Question 1

Which of the following best describes the four phases in the origin of the first cells on Earth?

Accepted Answer

Abiotic synthesis of simple organic compounds, abiotic polymerization into macromolecules, emergence of a replicating macromolecule, encapsulation within a simple membrane

Question 2

In the classic Stanley Miller experiment, which gases were used to simulate the early Earth's atmosphere?

Accepted Answer

Hydrogen ($$H_2$$), methane ($$CH_4$$), ammonia ($$NH_3$$), and water vapor ($$H_2O)$$

Question 3

What was the main result of the Miller-Urey experiment regarding the origin of organic molecules?

Accepted Answer

Simple amino acids such as alanine and glycine were produced under simulated early Earth conditions

Question 4

Which model for the formation of organic compounds suggests that deep-sea hydrothermal vents played a key role?

Accepted Answer

Vents enriched in minerals like $$FeS_2$$ could serve as catalysts for combining dissolved gases into organic molecules

Question 5

Which evidence most strongly supports the RNA World hypothesis?

Accepted Answer

The ribosome is a ribozyme capable of catalyzing peptide bond formation

Question 6

What is a major criticism of the RNA World hypothesis?

Accepted Answer

RNA is highly susceptible to alkaline hydrolysis, making it unstable in certain environments

Question 7

Liposomes are significant in the study of the origin of life because:

Accepted Answer

They can spontaneously form membrane-bound vesicles that encapsulate molecules, mimicking primitive protocells

Question 8

Which of the following is NOT a property of liposomes relevant to the origin of life?

Accepted Answer

They are composed exclusively of proteins and cannot form in water

Question 9

Which of the following statements about the three domains of life is correct?

Accepted Answer

Bacteria and Archaea are as divergent from each other as humans are from bacteria

Question 10

Which feature distinguishes eukaryotic cells from prokaryotic cells?

Accepted Answer

Presence of a membrane-bounded nucleus

Question 11

A scientist discovers a cell with circular DNA complexed with histone-like proteins. Which domain does this cell most likely belong to?

Accepted Answer

Archaea

Question 12

Which of the following is a limitation on cell size?

Accepted Answer

The requirement for adequate surface area relative to volume

Question 13

Why do cells specialized for absorption, such as those lining the small intestine, have microvilli?

Accepted Answer

Microvilli increase the surface area, enhancing nutrient absorption

Question 14

Which equation correctly describes how cell surface area and volume scale with cell length ($$l$$)?

Accepted Answer

Surface area $$\propto l^2$, Volume $$\propto $$l^3$$

Question 15

Which of the following statements about compartmentalization in eukaryotic cells is true?

Accepted Answer

Compartmentalization allows for higher local concentrations of substances required for cellular functions

Question 16

Which of the following is a function of proteins in the plasma membrane?

Accepted Answer

Transporting substances across the membrane

Question 17

Which organelle is responsible for synthesizing ribosomal RNA and beginning the assembly of ribosomes in eukaryotic cells?

Accepted Answer

Nucleolus

Question 18

According to the endosymbiont theory, mitochondria and chloroplasts share which of the following features with bacteria?

Accepted Answer

They have circular DNA molecules without associated histones

Question 19

A cell is found to have extensive internal membranes, multiple linear chromosomes, and organelles such as mitochondria. Which domain does it belong to?

Accepted Answer

Eukarya

Origins of Life and the First Cells: Key Concepts in Cell Biology

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