Refer to the Gene Tree Shown

question 223

Essay

Refer to the gene tree shown. Ribosomal RNA genes are present in the nuclear genomes of eukaryotes.There are also rRNA genes in the genomes of mitochondria and chloroplasts.Therefore photosynthetic eukaryotes have three different sets of rRNA genes, which encode the structural RNA of three separate sets of ribosomes.Translation of each genome takes place on its own set of ribosomes.The gene tree shows the evolutionary relationships among rRNA gene sequences isolated from the nuclear genomes of humans, yeast, and corn; from an archaeal species (Halobacterium), a proteobacterium (E.coli), and a cyanobacterium (Chlorobium); and from the mitochondrial and chloroplast genomes of corn.Based on the gene tree, why aren't the three rRNA genes of corn one another's closest relatives?

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Definitions:

Occipital Lobe

The region of the brain located at the back of the head, which is primarily responsible for visual processing.

Primary Visual Cortex

The part of the cerebral cortex responsible for processing visual information, located in the occipital lobe.

Limbic System

A complex system of nerves and networks in the brain, involved with instinct and mood. It controls the basic emotions (fear, pleasure, anger) and drives (hunger, sex, dominance, care of offspring).

Amygdala

A section of the brain that is involved in emotions, decision-making, and memory processing, particularly with emotional reactions.