Q: During cellular respiration, which of the following correctly represents the overall chemical equation?

$$\mathrm{C_6H_{12}O_6$} + 6\ \mathrm{O_2$} \rightarrow 6\ \mathrm{CO_2$} + 6\ \mathrm{H_2O} + \text{energy}$$

Question 1

Which of the following best explains why water is considered a polar molecule?

Accepted Answer

Because the oxygen atom is more electronegative than the hydrogen atoms, creating a partial negative charge near the oxygen and a partial positive charge near the hydrogens.

Question 2

A patient is diagnosed with acidosis, meaning their blood pH has dropped below the normal range. Which of the following best describes what has happened at the molecular level?

Accepted Answer

The concentration of $$\mathrm{H^+}$$ ions has increased.

Question 3

Which of the following is a correct example of a dehydration synthesis reaction?

Accepted Answer

Joining two amino acids to form a dipeptide and releasing a molecule of water.

Question 4

A scientist is studying a cell that lacks membrane-bound organelles. Which of the following is most likely true about this cell?

Accepted Answer

It is a prokaryotic cell.

Question 5

Which of the following best describes the function of the rough endoplasmic reticulum (RER) in eukaryotic cells?

Accepted Answer

It is the site of protein synthesis for proteins destined for secretion or insertion into membranes.

Question 6

A red blood cell is placed in a hypotonic solution. What will most likely happen to the cell, and why?

Accepted Answer

It will swell and possibly burst because water will move into the cell by osmosis.

Question 7

Which of the following best explains why enzymes are highly specific for their substrates?

Accepted Answer

The active site of an enzyme has a unique three-dimensional shape that fits only specific substrate molecules.

Question 8

During cellular respiration, which of the following correctly represents the overall chemical equation?

Accepted Answer

$$\mathrm{C_6H_{12}O_6$} + 6\ \mathrm{O_2$} ightarrow 6\ \mathrm{CO_2$} + 6\ \mathrm{H_2O} + 	ext{energy}$$

Question 9

A mutation causes a cell to produce a nonfunctional ATP synthase enzyme. Which process will be most directly affected?

Accepted Answer

Oxidative phosphorylation in the mitochondria

Question 10

Which of the following statements about the fluid mosaic model of the plasma membrane is correct?

Accepted Answer

Both phospholipids and proteins can move laterally within the layer, giving the membrane flexibility.

Question 11

A researcher adds a competitive inhibitor to an enzyme-catalyzed reaction. What is the most likely effect on the reaction rate, and how can it be overcome?

Accepted Answer

The reaction rate will decrease, but adding more substrate can restore the original rate.

Question 12

Which of the following best describes the role of NAD+ in cellular respiration?

Accepted Answer

It carries electrons from glycolysis and the Krebs cycle to the electron transport chain.

Question 13

A plant cell is placed in a solution with a lower water potential than its cytoplasm. What will happen to the cell?

Accepted Answer

It will lose water and the plasma membrane will pull away from the cell wall (plasmolysis).

Question 14

Which of the following is a correct statement about facilitated diffusion?

Accepted Answer

It moves substances down their concentration gradient with the help of membrane proteins.

Question 15

Which of the following best explains why phospholipids form bilayers in aqueous environments?

Accepted Answer

Their hydrophilic heads interact with water, while their hydrophobic tails avoid water, resulting in a bilayer.

Question 16

A cell is observed to have a large number of mitochondria. Which of the following is the most likely function of this cell?

Accepted Answer

Active transport of ions requiring large amounts of ATP

Question 17

Which of the following best describes the difference between active and passive transport across cell membranes?

Accepted Answer

Active transport requires energy input, usually in the form of ATP, while passive transport does not.

Question 18

A person is unable to digest lactose due to a deficiency in the enzyme lactase. Which type of macromolecule is directly affected by this deficiency?

Accepted Answer

Carbohydrates

Question 19

Which of the following is a correct statement about the structure of DNA?

Accepted Answer

It consists of two antiparallel strands held together by hydrogen bonds between complementary bases.

Question 20

A cell is placed in a solution and neither gains nor loses water. What can you conclude about the solution?

Accepted Answer

The solution is isotonic to the cell.

APB Midterm #1 Study Guide: Chemistry and Cell Biology

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