Chapter 8: Photosynthesis

Adenosine diphosphate

Adenosine diphosphate

________ (ADP) is similar to ATP but has only two phosphate groups instead of three

Photosynthesis

________ takes place inside organelles called chloroplasts.

light independent reactions

During the ________, ATP and NADPH are used to make high- energy sugars.

Stroma

The liquid-filled space around the thylakoids in chloroplasts

Photosystem II

________: Light shining on pigments energizes electrons that come from water.

Plants

________ gather the suns energy with light- absorbing molecules called pigments.

Temperature

________ is one factor that can affect the rate of photosynthesis, as photosynthesis enzymes work best between 0°C and 35°C.

Plant cells

________ use molecules to carry high- energy electrons from chlorophyll to other places.

NADPH

The ________ carries the electrons to other parts of the cell, where the electrons and their energy can be used to help build useful molecules, such as sugars.

ATP

________ also helps proteins in muscles to slide closer together, a motion that makes muscles flex.

carbon dioxide

In the dark, ________ is used to make acids.

Energy

The ability to do work

phosphate groups

The ________ are the key to why ATP can store and release energy.

Water levels

________ also affect the rate of photosynthesis.

extra energy

When a cell has ________, it can store small amounts of it by adding a phosphate group to ADP molecules, which turns ADP into ATP.

Electron Transport

________: High- energy electrons move down the chain, which pumps H+ ions to the inside of the thylakoid.

Calvin cycle

The ________ is named after the American scientist Melvin Calvin.

light dependent reactions

The ________ take place in the thylakoids of chloroplasts, where they hold groups of chlorophyll and proteins known as photosystems that take in sunlight and use it to add energy to electrons; these electrons are passed to a set of carriers in the thylakoid membrane.

C4 plants

________ have a special chemical pathway that gets carbon into the Calvin cycle even when there is not much carbon dioxide available.

high energy

The process by which autotrophs use the energy of sunlight to produce ________ carbohydrates- sugars and starches- that can be used as food is known as photosynthesis.

ATP

________ comes from the chemical compounds that we call food, though different living things get their food from different sources.

phosphate groups

A cell can add or subtract these ________ whenever it needs to store or use energy.

Electron Transport

________: The reenergized electrons are transferred to NADP+, to make NADPH.

ATP

One of the principal chemical compounds that living things use to store and release energy

ATP

Cells can give off the energy stored in ________ by breaking the chemical bonds between the second and third phosphate groups.

ATP

________ powers active transport by providing the energy needed to move material into and out of many cells.

There are two stages of photosynthesis

light-dependent reactions and light-independent reactions

Photosystem II

Light shining on pigments energizes electrons that come from water

Electron Transport

High-energy electrons move down the chain, which pumps H+ ions to the inside of the thylakoid

Photosystem I

Electrons are reenergized with more light

Electron Transport

The reenergized electrons are transferred to NADP+, to make NADPH

ATP Formation

Excess H+ ions spill out through ATP synthase; the protein rotates as each ion passes through, which changes ADP to ATP

Step 1

Carbon dioxide combines with molecules from the cycle that have five carbon atoms; molecules with three carbon atoms result

Step 2

Energy from ATP and NADPH energizes the 3-carbon-atom molecules

Step 3

Some of these molecules leave the cycle to make sugars and other compounds

Step 4

Energy from ATP changes the rest of the 3-carbon-atom molecules back into 5-carbon-atom molecules

Step 5

The 5-carbon-atom molecules can go through the cycle again

Heterotroph

A living thing that gets food by consuming, or eating, other living things

Autotroph

A living thing that can capture energy from sunlight or chemicals to make its own food

Photosynthesis

The process by which plants and other autotrophs use light energy to convert water and carbon dioxide into oxygen and high-energy carbohydrates such as sugars and starches

Thylakoid

A baglike photosynthetic membrane found in chloroplasts

NADP+

One of the molecules that accepts high-energy electrons from chlorophyll and carries them to other molecules during photosynthesis

Light-dependent reaction

A reaction of photosynthesis that uses ATP, NADPH, and carbon dioxide to make high-energy sugars

Light-independent reaction

A reaction of photosynthesis that uses light energy to make ATP and NADPH

Photosystem

The light-collecting units of the chloroplast

Electron transport chain

A series of proteins in which high-energy electrons are used to change ADP to ATP

Chemical energy

The energy stored in chemical bonds

Pigments

Plants gather the sun’s energy with light-absorbing molecules called _______

Chlorophyll

The most important pigment in plants is _______, which absorbs blue-violet light and red light best, though it does not absorb green light very well

Chloroplasts

Photosynthesis takes place inside organelles called _______

Grana

Stacks of thylakoids

Calvin cycle

Another name for light-independent reactions