Photosynthesis 8.1-8.3

Explain how ADP and ATP are each like a battery. Which one is "partially charged" and which one is "fully charged?" Why?

ADP and ATP are like batteries because they store energy in the chemical bonds they contain. ADP has only two phosphate groups (and fewer bonds), so it's like a par- tially charged battery. ATP has three phos- phate groups, so it is like a fully charged battery and has more bonds available for energy storage.

What happens during light independent reactions

ATP & NADPH from light dependent reactions are used to produce high energy sugars

How does the structure of ATP make it an ideal source of energy for the cell?

ATP can easily release and store energy by breaking and re-forming the bonds between its phosphate groups.

Why is ATP useful to cells?

ATP can easily release and store energy by breaking and re-forming the bonds between its phosphate groups.

What is ATP and what is its role in the cell?

ATP is an abbreviation for the compound adenosine triphosphate. Cells use ATP to store and release energy.

What are electron carrier molecules?

An electron carrier is a compound that can accept a pair of high-energy electrons and transfer them, along with most of their energy, to another molecule.

How would photosynthesis be affected if there were a shortage of NADP+ in the cells of plants?

Because photosynthesis depends on the conversion of NADP+ to NADPH to carry electrons to chemical reactions in other parts of the cell, the process could not occur efficiently if there were a shortage of NADP+ in the cells of plants.

Why are decomposers, such as mushrooms, considered heterotrophs and not autotrophs?

Decomposers consume the remains of living things for energy and cannot make their own food.

How do heterotrophs obtain energy? How is this different from how autotrophs obtain energy?

Heterotrophs obtain energy by feeding on other living things. Autotrophs, by contrast, make their own food.

What happens during the process of photosynthesis?

In the process of photosynthesis, plants convert the energy of sunlight into chemical energy stored in the bonds of carbohydrates.

How well would a plant grow under pure yellow light?

It would not grow well because chloro- phyll does not absorb much light in the yellow region of the visible spectrum.

What happens during the light dependent reactions

Light dependent reactions use energy from sunlight to produce oxygen and convert ADP & NADP+ into energy carriers ATP & NADPH

How is light energy converted into chemical energy during photosynthesis?

Light energy absorbed by pigments pro- duces high-energy electrons that are used to convert NADP+ and ADP to the compounds NADPH and ATP, trapping the energy in chemical form.

Put the events of the light- dependent reactions in the order in which they occur and describe how each step is dependent on the step that comes before it.

Light energy is absorbed by electrons in the pigments and water molecules are split into H+ ions, oxygen, and electrons. Highenergy electrons move down the electron transport chain, where energy from the electrons is used to pump H+ ions into the thylakoid space. NADP+ molecules pick up the high-energy electrons along with H+ ions to become NADPH. H+ ions in the thylakoid space pass through ATP synthase in the thylakoid membrane, causing the ATP synthase base to rotate and produce ATP.

What is the function of NADPH?

NADPH transferes high-energy electrons between molecules.

Describe the overall process of photosynthesis, including the reactants and products.

Photosynthesis uses the energy of sunlight to convert water and carbon dioxide (reactants) into high-energy sugars and oxygen (products).

What are the reactants and products of photosynthesis?

Photosynthesis uses the energy of sunlight to convert water and carbon dioxide (reactants) into high-energy sugars and oxygen (products).

What role do pigments play in the process of photosynthesis?

Photosynthetic organisms capture energy from sunlight with pigments.

List at least three differences between the light-dependent and light-independent reactions of photosynthesis.

The light-dependent reactions require light and water, occur in the thylakoids, and produce ATP and NADPH. The light-independent reactions require carbon dioxide, occur in the stroma, and produce high-energy sugars.

Summarize what happens during the light-dependent reactions of photosynthesis.

The light-dependent reactions use energy from sunlight to produce oxygen and con- vert ADP and NADP+ into the energy carri- ers ATP and NADPH.

What is the ultimate source of energy for plants?

The sun

Why are pigments such as chlorophyll needed for photosynthesis?

They capture energy from sunlight.

What is the Calvin cycle?

light-independent reactions in which ATP and NADPH from the light-dependent reactions are used to produce high-energy sugars. Melvin Calvin discovered it.

What are the three primary factors that affect the rate of photosynthesis?

temperature, light intensity, availability of water