ch 10

Question 1

photosynthesis

Answer 1

the process that converts solar energy into chemical energy

Question 2

autotrophs

Answer 2

organisms that sustain themselves without eating anything derived from other organisms

Question 3

chemosynthesis

Answer 3

organisms build organic molecules using energy from oxidation of inorganic molecules such as hydrogen gas, hydrogen sulfide, or methane

Question 4

where do most chemosynthetic organisms live

Answer 4

in oceans near hydrothermal vents

Question 5

heterotrophs

Answer 5

organisms that obtain their organic material from other organisms

Question 6

chloroplasrs

Answer 6

site of photosynthesis
organelles responsible for feeding the vast majority of organisms
contain the grandma thylakoids
leaves are major location of photosynthesis
found mainly in cells of mesothelioma (interior tissue of leaf)

Question 7

chlorophyll

Answer 7

green pigment in chloroplast
absorbs light energy to drive synthesis of organic molecules in chloroplast
in the membranes of thylakoids

Question 8

how does CO2 enter the leaf

Answer 8

through the stomata, and O2 exits

Question 9

photosynthesis equation

Answer 9

6CO2 + 12H2O + Light Energy —> C6H12O6 + 6O2 + 6H2O

Question 10

two stages of photosynthesis

Answer 10

light reactions (photo part)
calvin cycle (synthesis part)

Question 11

where do light reactions occur

Answer 11

in the thylakoids

Question 12

brief summary of light reactions

Answer 12

light absorbed by the chlorophyll in the thylakoid drives transfer
of electrons to NADP+ forming NADPH
water is split in process and O2 is released
also generates ATP using chemiosmosis in a process called photophosphorylation

Question 13

where does calvin cycle occur

Answer 13

in the stroma
begins with incorporation of CO2 into organic molecules and fixed carbon is reduced with electrons from NADPH
ATP powers calvin cycle

Question 14

light is a form of electromagnetic energy
what does this mean

Answer 14

light travels in rhythmic waves
wavelength determines the type of electromagnetic energy
light also behaves as though it consists of photons

Question 15

how does wavelength affect photosynthesis

Answer 15

pigments absorb visible light
certain pigments absorb certain wavelengths
leaves appear green because it absorbs every color but reflects green
violet-blue and red light work best for psyn

Question 16

two systems of light reactions

Answer 16

photo system II (best at absorbing 680nm)
photo system I (best at absorbing (700nm)

Question 17

what occurs in photo system II

Answer 17

The pigment molecules bound to the photo system protein absorb the light energy and transfer among other pigment molecules until the energy reaches the reaction center. This energy energizes the chlorophyll a molecule in the reaction center that it causes an electron to escape (captured by primary acceptor molecules)
the electrons released are then replaced by H2O which is split by an enzyme
electrons are sent down an ETC and the chain captures energy to create a H+ gradient
the gradient causes the ATP synthase to work and produce ATP

Question 18

what occurs in Photosystem I

Answer 18

Pigment molecules are energized through light energy and transfer it to the chlorophyll a in the reaction center
energized electrons then leave chlorophyll a and go to primary acceptor
the electrons from PSII come down the ETC and replace the electrons that left chlorophyll a
the primary acceptor passes electrons down another ETC that pass it to NADP+
each NADP+ accepts 2 electrons and H+ to form NADPH

Question 19

cyclic electron flow
cytochrome complex

Answer 19

using only photosystem I
the cyclic electron flow generates surplus ATP satisfying the higher demand for ATP in calvin cycle

Question 20

difference between chemiosmosis in chloroplasts and mitochondria

Answer 20

chloroplasts and mitochondria generate ATP by chemiosmosis but use different sources of energy
mitochondria transfers chemical energy from food to ATP
Chloroplasts transforms light energy into chemical energy of ATP
spatial organization of chemiosmosis differs ( intermembrane space and matrix vs stroma and thylakoid space)

Question 21

calvin cycle

Answer 21

series of reactions producing carbohydrates before returning to starting point
uses co2 from atmosphere to produce sugars by using ATP and the reducing power of electrons carried by NADPH
carbon enters cycle as CO2 and leaves as G3P
cycle must occur 3 times for one G3P

Question 22

three phases of calvin cycle

Answer 22

carbon fixation
reduction
regeneration of CO2 acceptor (RuBP0

Question 23

carbon fixation

Answer 23

CO2 is attached to RuBP to form one 6C molecule
this is immediately split into 2 3C molecules
RuBP is a slow enzyme

Question 24

reduction of CO2

Answer 24

each 3C molecule undergoes a reduction in 2 steps using some ATP and NADPH
each 3C receives another phosphate from ATP
pair of electrons from NADPH reduces that molecule to G3P
one G3P leaves

Question 25

regeneration of G3P

Answer 25

G3P remaining in cycle used to form RuBP
5 G3P usef to reform 3 RuBP
this also causes three molecules of ATP to become ADP and Pi

Question 26

what happens to g3p after calvin cycle

Answer 26

two g3P needed to form glucose
g3p exported out of chloroplast to cytosol
converted to heroes sugars

Question 27

C3 plants

Answer 27

produce 3c sugars
majority of land plants
use RuBP to fix CO2
make O2 as by-product during photosynthesis

Question 28

what happens to plants during hot climates

Answer 28

stomata closes to conserve water
this reduces access to CO2 and causes O2 to build up
photorespiration occurs
when O2 rises it combines with RuBP
no g3p is made but 3pg is made which releases CO2 (no sugar can be made)

Question 29

C4 plants

Answer 29

angiosperms that have developed adaptations which minimizes the losses to photorespiration
incorporates CO2 into four-carbon compounds in mesothelioma cells
the compounds are exported to bundle-sheath cells where they release CO2 that is then used by calvin cycle

Question 30

CAM plants (succulents)

Answer 30

C4 plants
open stomata at night
CO2 is released from organic acids