Transport In Plants

Question 1

Xylem transports

Answer 1

Water and mineral salts
Long, narrow, hollow tubes whose walls are lined with lignin ligninfied
Xylem have no cross walls and therefore allow for the continuous flow of water
Cells therefore permeable membrane

Question 2

Water moves through a plant

Answer 2

Root pressure
Transpiration
Capillarity

Question 3

Root hair

Answer 3

Extension of a single epidermal cell
Increases the surface are of the roots

Question 4

Cortex/pith

Answer 4

Packing tisse, spherical unspecialised cells packed loosely

Question 5

Vascular cambium

Answer 5

Constantly dividing cells between the xylem and phloem to form the xylem on the inside and phloem on the outisde

Question 6

Epidermis

Answer 6

Single layer of cells (flatten

Question 7

Bark

Answer 7

Waterproof layer composed of cork cells

Question 8

Cork cambium

Answer 8

Constantly dividing cells to form cork on the outside

Question 9

Lignin- xylem vessels

Answer 9

Tough and strong helps the xylem vessels support the plant

Question 10

Root pressure

Answer 10

Push from the roots
Water enters root hairs and epidermal cells of roots by osmosis,
Water travels up the cortex of the root by osmosis

Water is pushed up the xylem vessels of the roots to the bottom of xylem vessels of the stems by the water entering the roots and epidermal cells (root pressure is a push from the roots)

Question 11

Transpiration

Answer 11

Is a loss of water vapour from the surface of the leave which creates a pull

Water evaporates from the spongy mesophyll cells diffuses out of them through the air spaces and exits through the stomata, more water is pulled from the spongy mesophyll cells by osmosis, this pull/loss of water brings/draws the water in the xylem vessels of the stem to the xylem vessels of the leaves and into the palisade mesophyll cells where it is used for photosynthesis

Question 12

Capillarity

Answer 12

Helps water move
The cohesion of water molecules between the molecules in the walls of the xylem vessels allow for a continuous flow of water from the roots and helps water move upwards

Question 13

Transpiration stream

Answer 13

Flow of water through xylem vessels

Question 14

Control of the loss of water by stomata

Answer 14

Stomata found in the lower epidermis of leaves, open and almost close depending on the turgidity of the guard cells.
If the guard cells are turgid, meaning alot of water(supply of waterin the soil), this means rapid Transpiration
If they are flaccid meaning less water, or water loss, Transpiration decreases

Question 15

Environmental factors affecting rate of Transpiration

Answer 15

Wind speed
Humidity
Light
Temperature

Question 16

High temperature low temp

Answer 16

High temp causes water to evaporate quickly and water vapour to diffuse rapidly
Low temp causes water to evaporate slowly and water to diffuse slowly so Transpiration is slowe

Question 17

Wind speed

Answer 17

Windy conditions water vapour is pulled from the surface of the leaves quickly

Question 18

Humidity

Answer 18

High humidity the surface of the leaves are saturated with water vapour decreasing the concentration, hence diffusion is slowed and Transpiration slowed

Question 19

Light intensity

Answer 19

Dim light the stomata almost close, very little water vapoyr can duffuse out reducing the rate of transpiration

Question 20

Importance of Transpiration

Answer 20

1. It cools the leave as water moves through it
2. For photosynthesis draws water to palisade cells
3. Keeps stems turgid due to the flow of water
4. Moving water dissolves mineral salts

Question 21

Water conservation in plants

Answer 21

Reducing the rate of Transpiration
1. Plantas shed their leaves in dry seasons and winter months
2. Leaves have extra thick waxy cuticles
3. Some Leaves have reduced numbers of stomata
4. Stomata are grouped together in sunken pits that trap water vapour
Have fine hair on their surface that water vapour

Question 22

Storing water in plants

Answer 22

Many succulent plants store water in their leaves aloe
Many succulent plants store water in the stems cacti
Roots of some plants store water

Question 23

Increasing water uptake

Answer 23

Some plants have long vertical deep plant roots to ABSORD water from deep within the soil
Some plants have shallow widespread root (ROOT SYSTEMSs to obtain water from the surface of the soil in a wide area

Question 24

Pholem sieve tibes

Answer 24

Phloem vesels have sieve plates, companion cells that control the functioning of the cells transports organic food mainly sucrose and amino acids contains living cytoplasm

Question 25

Sugar sources

Answer 25

Produce sugars where the phloem obtains sucrose from e.g. photosynthesizing leaves

Question 26

Sugar sinks

Answer 26

Parts of plants that require sugars fruits, seeds, stems roots

Question 27

Mechanism of translocation

Answer 27

Sugars move from the cells of the Sugar source to the pholem by active transport, increases the sugar concentration inside the phloem sieve tubes

