Chapter 8: Photosynthesis

Front 1

define heterotroph

Back 1

Must eat food, organic molecules from their environment, to sustain life

Front 2

define autotroph

Back 2

Make organic molecules from inorganic sources

Front 3

define photoautotroph

Back 3

Uses light as a source of energy
--Green plants, algae, cyanobacteria

Front 4

name the photosynthesis substrates

Back 4

light, carbon dioxide, and water

Front 5

name the photosynthesis end products

Back 5

sugar (C6H12O6) and gives off oxygen and water

Front 6

describe photosynthesis

Back 6

CO2 + H2O + light energy → C6H12O6 + O2 + H2O

~CO2 is reduced, H2O is oxidized
~~Energy from light drives this endergonic reaction

Front 7

define chlorophlasts

Back 7

Double membrane bound organelles in plants and algae that carry out photosynthesis

Front 8

define chlorophyll

Back 8

pigment that gives plants green color

Front 9

define central mesophyll

Back 9

• Majority of photosynthesis occurs in leaves in central mesophyll (which is where the chloroplasts are), but can happen anywhere the plant is green

Front 10

define stomata

Back 10

pores where carbon dioxide enters and oxygen exits leaf

Front 11

define thylakoid membrane

Back 11

third membrane containing pigment molecules (including chlorophyll)

Front 12

contrast thylakoid, thylakoid lumen, and granum

Back 12

-Flattened, fluid-filled disk is called a thylakoid

-Thylakoids enclose a compartment called the thylakoid lumen

-Stack of thylakoids form a granum

Front 13

define stroma

Back 13

fluid-filled region inside the chloroplast between thylakoid membrane and inner membrane

Front 14

where do light reactions occur?

Back 14

thylakoid

Front 15

substrates of the light reactions?

Back 15

water, light energy

Front 16

products of light reactions?

Back 16

O2, ATP, NADPH

Front 17

where do dark reactions (Calvin cycle) occur?

Back 17

stroma

Front 18

substrates of calvin cycle?

Back 18

CO2, ATP, NADPH

Front 19

product of calvin cycle?

Back 19

glucose (or general carbs)

Front 20

define chlorophyll a

Back 20

blue-green pigment (reflect blue-green) and is the “primary photosynthetic pigment.”

-Primary electron acceptor (when electron gets excited).

Front 21

define chlorophyll b

Back 21

reflects yellow-green spectrum of light and is a secondary electron acceptor (therefore still participating in photosynthesis).

-Kind of like a backup that increases the wavelength of light that will help generate photosynthesis

Front 22

define carotenoids

Back 22

-group of accessary pigments that are yellow-orange and sometimes red.

-In the spring and summer, the carotenoids act as a sunscreen for the plant (to prevent burn spots).

-Don’t participate in photosynthesis; more of a protective pigment.

Front 23

describe photosystem I

Back 23

-generates ATP


1.Light-harvesting complex
---Directly absorbs photons

2. Reaction center
---Transfered to primary electron acceptor

Front 24

describe photosystem II

Back 24

-generates NADPH

-Light striking light-harvesting complex of PSI transfers energy to a reaction center

Front 25

describe noncyclic electron flow

Back 25

-Linear process produces ATP and NADPH in equal amounts

-light reactions=noncyclic

-Electrons come from water

Front 26

define cyclic photophosphorylation

Back 26

path of electrons is cyclic, light energizes the electrons, and ATP is made via the phosphorylation of ADP

Front 27

what environmental conditions can influence the efficiency and the way calvin cycle works?

Back 27

light intensity, temperature, water availability

Front 28

define C3 plants

Back 28

plants that use Calvin cycle = more efficient at producing sugar

-In cooler climates, C3 plants use less energy to fix CO2

-90% of plants are C3

Front 29

define C4 plants

Back 29

plants that don’t use the Calvin cycle = more efficient at conserving water

-Make a 4 carbon compound in the first step of carbon fixation

-In warm dry climates C4 plants have the advantage in conserving water and preventing photorespiration

Front 30

define CAM plants

Back 30

plants were photosynthesis occurs directly within mesophyll cells

-open stomata at night, closed during day to conserve water

Front 31

T/F: Chloroplasts are the organelles responsible for carrying out photosynthesis in plants and algae.

Back 31

True

Front 32

The addition of an oxygen molecule to ribulose bisphosphate (RuBP) resulting in phosphoglycolate is most accurately referred to as...

Back 32

photorespiration.

Front 33

Organisms which synthesize organic molecules from inorganic sources using light energy are most accurately referred to as ________, while organisms which must consume organic molecules from their environments to survive are most accurately referred to as ________.

Back 33

photoautotrophs; heterotrophs

Front 34

Calvin cycle reactions occur in the ________, while light reactions occur in the ________.

Back 34

stroma; thylakoid membranes

Front 35

When an electron absorbs energy and exists in an excited state, the electron can...

Back 35

drop back down to its original energy level and release light, be removed from one molecule and transferred to a different molecule, and drop back down to its original energy level and release heat.

Front 36

Which of the following statements regarding cyclic electron flow is incorrect?
A) Cyclic electron flow is favored when NADPH levels are high
B) ATP is produced via an electrochemical gradient
C) High energy electrons are transferred to QB via ferredoxin
D) Cyclic electron flow results in high levels of NADPH
E) ATP is the final product of cyclic electron flow

Back 36

D) Cyclic electron flow results in high levels of NADPH

Front 37

True or False: The absorption of light in photosystem II results in an electron with a higher energy level than was attained in photosystem I.

Back 37

False

Front 38

The production of 1 G3P molecule requires

Back 38

6 ATP : 9 NADPH and 3CO2

Front 39

The most common storage form of carbohydrate in chloroplasts is...

Back 39

starch

Front 40

C4 plants are particularly suited for conditions of high temperatures and intense sunlight due to...

Back 40

the physical separation of mesophyll cells and bundle sheath cells.

Front 41

Water necessary for photosynthesis...

Back 41

provides electrons to replace lost electrons in photosystem II

Front 42

Cyclic electron flow that occurs in photosystem I produces...

Back 42

ATP

Front 43

During the first phase of the Calvin cycle, CO2 is incorporated into ribulose biphosphate by..

Back 43

rubisco

Front 44

The NADPH produced during light reactions is nesc. for...

Back 44

the reduction phase which produces carbohydrates in the Calvin cycle

Front 45

The majority of the G3P produced during reduction and carb production phase is used to produce...

Back 45

RuBP

Front 46

Plants commonly found in hot and dry enviornments that carry out carbon fixation at night are...

Back 46

CAM plants