Chapter Eight Sapling

During one of the three phases of the Calvin cycle, 3 molecules of ATP are used to catalyze the rearrangement of five three-carbon sugars, known as G3P, into three five-carbon sugars, known as RuBP. One other molecule of G3P is exported to the cytoplasm to form glucose. In which phase of the Calvin cycle does this occur?

regernation

Plants synthesize their own food in the form of sugars without the direct input of carbon dioxide. Which of the following statements describe photosynthesis?

-cannot convert sunlight energy to sugars without the direct input of carbon dioxide -produces sugars for the plant using the energy from sunlight -is a cellular process that occurs in the chloroplasts of plant cells

Choose all the events that occur during the light-dependent reactions of photosynthesis

-electrons on special chlorophyll molecules gain energy from light -H+ ions are used to help produce the energy carriers, ATP and NADPH -excited electrons help move H+ ions to create a concentration gradient

Which statements describe characteristics of stomata in plants?

-permit carbon dioxide to enter and oxygen to escape from a plant -are openings into a plant that are surrounded by guard cells

Arrange the events of the light-dependent reactions of photosynthesis in the order they occur

1. Photons of light excite electrons on specific chlorophyll molecules 2. Chlorophyll molecules release electrons that travel down an electron transport chain 3. Hydrogen ions are pumped into the interior of the thylakoid 4. H+ ions flow out of the thylakoid through an enzyme channel 5. ATP and NADPH are produced

Classify each description as applying to either autotrophs or heterotrophs.

Autotrophs: -producers -many use photosynthesis to produce organic compounds -use inorganic materials to produce energy -synthesize their own food Heterotrophs: - consumers -unable to produce organic compounds from inorganic materials -obtain their food by consuming other organisms -rely on other organisms for energy

Which colors correspond to the wavelengths of light that are strongly absorbed by each pigment?

Carotenoids: -Violet/blue Chlorophyll B: -Violet/blue -Orange/red Chlorophyll A: -Violet/blue -Orange/red

Consider what happens to energy in photosynthesis . How does this differ from what happens to energy in cellular respiration?

In photosynthesis, energy is captured from light, whereas in cellular respiration, energy is transferred from storage molecules to ATP

Which statements describe the light-dependent reactions of photosynthesis, which describe the Calvin cycle (light-independent reactions of photosynthesis), and which describe both?

Light-Dependent Reactions: -use H2O -capture light energy using chlorophyll -synthesize ATP and NADPH -generate oxygen gas Calvin Cycle: -use carbon dioxide -produce sugars -need ribulose bisphosphate Both the Light-Dependent Reactions and the Calvin cycle: -take place in the chloroplasts of plants

t-independent reactions of photosynthesis, also known as the Calvin cycle, use and produce a variety of molecules. Sort the molecules below into three categories: molecules brought in and used in the Calvin cycle, molecules produced during the Calvin cycle that leave the cycle, and molecules used and regenerated within the Calvin cycle.

Molecules brought in and used in the Calvin Cycle: -carbon dioxide -NADPH Molecules produced during the Calvin Cycle that leave the cycle: -NADP+ -A few of the G3P Molecules used and regenerated within the Calvin Cycle: -Most of the G3P -Ribulose Biphosphate (RuBP)

The light-independent reactions of photosynthesis, also called the Calvin cycle, use and produce a variety of molecules. Sort the molecules below into three categories, molecules brought in and used in the Calvin cycle, molecules produced during the Calvin cycle that leave the cycle, and molecules made in the cytoplasm from the products of the Calvin cycle.

Molecules brought in and used in the Calvin cycle: -CO2 from outside the cell -Energy-carrier molecules formed in the light-dependent reactions Molecules produced in the Calvin cycle that leave the cycle: -3 carbon molecules that store energy -energy-carrier molecules that have lost some energy Molecules made in the cytoplasm from the products of the Calvin cycle: glucose and other organic molecules

What is needed for the light-dependent reactions and what is produced by light dependent reactions?

Needed: -light energy -water -chlorophyll Produced: -Energy-rich ATP and NADPH

Classify each of the characteristics below as being exclusive to photosynthesis, exclusive to cellular respiration, or shared by both photosynthesis and cellular respiration.

Photosynthesis: -occurs in the chloroplasts of plant cells -requires sunlight to proceed -synthesizes carbohydrates to store energy Cellular Respiration: -releases CO2 -occurs in both plant and animal cells Both Photosynthesis and Cellular Respiration: -generates ATP -generates energy using a proton (H+) gradient -occurs in plants -requires an electron transport chain

Why do most plant leaves appear green?

Pigments in plants cells absorb blue and red light, but much of the green light is reflected

What are the photosynthesis reactants, energy sources, and products

Reactants: - 6 CO2 -6 H20 Energy Source: -light Products: -C6H12O6 -6 O2

Which of the following scenarios is a direct effect on the absence of carbon dioxide during photosynthesis?

The carbon fixation stage of the Calvin cycle would be unable to synthesize the sugar 3-PGA

Sort the statements into those that describe similarities between the two photosystems in the light-dependent reactions of photosynthesis and those that are unique to each of the photosystems.

Unique to Photosystem II: -the bonds of water molecules are broken, producing H+, O2, and replacement electrons for chlorophyll molecules -energy from electrons excited in this photosystem is used to help pump H+ ions into the thylakoid for ATP production Unique to Photosystem I: -the energized electrons are used to form NADPH after leaving this photosystem -electrons from the electron transport chain are used to replace electrons lost from chlorophyll molecules Similarities Between The Two Systems: -Light energy is used to excite an electron on specialized chlorophyll molecules

which statement describes the function of photosynthetic pigments in leaves?

they capture light energy and remove electrons from a donor