what is necessary to form life
- synthesis of carbon-containing molecules, polymerization, aggregation, and reproduction are necessary.
polymer
- a molecule made of subunits linked to one another. Polymerization is the process of linking these subunits
central dogma of biology
- states that DNA makes RNA, and RNA makes protein.
RNA
- may have been the first genetic material
- a polymer made up of subunits called
nucleotides. - In the 1970s, Eigen found that small portions
of RNA can self-replicate. RNA’s ability to selfreplicate
means that RNA can make a complementary strand of itself without enzymes. If zinc is added, long strands of
RNA can be replicated. - can (1) reproduce itself, (2) bind to amino acids, and (3) make chains of amino acids that can act as catalysts.
ribozyme
- an RNA catalyst
- RNA catalysts found in cells. Ribozymes take part in RNA editing and RNA synthesis.
protobionts with RNA
- may have been able to reproduce.
- RNA-containing protobionts may have been able to make proteins and additional RNA. It is possible that protobionts with RNA could also reproduce.
catalyst
- In 1981, researchers discovered that RNA could act as a catalyst. Catalysts are substances that speed up the rate of a reaction without being consumed.
In Manfred Eigen’s experiments, what was the role of zinc?
- Zinc acts as a catalyst in RNA replication.
One reason RNA is thought to have been the first genetic material is because
- RNA can act as a catalyst
A ribozyme is
- an RNA molecule that can catalyze chemical reactions.
Which of the following molecules is not formed by the process of polymerization?
- a nucleotide
Which of the following does not support the hypothesis that RNA served as the first genetic material?
- In experiments that re-create the atmosphere of primitive Earth, RNA acts as a template for DNA synthesis
True or false?
DNA is an unlikely choice for the original unit of heredity because it is a large, stable molecule, unlikely to form spontaneously in the “thin primordial soup.”
- true
Which of the following may not have been required at the beginnings of life on earth?
- DNA