9.1.1

Draw and label plan diagrams to show the distribution of tissues in the stem and leaf of a dicotyledonous plant

[image][image][image][image]

[image]

9.1.2

What are 3 differences between the structures of monocots and dicots?

Veins - monocots have parallel veins but dicots have net veins

Vascular bundles - monconts have scattered bundles but dicots have them in a ring

Roots - Monoconts have a fibrous root system but dicots have a tap root system

9.1.3

 What is the function of the upper dermis?

9.1.3

What is the function of the Palisade mesophyll?

To do photosynthesis

the cells have lots of chloroplasts

they are located near the top of the leaf

9.1.3

What is the function of the spongy mesophyll?

To allow rapid diffusion of oxygen and carbon dioxide - by air spaces

some photosynthesis

9.1.3

What is the function of the lower epidermis?

Has stomata - controls release of gas

secretes cuticle and provides a barrier against infection

9.1.4

What are modifications of roots for different functions?

Storage roots - for example a carrot

stores food and water

9.1.4

What are modifications of stems for different functions?

Bulbs - such as an onion - to store nutrients

Stem Tubers - such as potatoes - to store nutrients and water underground

9.1.4

What are modifications of leaves for different functions?

Tendrils - such as on a sweet pea plant.

Tendrils grow out until they hit something solid, then grow around it to support the plant.

9.1.5

What are two types of meristems found in dicot plants?

Lateral and Apical

9.1.6

What's the difference in growth between apical and lateral meristems?

Apical - primary growth - leaves stems stc. - growth upwards.

Lateral - secondary growth - thickening of the stem.

9.1.7

What is the role of Auxin in phototropism?

Auxin is a plant growth hormone which causes elongation of the cells.

It is inhibited by light.

This means that only the dark side of a stem will elongate thus causing the stem to bend towards the light.

It is produced by the apical bud

and transported down the stem to the area of elongation

9.2.1

How does the root system provide a large surface area for water and nutrient uptake?

Branching of roots - this provides a larger surface area because there are many different branches of the roots

Root hairs - each cell in the roots have small hair like extensions which increase the surface area similar to villi.

9.2.2

How do mineral ions in the soil move into the root?

Diffusion

Fungal  Hyphae

Mass flow of water and mineral ions

9.2.3

How are mineral ions absorbed into the root?

By active transport

root cells have lots of mitochondria

9.2.4

How do terrestrial plants support themselves?

Thickened cellulose

cell turgor

lignified xylem

9.2.5

What is transpiration?

The loss of water vapour from the leaves and stems of plants

9.2.6

How is water carried by the transpiration stream?

Water enters the plants via the roots and enters the xylem.  Xylem vessels are very strong so that they can withstand water pressure, and have a wide diameter.

By cohesion (water molecules sticking together) and adhesion (water molecules sticking to the cellulose in xylem wall) the water is pulled up the xylem by the transpiration pull.

When water evaporates from the top of the plant it cause water to move up the xylem and therefore pulls more water in via the roots.

9.2.7

What is the function of guard cells?

To regulate transpiration by opening and closing the guard cells.

9.2.8

What is Abscisic Acid?

A plant hormone that causes the closing of the guard cells of the stomata

9.2.9

How does light affect the rate of transpiration?

Guard cells close at night so greatest water loss is during the day.

9.2.9

How does temperature affect the rate of transpiration?

9.2.9

How does humidity affect the rate of transpiration?

Water moves from an area of high concentration to an area of low concentration.  When there is not much water in the air outside the plant, the water vapour will diffuse out.  Greatest transpiration occurs which the humidity is lowest.

9.2.9

How does wind affect the rate of transpiration?

Little pockets of air are located around the stomata and are saturated with water vapour.  The wind blows these pockets of air away and increases water loss.

9.2.10

What are four adaptations of xerophytes that help to reduce transpiration?

Stomata are located in pits beneath the surface of the leaf

thick waxy cuticle - impenetrable to water

Layers of hair on the epidermis - trap layers of moist air

Reduced leaves - small leaves such as pine needles

9.2.11

What is the role of phloem in the active translocation of sucrose?

Phloem is made up of sieve tubes and companion cells

The sieve cells have no nucleus so the companion cells give all the instructions.

Sugars are transported from the source to the sink

Sieve cells take up sugar by active transport.  Water then follows by active transport.  This causes high pressure which causes the sap (water and sugar) to flow away from that area.  At the sink the sugars move out of the cell by diffusion and water follows by osmosis.  This causes an area of low pressure causing sap to flow towards it.

9.3.1

Draw and label a diagram of a dicot animal-pollinated flower.

9.3.3

Draw and label a dicot seed.

9.3.2

What is the difference between pollination, fertilisation, and seed dispersal?

Pollination is the act of transferring a pollen grain from the anther to the stigma.

Fertilisation is the fusing of the male and female gametes

Seed dispersal is when an animal, or the wind moves the actual seeds away from the original parent plant.

9.3.4

What conditions are need for the germination of a typical seed?

Water - to crack the seed coat and hydrate the nutrients and enzymes

oxygen - for aerobic respiration

Temperature

9.3.5

What metabolic processes occur during the germination of a starchy seed?

Water is absorbed and the seed is rehydrated

Gibberellin is produced in cotyledons 

This stimulates the production of Amylase

Amylase turns starch into Maltose

Maltose is transported to the growth area

Maltose is converted to glucose for aerobic respiration

9.3.6

How is flowering controlled in short day and long day plants?

The length of the night is the most important thing.

Pr and Pfr are two interconvertible forms of phytochrome.  During daylight Pr turns into Pfr and during the night Pfr spontaneously turns back into Pf.

When the day is longer than the night, Pr is left over

When the night is longer than the day Pfr is left over 

Pfr stimulates flowering in long day plants and inhibits it in short day plants