Biology 1 - Week 7 Photosynthesis

The role of the light-harvesting complex is to ______.

absorb photons of light

The incorporation of carbon from CO2 in the atmosphere into an organic molecule is called carbon

carbon fixation

In plants, which of the following is polymerized to form starch?

glucose

What is the product of the oxidation of water during photosynthesis?

oxygen

During photosynthesis, NADPH is synthesized by Blank______.

photosystem I

An electron carrier that can accept two high-energy electrons during photosynthesis is

NADPH

Sequence the phases of the Calvin cycle from first (on top) to last.

1. Carbon fixation 2. Reduction of carbohydrate production 3. Regeneration of ribulose bisphosphate

In photosynthesis, light energy is converted to _______ energy, which in turn is converted to __________ energy in a sugar molecule.

1. Electrochemical 2. Chemical

PSI and PSII have two main components:

1. Light harvesting complex 2. Reaction center

Based on the Z scheme, how many photoactivation events occur during photosynthesis?

2

What is the product of the carbon fixation reaction catalyzed by rubisco in the Calvin cycle?

3-phosphoglycerate

n C4 plants, the first product of carbon fixation is ______.

4 carbon molecule

A major purpose of the electrochemical gradient generated in the light reactions of photosynthesis is to synthesize

ATP

Which of the following are products of the light reactions of photosynthesis that are used as reactants in the Calvin cycle?

ATP NADPH

The Calvin cycle uses ________, which are products of the light reactions of photosynthesis.

ATP and NADH

Light is a type of Blank______ radiation because it consists of energy in the form of electric and magnetic fields.

Electromagnetic

Photosynthesis only occurs in plants

False

How do CAM plants avoid water loss?

CAM plants close their stomata during the day and open them at night.

Sunlight enables the synthesis of glucose from carbon dioxide by providing _____ that is necessary for the process.

Energy, ATP

Products of light dependent reactions

NADPH ATP Oxygen

PEP carboxylase can attach CO2 to phosphoenolpyruvate, resulting in the synthesis of a four-carbon molecule called

Oxaloacetate (OAA)

What molecule is produced by photosystem II?

Oxygen

The generalized equation for photosynthesis includes two main reactants: CO2 and H2A. The two elements that can be the "A" in H2A are

Oxygen Sulfur

A molecule that can absorb light energy is called a(n)

Pigment

What enzyme is responsible for carbon fixation?

Rubisco

What happens during photorespiration?

Rubisco attaches O2 to RuBP, and CO2 is produced.

The oxidization of water by photosystem II causes the pH of the thylakoid lumen to

decrease

The light independent reactions of photosynthesis require NADPH. Where does this molecule come from?

light dependent reactions

Arrange the following molecules according to the order of electron flow during photosynthesis. Begin at the top with the location where electrons are first excited in noncyclic electron flow.

p680 --> Cytochrome complex --> Plastocyanin --> P700 --> NADP+

In hot dry conditions, rubisco can attach O2 to RuBP in a process called Blank______. which ultimately produces CO2.

photorespiration

During noncyclic electron flow, electrons flow from water to ______.

photosystem II, then to photosystem I, and ultimately are transferred to NADP+

The energy released as electrons pass from an electron carrier to another in the electron transport chain between photosystem II and photosystem I is used to Blank______.

pump H+ establish an electrochemical gradient

Calvin cycle occurs in the

stroma of the chloroplast

During photosynthesis in green plants, what molecule is oxidized?

water

Why does CO2 enter CAM plants at nighttime?

Because the stomata of CAM plants are only open at night

Similar to ATP synthesis in mitochondria, ATP synthesis in chloroplasts is achieved by a ______ mechanism called photophosphorylation.

Chemiosmosis

Green plants absorb light energy in photosynthesis using

Chlorophyll a and b

Multiple Choice Question Both PEP carboxylase and rubisco can fix carbon dioxide. However, PEP carboxylase ______.

Does not bind oxygen

What is carbon fixation?

The incorporation of carbon into an organic molecule that is not a gas

A greenhouse owner made an error and bought lightbulbs that only emit green light. How will this impact the growth of his plants?

The plants will grow more slowly, if at all

Which of the following statements are true of carotenoids?

