Unit 5 Lesson 3: Photosynthesis: Energy conversion

Question 1

What is photosynthesis

Answer 1

Photosynthesis is the process of taking light energy, water, and carbon dioxide to make sugars and oxygen.

Question 2

How is light energy from the sun stored

Answer 2

Light energy from the sun is stored as chemical energy in the bonds of the sugar molecules. This chemical energy can be used in the future.

Question 3

Where does photosynthesis take place

Answer 3

Photosynthesis takes place inside the chloroplasts of plants and other photosynthetic eukaryotes.

Question 4

What is the role of Chlorophyll

Answer 4

Chlorophyll and other pigments, molecules that absorb light energy from the sun, are inside the outer membrane of the thylakoids.

Question 5

What happens during light-depedent reactions

Answer 5

Light-dependent reactions of photosynthesis happen within chloroplasts. During the light-dependent stage, chlorophyll in the thylakoid membranes absorb light energy from the sun and use it to split water molecules into oxygen ions and hydrogen ions.

Question 6

What does light energy do to water

Answer 6

Light energy from the sun makes low energy electrons from water into very high energy electrons.

Question 7

Every pair of water molecule makes..

Answer 7

Every pair of water molecule makes two negatively charged oxygen ions, four positively charged hydrogen ions, and four very high-energy electrons.

Question 8

Every pair of water molecule makes two negatively charged oxygen ions, four positively charged hydrogen ions, and four very high-energy electrons. What does this result in

Answer 8

The oxygen ions bind together, becoming an oxygen molecule, and are released into the atmosphere.

Question 9

What binds to an electron carrier called NADP+ to become NAPH

Answer 9

One hydrogen ion and two of the high-energy electrons bind to an electron carrier molecule, called NADP+, to become NADPH.

Question 10

What is NADP+

Answer 10

nicotinamide adenine dinucleotide phosphate; an electron carrier molecule that accepts two high-energy electrons and one hydrogen ion to become NADPH

Question 11

What is NADPH

Answer 11

nicotinamide adenine dinucleotide phosphate hydrogen; a product of the light-dependent reactions of photosynthesis used to power some of the reactions in the light-independent stage of photosynthesis

Question 12

What does NADPH do

Answer 12

NADPH stores energy from the electrons by binding them to hydrogen ions, and moves them to many places, including the stroma.

Question 13

Where is NADPH used

Answer 13

NADPH is used in the light-independent reactions of photosynthesis.

Question 14

What is ADP

Answer 14

adenosine di-phosphate; a lower energy, intermediate molecule used to convert to ATP by adding a third phosphate group/ADP, adenosine diphosphate, is a lower energy molecule that is changed to ATP by adding a third phosphate group.

Question 15

What does chlorophyl, light energy, ADP ATP have to do with each other

Answer 15

Chlorophyll also uses light energy to attach a third phosphate group to ADP, making ATP.

Question 16

What is ATP role in cells

Answer 16

ATP, adenosine triphosphate, is a molecule that carries energy inside cells

Question 17

ATP is the product of waht

Answer 17

ATP is a product of the light-dependent reactions of photosynthesis.

Question 18

Where is ATP made

Answer 18

ATP is made across the thylakoid membrane.

Question 19

What causes the huge differtence between the inside and outside of thylakoid

Answer 19

As water molecules are split, hydrogen ions are moved inside the thylakoid. So many hydrogen ions cross the membrane that there is a large difference in charge between the inside and the outside of the thylakoid.

Question 19

Inside of thylakoid VS outside

Answer 19

The inside is positively charged and the outside is negatively charged.

Question 20

Why cant thylakoid reblance itself

Answer 20

Normally the charges would rebalance themselves, but hydrogen ions cannot pass back through the thylakoid membrane without help.

Question 20

To rebalance both sides, a large protein called ? allows the hydrogen ions to pass through the membrane.

Answer 20

ATP synthase

Question 20

What is ATP synthase

Answer 20

a protein that creates ATP from ADP during photosynthesis

Question 21

What does the roation of ADP allow the cell to do

Answer 21

The rotation allows adenosine di-phosphate (ADP) to bond with a third phosphate group, making adenosine tri-phosphate (ATP). The energy stored in this new bond is what makes ATP a higher-energy output. ATP stores this energy until it is needed by the cell. When a cell needs energy, a phosphate group splits off from ATP releasing energy stored in the bond. This leaves ADP and a free phosphate group ready to be rebonded. ATP is like a charged rechargeable battery and ADP is like a used rechargeable battery.

Question 21

Changes in the energy levels of compounds also take place during the..

Answer 21

light-independent phase of photosynthesis

Question 21

What happens when hydrogen ions pass thorugh ATP synthase

Answer 21

As the hydrogen ions pass through ATP synthase, the protein rotates

Question 22

What is carbon dioxide used for

Answer 22

Carbon dioxide, a lower energy input, is used to make sugars, high energy outputs.

Question 23

The ATP and NADPH that were made in the light-dependent stage are moved to

Answer 23

the stroma and are used in the light-independent stage, also called the Calvin cycle.

