apbio u3

What role do enzymes play in biological reactions?

Enzymes facilitate the connection between substrates, allowing reactions to occur that wouldn't happen otherwise.

What happens to enzymes at high temperatures?

High temperatures can lead to denaturation, causing enzymes to lose their shape and decrease activity.

What is denaturation in the context of enzymes?

Denaturation is the change in shape of an enzyme to the point where its active site no longer fits the substrate.

What are the two types of enzyme inhibition?

Competitive inhibition, which blocks substrates from binding to the active site, and noncompetitive inhibition, which changes the active site shape.

What is the significance of the Calvin cycle in photosynthesis?

The Calvin cycle produces carbohydrates from CO2 using ATP and NADPH generated in the light reactions.

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

Inputs: light and water; Outputs: oxygen, ATP, and NADPH.

What is the overall equation for photosynthesis?

6CO2 + 6H2O + light energy → C6H12O6 + 6O2.

What is photorespiration and why is it a problem for C3 plants?

Photorespiration occurs when stomata close in hot conditions, leading to O2 competing with CO2 for Rubisco, resulting in less sugar production.

How do C4 and CAM plants adapt to reduce photorespiration?

C4 plants use spatial separation to fix CO2, while CAM plants open stomata at night to store CO2 for use during the day.

What is glycolysis and what are its inputs and outputs?

Glycolysis is the breakdown of glucose; Inputs: glucose, 2 ATP, 2 NAD+; Outputs: 2 pyruvate, net gain of 2 ATP, and 2 NADH.

What is fermentation and when does it occur?

Fermentation occurs without oxygen when pyruvate cannot enter the mitochondria, allowing ATP production through anaerobic processes.

What are the two types of fermentation?

Alcohol fermentation, where pyruvate is converted into ethanol, and lactic acid fermentation, where pyruvate is reduced to lactate.

What is the main purpose of cellular respiration?

Cellular respiration converts food into energy (ATP) for heterotrophs, using a series of redox reactions.

What are the four stages of cellular respiration?

Glycolysis, pyruvate oxidation, citric acid cycle (Krebs cycle), and oxidative phosphorylation.

What is the role of chlorophyll in photosynthesis?

Chlorophyll absorbs light energy, but cannot absorb green light, which is why plants appear green.

What is the significance of stomata in plants?

Stomata are pores that allow CO2 to enter and O2 to exit, playing a crucial role in photosynthesis.

What is the difference between autotrophs and heterotrophs?

Autotrophs can generate their own food (like plants), while heterotrophs must consume other organisms for nourishment.

What is a redox reaction in the context of photosynthesis?

A redox reaction involves the transfer of electrons, where water is oxidized (loses electrons) and carbon dioxide is reduced (gains electrons).

What is the maximum internal temperature increase before death in humans?

The internal temperature can only increase by 8 degrees before it leads to death.

What happens to ATP and NADPH after the light reactions?

ATP and NADPH are used in the Calvin cycle to produce carbohydrates from CO2.

What is the relationship between enzyme activity and substrate concentration?

Increasing substrate concentration increases enzyme activity until a maximum rate is reached, after which it plateaus.

How does high energy exposure affect photosynthesis?

Exposure to high energy can be detrimental, similar to 'lovebombing', as it can overwhelm the system.

What is the function of NAD+ in fermentation?

NAD+ is regenerated during fermentation, allowing glycolysis to continue and produce ATP.

What is the role of Acetyl CoA in cellular respiration?

Acetyl CoA is produced during pyruvate oxidation and enters the citric acid cycle for further energy extraction.