Campbell Biology Concepts and Connections Chapter 7 - Study Questions

__________ reacts with ozone to turn it into ____________.

Chlorine; CO2

You are the CEO of a major manufacturing company that decides to use CFCs in production of your products. What are you failing to abide by?

Montreal Protocol

Oxygen is the final electron acceptor for cellular respiration. What is the final electron acceptor in the light reactions of photosynthesis?

NADP+

What do cyclic reactions do in light reactions?

NADP+ turned into NADPH, ATP is transformed, electrons turn back to chlorophyll after going away

In photosynthesis, the electrons come from water and end up in _____.

NADPH

What transports electrons from the light reactions to the Calvin cycle?

NADPH

the process in which a plant adds O2 to RuBP instead of CO2

Photorespiration

Current evidence indicates that the process of photosynthesis arose more than three billion years ago. Its origin had a huge impact on existing organisms and on the physical characteristics of the biosphere. Which major physical change could be attributed to photosynthesis?

Photosynthesis drastically increased the oxygen content of the atmosphere.

You obtain the pigments called carotenoids in your diet when you eat carrots. Why do carotenoids appear yellow and orange?

They absorb blue/green light and reflect yellow and red wavelengths of light.

What is the function of chlorophyll in photosynthesis?

capture light energy

ATP synthesis in both chloroplasts and mitochondria involves the process called _____________.

chemiosmosis

What are two things that work in conjunction to make CFC'S harmful to ozone?

chlorine and sunlight

A plant's leaves are the primary site of photosynthesis. A plant's leaves would be expected to have a large amount of ____________.

chlorophyll

What do non-cyclic reactions do in light reactions?

electrons transfer to NADPH

Photosynthesis is an __________ process in which carbon is __________, whereas cellular respiration is an __________ process in which carbon is __________.

endergonic : reduced : exergonic : oxidized

What is an example of a photoautotroph?

corn stalks just before harvest: any plant that is able to produce its own food and act as producers to the biosphere

Is the stratosphere moist or dry?

dry

In both cellular respiration and photosynthesis, a(n) ________ _________ _______ built into a membrane pumps H+ across the membrane as electrons are passed from one electron carrier to the next in a series of redox reactions.

electron transport chain

When a pigment absorbs a photon of light, if a substance somehow kept the boosted electron from falling back to its ground state, would light and hear still be released in the same amount?

energy would not be given off as light and heat at that time

Incoming photons of light energy initiate photosynthesis by _____.

exciting electrons in pigment molecules within the photosystems, raising them to a higher energy level

What is the function of RuBP?

fixes/binds to CO2

What are benefits of photosynthetic products to humans?

food, fuel, removal of CO2 from the atmosphere

Which parts of the visible light spectrum do plants reflect?

green

Where does photosynthesis take place?

in the chloroplast

What is the equation that represents photosynthesis?

6CO2 + 6H2O → C6H12O6 + 6O2

What are the differences between C4 and CAM plants in photosynthesis?

*C4*: stomata closed, conserves water, 4 carbon compound (fix CO2), ex. corn, sugarcane *CAM*: open stomata at night to bank CO2 at night and release it during the day, ex. ferns, pineapple, cacti, aloe, jade *Same*: minimize photorespiration, maximize photosynthesis, hot and dry climates, ways to cool down the cell without stopping sugar production, stores water

What are two additional pigments that can be found in plants?

*carotenoids*: help absorb extra light that could damage. Interacts with oxygen to form a reactive oxidative molecule. various shades of yellow and orange *xanthophylls*

What are the two types of chlorophyll found in plants?

*chlorophyll a*: participates directly in light reactions, absorbs mainly blue-violet and red light. Looks blue-green *chlorophyll b*: broadens the range of light that a plant can use by conveying absorbed energy to chlorophyll a. Absorbs blue-orange light and reflects olive green

What are the differences between photosystem I and photosystem II?

