The Atmosphere + plant chemistry

Question 1

describe the troposphere (4)

Answer 1

a planetary boundary up to 1km
an inversion/friction layer
mass of air up to 80%
lots of h2o

Question 2

What layer does the stratosphere include and why is it significant?

Answer 2

• contains the ozone layer which protects life on earth

- ozone absorbs UV light which reduced UV light to earth surface allowing organisms to form

Question 3

what are some properties of O3?

Answer 3

• a strong absorber of longer wavelengths UV radiation and the absorbed energy heats the atmosphere

Question 4

what is the ideal gas law?

Answer 4

Pv = nRT

Question 5

What does the ideal gas law allow us to calculate?

Answer 5

calculates and exactly inter convert concentration and mixing ratio at a given pressure and temperature

Question 6

what do the following letters stand for in the ideal gas law
P ?
V?
n?
R?
T?

Answer 6

P = pressure in pa
V = volume in m3
n = number of moles
R = 8.314 jk-1 mol-1
T = temperature in kelvin

Question 7

How can you calculate pressure?

Answer 7

pressure = force/area

Question 8

what is the purpose of the thermosphere, mesosphere and stratosphere?

Answer 8

• shield life on earth from the damaging rays

Question 9

define mixing ratio

Answer 9

the fraction of the air made up of a particular species

Question 10

define concentration

Answer 10

the amount of a substance per unit volume

Question 11

what does 1 mole equal?

Answer 11

6.022 x 10^23

Question 12

How can you calculate mass?

Answer 12

mass = volume x density

Question 13

how does mixing ratio and concentration change at different altitudes?

Answer 13

• mixing ratio is constant at different altitudes

- concentration changes with altitude and temperature

Question 14

what is the conversion of 1ppm to molecules cm-3?

Answer 14

1 ppm = 2.5 x 10^13 molecules cm^-3

Question 15

what is the link between abundance of a gas and its reactivity?

Answer 15

lower abundance of a gas in the atmosphere means higher reactivity

Question 16

describe the properties of vascular plants

Answer 16

they have vessel like structure to transport nutrients and water

Question 17

name the structures in plants involved in its chemistry

Answer 17

• DNA
• protein
• lipids
• phytochemical pigments
• plant hormones
• self-defence chemicals

Question 18

How are nutrients taken up by plants?

Answer 18

• transpiration, provides a pilling force
• absorption, water and nutrients absorbed by root
• conduction, upward transport of h2o and nutrients

Question 19

what is a rhizosphere?

Answer 19

a narrow region of soil in the vicinity of plant roots in which the chemistry and microbiology is influenced by their growth, respiration, and nutrient exchange.

Question 20

name the main components of the rhizosphere

Answer 20

• root exudates
• dead root cells
• microorganisms

Question 21

what are root exudates? (3)

Answer 21

• secondary metabolites of photosynthesis
• composed of amino acids and organic acids
• carbohydrates, sugars, vitamins, mucilage

Question 22

what is mucilage?

Answer 22

• a polysaccharide
• maintains plant-soil contact
• symbolise relationship with soil dwelling funghi
• prevents roots from damage

Question 23

what are organic acids?

Answer 23

small organic molecules with at least one carboxylic acid

Question 24

describe a carboxylic acid

Answer 24

C = O

• R
• OH

Question 25

what is the main roles of organic acids

Answer 25

mobilization and detoxication

Question 26

what is allelopathy?

Answer 26

when plant roots release chemicals influencing the growth of other species

Question 27

what is biotransformation?

Answer 27

the chemical alteration of chemicals by an organism