Photosynthesis

Front 1

Which of the step of photosynthesis requires light?

Back 1

Light-dependent reactions.

Front 2

During which step is carbon dioxide (CO2) used?

Back 2

Calvin Cycle

Front 3

Which step produces ATP? Consumes ATP?

Back 3

Light dependent reactions produce ATP; the Calvin Cycle consumes ATP.

Front 4

Where are the photosystems located?

Back 4

Thylakoid membranes.

Front 5

What is inside the photosystems?

Back 5

A cluster of pigment molecules.

Front 6

What are the roles of the photosystems?

Back 6

Together they use light to energize electrons.

Front 7

Photosystem 2

Back 7

Splits water into H+, O2, and E-.

Front 8

Photosystem 1

Back 8

Energizes and charges the electrons that are used to create NADPH.

Front 9

Why is water necessary for photosynthesis?

Back 9

It provides the necessary H ions to make ATP and NADPH. It also releases oxygen as a byproduct.

Front 10

Explain how ATP Synthase works.

Back 10

H+ ions collect in the thylakoid space and have potential energy then enter the ATP synthase where their potential energy is converted into kinetic energy and causes the synthase to spin. The energy causes ADP and P in the synthase to bind and the kinetic energy of the spinning synthase is converted into chemical energy and stored in the bonds of the ATP.

Front 11

Why is chlorophyll green?

Back 11

It’s green because it absorbs the colors ROY BIV and reflects G.

Front 12

What is the job of chlorophyll a and b?

Back 12

Chlorophyll A contains the reaction center. Chlorophyll B absorbs light, which charges electrons that are eventually transferred to the reaction center in Chlorophyll A.

Front 13

Why does the thylakoid space become positively charged?

Back 13

H+ ions from split water from photosystem 2 collects in the thylakoid space causing it to be positively charged

Front 14

How do electrons become energized?

Back 14

The light gets absorbed by the photosystems and its energy is transferred to the electrons.

Front 15

How are the electrons and protons related in the light dependent reaction?

Back 15

Electrons move down the electron transport chain, losing energy. That energy moves to the protons, into the thylakoid. Electrons move to PS1 to replace the lost electrons. The thylakoid membrane splits water into proton. (H+) e- + O.

Front 16

Explain how electrons are able to travel down the ETC?

Back 16

Occurs in the thylakoid membranes of chloroplasts during photosynthesis. Both Photosystems I and II are used to split water to get electrons. Electron transport helps establish a proton gradient that powers ATP production and also stores energy in the reduced coenzyme NADPH. This energy is used to power the Calvin Cycle to produce sugar and other carbohydrates.

Front 17

What is the enzyme at the end of the thylakoid membrane that accepts electrons?

Back 17

NADP+ reductase where the energy from the electrons is used to bind H+ and NADP+ to make NADPH.

Front 18

What are the products of the Light Reaction?

Back 18

Oxygen, ATP, and NADPH.

Front 19

The first stage of the Calvin cycle

Back 19

fixing carbon. Using RuBP and the enzyme Rubisco, the carbon is changed into an organic molecule.

Front 20

Second Stage of the Calvin cycle

Back 20

organizing the carbon. It begins as an unstable PGA molecule. ATP loses a phosphate, and becomes ADP. The phosphate joins with the PGA to make BPGA. NADPH then loses an electron and hydrogen and becomes NADP+. The electron and the hydrogen join the BPGA and it becomes PGAL. It is now stable. One PGAL leaves the cycle, and 5 of them move on to the third stage. The one that leaves waits for the cycle to repeat itself, and together the two PGALs form a glucose.

Front 21

Third stage of the Calvin cycle

Back 21

Reforming RuBP. The 5 PGALs from the second stage combine with 3 carbon dioxides and form RuBP. The RuBP is then used to fix the carbon in the first stage as the cycle repeats itself.

Front 22

What is the actual product of the Calvin Cycle?

Back 22

Glucose.

Front 23

How do ATP, ADP, NADPH and NADP+ relate to photosynthesis?

Back 23

The light reactions use sunlight to convert NADP+ to NADPH by adding a pair of electrons along with a hydrogen nucleus. The light reactions also generate ATP by the addition of a phosphate group to ADP.

Front 24

Why is NADPH called an electron carrier?

Back 24

The Electron Transport Chain ends with the NADPH Reductase. The electron used to combine NADP+ and H+ is held in/carried by the NADPH.

Front 25

Explain photoinhibition

Back 25

Photoinhibition of PSII leads to loss of PSII electron transfer activity.

Front 26

Explain photorespiration

Back 26

Carbon dioxide and oxygen both have the ability to bond with rubisco. Photorespiration is when oxygen is used instead of carbon dioxide. When oxygen bonds with rubisco, it creates one PGA. It takes time and 6 PGA’s to create a PGAL. If carbon were used instead of oxygen, the PGAL would be made much quicker.

Front 27

How are the cells of C3 plants different from C4 plants?

Back 27

They use different enzymes to accept CO2 from the atmosphere. C3 plants use RuBisCo, C4 plants use PPPC.

Front 28

Explain what happens in the mesophyll cells of C4 plants?

Back 28

C4 plants have 2 separate cells, mesophyll cells and bundle sheath cells. C4 plants use this method in photorespiration, which is when the plants break down glucose to form CO2 instead building glucose from CO2 and releasing O2. The CO2 enters the mesophyll cell, and PEP (phosphoenolpyruvate) carboxylase binds the CO2 to PEP to produce a 4 carbon compound.

Front 29

How does having chloroplasts in the bundle sheath cells help C4 and CAM plants?

Back 29

bundle sheath cells in the C3 plants do not have chloroplasts. The bundle sheath cells in the C4 plants do have chloroplasts. C4 plants survive better with environments that have more oxygen.

Front 30

What do we notice about CAM plants that distinguishes them from C4 plants?

Back 30

CAM plants have only one cell, and they they open their stomata at night and close them during the day. the CO2 they take in at night is incorporated into 4 carbon compounds and is sent off to the calvin cycle during the day to make glucose. CAM plants are usually found in dry desert areas.

Front 31

Explain why the Calvin Cycle can’t operate in the dark?

Back 31

It requires sufficient levels of ATP and NADPH (produced from the Light Dependent Reaction). At night time, the Light Dependent Reaction will not be working to produce the necessary ATP and NADPH. Therefore, as it is dark, the Light Dependent Reaction will have not produced enough ATP and NADPH to keep the Calvin Cycle going through the night.

Front 32

Why are there more C3 plants on earth?

Back 32

More CO2 in atmosphere due to fossil fuel combustion & less trees. More C3, less C4 due to increased of CO2.

Front 33

What do chemoautotrophs oxidize?

Back 33

They oxidize inorganic substances and that is how they get energy

Front 34

How do chemoautotrophs similar and different from photoautotrophs?

Back 34

They both make their own food.
Photoautotrophs use sunlight as their source of energy.
Chemoautotrophs use the energy produced from chemical reactions.