Biology Practice Test: MCQ Quiz

There is an abundant amount of CO2 so it is not important to worry about that aspect of this question. You know that in the Calvin Cycle, 3 CO2 9 ATP and 6 NADPH are required to make 1 G3P molecule. So if you imagine that you had unlimited CO2 and ATP, 100,000 NADPH would be able to make 16,666 molecules of G3P (100,000/6 = 16,666). If you had unlimited CO2 and NADPH, 90,000 ATP would be able to make 10,000 molecules of G3P (90,000/9 = 10,000). In this case, the amount of ATP that we have limited the amount of G3P we can synthesize to just 10,000 molecules.

The polar amino acids Serine, Threonine, and Tyrosine indicate that this portion of the protein is hydrophilic. Hydrophilic regions are typically located on the outer surface of the cell membrane, facing the extracellular matrix (outside the cell) or the cytoplasm (inside the cell). Therefore, this portion of the transmembrane protein is most likely located both outside the cell (in the extracellular matrix) and inside the cell (in the cytoplasm).

The pH of a solution is a measure of its acidity or alkalinity. It is determined by the concentration of hydrogen ions (H+). In this case, the solution has an H+ concentration of 1 x 10^-2 M, which is equivalent to 0.01 M. The pH scale ranges from 0 to 14, with a pH of 7 being neutral. Since the solution has a higher concentration of H+ ions, it is considered acidic. A pH of 2 indicates a strong acidity. Therefore, the correct answer is 2.

Nonpolar bonds contain the most energy. A non-polar bond occurs between atoms with similar electronegativity. This is why a mole of fat has more energy than a mole of glucose or a mole of water for example. This is also the reason why glucose is used for "short-term" energy because they can be broken down more rapidly since they absorb less energy to break down due to the fact they don't hold as much chemical potential energy in its polar bonds. Fat molecules are used for the storage of chemical potential energy since it absorbs more energy to break down because it has more energy from it's non-polar bonds.

NADH acts as the reducing agent in the system. It donates electrons to Complex I in the mitochondria, causing NADH to become reduced. This transfer of electrons is a key step in oxidative phosphorylation, where energy is generated through the electron transport chain.

H2O, NO2, and NH3 have polar bonds and would dissolve in a polar solution. ("Like dissolves like")

The presence of disulfide bridges and hydrophobic interactions indicates the formation of tertiary structure in the protein. The fact that the protein is made up of one polypeptide chain suggests that it does not have a quaternary structure involving multiple polypeptide chains. Therefore, the protein has both primary and tertiary structures.

The correct answer is that the cells receiving the signal must have receptors that bind to the signaling molecule, respond with the activation of the signal transduction pathway, and finally respond by ceasing cell division. This is because the signal released by the cell needs to be detected by the neighboring cells through their receptors. Once the signal binds to the receptors, it triggers a series of intracellular events known as the signal transduction pathway. This pathway ultimately leads to the cells ceasing division in response to the signal.

Primary active transport requires ATP to directly move molecules against their concentration gradient, while secondary active transport uses the energy stored in the electrochemical gradient of one molecule to drive the transport of another molecule against its concentration gradient. Therefore, the main difference between primary and secondary active transport is the requirement of ATP.

Antioxidants are reducing agents because they are able to donate electrons to another molecule. Once the antioxidant donates its electrons, the antioxidant becomes oxidized. The damaged DNA accepts these electrons and the damaged DNA becomes reduced since it has accepted the electrons from the antioxidant.

The correct answer is that the ATP that is produced in the Light reactions provides the energy that is required to form the bonds in sugars. This is because ATP is a high-energy molecule that can be used as a source of energy for various cellular processes, including the synthesis of sugars. In photosynthesis, ATP is produced during the light reactions, where energy from sunlight is used to generate ATP through the process of photophosphorylation. This ATP can then be used in the Calvin Cycle, the dark reactions of photosynthesis, to provide the energy needed to form the bonds between sugars.

If there was a mutation to Complex I and Complex II of the electron transport chain that prevented them from oxidizing NADH, the electrons from NADH would not be able to be obtained. This means that the proton gradient, which is formed by the movement of electrons through the electron transport chain, would not be able to form. Without the proton gradient, ATP synthesis cannot occur, as ATP synthase relies on the proton gradient to generate ATP. Therefore, the correct answer is that no ATP synthesis would occur.

