Section 6 Flashcards
What is the genome?
The complete set of genetic material encoded in a cell or virus
How many chromosomes does the human genome contains?
23 pairs
True or false:
The genome does not include DNA from organelles like mitochondria
True. This does not count as part of the human or nuclear genome
How many pairs of chromosomes do humans have?
23 pairs
22 pairs of autosomes and 2 sex chromosomes
True or false:
Intronic and intergenetic regions are classified as “junk DNA”
False
What are promoters?
Regulatory sequences
What are intronic regions
Non-coding regions
As organisms become more sophisticated, we see ______ regulatory and structural sequences
a) less
b) more
c) normal
b) more
more splitting of genes
What are the essential components of genes and their regulatory elements?
Promoter: The promoter is a regulatory region located upstream of the transcription start site. It plays a critical role in initiating transcription.
Exons: Exons are the coding regions of genes and contain the information necessary for protein synthesis.
Introns: Introns are non-coding regions within genes. They are transcribed but later spliced out of the mature RNA.
Untranslated Regions (UTRs): UTRs, including the 3’ and 5’ UTRs, are non-coding regions present in the final mature RNA. They are essential for mRNA stability and translation regulation.
What are homologs in the context of genomics?
Homologs are any two genes with a demonstrable sequence similarity, implying an evolutionary relationship. The sequence similarity often goes hand-in-hand with a functional relationship, but it’s not always required.
(came from the same gene but they don’t necessarily have the same function now)
Define orthologs in comparative genomics.
Orthologs are genes from different species that possess both clear sequence and functional relationships to each other. They are derived from an ancestral gene in the last common ancestor of those species.
(both sequence and function came from a common ancestor)
What are paralogs in genomics, and how do they typically arise?
Paralogs are genes that are similarly related to each other but are within a single species. They often arise from gene duplication within a single genome, followed by the specialization of one or both copies during evolution.
e.g. gene families
What are examples of two large genomic rearragnments?
Inversions and fusions
Explain the concept of inversions in the context of genomic rearrangements.
Inversions occur when a segment of DNA on a chromosome becomes inverted, resulting from segmental duplication, transposition, or recombination events. These rearrangements can change the orientation of the DNA sequence.
What are fusions in genomic rearrangements, and how do they typically occur?
Fusions involve rearranging chromosomal DNA through processes like deletion, duplication, insertion, or transposition to create hybrid genes. One notable example is the fusion of two chromosomes in the human lineage to form human chromosome 2.
How do genomic rearrangements, such as fusions, affect the genetic differences between species like humans and chimpanzees?
Genomic rearrangements contribute to genetic differences between species. For instance, humans and chimpanzees share about 98.94% of their genomes, but these differences include 5 million short insertions or deletions and larger changes, totaling about 4% of their genomes, which are unique to each species.
______ are genes in different organisms that possess a clear sequence and functional relationship to each other
Orthologs
________ are genes within a species that possess a clear sequence and functional relationship to each other and probably arose as the result of gene duplication.
Paralogs
__________ are genes or proteins with sequence similarities
Homologs
What is the process known as when introns are removed from a primary RNA transcript?
The process of removing introns from a primary RNA transcript is known as splicing.
How do alternative modes of gene expression and RNA splicing contribute to the diversity of proteins produced from a single gene?
Alternative modes of gene expression and RNA splicing allow for the production of alternative combinations of exons within a gene. This leads to the generation of more than one protein from a single gene.
Do humans and vertebrates engage in alternative gene expression and RNA splicing more extensively compared to other life forms?
Yes, humans and other vertebrates engage in alternative gene expression and RNA splicing more extensively than bacteria, invertebrates, and many other life forms. This increased complexity allows for greater diversity in the proteins produced.
This is because bacteria and other single-celled organisms lack introns. THis causes bacteria to lack a level of diversity found in eukaryotes
