Back to AI Flashcard MakerBiology /Biology IB HL - 7.1 DNA Structure Part 4
What are 2 characteristics of gene regulatory sequences?
role and structure
sequences that are involved in the process of transcription
| includes promoters, enhancers and silencers
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Key Terms
Term
Definition
What are 2 characteristics of gene regulatory sequences?
role and structure
sequences that are involved in the process of transcription
| includes promoters, enhancers and silencers
What is DNA profiling?
DNA profiling is a technique by which individuals can be identified and compared via their respective DNA profiles
What is identified in DNA profiling?
Within the non-coding regions of an individual’s genome there exists satellite DNA – long stretches of DNA made up of repeating elements called short ...
How can tandem repeats be excised? DNA profiling
Tandem repeats can be excised using restriction enzymes and then separated with gel electrophoresis for comparison
Why are DNA profiles unique?
As individuals will likely have different numbers of repeats at a given satellite DNA locus, they will generate unique DNA profiles
Longer repeats wil...
How is DNA packaged in eukaryotic organisms?
In eukaryotic organisms, the DNA is packaged with histone proteins to create a compacted structure called a nucleosome
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| Term | Definition |
|---|---|
What are 2 characteristics of gene regulatory sequences? | role and structure
sequences that are involved in the process of transcription
| includes promoters, enhancers and silencers |
What is DNA profiling? | DNA profiling is a technique by which individuals can be identified and compared via their respective DNA profiles |
What is identified in DNA profiling? | Within the non-coding regions of an individual’s genome there exists satellite DNA – long stretches of DNA made up of repeating elements called short tandem repeats (STRs) |
How can tandem repeats be excised? DNA profiling | Tandem repeats can be excised using restriction enzymes and then separated with gel electrophoresis for comparison |
Why are DNA profiles unique? | As individuals will likely have different numbers of repeats at a given satellite DNA locus, they will generate unique DNA profiles
Longer repeats will generate larger fragments, while shorter repeats will generate smaller fragments |
How is DNA packaged in eukaryotic organisms? | In eukaryotic organisms, the DNA is packaged with histone proteins to create a compacted structure called a nucleosome |
What is the role of nucleosomes? | Nucleosomes help to supercoil the DNA, resulting in a greatly compacted structure that allows for more efficient storage |
What is the role of supercoiling? | Supercoiling helps to protect the DNA from damage and also allows chromosomes to be mobile during mitosis and meiosis |
What is the DNA complexed with and what does it form? | The DNA is complexed with eight histone proteins (an octamer) to form a complex called a nucleosome |
What are nucleosomes linked by and what do they form? | Nucleosomes are linked by an additional histone protein (H1 histone) to form a string of chromatosomes |
What does a string of chromatosomes form? | These then coil to form a solenoid structure (~6 chromatosomes per turn) which is condensed to form a 30 nm fibre |
What is done to the fibres and what do they form? organisation of eukaryotic dna | These fibres then form loops, which are compressed and folded around a protein scaffold to form chromatin |
What is the final step of the organisation of eukaryotic DNA, involving chromatin? | Chromatin will then supercoil during cell division to form chromosomes that are visible (when stained) under microscope |
What is the structure of a nucleosome? | A nucleosome consists of a molecule of DNA wrapped around a core of eight histone proteins (an octamer) |
How are the charges arranged in a histone? | The negatively charged DNA associates with positively charged amino acids on the surface of the histone proteins |
What extrudes from the histone? | The histone proteins have N-terminal tails which extrude outwards from the nucleosome |
What happens during chromosomal condensation? | During chromosomal condensation, tails from adjacent histone octamers link up and draw the nucleosomes closer together |