Lab Exam 2 10-12

What are the major steps of cellular respiration, and where do they happen?

glycolysis - BREAKS glucose into smaller molecules and happens in the cytoplasm.

krebs cycle - BREAKS down molecules further and releases carbon dioxide and it happens in the mitochrondrial matrix.

electron transport chain - uses electrons and oxygen to make most of the ATP and it happens in the inner mitochrondrial membrane.

When is carbon released as carbon dioxide and what does oxygen do?

carbon dioxide - released when carbon-containing molecules are broken down, mainly during pyruvate oxidation and the krebs cycle.

oxygen - accepts electrons and oxygen to make most of the ATP and happens in the inner mitochondrial membrane.

What are the inputs and outputs of aerobic celullar respiration?

Inputs - glucose and oxygen.

Outputs - carbon dioxide, water, and ATP.

How can you tell if beans are carrying out cellular respiration?

Measure oxygen consumption and carbon dioxide production.

• Oxygen decreases: Beans are using oxygen.

• Carbon dioxide increases: Beans are releasing CO₂.

• Germinating beans usually respire more because they are actively growing.

What is fermentation, and what are its products in animal cells and yeast?

Fermentation allows glycolysis to continue making a small amount of ATP when oxygen is unavailable.

• Animal cells: Produce lactic acid (lactate).

• Yeast cells: Produce ethanol (alcohol) and CO₂.

• ATP: Glycolysis provides a net 2 ATP per glucose.

What is the difference between aerobic respiration and fermentation?

Aerobic respiration: Uses oxygen, produces much more ATP, and releases CO₂ and water.

Fermentation: Does not require oxygen, produces only 2 net ATP per glucose through glycolysis, and allows glycolysis to continue.

How do you use a spectrophotometer to collect quantitative data?

A spectrophotometer measures how much light a sample absorbs or transmits. First, blank the machine, place your sample in a cuvette, and measure the absorbance.

How do you interpret spectrophotometer data?

Compare the absorbance values to draw conclusions about your samples. Higher absorbance usually means a higher concentration of the substance being measured, if the experiment is set up correctly.

How is oxygen produced during the light reactions of photosynthesis?

Light energy splits water molecules, releasing oxygen (O₂).

What wavelengths of light work best for photosynthesis?

Blue-violet and red light are absorbed best by chlorophyll and usually work best for the light reactions.

Blue-violet light: Around 400–500 nm.

Red light: Around 600–700 nm.

Green light: Mostly reflected, which is why plants look green.

What roles do water and light play in the light reactions?

Light: Provides energy to power the reactions

Water: Supplies electrons and hydrogen ions, and releases oxygen as a byproduct.

What is the relationship between transmittance and absorbance?

Transmittance: How much light passes through a sample.

Absorbance: How much light the sample absorbs.

How do you determine which wavelength a pigment absorbs the most?

Look at the data table or graph and find the wavelength with the highest absorbance or lowest transmittance.

How can you determine the color of a pigment from the data?

The pigment usually appears the color of the light it reflects or transmits, not the color it absorbs most. The color you see is the color that is not absorbed.