Table of contents

1. Introduction to Biology2h 42m
2. Chemistry3h 37m
3. Water1h 26m
4. Biomolecules2h 23m
5. Cell Components2h 26m
6. The Membrane2h 31m
7. Energy and Metabolism2h 0m
8. Respiration2h 40m
9. Photosynthesis2h 49m
10. Cell Signaling59m
11. Cell Division2h 47m
12. Meiosis2h 0m
13. Mendelian Genetics4h 44m
14. DNA Synthesis2h 27m
15. Gene Expression3h 6m
16. Regulation of Expression3h 31m
17. Viruses37m
- Viruses
  37m
18. Biotechnology2h 58m
19. Genomics17m
- Genomes
  17m
20. Development1h 5m
21. Evolution3h 1m
22. Evolution of Populations3h 53m
23. Speciation1h 37m
24. History of Life on Earth2h 6m
25. Phylogeny2h 31m
26. Prokaryotes4h 59m
27. Protists1h 12m
28. Plants1h 22m
29. Fungi36m
- Fungi
  19m
- Fungi Reproduction
  17m
30. Overview of Animals34m
- Overview of Animals
  34m
31. Invertebrates1h 2m
32. Vertebrates50m
33. Plant Anatomy1h 3m
34. Vascular Plant Transport1h 2m
- Water Potential
  1h 2m
35. Soil37m
- Soil and Nutrients
  20m
- Nitrogen Fixation
  16m
36. Plant Reproduction47m
- Flowers
  33m
- Seeds
  14m
37. Plant Sensation and Response1h 9m
38. Animal Form and Function1h 19m
39. Digestive System1h 10m
- Digestion
  1h 3m
- Blood Sugar Homeostasis
  7m
40. Circulatory System1h 49m
41. Immune System1h 12m
42. Osmoregulation and Excretion50m
- Osmoregulation and Excretion
  50m
43. Endocrine System1h 4m
- Endocrine System
  1h 4m
44. Animal Reproduction1h 2m
- Animal Reproduction
  1h 2m
45. Nervous System1h 55m
- Neurons and Action Potentials
  1h 8m
- Central and Peripheral Nervous System
  46m
46. Sensory Systems46m
- Sensory System
  46m
47. Muscle Systems23m
- Musculoskeletal System
  23m
48. Ecology3h 11m
49. Animal Behavior28m
- Animal Behavior
  28m
50. Population Ecology3h 41m
51. Community Ecology2h 46m
52. Ecosystems2h 36m
53. Conservation Biology24m
- Conservation Biology
  24m

24. History of Life on Earth

History of Life on Earth

General Biology

24. History of Life on Earth

History of Life on Earth

Previous problemNext problem

1:07 minutes

Problem 5

Textbook Question

Which of the following steps has not yet been accomplished by scientists studying the origin of life?
a. Synthesis of small RNA polymers by ribozymes
b. Formation of molecular aggregates with selectively permeable membranes
c. Formation of protocells that use DNA to direct the polymerization of amino acids
d. Abiotic synthesis of organic molecules

Verified step by step guidance

Step 1: Begin by understanding the context of the question, which is about the origin of life and the scientific progress made in studying it. Scientists have explored various steps that could have led to the emergence of life on Earth.

Step 2: Review the listed options and identify the processes described. For example: (a) Synthesis of small RNA polymers by ribozymes refers to the ability of RNA molecules to catalyze reactions, (b) Formation of molecular aggregates with selectively permeable membranes refers to the creation of structures resembling cell membranes, (c) Formation of protocells that use DNA to direct the polymerization of amino acids refers to a more advanced step involving genetic material and protein synthesis, and (d) Abiotic synthesis of organic molecules refers to the creation of organic compounds without biological intervention.

Step 3: Recall the scientific advancements in each area. Scientists have successfully demonstrated abiotic synthesis of organic molecules in experiments like the Miller-Urey experiment. They have also observed the formation of molecular aggregates with selectively permeable membranes and the catalytic activity of ribozymes in synthesizing RNA polymers.

