L2 Eukaryotic Genomes Flashcards
(21 cards)
What is a genome?
The complete DNA of an organism. In humans, this includes nucleic RNA and mitochondrial DNA (mtDNA)
What is DNA splicing?
DNA splicing refers to the natural and artificial processes of cutting, joining, or rearranging DNA segments.
When does DNA splicing happen naturally?
DNA Repair: Homologous recombination and non-homologous end joining repair DNA breaks and maintain genomic integrity.
Alternative Splicing: During gene expression, introns are removed, and exons are joined in various combinations to produce different protein isoforms from a single gene.
Viral Integration: Some viruses integrate their genetic material into the host genome, leading to natural splicing events.
Transposons: Mobile genetic elements, or “jumping genes,” can insert or excise themselves from the genome, causing rearrangements in DNA sequences.
Meiosis: During the formation of gametes, crossing over occurs, mixing genetic material between homologous chromosomes, resulting in genetic diversity.
What are exons
Exons are the segments of a gene that contain the coding information for proteins. They are the parts of the DNA that are expressed and translated into amino acids, forming proteins.
What is the major groove?
the wider space in the DNA double helix where proteins can bind to the DNA more easily. It plays an essential role in DNA-protein interactions.
What is the minor groove
the narrower space in the DNA double helix. It doesn’t allow as much access for proteins but can also play roles in binding.
What does it mean to say DNA is antiparallel?
Antiparallel - refers to the orientation of the two strands of DNA. One strand runs in the 5’ to 3’ direction, while the other runs in the 3’ to 5’ direction.
What do the 5’ and 3’ ends of DNA do?
5’-3’ direction - the 5’ end has a phosphate group, and the 3’ end has a hydroxyl group. DNA is built by adding nucleotides to the 3’ end.
What do the hydrogen bonds in DNA do?
They are weak covalent bonds that hold the two strands of THE DNA double helix together. They form complementary bases.
Name 5 key differences between eukaryotic and prokaryotic cells
E ahas nucleus, P does not
E has mostly non motile , P bacteria motile others not so much.
E has multiple linear chromosomes, P has circular DNA and some have plasmids.
E has mitochondria, P does not.
E has cell walls, P has peptidoglycan layers.
What is the organisational order of the Gemone
Gene wraps arounds histones. Histones form nucleosomes. Nucleosomes form chromatin. Chromatin forms chromosomes.
What is chromatin remodelling?
Conformational change from loosely packed (euchromatin) to tightly packed (heterochromatin.) Gene expression is on in the former, and off in the latter.
What is a promoter
A promoter is a DNA sequence that helps initiate the transcription of a gene by providing a binding site for RNA polymerase and other regulatory proteins.
What is transcription?
the process by which DNA is copied to produce messenger RNA (mRNA), which carries genetic information from the nucleus to the ribosome for protein synthesis.
What is pre-RNA splicing?
the process of removing non-coding regions (introns) from the initial RNA transcript (pre-mRNA) and joining the remaining coding regions (exons) together to produce a mature mRNA molecule.
what is an intron?
A non-coding section of a gene that is removed during RNA splicing and does not contribute to the final protein product.
What is mature mRNA?
The final processed form of messenger RNA that has had its introns removed and exons joined together. It is ready to be translated into a protein.
Describe bacterial chromosomes
Typically circular, double-stranded DNA molecules that contain the genetic information necessary for the growth and reproduction of bacteria. They are usually located in the nucleoid region of the cell, not enclosed in a nucleus, and are less complex than eukaryotic chromosomes.
What is an operon?
A group of genes in bacteria that are controlled together and share a single promoter. It regulates the expression of those genes as a unit, allowing the bacteria to efficiently respond to environmental changes.
How many base pairs make up the human genome?
3.2billion
