Mastering Biology 4

What is the correct general equation for cellular respiration?

C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + ATP energy

Which of the following best describes the flow of energy through an ecosystem?

sunlight → chemical energy → heat

Which part(s) of cellular respiration take(s) place in the mitochondria?

the Citric Acid cycle and the electron transport chain

Which stage of cellular respiration uses O2?

the electron transport chain

NADH and FADH 2 are important in cellular respiration because they deliver high-energy electrons to the electron transport system. Electron transport produces _____ ATP molecule(s) per NADH molecule and _____ ATP molecules(s) per FADH 2 molecule.

three ... two

Why do plants have two photosystems?

One photosystem stores energy in the form of ATP and the other photosystem stores energy in the form of NADPH.

What is the role of oxygen in cellular respiration?

Oxygen accepts high-energy electrons after they are stripped from glucose.

Which statement describes glycolysis?

This process splits glucose in half and produces 2 ATPs for each glucose.

Which statement describes the electron transport chain?

This process uses energy captured from electrons flowing to oxygen to produce most of the ATPs in cellular respiration.

Glycolysis is the multi-step breakdown of _____. Several different _____ play a role in this process.

glucose ... enzymes

How do we derive energy from fats?

Breakdown products from fatty acids bypass glycolysis and feed directly into the citric acid cycle.

Which part(s) of cellular respiration require(s) oxygen gas?

(1) the Citric Acid cycle (2) the electron transport chain

Which energy-rich molecule produced by cellular respiration directly powers cell work?

ATP

__________ is a form of kinetic energy that is manifested in the random motions of atoms and molecules.

Heat

Approximately what wavelength of light is best absorbed by chlorophyll a, the pigment that participates directly in the light reactions?

435 nm

Which wavelength of light is best absorbed by chlorophyll b?

455 nm

Which statement describes the citric acid cycle?

This process produces some ATP and carbon dioxide in the mitochondrion.

Which of the following molecules is broken down in cellular respiration, providing fuel for the cell?

glucose

Which of the following processes takes place in the cytosol of a eukaryotic cell?

glycolysis

Select the correct sequence of steps as energy is extracted from glucose during cellular respiration.

glycolysis → acetyl CoA → citric acid cycle → electron transport chain

Which of the following is highest in chemical energy?

one molecule of glucose

During the light reactions of photosynthesis, chlorophyll absorbs energy from sunlight. This energy is used to __________.

split water to produce O2 and high-energy electrons

In photosynthesis, carbon dioxide enters a leaf through pores called __________.

stomata

Kinetic energy is energy in motion. Potential energy is _____ energy.

stored

What is the difference between lactic acid fermentation and alcohol fermentation?

Alcohol fermentation produces carbon dioxide, but lactic acid fermentation does not.

In the 1640s, the Flemish chemist Jan Baptista van Helmont performed the classic experiment paraphrased below: I filled a pot with 200 pounds of dirt that had been dried in an oven. Then I planted the stem of a willow tree and watered it with rainwater. At the beginning, the willow stem weighed 5 pounds. For 5 years, I watered the tree with either rainwater or distilled water whenever it was needed. The pot was large, and planted in the ground. I covered the pot with an iron plate. This had many holes, which allowed water through but not dust. In this way, I could be assured that possible dust accumulation over these 5 years did not significantly add to the weight of the dirt. After 5 years, the tree weighed 169 pounds, and about 3 ounces. I did not take into account the weight of the leaves that fell each autumn. At length, I again dried the dirt, which weighed only 2 ounces less than the initial 200 pounds. I concluded that the 164 pounds of wood, bark, and roots, arose out of water only. In what way was Van Helmont's conclusion incorrect?

He did not account for the role of atmospheric carbon dioxide in photosynthesis.

Can you tell from these absorption spectra whether red light is effective in driving photosynthesis?

One cannot tell from this graph, but because chlorophyll a does absorb red light, we can predict that it would be effective in driving photosynthesis.

If only chlorophyll a were involved in the light reactions, would blue light (wavelength about 490 nm) be effective in driving photosynthesis?

The graph indicates that chlorophyll a absorbs very little blue light, so we can predict that blue light would not be effective.

An action spectrum plots the rate of photosynthesis at various wavelengths of visible light, and it shows that blue light with a wavelength of about 490 nm is effective in driving photosynthesis. Based on this information and the absorption spectra shown at left, what role may chlorophyll b and carotenoids play in photosynthesis?

These pigments are able to absorb more wavelengths of light (and thus more energy) than chlorophyll a alone can absorb. As part of light-harvesting complexes in photosystems, they broaden the range of light that can be used in the light reactions.

You obtain the pigments called carotenoids in your diet when you eat carrots. Why do carotenoids appear yellow and orange?

They absorb blue/green light and reflect yellow and red wavelengths of light.

In cellular respiration, most energy is released and transferred to ATP when _____.

high-energy electrons "fall" to lower energy levels

Unlike the Citric Acid cycle and electron transport, glycolysis occurs _____.

in the cytoplasm

In what organelle would you find acetyl CoA formation, the citric acid cycle, and the electron transport chain?

mitochondrion

Cellular respiration requires fuel (glucose) and oxygen gas. The main process that produces these inputs is _____.

photosynthesis

Cellular respiration accomplishes two major processes: (1) it breaks glucose down into smaller molecules, and (2) it harvests the chemical energy released and stores it in ATP molecules. By the end of _____, the breakdown of glucose is complete; most ATP molecules are produced during _____.

the Citric Acid cycle ... electron transport

During the Calvin cycle, plants use energy from ATP and NADPH to drive __________.

the synthesis of sugar from carbon dioxide

Energy is conserved. This means that in any system, _____.

total energy input equals total energy output

In electron transport, high-energy electrons "fall" to oxygen through a series of reactions. The energy released is used to _____.

transport protons into the intermembrane space of the mitochondria, where they become concentrated. They then flow back out into the the inner compartment (matrix) of the mitochondria. On the way back, protons turn ATP synthase turbines and produce ATP.

What is/are the most important output(s) of glycolysis?

two pyruvic acid and two NADH molecules