*photosystem I*: occurs second, produces NADPH *photosystem II*: happens first, produces ATP, splits water *same*: cooperate in light reactions, characteristic reaction center complex, special pair of chlorophyll a molecules with a particular primary electron acceptor, thylakoid membrane, drives flow of electrons from water to NADPH, light excites the electrons, 2 complexes of pigments linked by the electron transport chain

A student has been shrunk to fit inside the thylakoid space of a granum. How many layers of phospholipids would he or she need to cross through to get completely out of the mesophyll cell?

8 layers- 8 layers of phospholipids

What summarizes the inputs and outputs of the Calvin cycle?

ATP + NADPH + 3CO 2 → G3P

What links the two stages of photosynthesis with each other?

ATP and NADPH

What two molecules are produced by the light reactions and used to power the Calvin cycle?

ATP and NADPH

Briefly, explain what would happen to the levels of NADPH and ATP within the stroma is the passage of electrons to the primary electron acceptor of photosystem I were inhibited.

ATP production would stop- cell would die because it needs energy. Halt production of NADPH, no NADP+ going through cycle

What connects the two photosystems in the light reactions?

An electron transport chain

In __ plants, the first product of carbon fixation is the three-carbon compound 3-PGA formed in the Calvin cycle.

C3

In __ plants, CO2 is first fixed into a four-carbon compound, which moves into bundle-sheath cells and releases CO2 to the Calvin cycle.

C4

In ___ plants, stomata are open at night, and CO2 is first fixed into a four-carbon compound, which releases CO2 to the Calvin cycle during the day.

CAM

Which gas contributes to both global warming and the deterioration of the ozone layer?

CFCs

The carbon in glucose comes from what source?

CO2

The oxygen in glucose comes from what source?

CO2

A toxin is found to inhibit the uptake of CO2 into plant leaves. This toxin would most directly affect the ____________ ____________.

Calvin Cycle

What substance provides the majority of the atoms that make up the sugar produced by photosynthesis?

Carbon Dioxide

What provides the carbon atoms that are incorporated into sugar molecules in the Calvin cycle?

Carbon dioxide (CO2)

How is the primary electron acceptor reduced in light reactions?

Electrons are supplied to chlorophyll P680 as it reduces the primary electron acceptor.

What is the final product of the Calvin Cycle?

G3P

In both respiration and photosynthesis, the potential energy of a(n) __ ____________ _______ is tapped to drive the phosphorylation of ADP to ATP. As H+ diffuses back through ___ _______ (an enzyme complex embedded in the membrane), ATP is produced.

H+ concentration gradient; ATP synthase

What provides electrons for the light reactions?

H2O

What is the potential benefit of photorespiration in plants?

It allows plant cells to reduce the buildup of oxygen gas without opening stomata.

A botanist discovers a new plant species in the Amazon rainforest that has blue leaves. Briefly explain what can be inferred about the pigments in the leaves of this plant

It contains lots of Chlorophyll A and participates directly in light reactions

When such plants close their stomata on hot, dry days to conserve water, __ builds up in the leaf and is added to RuBP in place of CO2. A two-carbon product of this reaction is broken down to CO2, consuming ATP and generating no sugar.

O2

Where was the thinning of ozone initially discovered?

Over the Antartic

One of the important waste products of photosynthesis is oxygen gas. Where does this oxygen gas come from?

Oxygen is released when water is broken down to extract electrons and protons for use in the light reactions.

Hydrogen is a likely candidate in the search for a replacement for petroleum. However, removing hydrogen from water requires the investment of a great deal of energy. Why are plants considered to be one step ahead in the utilization of hydrogen as an alternative fuel source?

Plant cells possess water-splitting enzymes.

Why is the Calvin Cycle Cyclic?

RuBP is regenerated in the final chemical reactio

Although the reactions of the Calvin cycle are not directly dependent on light, they usually do not occur at night. Why?

The Calvin cycle depends on products of the light reactions.

A red chemical dye known as phenol red changes to yellow when CO2 is present. A small green plant seedling is placed in phenol red and then placed in the dark. Which of the following is most likely to occur?

