Q: A solution has a pH of 4. What is the concentration of hydrogen ions ($$[H^+]) in $$the solution?

$$[H^+] = 1 \times 10$$^{-4}$$ \text{ M}$$

Question 1

Which property of water allows it to moderate Earth's climate by absorbing and releasing heat with minimal temperature change?

Accepted Answer

High specific heat capacity ($$C = \frac{q}{m \Delta T})$$

Question 2

A freshwater Paramecium is suddenly transferred to salty seawater. What is the most likely outcome for the cell?

Accepted Answer

It will shrink as water leaves the cell by osmosis.

Question 3

Which of the following best describes the difference between a saturated and an unsaturated fatty acid?

Accepted Answer

Saturated fatty acids have only single bonds; unsaturated fatty acids contain one or more double bonds.

Question 4

Which of the following molecules is most likely to pass freely through the plasma membrane without the aid of a transport protein?

Accepted Answer

Oxygen ($$O_2)$$

Question 5

A red blood cell is placed in a hypotonic solution. What will happen to the cell?

Accepted Answer

It will gain water and burst (lyse).

Question 6

Which of the following best explains why ice floats on water?

Accepted Answer

Ice has a lower density than liquid water because its molecules form a crystalline lattice.

Question 7

Which functional group is present in all amino acids and is responsible for their acidic properties?

Accepted Answer

Carboxyl group ($$-COOH)$$

Question 8

Which of the following statements about phospholipids is correct?

Accepted Answer

They have two hydrophobic tails and a hydrophilic head.

Question 9

Which organelle is responsible for the synthesis of ATP during cellular respiration?

Accepted Answer

Mitochondrion

Question 10

A solution has a pH of 4. What is the concentration of hydrogen ions ($$[H^+]) in $$the solution?

Accepted Answer

$$[H^+] = 1 	imes 10$$^{-4}$$ 	ext{ M}$$

Question 11

Which of the following best describes the role of enzymes in biological reactions?

Accepted Answer

Enzymes lower the activation energy, speeding up reactions.

Question 12

Which of the following is a polymer of glucose that serves as an energy storage molecule in animals?

Accepted Answer

Glycogen

Question 13

Which of the following best explains why we cannot digest cellulose, even though it is made of glucose?

Accepted Answer

Humans lack the enzyme to break $$\beta-$$glycosidic bonds in cellulose.

Question 14

Which of the following statements about the plasma membrane is true?

Accepted Answer

It is a fluid mosaic of lipids and proteins.

Question 15

Which of the following best describes the function of the Golgi apparatus?

Accepted Answer

It packages and modifies proteins for secretion.

Question 16

A cell is placed in a solution with a higher solute concentration than its cytoplasm. What type of solution is this, and what will happen to the cell?

Accepted Answer

Hypertonic; the cell will lose water and shrink.

Question 17

Which of the following is NOT a function of proteins in the plasma membrane?

Accepted Answer

Energy storage

Question 18

Which of the following best describes the structure of a phospholipid?

Accepted Answer

A glycerol backbone, two fatty acid tails, and a phosphate group

Question 19

Which of the following organelles is found in plant cells but not in animal cells?

Accepted Answer

Chloroplast

Question 20

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

Accepted Answer

Their hydrophobic tails avoid water while hydrophilic heads interact with water.

General Biology: Chemical Context, Water, Macromolecules, Cell Structure, and Membrane Transport

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