They are abundant in flowers and fruits. They are found in chloroplasts. They may appear yellow, orange, or red.

You are at the hardware store and find an herbicide that stops the process of photosynthesis in plants by preventing chlorophyll from absorbing solar energy. You take it home and spray it across your entire yard to kill the weeds that are growing with the grass. What happens?

You kill all the plants in your yard, including the weeds and grass

The model for photosynthesis that incorporates two photoactivation events and shows the series of energy changes during the light reactions of photosynthesis is called the

ZigZag (or Z) Scheme

A graph that shows the rate of photosynthesis plotted as a function of light wavelength is called a ________ spectrum for photosynthesis

action Spectrum

A diagram that depicts the wavelengths of electromagnetic radiation that are absorbed by a pigment is termed a(n

Absorption Spectra

As a tree grows, it increases in mass over time. Where does this mass come from?

Air/CO2

A new flower species has flowers that are a beautiful deep red color. What wavelengths of light does this flower absorb?

All but red

The table shown here displays the data from 5 different herbicides (H-1 to H-5) and how they affect photosynthesis. Which of these herbicides would be effective at killing weeds?

All of these herbicides will kill weeds

Which of the following summarizes the events of the first phase of the Calvin cycle?

Atmospheric carbon dioxide is fixed into a five carbon sugar.

Organisms that can synthesize organic molecules from inorganic molecules are called

Autotrophs

Which of the following organisms can carry out photosynthesis?

Bacteria Algae Plants

During photosynthesis, CO2 is reduced to produce ______.

Glucose

the primary output of the Calvin cycle?

Glyceraldehyde-3-phosphate

If you wanted to have a plant produce radioactively labeled O2 gas, you would feed it 18O labeled ____.

H2O

Organisms that must consume food to obtain organic molecules are called

Heterotrophs

Genes that are derived from the same ancestral gene, and thus are similar to each other, are termed

Homologous genes

Some plants have a mutation that inhibits photosystem I but not photosystem II. What it the consequence of this for the plant?

It can no longer produce NADPH

What happens to a pair of electrons after it reaches QB?

It enters an electron transport chain in the thylakoid membrane.

Which of the following happens to the molecule formed by the addition of carbon dioxide to ribulose bisphosphate? Multiple choice question.

It is immediately split into two more stable three-carbon molecules.

What is the role of the reaction center in a photosystem?

It transfers a high-energy electron to another molecule.

If you place a plant in an environment that lacks carbon dioxide, what will happen?

It will be unable to carry out photosynthesis It will stop growing It will eventually cease cellular respiration

A small amount of ATP is actually made during photosynthesis. When does this occur?

Light dependent reactions

How does an electron located in the pigment of the light-harvesting complexes become excited?

Light excites an electron in a pigment found in the light-harvesting complexes of the photosystems.

What is the flow of electrons from PSII to PSI called?

Linear electron flow

What chemical reaction is catalyzed by the enzyme PEP carboxylase?

Phosphoenolpyruvate + CO2 → oxaloacetate

Uses light energy to drive synthesis or organic molecules from inorganic molecules

Photoautotrophs

What happens during photosynthesis?

Plants capture energy from sunlight and use it to synthesize organic molecules.

A new flower species has flowers that are a beautiful deep red color. What wavelengths of light does this flower reflect?

Red

Which phase of the Calvin cycle will require both ATP and NADPH?

Reduction and carbohydrate production

Which of these best represents the fixation of a carbon molecule?

The incorporation of CO2 into organic molecules.

The light reactions of photosynthesis take place in the

Thylakoid

The two independent, light capturing complexes of proteins and pigments called photosystems I and II, are located in the

Thylakoid

Which of the following is the purpose of phase 3 of the Calvin cycle?

To create a new 5-carbon sugar for the "next" Calvin cycle

he G3P produced at the end of the second phase of the Calvin cycle is directly used for which of the following?

To regenerate ribulose bisphosphate To make glucose or other carbohydrates

In the noncyclic pathway, solar energy removes an electron from photosystem two. Where does the electron come from to replace it?

Water

In the light reactions, ATP is generated via Blank______.

chemiosmosis