The solution is red to begin with, and it will turn yellow because respiration is occurring.

You have a large, healthy philodendron that you carelessly leave in total darkness while you are away on vacation. You are surprised to find that it is still alive when you return. What has the plant been using for an energy source while in the dark?

While it did have access to light before you left, the plant stored energy in the form of sugars or starch, and it was able to derive energy from those during your vacation.

Which parts of the visible light spectrum do plants absorb?

blue, red, orange

Where is carbon dioxide used?

calvin cycle

In photosynthesis, _____ ______ drives electrons from a low-energy state in water to a high-energy state.

light energy

The two complexes of pigments that constitute a photosystem include ________ __________ _____________ and the _________ __________.

light harvesting complex; reaction complex

The thylakoid membranes bring together the components necessary to carry out the _____.

light reactions

Where is light used?

light reactions

Where is oxygen made?

light reactions

Where is water used?

light reactions

Where are enzymes used?

light reactions and the calvin cycle

What are the two primary reactions in photosynthesis?

light reactions, calvin cycle

What is the purpose of enzymes in photosynthesis?

lower the energy needed to make chemical bonds

Can the light reactions take place in the dark? Why?

no- need light to function

The Calvin Cycle is also referred to as the referred to the light-independent reactions. Briefly explain why referring to the chemical reactions of the Calvin cycle as the light-independent reactions is only partially accurate.

none of the steps in the Calvin Cycle may require light directly but the reaction usually occurs in daylight because it depends on the products from light reactions which are light-dependent

Cellular respiration and photosynthesis are similar in that both involve _____.

oxidation-reduction (redox) reactions

In respiration, the electrons come from the oxidation of organic molecules, and ______ is the final electron acceptor.

oxygen

The light reactions produce _____.

oxygen, NADPH, and ATP

How can ultraviolet rays cause sunburn and skin cancer?

photons of wavelengths that are shorter than those of visible light have enough energy to damage molecules suck as proteins and nucleic acids

What is the function of water in photosynthesis?

replace electrons lost by photosystem II

In all three types of plants, the enzyme _______ brings CO2 into the Calvin cycle.

rubisco

What is the function of the electron transport system?

shuttle electrons during redox reactions to create ATP

What do plants do with excess glucose produce?

store it

The rate of photosynthesis depends of what 3 conditions?

sunlight, CO2, water

What eliminated the use of CFC's by all participating countries?

the Montréal Protocol of 1987

What links photosystem I with photosystem II?

the electrons passing between the two photosystems

If a scientist removes the pair of cholorophyll a molecules from the reaction-center complex, then what consequence would be likely to occur?

the transfer of energy from the light-harvesting complex to the reaction center complex would stop

What is the definition of photosynthesis in words?

the use of solar energy transformations to be stored to chemical energy; the making of glucose

A new bacterium is discovered in Lake Superior. Scientists are able to determine that these bacteria produce oxygen gas. What is likely to be true about these organisms?

they are photoautotrophs that undergo photosyntheses

The light reactions take place in the _________ and the Calvin cycle takes place in the _________.

thylakoids; stroma

What does a plant use the products of the Calvin Cycle for?

to make starch, cellulose, and molecules used in protein synthesis

Both mitochondria and chloroplasts _____.

use an H+ gradient to produce ATP

You are a graduate student studying the effects of global warming on photosynthesis. What are some different methods that you could think of to measure the rate of photsynthesis in a plant?

use small growth chambers to carefully measure changes to make sure you have control!

What is the function of PGAL (G3P)?

used to make glucose

The hydrogen in glucose comes from what source?

water

The oxygen plants give off comes from what source?

water

What molecule is broken down in the Light reactions?

water

What is the overall effect of increased CO2 levels on poison ivy growth?

weeds that are becoming poisonous are beginning to harm people more easily than ever before... putting people and animals in harms way

Why is the greenhouse effect not necessarily bad?

without the greenhouse effect, Earths average air temperature would be -18ºC which is too cold for many types of life