Cell Cycle, Cellular Ageing and Cell Death, Regulation of Gene Expression Flashcards
What is a purpose of DNA?
Dictates cells’ structure and function
What are a major source of mutations?
Errors in copying DNA during DNA replication
Why do cells progress through the cell cycle?
To undergo mitosis
What are the names of controlled and uncontrolled cell death?
Apoptosis: controlled cell death
Necrosis: uncontrolled cell death
What are the definitions of the following terms?
Gene
Allele
Exon
Intron
Genotype
Phenotype
Mutation
Gene: functional region of DNA that codes for a sequence of RNA
Allele: individual variant of a gene
Exon: portions of a gene product that are removed via RNA splicing
Intron: portions of a gene product that are retained following RNA splicing
Genotype: the genes (and alleles of them) in a cell/organism
Phenotype: physical features of an organism as of its genotype
Mutation: changes in the genetic sequence (order of base nucleotides)
How can RNA be derived from DNA?
Transcription
What are the multiple forms of RNA and their function/role?
Messenger RNA (mRNA): translated to produce polypeptides
Transfer RNA (tRNA): involved with translation
Ribosomal RNA (rRNA): major part of ribosomes
Short interfering and micro RNA (siRNA and miRNA): inhibit translation of complementary mRNA
How do miRNA and siRNA inhibit translation?
Bind to complementary mRNA and prevent the ribosome from binding and allowing translation to occur
Marks mRNA for degradation, therefore there is no protein synthesised
What is the function of miRNA and siRNA?
To not allow too much mRNA to be present, so as to have no extremes
Reduces likelihood of mutations
What is all gene expression due to?
Dictating factors such as methylation, acetylation and transcription factors
What is fine tuning?
Nuanced activity
Why may a cell have cell-signalling?
To prevent the translation of unnecessary proteins (hence miRNA and siRNA) as cell has multiple things in multiple directions
What is the meaning of “one gene, one protein”?
One gene codes for one protein and determines its function
Why is there controversy regarding “one gene, one protein”?
Not strictly true as multiple proteins may come from one gene as not all triplets read for the gene
Splicing causes certain exons to be lost or kept e.g., antibodies
