Photosynthesis terms

Question 1

autotroph

Answer 1

An organism that produces nutrients from light or chemical energy and biochemical processes that convert simpler inorganic molecules into complex organic molecules like sugars; examples are photosynthetic organisms.

Question 2

chlorophyll

Answer 2

The primary pigment in green plants; absorbs light in photosynthesis.

Question 3

chloroplast

Answer 3

Organelle that contains chlorophyll and carries out photosynthesis.

Question 4

heterotroph

Answer 4

An organism that must acquire energy from other organisms.

Question 5

photosynthesis

Answer 5

The biochemical process by which light energy is used to convert carbon dioxide and water into complex organic molecules.

Question 6

stroma

Answer 6

The area in the chloroplast outside the thylakoids; site of the carbon reactions of photosynthesis.

Question 7

thylakoid

Answer 7

Continuous internal membrane system of the chloroplast where the light-dependent reactions occur. Stacks of thylakoids are known as grana.

Question 8

absorption spectrum

Answer 8

Graph of the percentage of light absorbed as a function of light wavelength.

Question 9

action spectrum

Answer 9

Graph depicting the efficiency of photosynthesis for an organism across the visible light spectrum.

Question 10

carotenoid pigment

Answer 10

An accessory pigment that absorbs light energy primarily in the purple and blue wavelengths.

Question 11

chlorophyll a

Answer 11

One of the pigments in photosynthesis; absorbs best in the red and purple wavelengths.

Question 12

chlorophyll b

Answer 12

One of the pigments in photosynthesis; absorbs best in the blue and orange wavelengths.

Question 13

chloroplast

Answer 13

Organelle that contains chlorophyll and carries out photosynthesis.

Question 14

electromagnetic spectrum

Answer 14

Full range of electromagnetic energy.

Question 15

light harvester

Answer 15

A pigment that absorbs energy and passes it on to other pigments.

Question 16

light-harvesting complex

Answer 16

A complex of proteins that serves as the light collector of a photosystem.

Question 17

photon

Answer 17

A particle of light.

Question 18

photosystem

Answer 18

A collection of pigment-protein complexes organized to harvest light energy.

Question 19

pigment

Answer 19

A naturally occurring molecule specialized for absorbing light energy and which can be coupled to energy-producing mechanisms in photosynthetic organisms; exists in a variety of types that absorb light at specific wavelengths.

Question 20

reaction center complex

Answer 20

Site of the energy-converting reactions of photosynthesis.

Question 21

spectrophotometer

Answer 21

An instrument used to measure the amount of light of a given wavelength that a sample absorbs.

Question 22

thylakoid membrane

Answer 22

Membrane within the chloroplast in which many photosynthetic pigments are embedded.

Question 23

visible light

Answer 23

Narrow portion of the electromagnetic spectrum ranging from 400-700 nm; corresponding to the colors visible to the human eye.

Question 24

wavelength

Answer 24

Distance from one wave crest to the next successive wave crest.

Question 25

carbon fixation reactions

Answer 25

A collective set of reactions by which the cell converts or fixes inorganic carbon from carbon dioxide into organic carbon.

Question 26

cyclic electron flow

Answer 26

A process by which electrons leaving photosystem I are passed back to the cytochrome complex and re-enter photosystem I; generates ATP but not NADPH.

Question 27

glyceraldehyde-3-phosphate

Answer 27

A Calvin cycle product; one of the building blocks for carbohydrates.

Question 28

linear electron flow

Answer 28

The process by which electrons leaving photosystem II are transferred through electron carriers to photosystem I and ultimately to NADP+ to form NADPH.

Question 29

photophosphorylation

Answer 29

The process by which ADP is phosphorylated into ATP using the energy from sunlight.

Question 30

photosystem I

Answer 30

A photosystem with an absorption peak at 700 nm; occurs after photosystem II in the photosynthetic electron transport chain.

Question 31

photosystem II

Answer 31

A photosystem with an absorption peak at 680 nm; first of the two photosystems in the photosynthetic electron transport chain.

Question 32

primary electron acceptor

Answer 32

A modified chlorophyll a molecule that accepts the high-energy electrons at the center of photosystem II.

Question 33

ribulose bisphosphate carboxylase-oxygenase (RuBisCO)

Answer 33

An enzyme that binds a carbon dioxide molecule to ribulose-1,5-bisphosphate as it enters the Calvin cycle; the most abundant enzyme on Earth.