ap bio unit 3 exam 2

All living systems require a continuous input of energy. Describe how energy enters a cell, an organism, and an ecosystem

• cell: ATP (made from sunlight by photosynthetic cells or macromolecules like glucose for autotrophs)

• organism: using electromagnetic energy from sunlight to make their own chemical energy (autotrophs/photosynthesizers) or consuming other organisms to get chemical energy from food (autotrophs)

• ecosystem: sunlight and geothermal energy (organisms make their own energy from sunlight which then powers the ecosystem)

What is the first law of thermodynamics?

• law of conservation of energy

• energy cannot be created or destroyed, but it can be changed from one form to another

What is the second law of thermodynamics?

• law of efficiency

• energy cannot be changed from one form to another without a loss of usable energy

• each energy conversion loses energy to the environment increasing the entropy in the universe

What occurs if there is a significant loss of organization or loss of energy flow?

a cell or organism will no longer be able to maintain structure and continue with vital functions, leading to death

• all living systems require a constant input of energy to fight against entropy and maintain order

What is a coupled reaction? How is ATP used in coupled reactions?

a coupled reaction occurs when a non-spontaneous/endergonic reaction is driven by a spontaneous/exergonic reaction to use energy in a more efficient way

• ATP would be released by an exergonic reaction then used in an endergonic reaction

What is the formula for photosynthesis?

6H2O + 6CO2 + sunlight energy —> C6H12O6 + 6O2

• H2O from soil

• CO2 from atmosphere via leaves

What is the purpose of photosynthesis?

convert energy from the sun to usable energy in the form of glucose (carbohydrate)

What organisms did photosynthesis first evolve in and how did this lead to the development of modern photosynthetic eukaryotes?

ancient prokaryotic bacteria originally performed photosynthesis through their cell membranes, but by the endosymbiotic theory, the chloroplast was consumed and established a mutualistic relationship with another cell, leading to the photosynthesis we see today

What is the connection between photosynthesis and the earth’s atmosphere?

photosynthesis releases oxygen into the atmosphere and takes in carbon dioxide from the atmosphere

What does a chloroplast look like? Identify the location of the light dependent and light independent reactions

What is the purpose of the light dependent and light independent reactions?

• light dependent: change energy from sunlight into usable energy (ATP and NADPH)

• light independent: use ATP and NADPH to make glucose to be used for energy

What structures contain chlorophyll, and which absorbs energy from the sun and uses it to energize electrons?

• chloroplasts, specifically photosystems I and II in the thylakoids, contain chlorophyll

• photosystems I and II use sunlight to energize electrons

What occurs when electrons pass through the electron transport chain?

they release energy as they fall back down to their original energy level. this energy is then used to pump hydrogen ions into the thylakoid

What is chemiosmosis and how does it relate to the production of ATP during the light dependent reactions?

the movement of ions (such as H+ or protons) from a region of high concentration to a region of low concentration across a selectively permeable membrane

• powers and provides the energy for the synthesis of ATP by ATP synthase

What is the electron donor for the light dependent reactions? Is this oxidized or reduced?

water, which is oxidized

What is the final electron acceptor for the light dependent reactions? Is this oxidized or reduced?

NADPH, which is reduced

What is photophosphorylation?

the process by which energy from sunlight drives the movement of electrons along an electron transport chain, leading to ATP synthesis

What is the overall purpose of respiration and fermentation?

break down energy from organic molecules, such as glucose, and convert it to ATP

Explain how the act of respiration/fermentation are characteristics of life

all living organisms must perform respiration/fermentation in order to live. the energy from these processes power essential cell processes and prevent breakdown/loss of order

How does the process of glycolysis provide evidence of the common ancestry of living organisms?

because it also occurs in prokaryotes, indicating it first evolved in prokaryotes, as well as occuring in fermentation

Compare and contrast the processes of cellular respiration and fermentation

• Fermentation produces NAD+ and CO2 (in alcohol fermentation) as well as alcohol or lactic acid

  • Does not produce ATP, but the glycolysis before it produces 2 net ATP

• Cellular respiration also includes glycolysis (producing 2 net ATP)

  • Also includes three other stages, producing more ATP as well as NADH, CO2 and FADH2

What does a mitochondria look like?

