Chapter One - Introduction to Molecular Genetics

Molecular Biology

The study of essential macromolecules including DNA, RNA, and proteins. It has a fairly short history because its study only began in the second half of the 20th century.

Definition of Life

According to NASA, this describes a chemical system capable of Darwinian evolution. Several requirements for this include the ability to undergo catalysis, the ability to store and transmit biological information, the presence of an envelope or barrier surrounding the being, and the use of raw materials and energy.

1) Adaptation

2) Energy acquisition

3) Transmission of genetic information between generations

4) Homeostasis

5) Interaction with other cells, organisms, or the environment

6) Complexity and organization

7) Growth, development, and death

What are some basic characteristics of living organisms?

Homeostasis

The constant maintenance of equilibrium despite what is occurring in the environment or outside the cell.

Ex) The cell membrane is the main maintainer of equilibrium

Billion

The Earth is about 4.6 billion years old, but life didn’t appear for the first ( ) years.

Oxygen

Before life appeared on Earth, there was no molecular ( ) in the atmosphere, making the Earth incompatible with life as we know it.

1) Carbon dioxide, methane, water, molecular hydrogen, amine, etc

2) Aldehydes, ketones, and HCN

3) Amino acids, purines, sugars, and pyrimidines

4) Polymers

List the following materials in the order in which they appeared during Earth’s early development.

> Aldehydes, ketones, and HCN

> Polymers

> Amino acids, purines, sugars, and pyrimidines

> Carbon dioxide, methane, water, molecular hydrogen, amine, etc

Lightning and volcanism

What form of energy likely propelled a number of chemical reactions forward in the first billion years on Earth?

RNA has been found to catalyze the reactions needed to make many complex molecules required for many living mechanisms

Why is the first living system on Earth believed to be RNA-based?

Ribozymes

RNA molecules that can catalyze basic reactions, which helped form the belief that the first living system was likely RNA based due to their ability to catalyze reactions that produced molecules needed for various processes.

LUCA

Stands for last universal common ancestor, which lived more than three billion years ago. This ancestor likely had the same genetic code that we use today, as well as a similar mechanism for taking in energy and making needed materials.

Chemoheterotroph

LUCA was most likely a ( ) because of all the organic molecules lying around for consumption during Earth’s early years.

Wasn’t

LUCA probably (was/wasn’t) entirely RNA-based, unlike early cells.

1) Bacteria

2) Archaea

3) Eukarya

LUCA evolved into what three domains of life?

1) Population variation

2) Competition

Natural selection depends on what two things?

Random events/natural selection

Populations contain many forms of a given gene. The frequency of these alleles changes generation to generation based on ( ) and ( ).

Small

Genetic changes that don’t kill an organism will produce ( ) changes in function, which can be beneficial, neutral, or harmful.

Higher

Good changes in function due to mutation will be passed on at a ( ) frequency than bad changes.

Genetics

Darwin knew what occurred in terms of natural selection and evolution, but couldn’t explain the ( ) behind the changes he observed.

1) Vertical descent with modification

2) Horizontal gene transfer

What are the two mechanisms of evolutionary change?

Vertical Descent with Modification

A progression of changes passed from parent to offspring. New species evolve from pre-existing species by the accumulation of mutations, and natural selection takes advantage of beneficial mutations.

Horizontal Gene Transfer

Genetic exchange between different species, which is relatively rare.

Transferred

Genes that confer antibiotic resistance are sometimes ( ) between different bacteria species.

Transduction

The transfer of genetic material from a bacterial virus to a bacterial species.

Conjugation

When two organisms from the same or different species connect and transfer genetic material between them.

Transformation

The transfer of genetic material that occurs when genetic material from a dead cell is taken up by a living organism and incorporated into its own genetic material with the help of transposans.

Transposans

Enzymes that move bacterial DNA from one bacterial organism to another.

Discovery Based Science

Doesn’t make a formal hypothesis.

Scientific Theory

Provides an explanation for a large number of experiments.

Hypothesis

Provides a reasonable explanation for observations.

Science

Both a body of knowledge and a process for generating more knowledge. It focuses on the natural universe and relies on ideas that can be tested by experiments, original and reproduced.