Cells and Energy

- Electron Transport:

- Electron Transport: The high energy electrons are passed to a series of electron carriers embedded in the thylakoid membrane. The electrons go down the chain to photosystem I. Energy generated is used to pump H+ ions across the thylakoid membrane and into the thylakoid space.

Light-Independent Reactions

-Carbon dioxide molecules enter the Calvin cycle from the atmosphere. -An enzyme in the stroma of the chloroplast combines these carbon dioxide molecules with 5-carbon compounds that are already present in the organelle, producing 3-carbon compounds that continue into the cycle. For every 6 carbon dioxide molecules that enter the cycle, a total of twelve 3-carbon compounds are produced. Other enzymes in the chloroplast convert these compounds into higher energy forms in the rest of the cycle. The energy for these conversions comes from ATP and high-energy electrons from NADPH. -Sugar production: At midcycle, two of the twelve 3-carbon molecules are removed from the cycle. These molecules becomes the building blocks that the plant cell uses to produce sugars, lipids, amino acids and other compounds. The remaining ten 3-carbon molecules are converted back into six 5-carbon molecules. These molecules combine with six new carbon dioxide molecules to being the next cycle.

-Photosystem II:

-Photosystem II: photosystems absorb light and generate high=energy electrons. Water molecules are split to replace those electrons releasing H+ ions and oxygen.

Steps in light-dependent reactions

-Photosystem II: photosystems absorb light and generate high=energy electrons. Water molecules are split to replace those electrons releasing H+ ions and oxygen. - Electron Transport: The high energy electrons are passed to a series of electron carriers embedded in the thylakoid membrane. The electrons go down the chain to photosystem I. Energy generated is used to pump H+ ions across the thylakoid membrane and into the thylakoid space. -Photosystem I: Electrons are reenergized in photosystem I. A second electron transport chain then transfers these electrons to NADP+, producing NADPH -Hydrogen ion movement and ATP formation- the thylakoid space fills up with positively charged H+ ions, the thylakoid membrane becomes positively charged relative to the outside of the membrane. H+ ions pass back across the thylakoid membrane through ATP synthase. AS the ions pass through, the ATP synthase molecule rotates and the energy produce is used to convert ADP to ATP.

Compare and contrast photosynthesis and cellular respiration

-The energy flow in photosynthesis and cellular respiration occur in the opposite directions -photosynthesis has oxygen as a byproduct and uses carbon dioxide, while cellular respiration uses oxygen. -Cellular respiration takes place in nearly all life, whereas photosynthesis only in plants

How do light-dependent reactions occur (in photosynthesis)?

1) Chlorophyll absorbs energy from sunlight 2) Energy transferred along thylakoid membrane. 3) H2O molecules are broken down 4) Oxygen molecules are produced

The Calorie used on food labels is equivalent to what?

1,000 calories

Four functions of photosynthesis

1. Plant produce food for themselves and other organisms 2. Animals use oxygen produced by photosynthesis in cellular respiration 3. It provides materials for plant growth and development (simple sugars bonded together to form carbohydrates like starch and cellulose) 4. Helps regulate Earth's environment (removes carbon dioxide from Earth's atmosphere)

The electron transport chain generates how many molecules of ATP per molecule of glucose?

36

Photosynthesis Equation- in symbols

6CO(subscript 2) + 6H(subscript 2) (light over arrow pointing right) C(subscript 6)H(subscript 12) + 6O(subscript 2)

A Calorie is also referred to as what?

A kilocalorie

ADP is like a what?

A rechargeable battery that is partially charged. It can be fully charged (and made into ATP) by adding a phosphate group.

Most cells have how much ATP?

A small amount

Difference between ATP and ADP

ATP has three phosphates ADP has two phosphates

What are the functions of ATP?

ATP is a chemical compound cells use to store and release energy.

How doe ATP release energy?

Cells release energy from ATP molecules by subtracting a phosphate group (breaking the bonds).

How does ATP store energy?

Cells store energy by adding a phosphate group to ADP molecules.

Light-independent reactions

Do not use light energy. They use carbon dioxide form the atmosphere, NADPH, and ATP to make energy-rich carbon compounds.

How light independent reactions work:

How light independent reactions work 1) CO2 added to cycle to build larger molecules 2) Energy from light-dependent reactions is used 3) Molecule of simple sugar are produced (usually glucose C6H12O6)

Hydrogen ion movement and ATP formation-

Hydrogen ion movement and ATP formation- the thylakoid space fills up with positively charged H+ ions, the thylakoid membrane becomes positively charged relative to the outside of the membrane. H+ ions pass back across the thylakoid membrane through ATP synthase. AS the ions pass through, the ATP synthase molecule rotates and the energy produce is used to convert ADP to ATP.

