Unit 4:(Ch 8) Photosynthesis

The Calvin cycle uses carbon dioxide molecules as well as ATP and NADPH from the light-dependent reactions to make sugars.

What does the Calvin Cycle use to produce high-energy sugar?

Ribose

What is a 5-carbon sugar molecule that is part of an ATP molecule?

NADPH

What is the product of photosystem I?

The compound with which CO2, from the air combines is a product of the cycle, which enables the series of reactions to occur over and over.

What makes the Calvin cycle a cycle?

Electron transport chains

What moves high-energy electron between photosystems?

ATP synthase

What spins to provide the energy for adding a phosphate group to ADP?

ATP and NADPH are two types of energy carriers.

What types of carriers are ATP and NADPH?

spongy mesophyll

allow for the interchange of gases (CO2) that are needed for photosynthesis, layer of loose tissue found beneath the palisade mesophyll in a leaf. Spongy mesophyll also captures light and makes food. They are the layer of cells under the upper epidermis of a leaf.

chemical energy bond

chemical energy stored in bonds

grana

the stacks of thylakoids embedded in the stoma of a chloroplast.

palisade mesophyll

these cells are tall and closely packed to absorb maximum light. They contain many chloroplasts. Most photosynthesis takes place in the palisade cells.

guard cells

two special cells on either side of the stomata that open and close so that the plant will not lose too much water by evaporation during the heat of the day

oxygen, ATP and NADPH

What are the products of the light-dependent reactions?

carbon dioxide and water

What are the reactants of the photosynthesis reactions?

Chlorophyll

principal pigment of plants and other photosynthetic organisms

Thylakoids

A saclike photosynthetic membrane contained in chloroplast

ADP + Pi

ADP is combined with a phosphate to form ATP in the reaction ADP+Pi+free energy→ATP+H2O.

Byproduct

Anything produced in the course of making another thing; oxygen is a byproduct of the light-dependent reactions of photosynthesis

Occurs in plants that have a specialized chemical pathway that allows them to capture even very low levels of carbon dioxide and pass it to the Calvin cycle. corn, sugar cane and sorghum

C4 Photosynthesis

CAM plants only allow air into their leaves at night which minimize water loses. Carbon dioxide is trapped in the leaves and it is released during the day, enabling carbohydrate production. Pineapple trees, many desert cacti and "ice plants"

CAM

electron transport chain

Energy from the electrons is used by the proteins in the chain to pump H+ ions from the stroma into the thylakoid space. At the end of the electron transport chain, the electrons themselves pass to photosystem I.

Food molecules such as sugars and starches provide energy for making ATP.

Energy is needed to add a third phosphate group to ADP to make ATP. What is a cell's source of this energy?

The hot potato represents two high-energy electrons.

In the visual analogy of carrying electrons, what represents the high-energy electrons?

ADP (Adenosine diphosphate)

In the visual analogy, what chemical is represented by the low battery?

The energy of sunlight is stored in the chemical bonds of carbohydrates.

In what form is the energy of sunlight is stored?

light-independent reactions.

In which reactions is Carbon dioxide used to make sugars?

photosystem II

It absorbs light and increases the electrons' energy level. The electrons are passed to the electron transport chain. Enzymes in the thylakoid break up water molecules into 2 electrons, 2 H+ ions and 1 oxygen atom. The 2 electrons replace the high-energy electrons that have been lost to the electron transport chain.

Pigments

Light-absorbing molecule used by plants to gather the sun's energy

Autotrophs

Organisms that makes their own food.

Heterotrophs

Organisms that obtain food by consuming other living things.

Photosynthesis is the way in which new organic macromolecules are added to the living portion of the biosphere. All living things that are not photosynthetic rely on photosynthesis as a source of the organic building blocks needed for groth. Photosynthesis also releases oxygen into the atmosphere. Without this oxygen we would not be able to breath.

Photosynthesis plays an important role in supplying energy to living things. Considering what the products of photosynthesis are, what is another way in which photosynthesis is vital to life?

primary production

Primary production is when plants make their own food and use that food to live and grow.

photosystem I

The electrons do not contain as much energy as they used to. Pigments use energy from light to reenergize the electrons. At the end of a short second electron transport chain, NADP+ molecules in the stroma pick up the high-energy electrons, along with H+ ions, at the outer surface of the thylakoid membrane, to become NADPH.

