movement of molecules

Question 1

define osmosis

Answer 1

osmosis is the (net) movement of WATER molecules from a HIGH WATER concentration to a LOW WATER concentration across a SEMI PERMEABLE MEMBRANE

Question 2

define dilute in terms of amount of water

Answer 2

lots of water

Question 3

define concentrated in terms of amount of water

Answer 3

little water (think of a concentrated drink)

Question 4

what is the role of visking tubing in terms of osmosis

Answer 4

the semi permeable membrane

Question 5

on an osmosis graph (salt solution concentration- x-axis and % change in mass - y-axis) how can you find the concentration/isotonic point

Answer 5

point where line crosses the x-axis = concentration of solution/isontonic point

Question 6

what are you trying to find out in the potato chip experiment

Answer 6

the sugar concentration in potato

Question 7

what is your independent variable in the potato chip experiment

Answer 7

concentration of sugar solution

Question 8

what is your dependent variable in the potato chip experiment

Answer 8

change in mass

Question 9

how will you control other variables in the potato chip experiment

Answer 9

same:
size - SA of potato
time in solution
temperature
age/specie of potato

Question 10

write a CORMS for the potato chip experiment

Answer 10

C - concentration of sugar
O - same size of potato
R - x3
M1 - change in mass
M2 - 30 mins - leave
S1 - time in solution
S2 - temperature
S3 - specie/age of potato

Question 11

what happens to the plant when it is placed in pure water

Answer 11

water goes in - cell membrane pushes AGAINST cell wall - therefore plant goes TURGID

Question 12

what happens to the plant when it is placed in concentrated salt solution

Answer 12

water moves out - cell membrane pushes AWAY from cell wall - PLASMOLYSE

Question 13

how does the plant being turgid benefit it

Answer 13

gives it structure to reach sunlight

Question 14

what do we call a solution that has the same concentration of water inside and outside

Answer 14

isotonic solution

Question 15

describe the method - onion epidermis in 6 steps

Answer 15

1 - carefully peel away the onion epidermis and place on side
2 - add a drop of distilled water
3 - put cover slip on top
4 - observe underneath a microscope
5 - repeat with concentrated salt solution (on another slide)
6 - take a photo of each to compare

Question 16

describe the method - osmosis in potato cells in 6 steps

Answer 16

1 - cut a potato into equal-sized cubes
2 - record the mass of each potato cube
3 - please each potato cube into different concentrations of salt solution
4 - remove the potato cubes after 30 minutes
5 - dry the potato cubes and record the final mass of each cube - % change in mass was then calculated
6 - repeat the whole procedure for swede cubes

Question 17

how does this procedure ensure the method is valid? - osmosis in potato cells experiment

Answer 17

surface area
species
percentage change

Question 18

how could the validity of the method be improved - osmosis in potato cells experiment

Answer 18

precision of balance

Question 19

where is water absorbed by the plant?

Answer 19

roots

Question 21

what process requires water plants?

Answer 21

photosynthesis

Question 22

where does this process happen?

Answer 22

leaves - chloroplasts

Question 23

which direction does water need to flow in in a plant - one way journey

Answer 23

up

Question 24

how do plants make sugar (glucose)

Answer 24

leaves

Question 25

what do plants need sugar for

Answer 25

respiration

Question 26

where do plants store their excess sugar?

Answer 26

roots

Question 27

where will sugar be needed in a plant?

Answer 27

everywhere

Question 28

will sugar (in solution) flow in only one direction, or will it flow all over the plant?

Answer 28

up and down

Question 29

describe the colour and shape of the xylem on a diagram

Answer 29

orange and is an X shape (therefore think of Xylem)

Question 30

describe the and shape/position of the phloem on a diagram

Answer 30

it surrounds the xylem

Question 31

what is transported in the xylem and in which direction

Answer 31

water (up) and mineral ions (nitrates, magnesium, ions…) (pulled up)

Question 32

what surrounds the xylem vessel that makes it turgid

Answer 32

the lignin - provides strength/support

Question 33

what cells are in the xylem

Answer 33

dead cells - no organelles inside - provides space for water - therefore is hollow

Question 34

what is transported in the phloem vessel and in which direction do they move in the phloem

Answer 34

sucrose and amino acids - move up and down

Question 35

what is the name of the cells that support the outside of the phloem

Answer 35

companion cells

Question 36

how many organelles are in the phloem

Answer 36

few organelles

Question 37

are the cells alive or dead in the phloem vessel

Answer 37

alive

Question 38

what are the spaced, plate-like structures called in the phloem

Answer 38

sieve plate - (has holes therefore think of a sieve)

Question 39

what only moves up in the xylem but up and down in the phloem

Answer 39

minerals

Question 40

does the xylem have any organelles

Answer 40

no

Question 41

where is the phloem and xylem found (animal or plant cell)

Answer 41

plant cell

Question 42

define translocation

Answer 42

movement of sugars

Question 43

what are the sugars transported in the phloem (sucrose) converted into in the roots

Answer 43

starch

Question 44

the sugars are transported in a vessel known as the phloem, this requires energy so we call it an ______ process

Answer 44

active

Question 45

what does the root hair cell not contain that other plant cells do

Answer 45

chloroplast

Question 46

describe the vaseline experiment (with the leaves) in 11 steps

Answer 46

1 - pick four leaves from the plant - try to select leaves of a similar size 2 - tie a string between two retort strands — you will clip the leaves to do this string 3 - measure the mass of the first leaf and clip it to the string — this is your control 4 - cover the bottom surface of the second leaf with Vaseline 5 - measure the mass of the second leaf and clip it to the string (make sure leaves 1-4 are arranged left to right, or label them) 6 - cover the top surface of the third leaf with vaseline 7 - measure the mass of the third leaf and clip it to the string 8 - cover the top and bottom surfaces of the fourth leaf with the Vaseline 9 - measure the mass of the fourth leaf and clip it to the string 10 - leave the leaves for three days 11 - measure the mass of each leaf again

Question 47

why do we use a control leaf (no vaseline)

Answer 47

for comparison to check vaseline is causing the change

Question 48

why did you measure the mass of the leaves after applying Vaseline?

