Ch. 1 Evolution, Science, and Molecular Biology Flashcards
What is molecular biology?
The study of cellular macromolecules including DNA, RNA, proteins, and the processes that connect them.
How long has molecular biology been around?
Not long. It is a somewhat young field (mid 1950s) but it has had tremendous impacts in medicine, technology, agriculture, forensic science, etc.
What does molecular biology apply to?
It applies to all living things, and some non-living things like viruses.
What is life according to NASA and why is their definition different than biologists’ definition?
“Life is a chemical system capable of Darwinian evolution.” It is more broad to cover things like aliens, if they are ever discovered.
What is life according to biologists?
“Life follows the seven characteristics of life… adaptation, homeostasis, transmission of genetic information between generations, energy acquisition, interactions, growth/development/death cycle, and complexity & organization.
What do molecular processes in cells provide?
Molecular processes in cells provide mechanisms through which adaptation and evolution occur.
What is a way adaptation and evolution can occur?
Genetic information can change in various ways (i.e. being gained or lost) and these changes lead to phenotypic alteration in species, and potentially the evolution of new species.
What are examples of genetic alterations causing new phenotypes (4)?
Mutagenesis (mutation), repair, recombination (natural and lab induced), and transposition (moving) all lead to a different genome, which leads to new proteins, which leads to new functions… evolution.
Why are viruses not classified as living things according to biologists (3) ?
They don’t maintain homeostasis, they don’t perform energy acquisition/energy conversion, and they don’t follow a growth/development/death cycle.
What is the Central Dogma of Biology?
DNA replicated to make more DNA, DNA transcribed to RNA, RNA translated to Polypeptides. Viruses can reverse transcribe and replicate RNA.
What are the two theories of how life began?
- “Life” molecules formed through chemical reactions on Earth over the span of hundreds or millions of years.
- Complex molecules formed, and a molecule gained the ability to reproduce. Current evidence points to this molecule being RNA.
What is RNA World Hypothesis?
A hypothesis that states the chemistry and and current roles of RNA in cells suggest it could have been the first self-replicator.
Why is RNA World Hypothesis so credible (2)?
It was proposed in the 60s by separate people in separate papers.
RNA has information storage abilities, catalytic abilities, and has roles in protein synthesis.
Despite how life began, what has all life done over time?
evolved
How did evolution occur all those years ago?
As environments changed, they selected for adaptations that worked best in the new surroundings.
What do the shared properties of today’s diverse life forms indicate?
The shared properties are likely from an early life form that outcompeted other forms. This life form is called the last universal common ancestor (LUCA).
Do we know what LUCA was?
No, but experimentation can provide some insight.
Was LUCA the only life form at the time of evolution?
It may not have been the only living thing present, but it was the only thing that evolved to life as we know it.
How can LUCA be studied (2)?
- Identify the minimum protein and genetic information needed for life.
- Survey all life and find universal genes.
How to researchers identify the minimum protein and genetic information needed for life?
You can strip genes from bacteria and figure out what is necessary for life. You can also build artificial genomes to accomplish the same task.
How do researchers survey all life to find universal genes (5)?
They look at the machinery for transcription and protein synthesis. They look at the genetic code. They look at amino acid, nucleotide, and lipid synthesis mechanisms.
Where does the “Tree of Life” place LUCA?
At the base of the tree. LUCA signifies the beginning of evolution of current day life as we know it.
What is evolution and how is it done?
A response to the environment so that as environments change, phenotypes and the genotypes that encode them change too. It is a result of many processes like genetic variation, competition, and natural selection.
How do changes to genotypes happen (3)?
Mechanisms that allow for genotypes to change include mutation, genetic recombination, and horizontal gene transfer.
