Question 1

Which of the following best explains why iron (Fe) and hydrogen sulfide (H$$_2S) $$are considered very reactive in hydrothermal vent environments?

Accepted Answer

Their chemical properties allow them to readily exchange electrons, driving key reactions that support early life.

Question 2

Why is RNA considered significant in the context of the origin of life?

Accepted Answer

RNA can catalyze chemical reactions and may have been the first self-replicating informational molecule.

Question 3

Which statement about ribozymes is correct?

Accepted Answer

Ribozymes are RNA molecules that can catalyze specific biochemical reactions.

Question 4

In the context of early Earth, what is a protocell?

Accepted Answer

A vesicle composed of lipids that encloses molecules like ribozymes, structurally similar to a cell but not alive.

Question 5

Which of the following best describes the transition from protocell to living cell?

Accepted Answer

It was a gradual process with no sharp boundary between protocell and living cell.

Question 6

What is the primary difference between autotrophs and heterotrophs?

Accepted Answer

Autotrophs synthesize required molecules using external energy sources, while heterotrophs obtain molecules from the environment.

Question 7

Which organelle is primarily responsible for energy production in eukaryotic cells?

Accepted Answer

Mitochondrion

Question 8

Which of the following elements makes up the majority of biological molecules?

Accepted Answer

Carbon (C), Hydrogen (H), Oxygen (O), and Nitrogen (N)

Question 9

What is the atomic number of an element?

Accepted Answer

The number of protons in the nucleus.

Question 10

Which type of chemical bond involves the sharing of electron pairs between atoms?

Accepted Answer

Covalent bond

Question 11

Why does ice float on water?

Accepted Answer

Ice is less dense than liquid water because hydrogen bonds create an open lattice structure.

Question 12

Which property of water allows it to moderate Earth's climate?

Accepted Answer

High heat of vaporization and high specific heat capacity

Question 13

What is the definition of pH?

Accepted Answer

The measure of the hydrogen ion concentration in a solution.

Question 14

Which equation correctly represents the relationship between pH and hydrogen ion concentration $$[H^+]$$?

Accepted Answer

$$pH = -\log_{10}[H^+]$$

Question 15

A solution has a hydrogen ion concentration of $$1 	imes 10$$^{-4}$$ M. What is its pH?

Accepted Answer

$$pH = 4$$

Question 16

Which of the following substances is hydrophilic?

Accepted Answer

Sodium chloride (NaCl)

Question 17

Which type of bond is the weakest among those commonly found in biological molecules?

Accepted Answer

Hydrogen bond

Question 18

Which scenario best illustrates the importance of water's cohesion?

Accepted Answer

Water molecules stick together, allowing plants to transport water from roots to leaves.

Question 19

Which of the following is true about isotopes?

Accepted Answer

Isotopes have the same number of protons but different numbers of neutrons.

Question 20

Which process is most directly responsible for the formation of new genes in early life?

Accepted Answer

The joining of RNA segments by ribozymes.

Lecture 3

Study Guide - Practice Questions