Answer 48

to make sure the final reading is reliable

Question 49

why did you select leaves of similar sizes?

Answer 49

similar sized stomata similar surface area = valid

Question 50

what is the name of the woody material that surrounds the xylem?

Answer 50

lignin

Question 51

what is the name of the movement from a low to high concentration using ATP?

Answer 51

active transport

Question 52

what is the name of the continuous stream of water through a plant?

Answer 52

transpiration stream

Question 53

what is the name of the xylem and phloem together?

Answer 53

vascular bundle

Question 54

what is the name of the end of each cell formed by a cross wall of cellulose with holes?

Answer 54

sieve plate

Question 55

what is the name of a living cells that lie alongside the sieve tubes of the phloem?

Answer 55

companion cells

Question 56

what is the name of the specialised cell that is adapted from water and mineral iron uptake

Answer 56

root hair cells

Question 57

what is the name of the movement of water from high to low concentration to semi-permeable membrane?

Answer 57

osmosis

Question 58

define transpiration

Answer 58

evaporation of water from leaf stomata

Question 59

what are the guard cells?

Answer 59

cells that open and close the stomata

Question 60

what is the name of water molecules clinging (sticking) to the side of the xylem?

Answer 60

adhesion

Question 61

what is the name of water molecules (same type of molecule) sticking together

Answer 61

cohesion

Question 62

what is the name of the concentration of water in the air?

Answer 62

humidity

Question 63

what is the name of the device to measure transpiration using the movement of a bubble?

Answer 63

potometer

Question 64

what is the name of the movement of sugars through a plant?

Answer 64

translocation

Question 65

what is the name of the holes found on the lower epidermis

Answer 65

stomata

Question 66

what do root hair cells do?

Answer 66

absorbed mineral ions and water

Question 67

where are most of the stomata found?

Answer 67

lower epidermis

Question 68

how does the sun make the plant turgid

Answer 68

sun - photosynthesis - makes glucose - decreases water potential in guard cell - water moves in via osmosis - turgid - stomata opens

Question 69

what are the four factors that will speed up water loss?

Answer 69

temperature, humidity, wind, speed light intensity

Question 70

how does temperature affect the speed of water loss?

Answer 70

A high temperature will speed up transpiration - kinetic energy increases - increases movement of water molecules - increases evaporation

Question 71

how does humidity affect the speed of water loss?

Answer 71

A low humidity (low = high concentration gradient/high = low concentration gradient) will speed up transpiration - evaporation

Question 72

how does wind speed affect the speed of water loss?

Answer 72

a high wind speed will speed up transpiration = less humid = less water in air = increase concentration gradient = increase evaporation

Question 73

how does light intensity affect the speed of water loss?

Answer 73

a high light intensity will speed up transpiration - increases photosynthesis - needs more CO2 - stomata needs to open - more water leaves leaf - therefore increase transpiration

Question 74

describe how to set up a potometer in 7 steps

Answer 74

1 - the potometer must be set up under water - this prevents any air bubbles from entering the system and blocking the xylem 2 - cut the stem of the shoot 3 - put the shoot system into a bung, grease the joint with plenty of vaseline - this prevents water loss and air entry 4 - put the bung into the potometer 5 - make sure the tap is closed and it is full of water (no bubbles), then lift the potometer out of the water 6 - leave the end of the capillary tube out of the water until an air bubble forms then put the end into a beaker of water 7 - you can measure the transpiration rate as distance the bubble travels in five minutes (or the time taken for the bubble to travel a set distance). you should take a number of readings and calculate the mean rate.

Question 75

how do minerals get into the plant?

Answer 75

active transport in the root hair cells

Question 76

if increasing light, increase the rate of photosynthesis — what can we say light is?

Answer 76

the limiting factor

Question 77

name 2 safety precautions when testing for starch

Answer 77

1 - goggles - to avoid iodine getting into eyes 2 - keep ethanol away from fire - very flammable - therefore turn bunsen off

Question 78

why do green parts of the leaf test positive for starch

Answer 78

lots of chlorophyll - photosynthesis - glucose is made - stored as starch

Question 79

what is the difference between excretion and egestion

Answer 79

EXCRETION - removal of METABOLIC waste EGESTION - removal of UNDIGESTED waste

Question 80

how is the leaf adapted for photosynthesis?

Answer 80

palisade mesophyll: vertical - lots of cells near surface lots of chloroplast - absorbs light for photosynthesis

Question 81

how is the leaf adapted for gas exchange

Answer 81

- lots of air spaces - increases surface area - stomata - allows air in and out - guard cells - open/close (control) stomata

Question 82

where is the compensation point

Answer 82

where there is no net gas exchange