Water moves from the xyelm vessels into the adjacent phloem sieve tube by osmosis

Turgor pressure increases as water increased and the turgor pressure forces the sugars and organic food/dissolved substances through the sieve plates

Sugars diffuse through the walls of the phloem into the cells of the sugar sink such as a fruit or seed and sugar concentration decreases

Water then dawn back into the xylem vessels by the suction created by the Transpiration stream and the turgor pressure inside the sieve tubes decreases once again

Question 28

Movement of mineral salts

Answer 28

Mineral salts are absorbed by the roots in the form of ions, they are dissolved in water present in the soil, move up by active transport where they enter the xylem vessels and carried thright the plant

Question 29

Importance of FOOD STORAGE in living organisms

Answer 29

• Overcomes the need for continuous food intake by heterotrophs and continuous food manufacture by autotrophs
• It provides food reserves in times of food scarcity in heterotrophs e.g. winter months and in times where food manufacture does not occur in plants e.g. during a drought
  enables hibernation in animals and plants to survive during dry season or winter months

it provides food reserves for special functions like the growth and development of an embyronic plant, new plants use stored food as they develop from vegetaive organs

Question 30

hydrolysis and condensation

Answer 30

the splitting of molecules by the addition of water
substances hydrolysed are: amino acids, fatty acids and glycerol and glucose

the joining of molecules by the loss of water
substances condensed are: starch, glycogen, proteins, and lipids and fats

Question 31

food storage in animals

Answer 31

storage in adipose (fat) tissue, excess fat is stored around organs and under skin, excess glucose is converted to fat and stored

storage in the liver
vitamins A, B12, D
Iron
Glycogen formed by the condenstaion of excess glucose in blood

storage in skeletal muscle
store glycogen formed from the condensation excess glucose in the blod

Question 32

storage of food in plants

Answer 32

fruits, stems, leaves, roots, seeds

the phloem sieve tubes transport sugars produced in photosyenthesis (and amino acids), to the above structures, where they are stored or converted to proteins, lipids and starch and stored

Question 33

storage in vegetative organs

STORE STARCH MIANLY

Answer 33

vegetative organs are undrground structures that are swollen with food at the end of growing seasons

they allow the plant to survive during the unfavourable season and allow it to grow rapidly, using stored food during the favourable season

they can also act as a means of sexual reproduction as new plants grow from the vegetative organs

Question 34

vegatative organs

stems

Answer 34

stem tubers
english potato yams

rihzomes ginger

corms
eddo

Question 35

vegatative organs

roots

Answer 35

root tubers
sweet potato

Question 36

vegatative organs

leaves and leaf bases

Answer 36

such as bulbs that grow from the leaf or make up the bulb

ONIONS ARE BULBS

Question 37

storage in TAP ROOTS

Answer 37

tap roots are single vertical roots.
sugars: carrot and sugar beet
starch: turnip

Question 38

storgae in succulent fruits

Answer 38

store mainly sugars
e.g. mango and pawpaw

fats and oils
avocado and olives

starch
breadfruit

thse stored fods attract anumals to eat it and aids in seed dispersal

Question 39

storage in seeds

Answer 39

the cotyledons and endosperm of seeds can store starch
e.g. rice and wheat

store proteins
peas and beans

store oils
nuts

STORED FOOD SUCH AS THOSE LISTED ABOVE IS USED WHEN THE SEEDS GERMINATE

Question 40

STORAGE IN LEAVES

Answer 40

MANY LEAVES OF SUCCULENT PLANTS STORE WATER

E.G ALOE

Question 41

Storage in stems.

Answer 41

the stems of sugar cane store sucrose, some succulent plants store water in their stems

Question 42

why do we need to cut the stems of celery underwater

Answer 42

This process is called transpiration. That new empty space inside the leaves creates a low pressure, and like a drinking straw, this low pressure allows water below the leaf to travel up the stem. You’ll see the little tubes the water travels up when you cut the celery stem, and you can see the colour up in the leaves.

Question 43

Why air bubbles are not good.

Answer 43

Cut the stem of the leafy shoot (at an angle to increase the surface area) under water . The reason we cut it under water is to prevent air bubbles entering the xylem vessel.

Water will no longer move up the xylem as a continuous column, as the transpiration pull will not occur if there are air bubbles.

Question 44

How a potometer works

Answer 44

the moving-bubble potometer, which measures water uptake by the shoot. (Note that water
uptake in a cut stem is likely to be greater than that in a rooted plant. This is due to the direct access to xylem vessels
in a cut shoot, rather than resistance to this across the apoplast in a rooted plant.