Transportation

Question 1

what do unicellular organisms need for movement of substances in and out of the cell and why do they not need a specialised transport system.

Answer 1

1. Unicellular organisms rely on diffusion to get oxygen and food nutrients.
2. Due to their small size diffusion takes place quick through their cell membrane.
3. They have large surface area to volume ratio and therefore they do not require a specialised transport system to supply the cell and remove waste products

Question 2

Understand the need for a transport system in multicellular organisms.

Answer 2

1. Multicellular organisms are made of billions of cells therefore have smaller surface area to volume ratio, making diffusion alone inefficient.
2. Therefore they need to have a specialized transport system to get things they need. For example they have lungs to get oxygen.

Question 3

What do animals have to move everything through the body.

Answer 3

Circulatory system: It is made of fluid that can pick up and carry substances around.

Question 4

What is a phloem and what does it do

Answer 4

1. Products of photosynthesis= sugars and amino acids that are transported by phloem tubes ( living cells)

Question 5

How does phloem tube work.

Answer 5

1. These cells joined end to and have holes in each ends call sieve plates.
2. these allow easy transportation of

Question 6

What is the transportation of sucrose and amino acids called

Answer 6

translocation

Question 7

where is sucrose and amino acids stored during winter, spring (growth period), summer (fully grown.

Answer 7

Winter: Plants usually don’t have any leaves so phloem tubes dissolved sucrose and amino acids from the storage organs to other parts for respiration continual.

Spring: The storage organs (roots) would be the source (where sucrose and amino acids made) and the growing parts of the plants would be the sink ( where it’s stored)

Summer: The plant would have grown therefore the leaves would be photosynthesising producing large amount of sugars becoming the source and roots would be the sink storing sucrose as strach until it is required.

Question 8

what does a xylem do

Answer 8

Xylem: transports water and mineral ions from roots to other parts of plant.

Question 9

How does xylem work and

Answer 9

1. H2O travels up xylem from the roots into the leaves of the plant to replace the water that has been lost due to transpiration

Question 10

what are xylem adaptations.

Answer 10

Adaptation=
1.A substance called lignin deposited in it’s cell walls which causes the cells to die.

2. These cells become hollow as they lose cytoplasm and organelles join end-to-end to form a continuous tube for water and mineral ions to travel through from the roots.
3. Lignin strengthens the plant to help it withstand the pressure of the water movement.
4. Movement only in one direction from roots to leaves.
5. Water molecules are attracted to each other by hydrogen bonding – creating a continuous column of water up the plant.
6. water evaporates from the leaves of the plant, creating the transpiration stream

Question 11

Difference between xylem and phloem

Answer 11

xylem Phloem

1. water and mineral ions 1.sucrose and amino acids
2. transpiration stream 2. translocation is the process
3. 1 direction 3. multiple directions
4. cells are dead 4. cells are living.

Question 12

How is water and mineral ions absorbed by the roots cells and a adaptation

Answer 12

1. Water enters root hair cells by osmosis
2. Roots hair cells have high mineral ion concentration therefore low H2O concentration compared to the soil.
3. Therefore water is drawn in. (enables water uptake to occur even if the soil is very dry)
4. Root hair cells get mineral ions by active transport. against their concentration gradient by active transport.
5. Have specialized shape which gives them a large surface area to volume ratio.

Question 13

How does mineral ion once inside the root get to the xylem cells.

Answer 13

Minerals move through the root cortex by diffusion as there is a greater concentration of them in the root hair cells than towards the centre of the root. Some active transport maybe also involved.

Question 14

What is transpiration

Answer 14

is the evaporation of water at the surfaces of the spongy mesophyll cells in leaves, followed by loss of water vapour through the stomata

Question 15

How does water move through the xylem vessels.

Answer 15

1. Water moves through the xylem vessels in a continuous transpiration stream from roots to leaves via the stem.
2. Transpiration creates a tension or pull on water in xylem vessels by the leaves.
3. As water molecules held together by cohesive bonds so it’s pulled up through the plant
4. If transpiration increases, water molecules are pulled up the xylem vessels quicker.

Question 16

Functions of transpiration

Answer 16

1. transport mineral ions.
2. Provide water to cells to keep them turgid allowing them to support structure of plant.
3. Provides H2O for photosynthesis
4. Keeps the plant cool.

Question 17

what are the factors that impact transpiration

Answer 17

Temperature, humidity, wind speed and light intensity

Question 18

How does temperature impact transpiration

Answer 18

1. It increases the rate of transpiration.
   explanation= If temp up kinetic energy in the H2O molecules increase meaning they move faster therefore evaporation quicker.

Question 19

How does humidity impact transpiration

Answer 19

1. It decreases the rate of transpiration
   explanation= If its humid air is almost saturated with H2O vapour.
   Therefore there is little concentration gradient between the air spaces in the leaf and outside air a as a result slowing down the rate of evapouration.

Question 20

How does wind speed impact transpiration

Answer 20

1. It increases the rate of transpiration.

explanation= Moves the H2O vapor away from the leaf therefore maintaining a high concentration gradient.

Question 21

How does light intesity impact transpiration

Answer 21

1. It increases the rate of transpiration.
   explanation= stronger light intensity = more H2O the guard cells will absorb due to osmosis. This would make them more curved, opening the stomata more to ensure as much CO2 is diffusing for photosynthesis.
   The more open the stomata, more water vapour can diffuse out.

Question 22

investigate the role of environmental factors in determining the rate of transpiration from a leafy shoot

Answer 22

1. Lay the capillary tube and rubber connector under the water and fill both parts
2. Cut a shoot underwater at an angle to prevent air entering the xylem and place in tube.
3. Assemble the potometer underwater
4. Push the plant into the tubing making sure its air tight, add Vaseline to seal any gaps.
5. Place the capillary tubing in the beaker with water and take apparatus out of the water.
6. Dry the leaves with a towel as this would affect results.
7. Remove the capillary tube from the beaker of water to allow a single air bubble to form and place it back.
8. Allow the plant to adapt to the new environment for 5 minutes
9. Record the starting point of the air bubble and leave it for a set time.
10. Record the end location of air bubble.
11. Change the light intensity or wind speed or level of humidity or temperature (only one – whichever factor is being investigated)
12. Reset the bubble by opening the tap below the reservoir and Repeat the experiment
    * The further the bubble travels in the same time period, the faster transpiration is occurring and vice versa

Question 23

How can the factors of transpiration be investigated.

Answer 23

Temperature : Temperature of room (cold room and warm room)
Humidity : Spray water in plastic bag and wrap around plant
Wind : Distance of fan to plant / different speeds of fan
Light intensity : Distance of lamp to plant