Lecture 13: Transport in Plants

Question 1

passive transport?

Answer 1

moves molecules short distances or across membranes without the use of energy. passive transport includes diffusion/simple and facilitated diffusion, and osmosis.

Question 2

diffusion?

Answer 2

movement of molecules down their concentration gradient across a plasma membrane without the use of energy and simple diffusion is directly across the phospholipid bilayer without any help and facilitated diffusion is across the membrane with the use of a transport protein

Question 3

osmosis?

Answer 3

net movement of water from an area of low solute concentration to an area of high solute concentration

Question 4

active transport?

Answer 4

movement of molecules against their concentration gradient across a membrane using transport proteins

Question 5

what is the primary mode of transporting materials in nonvascular plants?

Answer 5

nonvascular plants/bryophytes main mode of transporting material is diffusion. the reason for this is because nonvascular plants have no vascular/transport system. ALL plants use diffusion for gas exchange but the vascular plants use diffusion for everything

Question 6

cytoplasmic streaming?

Answer 6

cytoplasm circulates around the cells via actin myosin interactions:
- moves nutrients around the cell to speed up the distribution of material
- important in large plant cells
- moves chloroplasts from shady areas to sunny areas for photosynthesis

Question 7

are gases transported?

Answer 7

no gases arent transported; all living cells do gas exchange directly with the environment

Question 8

what materials are transported from root to shoot?

Answer 8

water and minerals are transported from root to shoot and released as water vapor from the stomata

Question 9

what materials are produced by the plant and transported throughout?

Answer 9

sugar that was made via photosynthesis

Question 10

what tissues perform long distance transport?

Answer 10

vascular tissue: the tissue system is xylem and phloem. the xylem transports water from root to shoot and phloem moves the sugar from the leaf to where it is needed.
SAP: includes the nutrients, water, and sugar being transported long distance. xylem sap consists of mainly water and phloem sap consists of mainly sugar.

Question 11

are plants or animals more efficient with water?

Answer 11

animals are more efficient with water than plants are: plants lose 95% of the water through evaporation from stomata but most animals resorb water through kidneys and colon, and vascular system.

Question 12

water moves from — to — via?

Answer 12

water moves from roots to leaves via bulk flow: movement of water from roots to shoots in response to pressure gradient

Question 13

what are the 3 ways of how water moves up against gravity in plants?

Answer 13

1. transpiration-cohesion-tension mechanism
2. capillary action
3. root pressure

Question 14

transpiration cohesion mechanism explained in easy way?

Answer 14

in plants, water moves up from the roots to the leaves through tiny tubes called the xylem due to a combination of 3 things including: transpiration, cohesion, and tension.
TRANSPIRATION: when water evaporates from the leaves into the air through the stomata.
COHESION: when water molecules stick together. it pulls more water up behind it.
TENSION: the pull that happens when water evaporates and pulls more water from the roots.
so, transpiration pulls water out of the leaves, cohesion makes water molecules stick together, and tension pulls water up through the plant.

Question 15

what happens if you stop evaporative water loss in plants?

Answer 15

that would stop water and mineral transport

Question 16

mesophyll cells are coated with? causing?

Answer 16

mesophyll cells are coated with a film of water causing the humidity to be higher inside of the lead than the surrounding air.

Question 17

what is capillary action?

Answer 17

the tendency of water to move up a tube due to cohesion, adhesion, and surface tension.
Plants have tiny tubes called xylem, when water gets into the tubes it starts to climb up. Cohesion is water molecules sticking together and adhesion is water molecules sticking to the xylem cell wall. surface tension acts to hold the surface intact.
SO as water moves up the xylem tubes, cohesion and adhesion help it stick together and stick to the sides of the tube.

Question 18

how far up can capillary action move water up?

Answer 18

only one metre

Question 19

root pressure?

Answer 19

inside the root of a plant, there are cells that pump minerals and water from the soil into the roots. this pumping action creates pressure pushing the water through the xylem tubes. it helps to push water up the plant especially at night when transpiration isnt happening much.

Question 20

active transport in root pressure?

Answer 20

the mineral concentration in root hairs is higher than in the soil so it goes against the concentration gradient and atp is required.

Question 21

where is sugar produced in the plant?

Answer 21

it is produced in mature leaves via photosynthesis

Question 22

what cells need sugar?

Answer 22

all living cells need sugar

Question 23

how does sugar get to the right areas?

Answer 23

transported in phloem

Question 24

how is sugar transported from source to sink? and what is it?

Answer 24

via the pressure flow model. source is organ where photosynthesis occurs or starch is broken down. sugar sink is the organ that consumes or stores starch

Question 25

source/sink in summer vs spring?

Answer 25

in summer, the leaves are the source and potato is sink and in spring, the potato is the source and the leaves are the sink

Question 26

pressure flow model?

Answer 26

1. sugar moves from the source cell to the sieve tube using active transport: the leaves produce sugar through photosynthesis so they are then loaded onto special cells called source cells using active transport.
2. water then moves into the sieve tube by osmosis. the sieve tubes are tubes for the sugars to travel through and the water moves into the seive tubes via osmosis which increases pressure which then pushes sugar through the tubes.
3. sugar transported from sieve tube to sink cell using passive transport. the pressure in the seive tube pushes the sugar along the tube towards the sink and into sink cells via passive transport.
4. water recycles back into xylem by osmosis. water recycles back into xylem by osmosis.after sugar is unloaded the water in the sieve tube recycles back into the xylem through osmosis.