Section 6

Question 1

What is the genome?

Answer 1

The complete set of genetic material encoded in a cell or virus

Question 2

How many chromosomes does the human genome contains?

Answer 2

23 pairs

Question 3

True or false:

The genome does not include DNA from organelles like mitochondria

Answer 3

True. This does not count as part of the human or nuclear genome

Question 4

How many pairs of chromosomes do humans have?

Answer 4

23 pairs

22 pairs of autosomes and 2 sex chromosomes

Question 5

True or false:

Intronic and intergenetic regions are classified as “junk DNA”

Answer 5

False

Question 6

What are promoters?

Answer 6

Regulatory sequences

Question 7

What are intronic regions

Answer 7

Non-coding regions

Question 8

As organisms become more sophisticated, we see ______ regulatory and structural sequences

a) less
b) more
c) normal

Answer 8

b) more

more splitting of genes

Question 9

What are the essential components of genes and their regulatory elements?

Answer 9

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.

Question 10

What are homologs in the context of genomics?

Answer 10

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)

Question 11

Define orthologs in comparative genomics.

Answer 11

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)

Question 12

What are paralogs in genomics, and how do they typically arise?

Answer 12

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

Question 13

What are examples of two large genomic rearragnments?

Answer 13

Inversions and fusions

Question 14

Explain the concept of inversions in the context of genomic rearrangements.

Answer 14

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.

Question 15

What are fusions in genomic rearrangements, and how do they typically occur?

Answer 15

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.

Question 16

How do genomic rearrangements, such as fusions, affect the genetic differences between species like humans and chimpanzees?

Answer 16

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.

Question 17

______ are genes in different organisms that possess a clear sequence and functional relationship to each other

Answer 17

Orthologs

Question 18

________ 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.

Answer 18

Paralogs

Question 19

__________ are genes or proteins with sequence similarities

Answer 19

Homologs

Question 20

What is the process known as when introns are removed from a primary RNA transcript?

Answer 20

The process of removing introns from a primary RNA transcript is known as splicing.

Question 21

How do alternative modes of gene expression and RNA splicing contribute to the diversity of proteins produced from a single gene?

Answer 21

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.

Question 22

Do humans and vertebrates engage in alternative gene expression and RNA splicing more extensively compared to other life forms?

Answer 22

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