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What Is LUCA?

Definition

LUCA (Last Universal Common Ancestor)

The last universal common ancestor of all present-day organisms, representing the root of the tree of life.

LUCA likely lived around 4 billion years ago.
Its existence is inferred from universal features shared across all life forms today.

Evidence For LUCA: The Genetic Code

Definition

Genetic code

The genetic code is a system that translates DNA instructions into proteins, the essential building blocks of life.

One of the strongest pieces of evidence for LUCA is the near-universality of the genetic code across all organisms.
The genetic code is a system that translates DNA sequences into proteins, essential for life.DNA is composed of four nucleotide bases: adenine (A), thymine (T), cytosine (C), and guanine (G).
These bases are read in groups of three, called codons.

Definition

Codon

A codon is a sequence of three nucleotides in DNA or RNA that specifies a particular amino acid or a start/stop signal during protein synthesis.

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Note

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Question 1

Recap question

Given four nucleotide bases and at least 20 standard amino acids, what is the minimal codon length required to encode all amino acids uniquely?

What is one reason the genetic code is consistent across organisms?

Note

Before diving into the evidence for a Last Universal Common Ancestor (LUCA), it's crucial to understand the concept of a universal genetic code. This code is a set of rules that all living organisms use to translate genetic information into proteins.

The genetic code is like a biological language that uses sequences of three nucleotides (called codons) to specify amino acids.
Amazingly, this code is nearly identical across all forms of life, from bacteria to humans.

DefinitionUniversal Genetic CodeA system of nucleotide triplets (codons) that specify amino acids, shared by almost all living organisms.

AnalogyThink of the genetic code as a universal alphabet that all living things use to write their "instruction manuals" for building proteins.

What Is LUCA?

Definition

LUCA (Last Universal Common Ancestor)

The last universal common ancestor of all present-day organisms, representing the root of the tree of life.

LUCA likely lived around 4 billion years ago.
Its existence is inferred from universal features shared across all life forms today.

Evidence For LUCA: The Genetic Code

Definition

Genetic code

The genetic code is a system that translates DNA instructions into proteins, the essential building blocks of life.

One of the strongest pieces of evidence for LUCA is the near-universality of the genetic code across all organisms.
The genetic code is a system that translates DNA sequences into proteins, essential for life.DNA is composed of four nucleotide bases: adenine (A), thymine (T), cytosine (C), and guanine (G).
These bases are read in groups of three, called codons.

Definition

Codon

A codon is a sequence of three nucleotides in DNA or RNA that specifies a particular amino acid or a start/stop signal during protein synthesis.

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(on a website) an arrangement whereby access is restricted to users who have paid to subscribe to the site.

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Note

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Excepteur sint occaecat cupidatat non proident

Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

Questions

Recap questions

1 of 5

Question 1

Recap question

Given four nucleotide bases and at least 20 standard amino acids, what is the minimal codon length required to encode all amino acids uniquely?

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What is one reason the genetic code is consistent across organisms?

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Note

The genetic code is like a biological language that uses sequences of three nucleotides (called codons) to specify amino acids.
Amazingly, this code is nearly identical across all forms of life, from bacteria to humans.

DefinitionUniversal Genetic CodeA system of nucleotide triplets (codons) that specify amino acids, shared by almost all living organisms.

AnalogyThink of the genetic code as a universal alphabet that all living things use to write their "instruction manuals" for building proteins.

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics

A2.1.7 Evidence for a last universal common ancestor Notes

What Is LUCA?

Evidence For LUCA: The Genetic Code

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Want a cheatsheet?

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics

What Is LUCA?

Evidence For LUCA: The Genetic Code

Unlock the rest of this chapter with a Free account

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

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