Light-dependent reactions and Light-independent reactions In

LD in: light, light-absorbing pigments, water LI in: carbon dioxide, NADPH, ATP

Where do the Light-dependent reactions and Light-independent reactions occur?

LD occurs in the chloroplast in the thylakoid membranes LI occurs in the stroma

Light-dependent reactions and Light-independent reactions Out

LD out: NADPH, ATP, oxygen LI out: energy rich carbon compounds

Where are most of the chloroplasts?

Most of the chloroplasts are in the leaf cells

Is ATP good for storing large amounts of energy?

No. A single molecule of glucose stores more than 90 times the energy required to add a phosphate group to ADP to produce ATP. Therefore, it's more efficient for a cell to only have a small amount of ATP on hand.

Where does the first stage (light-dependent) of photosynthesis occur?

Occurs within and across the membrane of thylakoids

Photosynthesis is a process that...

Photosynthesis is a process that captures energy from sunlight to make sugars that store chemical energy!

Photosystem I:

Photosystem I: Electrons are reenergized in photosystem I. A second electron transport chain then transfers these electrons to NADP+, producing NADPH

Light-dependent reactions

Require light, light-absorbing pigments, and water to form NADPH, ATP, and oxygen

Grana

Stacks of coin-shaped membrane enclosed compartments called thylakoids

Why are plants green?

The chlorophyll in plants does not absorb light well in the green region of the light spectrum, so the green is reflected and the plants look green.

Glycolysis

The first stage of cellular respiration means sugar-breaking The end result is 2 molecules of a 3-carbon molecule called pyruvic acid 2 ATP molecules are used at the start of glycolysis to get the process started. High-energy electrons are passed to the electron carrier NAD+, forming two molecules of NADH. 4 ATP are synthesized during glycolysis for a net gain of 2 ATP

Stroma

The fluid portion of the chloroplast that surrounds the grana (outside of the thylakoids).

Thylakoid

The individual compartments of the grana that contain chlorophyll. Thylakoids are saclike photosynthetic membranes. Thylakoids are interconnected and arranged in stacks known as grana. Pigments such as chlorophyll are located in the thylakoid membranes.

Photosystems

Thylakoids contain clusters of chlorophyll and proteins known as photosystems. The photosystems absorb light.

ATP is used for what? What are the specific functions

active transport, to contract muscles, to make proteins, responses to chemical signals, to produce light, and in many other ways.

ATP is made up of what?

adenine (2), ribose (a five-carbon sugar), and three phosphate groups

Photosynthesis Equation- in words

carbon dioxide plus water (light) yields sugars and oxygen

3 steps of cellular respiration

glycolysis, Krebs Cycle, electron transport chain

The Krebs Cycle produces which products?

high-energy electron carriers (NADH and FADHsubscript 2 2 ATO molecules (per glucose molecule) the 4-carbon molecule needed to start the cycle again

Compare and contrast photosynthesis and cellular respiration- energy capture vs release

photosynthesis energy capture cellular respiration energy release

Compare and contrast photosynthesis and cellular respiration-reactants

photosynthesis- carbon dioxide, water, and light cellular respiration-glucose and oxygen

Compare and contrast photosynthesis and cellular respiration- location

photosynthesis- chloroplasts cellular respiration- cytoplasm and mitochondria

Compare and contrast photosynthesis and cellular respiration products

photosynthesis-oxygen and glucose cellular respiration- carbon dioxide, water, and energy

A calorie is

the amount of energy needed to raise the temperature of 1 gram of water 1 degree Celsius. A calorie is a unit of energy.

What is the Calvin Cycle?

the light independent reaction used by plants the energy from ATP and NADPH are used to build stable, high-energy carbohydrate compounds that be stored for a light time.

The Krebs Cycle

the second stage of cellular respiration Must have oxygen It is a series of energy-extracting reactions -Pyruvic acid produced by glycolysis enters the mitochondria. In the matrix (innermost compartment of the mitochondrion), pyruvic acid molecules are broken down into carbon dioxide and acetyl-CoA molecules. -Acetyl-CoA combines with a 4-carbon compound, producing 6-carbon molecule (citric acid). Energy released by breaking and rearranging of carbon bonds is captured in ATP, NADH, an FADH (subscript 2).

Electron Transport Chain

the third step in cellular respiration The electron transport chain uses the high-energy electrons from glycolysis and the Krebs cycle to convert ADP into ATP. Oxygen is the final electron acceptor. The passing of electrons through the electron transport chain causes H+ ions to build up in the intermembrane space, making it positively charged relative to the matrix. The charge difference across the membrane forces H+_ ions through channels in enzymes (ATP synthases). The ATP synthases spin, a phosphate group is added to ADP, and ATP is generated.

Three parts to a chloroplast are

thylakoid, stroma, granum

What does the light-dependent stage of photosynthesis need?

water and sunlight