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Index
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Genetics
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Chapter 1
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Level 1
level: Level 1
Questions and Answers List
level questions: Level 1
Question
Answer
Protein or non coding RNA
Functional gene product
Process where gene information is used to produce a functional gene product
Gene expression
Generally regulate gene expression
Non-coding RNA function
tRNA, rRNA
non coding RNA examples
Cystic Fibrosis, Huntingtons, Downsyndrome, Fragile X, Thalassaemia
Common genetic disorders
Region of DNA that specifies production a functional gene product
Gene
Chemical that contains all the genetic information required to specify all aspects of what make a human
DNA
Passed down maternally, 1% of DNA
Mitochondrial DNA
Diploid (2n)
Somatic cells
haploid (n)
Gametes
99% of DNA, 46
Chromosomes
1 to 1.5% of all DNA
Protein coding genes
Regulatory DNA segment recognised by RNA polymerase to initiate transcription
Promoter
Contain regulatory elements that influence on gene expressional at the transcriptional and translational level. Transcribed but not usually translated
5' and 3' UTR
Contain regulatory elements that influence on gene expression at the transcriptional and translational level
Introns
Prevents mRNA degradation, regulated translation and nuclear export, promotes intron excision
5' G cap
Prevents mRNA degradation, regulates translation and nuclear export
Poly A tail
Short stretch to which activators bind. Increase rate of transcription
Enhancers
Bind inhibitors decrease rate of transcription
Silencer
Jumping genes, aka transposable elements, 45% of genome
Transposons
DNA changes that many of us have (natural variation)
Polymorphisms
Rare changes in DNA that deviate away from the norm
Mutation
No effect on functional gene product
Neutral mutation
A new or improved function
Advantageous mutation
Effect on gene product is deleterious and causes genetic disease
Disadvantageous mutation
Type of mutation, Location in gene and Location in protein structure or ncRNA sequence
Mutation effects on product depend on
Number of chromosomes changes
Chromosomal mutation
Trisomy 21
Chromosomal mutation example
Parts of a chromosome change or are rearranged
Subchromosomal mutation
Due to chromosomal mutation. Baby survives as chromosome 21 is the second smallest chromosome so the gene dosage is not big enough to cause death.
Trisomy 21
Insertion, deletion, duplication, inversion, translocation
Subchromosomal mutation types
Subchromosomal, creates 2 little genes
Deletion mutation
Subchromosomal, region is flipped only a problem if in coding or regulatory region
Inversion mutation
Small alteration of the DNA sequence
DNA mutation
Single nucleotide mutation, insertion or deletions, frameshift, dynamic
DNA mutation types
single nucleotide mutation, synonymous substitution
Silent mutation
single nucleotide mutation, non-synonymous substitution
Missense mutation
single nucleotide mutation, codes for premature stop codon
Nonsense mutation
Silent, missense, nonsense, frameshift
Single nucleotide mutation types
A small number of bases are inserted or deleted, indels that are not multiples of 3 will cause frameshift mutations
Insertion or deletion mutations
Sequence beyond mutation is changed, can often lead to stop codons
Frameshift mutation
expansion of polymorphic DNA repeat sequence beyond a copy number threshold
Dynamic mutation (?)
Huntingtons, fragile X
dynamic mutation examples
abnormal gene products, abnormal regulation or frameshift
Dynamic mutation consequences
10nm configuration, transcriptionally active
Euchromatin
50nm configuration, transcriptionally inactive
Heterochromatin
Special DNA packaging protein
Histone
DNA wrapped around a histone
Chromatin
Chemical covalent modifications of DNA that result in changes to regulation of a gene but don't affect the DNA sequence
Epigenetics
Change in response to stimuli
Dynamic chemical modifications of DNA
Are passed on to future generations
Stable chemical modification of DNA
genetics deals with a single gene whereas genomics deals with the entire genome
Epigenetics vs Epigenomics