Photosynthesis

Question 1

Photosynthesis Pathway

Answer 1

§ Photosynthesis as energy transfer process, it transfer ___light_____ energy into ___chemical_____ energy.

§ The light energy is needed for making ATP.

§ ______Water molecule__________is split by light to form ___oxygen_____
(which diffused out) and __hydrogen______ ( which used to make carbohydrates.)

§ The ATP produced is used to fix _______carbon dioxide_________and hydrogen to make __carbohydrates__

Question 2

2 reactions

Answer 2

light dependent and light independent pathways

Question 3

The absorption and action spectra

Answer 3

§ The sunlight compose of a range of light with different _____wavelengths_______ (Colors), plants absorb light at varies wavelength and thus show varies photosynthesis rate.

§ The absorption and action spectrum shows ____similar pattern_________, where the _______violet and blue_________ wavelength is used most efficiently and __red__ quite efficiently.

§ However, there is little light absorption in __green_____, as the chlorophyll is ___reflecting________ most of the green light.

§ There is more than one photosynthetic pigment in leaves. These include chlorophyll a and b, carotenoid because by having more than one type of pigment, plant can absorb _________as much different wavelength_________________as possible

________chromatography________ can be used to separate the pigments.

Question 4

Analyzing photosynthesis reaction

Answer 4

§ Photosynthesis rate can be measured ______directly or indirectly_____________.

§ To measure the photosynthesis rate directly, one can measure the amount of ______oxygen______ produced or carbon dioxide used _______per unit of time__

§ To measure the photosynthesis rate indirectly, one can measure the _____increase of biomass_ per unit of time

Question 5

Factors that affect the photosynthesis rate

Answer 5

§ The limiting factor for photosynthesis are: _______light intensity, carbon dioxide level and temperature

§ As there is more than one limiting factors, this suggest that photosynthesis contain more than one reaction pathway.

Question 6

chloroplast structures

Answer 6

Outer membrane

Inner membrane

Stroma

Thylakoid membrane

Grana (Stacks of thylakoid)

Lamellae

Question 7

outer membrane

Answer 7

Control what enters or exit the chloroplast

Question 8

inner membrane

Answer 8

Control what enters or exit the chloroplast

Question 9

stroma

Answer 9

Site for light independent reaction

Question 10

thylakoid membrane

Answer 10

Site for light dependent reaction

Question 11

Grana (stocks of thylakoid)

Answer 11

Site for light dependent reaction

Question 12

lamellae

Answer 12

Site for light dependent reaction

Question 13

chloroplasts

Answer 13

§ Usually round in appearance with a ______double membrane___ exterior

§ ___Flattened dics_________ (thylakoids) arranged into _stacks__ (grana), connected by lamellae

§ Internal lumen of thylakoids is very ____small________ (allows for a more rapid generation of a proton gradient)

§ ____Ribosomes________ and ______chloroplast DNA______are usually not visible at standard resolutions and magnifications

§ ___Starch granules_________may be visible and will appear as dark spots within the chloroplast

Question 14

Light dependent reaction (LDR)

Answer 14

§ Occurs at the intermembrane space of the _____thylakoid________ in the chloroplast.

§ Uses __________photosynthetic pigments_______________ (organized into photosystems) to convert _____light energy____________________into _______chemical energy__________________ (ATP and NADPH).

§ In the chlorophyll there are two enzyme complexes called ____photosystem I ______ (PSI) and _____photosystem II________ (PSII).

§ There are two reaction pathways in LDR: ____cyclic photophosphorylation ______________________and ________non-cyclic photophosphorylation __________________.

the limiting factors for LDR are temperature and light intensity

Question 15

LDR : Cyclic photophosphorylation

Answer 15

§ Electron is ____excited_______ by light in PSI to a ____higher energy level__________________.

§ The electron enters ________electron transport chain______________to make ___ATP_____ though _chemiosmosis__

§ The excited electron then _____returns______ to PSI.

Question 16

LDR : Non-cyclic photophosphorylation

Answer 16

§ Electron is ___excited_______ by light in PSI to a _________higher energy level___________.

§ Electron carrier, ____NADP______ carries the electron to the ___light independent reaction___.

§ Meanwhile, light excites PSII electron. This excited electron will pass through _________electron transport chain_____________________before passing to PSI to compensate electron loss in PSI.

§ PSII obtains its electron by _______breaking down water_____________water. As this process requires light, this reaction is called ____photolysis______.

Question 17

Light independent reaction (Calvin Cycle)

Answer 17

§ Occurs at the _____stroma_____ of the chloroplast.

§ The LIR uses the products of LDR: _________ATP and reduced
NADP___________to run the cycle.

§ Therefore, without LDR, there will be no LIR.

§ The limiting factor in LIR is ____temperature______ and ______carbon
dioxide________level.

Question 18

Carbon Fixation

Answer 18

Carbon fixation: a 5C compound, _____________Ribulose biphosphate (RuBP)_________________combines with _______carbon dioxide______to form a 6C compound, catalyzed by the enzyme ______________Ribulose biphosphate carboxylase____.

§ The reactive 6C compound is very unstable and immediately splits into two 3C compounds called ________glycerate 3 phosphate_____

§ A single cycle involves ____three_________ molecules of RuBP combining with _____three________ molecules of CO2 to make _____six________ molecules of GP

Question 19

Reduction

Answer 19

Each glycerate 3 phosphate is then converted to 2 triose phosphates.

During this process, _____ATP_____and ______reduce NADP (NADPH)_______are used.

Question 20

Lollipop Experiment

Answer 20

§ ______Radioactive carbon 14__________________is added to a ‘lollipop’ apparatus containing ______green algae__________ (Chlorella)
§ ____Light____ is shone on the apparatus to induce photosynthesis (which will incorporate the carbon-14 into organic compounds)
§ After different periods of time, the algae is killed by running it into a solution of ___heated_____ __alchohol______ (stops cell metabolism)
§ Dead algal samples are analyzed using ______2D chromatography__________, which separates out the different carbon compounds
§ Any radioactive carbon compounds on the chromatogram were then identified using __X-Ray______
§ By comparing different periods of light exposure, the ___order_____ by which carbon compounds are generated was determined

Question 21

Photosynthesis vs Respiration

Answer 21

§ Photosynthesis is an ____anabolic____ process, whereas cell respiration is a ___catabolic_____ process:
§ Photosynthesis uses Calvin cycle to synthesize glucose (requires hydrogen carriers and carbon dioxide)
§ Cell Respiration uses Krebs cycle to break down glucose (releases hydrogen carriers and carbon dioxide)

§ Photosynthesis and cell respiration ________both involve the production of chemical energy____________________________:
§ In photosynthesis, ATP is produced via ___light energy_____
§ In cell respiration, ATP is produced by _______brreaking down organic
molecules_________________

§ Transfer of electrons to _______________electron transport chain and
chemiosmosis______________________________:
§ In photosynthesis, electrons are donated by _____chlorophyll to
NADP___________and protons accumulate within the ________lumen of
the thylakoid_____________
§ In cell respiration, electrons are donated by _______electron carriers
(NAD/FAD)_________ and protons accumulate in the ____________intermembrane space of mitochondria____________________