Chapter 4 - Energy Flashcards
What do cells use ATP for? 4.1
Cells use ATP for functions such as building molecules and movie materials by active transport.
What is ATP? 4.1
- Adenosine Triphosphate
ATP is a molecule that transfers energy from the breakdown of food molecules to cell processes. - a wallet to carry money
- energy currency of the cell
How is energy carried by ATP released? 4.1
Energy is released when a phosphate group is removed from the molecule.
What is ADP? 4.1
ADP is a lower-energy molecule that can be converted into ATP by the addition of a phosphate group.
- Adenosine Diphosphate
- nearly empty wallet
What does the breakdown of a simple sugar glucose yield? 4.1
36 ATP molecules
What is chemosynthesis? 4.1
It is a process by which some organisms use chemical energy instead of light energy to make energy storing carbon based molecules.
What is photosynthesis? 4.2
Photosynthesis is the process that captures energy from sunlight to make sugars that store chemical energy.
How many calories per milligram do carbs and proteins yield? 4.1
4 calories per milligram
What is chlorophyll? 4.2
It is a molecule in chloroplasts that absorbs some of the energy in visible light.
What is a thylakoid? 4.2
A thylakoid is a coin-shaped membrane-enclosed compartment that contain light-absorbing molecules.
What is the formula for photosynthesis? 4.2
6CO2 + 6H2O = C6H12O6 + 6O2
Carbon dioxide + water —— light, enzymes—— a sugar + oxygen
What are the reactants and products of light dependent reactions? 4.2
Reactants : sunlight and water, ADP, NADP+
Products: oxygen and NADH and ATP
What are the products and reactants of light independent reactions? 4.2
Reactants: CO2, ATP, NADPH
Products: glucose and NADP+ , NADP
Where do light-dependent reactions take place? 4.2
- Within and across the thylakoid membranes
Where do light-independent reactions take place? 4.2
- In the stroma of the chloroplasts
What are the steps of the light-dependent reactions? 4.2
- ) Energy from the sunlight is transferred, and H2O molecules are broken down and O2 molecules are released.
- ) Energy is transferred to molecules that carry energy - ATP.
What happens in a light-independent reaction? 4.2
- ) CO2 is added to build larger molecules and light-dependent energy is used.
- ) A simple sugar, usually glucose, is formed, and it stores some energy captured from the sunlight.
What are 6-carbon simple sugars often used for? 4.2
- To build starches and cellulose
Where does photosynthesis occur? 4.2
Chloroplast
Where does cellular respiration occur?
Mitochondria
What are photosystems? 4.3
They are two groups of molecules in the thylakoid membrane that capture and transfer energy.
What is the electron transport chain? 4.3
- a series of proteins in the membrane of the thylakoid
- the passing if electrons along a series of molecules releasing energy as they go
What does cellular respiration do? 4.4
Cellular respiration releases chemical energy from sugars and other carbon-based molecules to make ATP when oxygen is present.
What’s the difference between aerobic and anaerobic? 4.4
Aerobic - needs oxygen to take place
Anaerobic - does not need oxygen to take place
What happens in photosystem 2? 4.3
- Energy is absorbed from sunlight and transferred to electrons (e-). High energy electrons leave the chlorophyll and enter an electron transport chain.
- Enzymes break down water molecules. Oxygen, hydrogen ions (H+) and electrons are separated from each other. The oxygen is released as waste. The electrons from water replace those electrons that left chlorophyll when energy from sunlight was absorbed.
- ) Electrons move from protein to protein in the electron transport chain, and their energy is used to pump H+ ions from outside to inside the thylakoid against a concentration gradient. The H+ ions build up inside the the thylakoid and the electrons move to photosystem 1.
What happens in photosystem 1? 4.3
4.) Energy is absorbed from the sunlight again, and the electrons are energized and leave the molecules.
5.) The energized electrons are added to NADP+ which functions like ADP and NADPH is made.
ATP Production -
6.) Hydrogen ions flow through a protein channel in the thylakoid membrane. The H+ ions is higher inside the thylakoid than outside. The chemiosmotic gradient is the difference in hydrogen ions which store potential energy.
7.) As ions flow through the channel, ATP synthase makes ATP by adding phosphate groups to ADP.
What is ATP synthase? 4.3
It is an enzyme that allows hydrogen ions to pass through a membrane in order to make ATP from ADP.
What is the process of the Calvin Cycle? 4.3
- ) Carbon dioxide molecules are added to 5-carbon molecules already in the Calvin cycle. 6-carbon molecules are formed.
- ) Energy - ATP and NADPH - from the light - dependent reactions is used by enzymes to split the 6-carbon molecules. 3-carbon molecules are formed and rearranged.
- ) Most of the 3-carbon molecules stay in the Calvin cycle, but one high-energy three-carbon molecule leaves the cycle. After 2 3-carbon have left the cycle, they are bounded together to build a 6-carbon molecule such as glucose.
- ) Energy from ATP molecules is used to change the 3-carbon molecules back into 5-carbon molecules. These stay in the Calvin Cycle and are added to new CO2 molecules that enter the cycle.
What does glycolysis do? 4.4
It splits glucose into 2 3-carbon molecules and makes 3 molecules of ATP.
- anaerobic
What is lactic acid and what does it do? 4.6
C3H6O3
It causes your muscles to burn during exercise.
What is fermentation and what does it do? 4.6
Fermentation is an anaerobic process that allows glycolysis to continue.
It does not make ATP.
