Exam 1

Question 1

fill in the blanks for the photosynthesis reaction H2O + ______+______+_______—>______+ O2

Answer 1

(H2O)+CO2+light+chlorophyl—>C6H12O6+O2

Question 2

how is absorption spectrum different from action spectrum

Answer 2

absorption spectrum shows the light absorption pattern of pigments such as chlorophyll

Question 3

how is action spectrum different from absorption spectrum

Answer 3

action is a graph that shows the relative effectiveness of the different wavelengths of light in inducing a particular light requiring process such as photosynthesis

Question 4

which family of pigments do xanthophylls belong to

Answer 4

carotenoids

Question 5

what unique role do xanthophylls (besides leaf color have in plants’ life?

Answer 5

they play a photoprotection role

Question 6

how do xanthophylls accomplish a photoprotective role in plant life?

Answer 6

excess light energy is used to convert xanthophylls from one form to another which helps redirect excess light and protects from photooxidation

Question 7

how do you tell if a leaf cross section is a C3 or C4 plant?

Answer 7

if C4 mesophyll cells are rounder and vascular bundle is rounder also the vascular bundle has bundle sheath cells surrounding it C3 does not

Question 8

what does Kranz anatomy refer to

Answer 8

the tightly fitted layer of cells known as the bundle sheath cells that fit around the vascular bundle in C4 plants

Question 9

What 2 enzymes differ C3 and C4 plants in photosynthesis?

Answer 9

in C3= RuBISCO in C4= PEP Carboxylase

Question 10

what cells are RuBISCO found in?

Answer 10

stroma of C3 and C4 plants

Question 11

what cells are PEP Carboxylase found in?

Answer 11

chloroplast of mesophyll cells

Question 12

what reaction does PEP Carboxylase catalyze?

Answer 12

fixes CO2 into a 4 Carbon compound (hense C4)

Question 13

what reaction does RuBISCO catalyze?

Answer 13

to fix CO2 into a 3 Carbon compound (C3)

Question 14

is C3 or C4 plants more efficient at photosynthesis?

Answer 14

C4

Question 15

what is photorespiration?

Answer 15

light-dependent oxidation of carbohydrates by the Oxygenase activity of RuBISCO

Question 16

how does photorespiration effect photosynthesis in C3 and C4 plants

Answer 16

photorespiration increases in C3 plants with the rise of temperature, at high temps CO2 diffusion is reduced and RuBISCO can not fix CO2 efficiently so PS is reduced, but PEP Carboxylase can fix CO2 at low availability levels therefore in C4 plants PS is not reduced as much

Question 17

how can C3 and C4 plants regulate photorespiration to their advantage?

Answer 17

C4 plants can use it to their advantage to take over the landscape during the summer when it becomes too hot for C3 plants to photosynthesize due to photorespiration

Question 18

do C3 or C4 plants do better in warmer drier conditions?

Answer 18

C4

Question 19

why do C4 plants do better in warmer drier conditions than C3 based on leaf anatomy

Answer 19

C4 plants have more chloroplasts in bundle sheath that are able to process higher concentrations of CO2 and because bundle sheath is close to vascular bundle sugars are exported quicker

Question 20

what is the double jepardy of C3 plants

Answer 20

1. rate of photorespiration increases in C3 2. stomata close during warm conditions and C3 cannot PS but C4 can due to PEP Carboxylase

Question 21

define inverted stomata cycle

Answer 21

CAM plants open their stomata and fix CO2 primarily at night

Question 22

what is the significance of inverted stomata cycle to geography and climate?

Answer 22

CAM plants can do better in warmer drier climates and locations because they can have their stomata closed during the day because CO2 fixation only occurs at night. This allows the plant to conserve enough water to survive in harsh conditions

Question 23

what is an example of a CAM plant

Answer 23

pineapple

Question 24

do C3 or C4 have higher CCP?

Answer 24

C3

Question 25

explain CCP and its relevance to PS efficiency

Answer 25

a lower CCP mean that plants can carry out PS even at lower CO2 concentrations in the air and this means more efficient PS

Question 26

what is the formula for water use efficiency?

Answer 26

WUE= g dry matter produced/g of water transpired

Question 27

how does WUE inform a horticulturist about a given plant?

Answer 27

WUE can tell conditions a plant will do best and the conditions it requires ie CAM has high WUE and C3 have low WUE

Question 28

do shade adapted or sun adapted leaves have lower respiration rates?

Answer 28

shade

Question 29

what is the impact of lower respiration of shade plants on growth, survival, and leaves in low light environments?

Answer 29

in order for a plant to grow net PS must exceed respiration. shade plants get little light so PS is low therefore in order for growth to occur it is beneficial that respiration is also low.

Question 30

leaves that are often exposed to full, bright sun have more than one layer of _____

Answer 30

palisade cells

Question 31

what is the role of multiples layers of palisade cells

Answer 31

they provide internal shading and protect the leaves from too much light

Question 32

where do C3 get its name

Answer 32

they fix CO2 into 3 carbon compounds

Question 33

where do C4 get its name

Answer 33

they fix CO2 into 4 carbon compounds

Question 34

what is the primary plant pigment involved in photosynthesis

Answer 34

chlorophyll

Question 35

what wavelengths are most useful for photosynthesis?

Answer 35

400-700 nm (red and blue)

Question 36

the overall process of PS is a two step process involving what sets of reactions

Answer 36

1. Light reactions (hill) and 2. dark reaction (calvin cycle)