Photosynthesis

Question 1

Photosynthesis

Answer 1

The process that converts solar energy into chemical energy

Question 2

Autotrophs

Answer 2

Sustain themselves without eating anything derived from other organisms (producers)

Question 3

Heterotrophs

Answer 3

Obtains their organic material from other organisms (consumers)

Question 4

Reactants

Answer 4

From air and soil (6CO2 + 6H2O + Light Energy)

Question 5

Products

Answer 5

Used in cellular respiration to make ATP (6O2 + C6H12O6)

Question 6

Chloroplasts

Answer 6

Structurally similar to photosynthetic bacteria- allows for the chemical reactions of photosynthesis

Question 7

Chlorophyll

Answer 7

Green pigments within chloroplasts- creates green color in leaves

Question 8

Mesophyll

Answer 8

The interior tissue of the leaf where most chloroplasts are found (cells contain 30-40 chloroplasts)

Question 9

Stomata

Answer 9

Microscopic pores where CO2 enters and O2 exits

Question 10

Thylakoids

Answer 10

Membrane (connected sacs in the chloroplast) where chlorophyll is in

Question 11

Grana

Answer 11

Stacked columns of thylakoids

Question 12

Stroma

Answer 12

A dense interior fluid contained in chloroplasts

Question 13

The splitting of water

Answer 13

Chloroplasts split H2O into hydrogen and oxygen, releasing oxygen as a by-product

Question 14

Oxidation

Answer 14

The substance that loses electrons is said to be oxidized (OIL)

Question 15

Reduction

Answer 15

The substance that gains electrons is said to be reduced (RIG)

Question 16

Light Reactions

Answer 16

• In the Thylakoids
• Split H2O -> release O2
• Reduce NADP+ to NADPH
• Generate ATP from ADP by photophosphorylation

Question 17

Calvin cycle

Answer 17

• In the stroma
• Forms sugar from CO2 using ATP and NADPH
• Carbon fixation

Question 18

Wavelength

Answer 18

The distance between crests of waves- determines the type of electromagnetic energy

Question 19

Electromagnetic spectrum

Answer 19

The entire range of electromagnetic energy, or radiation

Question 20

Visible light

Answer 20

Consists of wavelengths that produce colors we can see

Question 21

Photons

Answer 21

Light also behaves as though it consists of discrete particles

Question 22

Pigments

Answer 22

Substances that absorb visible light; Leaves appear green because chlorophyll reflects and transmits green light

Question 23

Spectrophotometer

Answer 23

Measures a pigment’s ability to absorb various wavelengths

Question 24

Absorption spectrum

Answer 24

A graph plotting a pigment’s light absorption verses wavelength

Question 25

Action spectrum

Answer 25

Profiles the relative effectiveness of different wavelengths of radiation in driving process

Question 26

Chlorophyll a

Answer 26

The main photosynthetic pigment

Question 27

Chlorophyll b

Answer 27

Broaden the spectrum used for photosynthesis

Question 28

Carotenoids

Answer 28

Absorb excessive light that would damage chlorophyll

Question 29

Excited state

Answer 29

When a pigment absorbs light it goes from a ground state to an excited state which is unstable

Question 30

Photosystem

Answer 30

Consists of a reaction-center complex (a type of protein complex) surrounded by light-harvesting complexes

Question 31

Light-harvesting complexes

Answer 31

Pigment molecules bound to proteins; Transfers the energy of photons to the reaction center

Question 32

Primary electron acceptor

Answer 32

In the reaction center; Accepts excited electrons and is reduced as a result

Question 33

Photosystem II

Answer 33

Functions first and is best at absorbing a wavelength of 680 nm (reaction-center chlorophyll a is called P680)

Question 34

Photosystem I

Answer 34

Best at absorbing a wavelength of 700 nm (reaction-center chlorophyll a is called P700)

Question 35

Linear electron flow

Answer 35

The primary pathway; Involves both photosystems and produces ATP and NADPH using light energy

Question 36

First step of the linear electron flow

Answer 36

A photon of light strikes a pigment molecule in a light-harvesting complex of PS II, boosting one of its electrons to a higher energy level (excited state). Energy is relayed to other pigment molecules until it reaches the P680 pair of chlorophyll a molecules in the reaction center complex

Question 37

Second step of the linear electron flow

Answer 37

An electron from the excited P680 (now P680+) is transferred to the primary electron acceptor

Question 38

Third step of the linear electron flow

Answer 38

P680+ is the strongest biological oxidizing agent; its electron "hole" must be filled -> An enzyme catalyzes the slitting of water molecule (2 electrons, 2 hydrogen ions (H+) -> released into the thylakoid lumen, an oxygen atom -> released in the form of O2)

Question 39

Fourth step of the linear electron flow

Answer 39

Each photoexcited electron passes from the primary electron acceptor of PS II to PS I via an electron transport chain (ETC) made up of plastoquinone (Pq), a cytochrome complex, nd plastocyanin (Pc)

Question 40

Fifth step of the linear electron flow

Answer 40

The exergonic "fall" of electrons to a lower energy level allows for the synthesis of ATP. As electrons pass through the cytochrome complex, H+ are pumped into the thylakoid lumen, contributing to the proton gradient that is used in chemiosmosis

Question 41

Sixth step of the linear electron flow

Answer 41

Light harvesting complexes in PS I are excited by another photon and transfer energy. An electron of the P700 pair chlorophyll molecules is excited and passed to the PS I primary electron acceptor. Now that P700+ has an electron "hole", it can act as an electron acceptor (PS I accepts the electron that reached the bottom of the ETC from PS II).

Question 42

Cyclic electron flow

Answer 42

Uses only photosystem I and produces ATP, but not NADPH; generates surplus ATP

Question 43

Chemiosmosis

Answer 43

The use of energy in a H+ gradient to drive cellular work; Protons build up in the thylakoid lumen -> can only diffuse through ATP synthase -> ATP is produced

Question 44

First step of carbon cycle

Answer 44

Carbon fixation (CO2 catalysed by rubisco)

Question 45

Second step of carbon cycle

Answer 45

Reduction (carbon molecules are reduced **using ATP which is then turned into ADP & NADPH which is then turned into NADP+ + P** until it creates a sugar named glyceraldehyde 3-phosphate (G3P))

Question 46

Third step of carbon cycle

Answer 46

Regeneration of the CO2 acceptor (RuBP)