Step 4: Consider the complexity of the processes described. The formation of protocells that use DNA to direct the polymerization of amino acids is a highly advanced step requiring the integration of genetic material and protein synthesis, which has not yet been fully accomplished in laboratory settings.

Step 5: Conclude that the step not yet accomplished by scientists studying the origin of life is the formation of protocells that use DNA to direct the polymerization of amino acids, as this represents a significant leap in complexity compared to the other steps.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above

Video duration:

Play a video:

Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Ribozymes and RNA Synthesis

Ribozymes are RNA molecules that can catalyze chemical reactions, including the synthesis of RNA polymers. This concept is crucial in understanding the RNA world hypothesis, which posits that self-replicating RNA molecules were precursors to current life forms. The ability of ribozymes to catalyze their own synthesis suggests a potential pathway for the origin of life.

Protocells and Membrane Formation

Protocells are simple, cell-like structures that are thought to be precursors to true cells. They typically consist of lipid membranes that can encapsulate biochemical reactions. The formation of protocells with selectively permeable membranes is significant because it represents a step towards cellular organization and the compartmentalization of biochemical processes necessary for life.

Abiotic Synthesis of Organic Molecules

Abiotic synthesis refers to the formation of organic compounds from inorganic precursors without the involvement of living organisms. This process is believed to have occurred on early Earth, leading to the creation of essential biomolecules like amino acids and nucleotides. Understanding abiotic synthesis is fundamental to exploring how life could have originated from non-living chemical systems.

Watch next

Master Geologic Record with a bite sized video explanation from Jason

Start learning

Related Videos

Related Practice

Textbook Question

Adaptive radiations can be a direct consequence of three of the following four factors. Select the exception:

a. Vacant ecological niches

b. Genetic drift

c. Colonization of an isolated region that contains suitable habitat and few competitor species

d. Evolutionary innovation

1192

views

Textbook Question

Ancient photosynthetic prokaryotes were very important in the history of life because they

a. Produced the oxygen in the atmosphere.

b. Are the oldest-known archaea.

c. Were the first multicellular organisms.

d. Showed that life could evolve around deep-sea vents.

1251

views

Textbook Question

Which of the following groups of amino acid residues would likely be found in the portion that crosses the lipid bilayer?

a. Acidic

b. Basic

c. Polar uncharged

d. Nonpolar

1353

views

Textbook Question

Scientists studying the origin of life have accomplished which of the following steps?(A)abiotic synthesis of protocells with self-replicating, catalytic RNA(B)formation of vesicles that use RNA as a template for DNA synthesis(C)formation of protocells that use DNA to direct the polymer-ization of amino acids(D)abiotic synthesis of RNA's bases (A, C, G, U)

2344

views

Textbook Question

The animals and plants of India are very different from the species in nearby Southeast Asia. Why might this be true?

a. India was once covered by oceans and Asia was not.

b. India is in the process of separating from the rest of Asia.

c. Life in India was wiped out by ancient volcanic eruptions.

d. India was a separate continent until about 45 million years ago.

857

views

Textbook Question

Adaptive radiations may be promoted by all of the following except one. Which one?

a. Mass extinctions that result in vacant ecological niches

b. Colonization of an isolated region with few competitors

c. A gradual change in climate

d. A novel adaptation

1090

views

Textbook Question

Consider the endosymbiosis theory for the origin of the mitochondrion. How did each endosymbiotic partner benefit from the relationship?

Draw and label the plasma membrane of a cell that is placed in a solution with concentrations of calcium ions and lactose that are greater than those on the inside of the cell. Use arrows to show the relevant gradients and the activity of the following membrane proteins:

(1) A pump that exports protons

(2) A calcium channel

(3) A lactose carrier

1979

views

Show more practices

Download the Mobile app

Privacy

Do not sell my personal information

Accessibility

Patent notice

Sitemap