Since the [H+]=3.2x10^-5 M, we know that this is acidic. To be exact, the pH is 4.5. The organelle that we know that has a pH this low is a lysosome. The matrix of the mitochondria would not have a low pH since the proton gradient is formed in the intermembrane space, instead it's pH would be higher since there is a low {H+].

The correct answer is that the final electron acceptor, oxygen, has a relatively high electronegativity, and therefore causes the driving force for the electrons to move down the chain. Electronegativity is a measure of an atom's ability to attract electrons towards itself. Oxygen, being highly electronegative, has a strong attraction for electrons, which creates a favorable environment for the movement of electrons down the electron transport chain (ETC). This attraction helps to maintain the flow of electrons and allows for the release of free energy in a spontaneous reaction.

Water is a polar molecule, meaning it has a slightly positive end and a slightly negative end. When water forms hydrogen bonds with other molecules, it can dissolve small, polar, or charged molecules. This is because the positive end of water is attracted to the negative end of the molecule being dissolved, allowing water to surround and separate the molecules, effectively dissolving them.

The high proton gradient is formed in the intermembrane space of mitochondria in eukaryotic cells and also in the thylakoid lumen of photosynthetic organisms. A high proton gradient would have a low pH since there is a high concentration of [H+]. Remember that a low pH is equal to a high proton concentration. Hint: [H+] is the same as saying proton concentration.

The movement described in the question, where the foot is placed on the ground, pushed down and back to propel forward, and then released and moved forward again, is similar to the process of muscle contraction. Muscle contraction involves the sliding of actin and myosin filaments in muscle cells, which shortens the muscle fibers and generates force for movement. This analogy suggests that the action described reflects the process of muscle contraction at the cellular level.

A strong oxidizing agent would mean that it is able to oxidize a molecule by taking it's electrons; this would mean that the oxidizing agent is reduced (gained electrons) because it just oxidized a molecule. In this case, the oxidizing agent would oxidize the NADPH in the stroma. If there isn't any NADPH, it can't enter the Calvin Cycle and it would not be able to synthesize sugars.

The H+ ions combine with bicarbonate (HCO3-) to shift the equilibrium towards making more CO2 and H2O. It wouldn't be able to combine with H2CO3 because already has as many hydrogen molecules as it can hold. Your body would not respond by breathing more because that would increase the CO2 concentration and shift the reaction to make more H+ and HCO3-. This does not happen because the blood already has a high [H+] and it would not want to make your blood any more acidic.

Flagella and cilia are both similar in terms of their 9-2 arrangement of microtubules and their use of the motor protein dynein. Both flagella and cilia are found in eukaryotic cells. However, the main difference between flagella and cilia lies in the way they move. Flagella typically have a whip-like motion and are responsible for cell propulsion, while cilia have a coordinated beating motion and are involved in moving substances along the surface of cells.

The tails are hydrophobic (not attracted to water) because of the high number of non-polar bonds it has because of the high number of C-H and C-C bonds. It doesn't interact with water and prefers to interact with non-polar molecules which is why they orient themselves towards each other. Think about oil in water; these interactions are analogous to fatty acid tails in the cell.

The plasma membrane is composed of lipids. Which organelle do we know of that is responsible for lipid synthesis? That would be the smooth endoplasmic reticulum.

The lower pH in the thylakoid creates a proton gradient, with a higher concentration of protons in the thylakoid lumen compared to the stroma. This proton gradient allows ATP synthase to pump protons out of the thylakoid and into the stroma, using the energy from this movement to synthesize ATP. Therefore, the lower pH in the thylakoid enables ATP synthase to form ATP.

Cellulose is able to provide rigidity to a cell because it is polar and can allow for extensive hydrogen bonding between its chains. Hydrogen bonding is a strong intermolecular force that occurs between the hydrogen atom of one molecule and the oxygen, nitrogen, or fluorine atom of another molecule. In the case of cellulose, the polar hydroxyl groups (-OH) on each glucose molecule can form hydrogen bonds with the hydroxyl groups of adjacent glucose molecules. This results in the formation of a strong and stable network of hydrogen bonds, which provides structural support and rigidity to the cell.