Stroma

The fluid portion of a chloroplast outside of the thylakoids

Grass, algae and some bacteria

What are the examples of autotrophs?

Cheetahs, hares and mushrooms.

What are the examples of heterotrophs?

The electrons take on a great deal of energy, which causes them to move to a higher energy level.

When sunlight excites electrons in chlorophyll, how do the electrons change?

The high energy electrons come from chlorophyll molecules that have absorbed sunlight.

Where do the high-energy electrons carried by NADPH come from?

The light-dependent reactions take place in the thylakoid membranes inside of chloroplasts

Where do the light-dependent reactions take place?

stroma

Where do the light-independent reactions occur?

The reactions of the Calvin cycle use ATP and NADPH as energy sources. They do not directly require light. However, Calvin Cycles does not operate at night because it needs ATP and NADPH from the light-dependent reactions.

Why are the reactions of the Calvin Cycle called light-independent reactions?

Accessory pigments contribute energy to drive photosynthesis

Why is the absorption spectrum of chlorophyll a not identical to the action spectrum of photosynthesis?

No. One of the materials that plants use in photosynthesis is carbon dioxide. None of this gas would be present in an atmosphere of pure oxygen. Therefore, photosynthesis could not occur.

Would a plant placed in an atmosphere of pure oxygen be able to conduct photosynthesis?

NADPH

a carrier molecule that transfers high-energy electrons from chlorophyll to other molecules. NADP+ accepts and holds 2 high-energy electrons along with a hydrogen ion (H+).

Adenosine triphosphate (ATP)

a chemical compound cells use to store and release energy

electromagnetic spectrum

a continuum of all electromagnetic waves arranged according to frequency and wavelength

photosystems

cluster of chlorophyll and proteins found in thylakoids

ATP synthase

cluster of proteins that span the cell membrane and allow hydrogen ions (H+) to pass through it

vascular bundle

clusters of xylem and phloem tissue in stems

Adenosine diphosphate (ADP)

compound that looks like ATP, except that has two phosphate groups instead of three.

lower epidermis

contains stomata cells that help prevent water loss and regulate the exchange of gases such as oxygen and carbon dioxide, enabling plants to survive. Other cells in the lower epidermis include a waxy cuticle to protect underlying layers.

xylem

dead hollow cells that carry water to the leaf

Calvin cycle

light-independent reactions of photosynthesis in which energy from ATP and NADPH is used to build high-energy compounds such as sugar

phloem

living cells that carry food (glucose) away from the leaf to other parts of the plant

transpiration (evapotranspiration)

loss of water from a plant through its leaves. It is caused by the evaporation and diffusion of water from a plant's surface. It mostly happens in the leaves.

chloroplast

organelle found in cells of plants and some other organisms that capture the energy from sunlight and coverts it into chemical energy

Photosynthesis

process used by plants and other autotrophs to use light energy to convert carbon dioxide and water into sugar and oxygen. 6 H2O + 6 CO2 + light energy -> C6H12O6 + 6 O2

Light-independent reactions

set of reactions in photosynthesis that do not require light; energy from ATP and NADPH is used to build high-energy compounds such as sugar; also called the Calvin cycle

light-dependent reactions

set of reactions in photosynthesis that use energy from light to produce ATP and NADPH

stoma (pl: stomata)

small opening in the epidermis of a plant that allows carbon dioxide, water, and oxygen to diffuse into and out of the leaf

radiant energy (photons)

the energy of electromagnetic and gravitational radiation

Chemiosmosis

the movement of ions across a selectively permeable membrane, down their electrochemical gradient.

Visible spectrum

the portion of the electromagnetic spectrum that is visible to the human eye. Electromagnetic radiation in this range of wavelengths is called visible light or simply light.

upper epidermis

upper epidermis provides protection for the plant. Below that is the palisade layer, which is the location of photosynthesis within the leaf. Below the palisade layer is the spongy layer, which contains cells that are more spread out, allowing for air pockets.

cuticle

waxy layer that prevents water loss in plants