key area 5;structures and functions in plants

Question 1

how does the life cycle of a plant go?

Answer 1

germinations,development,flower formation,pollination,seed formation and seed dispersal

Question 2

what does the phloem transport?

Answer 2

sugar

Question 3

explain the phloem

Answer 3

the sugar that is produced by photosynthesis in the leaves is transported up and down the plant to the meristems and other tissues in living phloem cells

Question 4

what do companion cells provide in the phloem?

Answer 4

they provide energy for the sieve cells

Question 5

why do the end walls of the sieve cells have pores?

Answer 5

because sugar is transported from cell to cell through them

Question 6

what does the xylem transport?

Answer 6

water and minerals

Question 7

explain the xylem

Answer 7

water and minerals are transported up through the plant stem is xylem vessels.

Question 8

what is a xylem?

Answer 8

they are a tissue consisting of dead,hollowed out cells that from a system of pipes

Question 9

what are the walls of the xylem cells covered in?

Answer 9

lignin

Question 10

why are the walls of the xylem cells lignified?

Answer 10

it allows the xylem to withstand pressure as the water moves through the plant

Question 11

what is transpiration?

Answer 11

it is the process of water moving through a plant and its evaporation through the stomata

Question 12

what are the stomata surrounded by?

Answer 12

guard cells which can control the opening and closing of the stomata

Question 13

when are the stomata open?

Answer 13

during the day

Question 14

when do the stomata close?

Answer 14

at night

Question 15

what are four factors than can effect transpiration?

Answer 15

wind speed increase,temperature increase,surface area increase and humidity increase

Question 16

what effect does a wind speed increase have on transpiration?

Answer 16

increase in rate

Question 17

what effect does a temperature increase have on transpiration?

Answer 17

increase in rate

Question 18

what effect does a surface area increase have on transpiration?

Answer 18

increase in rate

Question 19

what effect does a humidity increase have on transpiration?

Answer 19

decrease in rate

Question 20

explain the effect a wind speed increase will have on transpiration

Answer 20

wind moves humid air from the leaf surface replacing it with other air leading to more water leaving through the stomata

Question 21

explain the effect a temperature increase will have on transpiration

Answer 21

higher temperatures often trigger the opening of the stomata which allows more water to leave

Question 22

explain the effect a surface area increase will have on transpiration

Answer 22

higher surface areas means that there are more stomata for the water to leave through

Question 23

explain the effect a humidity increase will have on transpiration

Answer 23

the air already contains a high volume of water and the concentration gradient to drive water loss is decreased

Question 24

how can we measure transpiration?

Answer 24

using a potometer

Question 25

how do we know if transpiration is occuring when using a potometer?

Answer 25

as the plant transpires it should pull water from the potometer.the movement of the ir bubble along the capillary tube can be measured over time,providing an indication of the rate of water uptake