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level: 3.1 Genes

Questions and Answers List

level questions: 3.1 Genes

QuestionAnswer
How is DNA organised in nucleus?chromosomes
What is a gene?a heritable factor that has a DNA length and influences a specific trait
What is a locus? plural form?position of a gene on a specific chromosome loci
What is an allele? how do they differ? (3)different forms of a gene that codes for different versions of a trait have very similar gene sequences only differ by few bases eg: brown eye color and blue eye color are 2 different alleles
What is a mutation?a change in nucleotide sequence of a DNA section
How are new alleles formed?by mutation
What are the 3 categories of gene mutations?Beneficial Detrimental Neutral
What are beneficial mutations?missense - changes the DNA sequence to make new variations of a trait
What are detrimental mutations?nonsense - shorten gene sequence which affects the normal function
What are neutral mutations?silent - no effect on the feature
What is sickle cell anemia?caused by base substitution on the 6th codon of beta chain of hemoglobin
What are the steps of sickle cell anemia base substitution?DNA: GAG = GTG (non transcribed) DNA: CTG = CAC (Transcribed) MRNA: GAG = GUG (Identical to non transcribed) Polypeptide: glutamic acid = valine
What are the problems caused by sickle cell anemia? (4)forms insoluble fibrous strands = affects how much oxygen can be carried = tiredness and anemia strands can block capillaries forming clots bec of sickle shape sickle shaped blood is destroyed more easily
How does the shape of SCA change?bioncave = sickle shaped because it forms insoluble fibrous strands
what is the genome?total genetic info of an organism
How many chromosomes do humans have?46
What is the HGP?Human genome project sequenced the human genome by mapping screening meds ancestry
what are the 4 ways HGP has sequenced the human genome?mapping = number and size of sequences screening = gene probes to detect genetic diseases medicine = new proteins discovered led to better treatment ancestry = insight into evolution
what is the link between no of genes and biological complexity?differs between species but a greater number of genes doesn't mean greater biological complexity