Question 24

How is ATP and NADPG used int eh body

Answer 24

ATP and NADPH have a lot of chemical energy, but the molecules are not stable enough for long-term storage. An organism would use up the energy in ATP and NADPH quickly, so the plant uses this energy to make sugar molecules, which are more stable and store more energy.

Question 28

What is co2 used for during the Calvin cyce

Answer 28

. During the Calvin cycle, carbon dioxide is used to make larger carbon molecules.

Question 29

What are ATP and eclectrons from NADPH used for in the calvin cyccle

Answer 29

ATP and electrons from NADPH that were created in the light-dependent reactions are now used to make new carbon molecules that have a much higher energy level.

Question 30

What are the Carbon moclesus made int he Calvin cycle used for

Answer 30

Two of these new, high-energy carbon molecules are used to make sugars, amino acids, and other compounds.

Question 31

What happenes tot he rest of the carbon molecules in the Calvin cycle

Answer 31

The rest of the carbon molecules use ATP to get changed back into larger, low-energy carbon molecules and go through the Calvin cycle again.

Question 32

What common role does CO2, ATP and NADPH have

Answer 32

In the end, the CO2
, ATP, and NADPH have been used to make a stable sugar, which stores all the energy in its chemical bonds.

Question 33

Which low-energy input is used to make NADPH?

Answer 33

H2O

Question 34

Give two examples of a low energy input and the higher-energy output it is used to make during photosynthesis.

Answer 34

• carbon dioxide (low) is used to make sugar (high)
• water (low) is used to make NADPH (high)
• ADP (low) is used to make ATP (high)

Question 35

Explain how the energy in carbon dioxide changes as it goes through the Calvin cycle and becomes a sugar molecule.

Answer 35

Carbon dioxide is a low energy molecule that is converted to a larger carbon-based molecule during the Calvin cycle. This larger molecule is energized by the electrons in NADPH and in ATP.

Two of these new, high-energy carbon molecules are used to make sugars, amino acids, and other compounds. The rest of the carbon molecules use ATP to get converted back into larger, low-energy carbon molecules.

Question 36

Why do plants make sugars from sunlight instead of just using ATP directly?

Answer 36

ATP is not very stable for long-term storage and is used quickly after it is made.

Question 37

The energy of photosynthetic inputs is often __________ the outputs.

Answer 37

lower than

Question 38

What is the output of lower energy H20

Answer 38

The output of lower-energy H2O is NADPH .

Question 39

What is the output of lovwer enerfgy CO2

Answer 39

The output of lower-energy CO2 is sugar.

Question 40

If water and carbon dioxide contain low energy, where did the higher energy in the sugars that photosynthesis produces come from?

Answer 40

The chlorophyll in the thylakoid cells captures the light energy from the sun.

Question 41

What is electricty

Answer 41

Electricity is the movement of electrons through wires.

Question 42

What happens to an iten using electricy

Answer 42

When an item is using electricity, electrons are flowing from an outlet (or battery) through the wire and back to the energy source. When the item is turned off, the electrons stop moving.

Question 43

What are solar panels made out of

Answer 43

Solar panels are made up of many small pieces, called photovoltaic cells, that are linked together.

Question 44

What is a phtotvoltaic cell mde out of

Answer 44

Each photovoltaic cell is made up of two thin pieces of a material such as silicon that conducts, or carries, electricity.

Question 45

Why are other element s added tosilicon

Answer 45

Silicon is not a great conductor, so engineers add other elements to increase its conductivity.

Question 46

Where and why is phosphrous used in the photovoltaic cell

Answer 46

Phosphorus is added to the top, making that side of the photovoltaic cell more negatively charged

Question 47

Where and why is Boron used in the photovoltaic cell

Answer 47

Boron is added to the bottom making that side of the photovoltaic cell more positively charged.

Question 48

What does the Siliconine + ptotovoltaic + boron create

Answer 48

This results in an electric field where the silicone layers meet.

Question 49

What happens when sunlight reaches photovoltaic cells

Answer 49

When sunlight reaches the cell, the light energy knocks electrons free from the atoms. The electrons want to move from the negative layer to the positive layer, but the electric field pushes the electrons out, like an electron transport chain.

Question 50

What happens during the electron transport chain

Answer 50

system by which high-energy electrons are moved to photosystem I and hydrogen ions are pumped into the inside of the thylakoid during photosynthesis

Question 51

What do metal plates on photovolatic cells do

Answer 51

Metal plates on the sides of the cells collect the electrons and move them to wires, where the electrons flow like any other type of electricity.

Question 52

Compare how a plant cell and a photovoltaic cell use the energy from the sun.

Answer 52

A photovoltaic cell is similar to a plant cell in that it uses the energy from sunlight to separate electrons from atoms, only it does this in the silicone junction. Both the plant cell and the photovoltaic cell have a charge gradient; the thylakoid is positive, and the top of the panel is positive. The electrons in the photovoltaic cell want to flow from the negative layer to the positive layer. Instead of ATP synthase, an electric field pushes the electrons out of the silicone junction. Metal plates on the sides of the cells collect the electrons and transfer them to wires, where the electrons become usable energy in the form of electricity.