Where does each major process of cellular respiration take place?

• Glycolysis: outside of cell in cytoplasm

• Link/prep reaction: intermembrane space/mitochondrial matrix

• Krebs cycle: mitochondrial matrix

• Oxidative phosphorylation: inner mitochondrial membrane in the cristae (folds)

What is the role of glucose in cellular respiration?

Original source of chemical energy to eventually be turned into ATP

What is the role of pyruvate in cellular respiration?

Product of glycolysis; actually enters mitochondria and oxidized in the link/prep reaction

What is the role of NAD+/NADH in cellular respiration?

• NAD+ accepts an electron to form NADH

• NADH acts as an electron carrier that transports electrons to the ETC

What is the role of FAD+/FADH2 in cellular respiration?

• FAD+ accepts electrons to form FADH2

• FADH2 acts as an electron carrier that transports electrons to the ETC

What is the role of oxygen in cellular respiration?

Pulls electrons through electron transport chain to pump hydrogen ions into the intermembrane to allow for the formation of ATP by ATP synthase

What is the role of cytochrome c in cellular respiration?

Part of the ETC that passes the electrons to another protein within the chain. Thus it also helps form the chemiosmotic gradient necessary for the function of ATP synthase

What is the role of ATP Synthase in cellular respiration?

synthesize ATP using energy from chemiosmosis

What is the role of ADP/ATP in cellular respiration?

ADP is used to create ATP, which is then used to power cell processes

What are the inputs and outputs of glycolysis?

• Inputs: glucose, NAD+, and ADP and Pi

• Outputs: 2 pyruvate, NADH, and net 2 ATP

  • 4 gross ATP

What are the inputs and outputs of link/prep reaction?

• Inputs: pyruvate and NAD+

• Outputs: Coenzyme A, NADH, and CO2

What are the inputs and outputs of Krebs cycle?

• inputs: Coenzyme A, NAD+, FAD, ADP, and Pi

• Outputs: ATP, CO2, NADH, and FADH2

  • Most CO2

What are the inputs and outputs of oxidative phosphorylation?

• inputs: NADH, FADH2, oxygen, ADP and Pi

• outputs: 36 ATP, NAD+ and FAD, H2O

  • Produces most ATP

In which stage of cellular respiration does the ETC occur?

Oxidative phosphorylation

Which membrane is the ETC embedded in for cellular respiration?

Inner membrane

What serves as the electron donor for the ETC in cellular respiration? Is this oxidation or reduction?

NADH and FADH2 in oxidation

What serves as the final electron acceptor of the ETC? Is this oxidation or reduction, and what is formed as a byproduct?

Oxygen in reduction. Water is formed as a byproduct

Where are the hydrogen ions pumped into as electrons move down the ETC? Do you expect the pH of this space to be acidic, neutral, or basic?

• The intermembrane space

• pH of this space will be acidic

What is a chemiosmotic gradient and how is it harnessed to power the production of ATP in cellular respiration?

Chemiosomosis is the movement of ions (such as hydrogen ions or protons) from a region of low concentration across a selectively permeable membrane. This movement powers and provides the energy for the synthesis of ATP by ATP synthase

What are the inputs and outputs of the light dependent reactions of photosynthesis?

• Inputs: light, H2O, NADP+, ADP and Pi

• Outputs: O2 (to atmosphere), H+, NADPH, ATP

What are the inputs and outputs of the Calvin cycle?

• Inputs: ATP and NADPH (from LD reactions), CO2

• Outputs: glucose, ADP, NADPH+ and H+ (back to thylakoid/light dependent reactions)

  • ATP hydrolyzed