is the faster transpiration happens
! When it is warm the particles have more energy to evaporate and diffuse out of the stomata

Air Flow

! The better the air flow = the greater the transpiration
! If air flow around a leaf is poor the water vapour just surrounds the leaf and does not move away
! This means there is a high concentration of water in the air outside the leaf

Humidity

! The drier the air around the leaf = faster transpiration happen
! Air is humid lot of water is in it already so there is not much difference between the inside and the out side of the leaf
! Diffusion happens fastest when there is a high concentration in one place and a low concentration in the other

Describe The Structure Of Guard Cell s

! They have a kidney shape which opens and closes the stomata
! When the plant has a lot of water the guard cells fill with and go turgid = makes the stomata open so gases can be exchanged for photosynthesis
! When the plant is short of water the guard cell lose water and become flaccid making the stomata close = stops water vapour from escaping
! Thin outer walls and thickened inner walls make the opening and closing work
! Sensetive to light and close at night to save water without losing out on photosynthesis
! The lower surface is shaded and cooler less water is lost through the stomata than if they were on the upper surface