It removes electrons from NADH molecules and recycles NAD+ molecules for glycolysis.
What molecule does fermentation provide to glycolysis? 4.5
NAD+
Where do the Krebs Cycle occur? 4.4
Matrix of the mitochondria
About how many ATP molecules does fat produce? 4.1
146 ATP molecules
How many calories per milligram do lipids/fats yield? 4.1
9 calories per milligram
What is the source of energy for organisms that use chemosynthesis? 4.1
Chemicals such as sulfides
What are the two types of chlorophyll and what do they do? 4.2
The two types of chlorophyll, a and b, absorb mostly red and blue light and reflect green light.
What happens from glycolysis? 4.4
2 molecules of ATP are used in order to complete glycolysis and only 4 ATP are made in the process => Net profit = 2 ATP
What is the second part of the cellular respiration and what does it do? 4.4
Electron Transport Chain
- )_ Energy is transferred to a chain of proteins in the inner membrane of the mitochondrion.
- ) A large number of ATP molecules are made. Oxygen enters the process and is used to make water molecules. Water and heat are given off as waste products.
What is the first part of cellular respiration and what does it do? 4.4
Krebs Cycle
- ) The 2 3-carbon molecules from glycolysis further break down a series of chemical reactions into carbon dioxide (waste product).
- ) NADH molecules are made. 2 ATP is produced and energy is transferred.
How many ATP molecules are made from the breakdown of one glucose molecule? 4.4
2 from glycolysis
34 or 36 from cellular respiration
What is the formula for cellular respiration? 4.4
C6H12O6 + 602 —— 6CO2 + 6H20
a sugar + oxygen —— carbon dioxide + water
(the opposite of photosynthesis)
What happens specifically in the Krebs Cycle? 4.4
- ) A pyruvate molecule is split into two-carbon molecule and and a molecule of carbon dioxide, which is given off as a waste product. High-energy electrons are transferred from the two-carbon molecule to NAD+, forming a molecule of NADH. The NADH moves to the elctron transport chain.
- ) Coenzyme A bonds to the 2-carbon molecule made from the breakdown of pyruvate. This intermediate molecule goes to the Krebs Cycle.
- ) This 2-carbon part is added to the 4-carbon molecule to form a 6-carbon molecule called citric acid and coenzyme A goes back to step 2.
- ) The citric acid molecule is broken down by an enzyme and a 5-carbon molecule is formed. A molecule of NADH is made and moves out of the Krebs Cycle. A molecule of CO2 is given off as a waste prouduct.
- ) The 5-carbon molecule is broken down by an enzyme. A four-carbon molecule, a molecule of NADH, and a molecule of ATP are formed. The NADH leaves the Krebs Cycle. Carbon dioxide is given off as a waste product.
- ) Enzymes rearrange the four-carbon molecule. High energy electrons are released. Molecules NADH and FADH2, which is another electron carrier, are made. They leave the Krebs cycle and the 4-carbon molecule remains.
What are the products from the breakdown of one pyruvate molecule? 4.4
- 3 molecules of carbon dioxide
- 1 ATP molecule
- 4 NADH molecules in the electron transport chain
- 1 molecule of FADH2 to the electron transport chain
What happens in the electron transport chain for cellular respiration? 4.4
- ) Proteins inside the inner membrane of the mitochondrian take high-energy electrons from NADH and FADH2. The molecules of NADH and one molecule of FADH2 are used.
- ) High-energy electrons travel through the proteins in the electron transport chain. The proteins use energy from the electrons to pump hydrogen ions across the inner membrane to produce a chemiosmotic gradient, just as in photosynthesis. The hydrogen ions build up on the inside of the inner mitochondrial membrane.
- ) The flow of H+ ions is used to make ATP. Hydrogen ions diffuse through a protein channel in the inner membrane of the mitchondrion. The channel is part of the ATP synthase enzyme. ATP synthase adds phosphate groups to ADP to make ATP molecules. For each pair of electrons that passes through the electron transport chain, an average of 3 ATP molecules are made.
- ) Oxygen finally enters cellular respiration. The oxygen picks up electrons and hydrogen ions to form water. The water molecules are given off as a waste product.
What are the products of cellular respiration? 4.4
- Carbon dioxide from the Krebs cycle and from the breakdown of pyruvate before the Krebs cycle
- Water from the electron transport chain
- A net gai up to 38 ATP molecules for every glucose molecule - 2 from glycolysis, 2 from the Krebs cycle, and up to 34 from the ETC.
What happens in lactic acid fermentation? 4.6
- ) Pyruvate and NADH from glycolysis enter the fermentation process, and two NADH molecules provide energy pyruvate into lactic acid. As the NADH is used, it is converted back into NAD+.
- ) 2 molecules of NAD+ are recycled back to glycolysis. The recycling of NAD+ allows glycolysis to continue.
What happens in alcoholic fermentation? 4.6
- ) Pyruvate and NADH from glycolysis enter alcoholic fermentation. Two NADH molecules provide energy to break down pyruvate into an alcohol and carbon dioxide. As the NADH molecules are used, they are converted back into molecules of NAD+.
- ) The molecules of NAD+ are recycled back to glycolysis. The recycling of NAD+ allows glycolysis to continue.
What are the products from the breakdown of one molecule of pyruvate? 4.4
- ) 3 CO2 - waste
- ) 1 ATP
- ) 4 NADH molecules to the electron transport chain
- ) 1 FADH2 to the electron transport chain
Where does glycolysis take place? 4.4
Cell’s cytoplasm
