Chapter 17: The Origins of Life

perform a biological task (phenotype) and store and transmit the information (propagation) (genotype)

The primordial should be able to

> 2 bya

1st cellular life

recognizable sequence similarities, essential function in all organisms, subject to strong stabilizing selection

The 3 gene properties used to construct the tree of life

Most conserved and universal component of information processing unit of cell machinery, deoxyribonucleotides are made from ribonucleotides, many bacteria control transcription/translation of certain genes with riboswitches

Evidence of the RNA World

Life

if it forms a population capable of evolving by natural selection, then it is alive.

Protists

________ are scattered on the eukaryotic branch in the tree of life.

deoxyribonucleotides

In the cell, all ________ are synthesized from ribonucleotide precursors.

Universal phylogeny

________ is based on a concatenated sequence of 31 universal genes.

Ribozyme properties

________ include catalytic behavior and naturally occurring.

Tree of life

________: reconstructs the phylogeny of all living things.

ribozyme

A(n) ________ is NOT a ribosome, it is only a piece of mRNA.

4.5-4.6 billion years old

Age of the earth

Origins of Life

Primordial form

the first living thing

Cenancestor

Last Universal Common Ancestor (L.U.C.A)

The RNA world hypothesis

catalytic RNA molecules were a transitional form between nonliving matter and the earliest cells; the primordial form was an RNA-based living system

Ribozyme

an RNA molecule that is capable of catalyzing a chemical reaction

Small RNAs

post-transcriptional regulators that bind to complementary sequences in 3 untranslated region (3 UTRs) of target mRNAs usually resulting in gene silencing

MRCA

most recent common ancestor

Compartmentalization, accumulation of constituents, and allowing genotypes and phenotypes to be linked

The advantages of a cellular membrane

Tree of life

reconstructs the phylogeny of all living things

Archaea

usually live in extremely harsh environments

Horizontal Gene Transfer

the movement of genetic material across the species barrier