Genetic Mutations & Gene Regulation - C5 Flashcards
Define degenerate
Multiple bases able to code for an amino acid
What does it mean to use DNA?
To make proteins
Define Gene
A section of DNA that codes for a protein
What is an intron?
Part of a gene that remains in the DNA
What is an exon?
Part of a gene that is removed from the DNA and sewn into mRNA
on and off
What is the purpose of the regulatory gene (at the start of the gene cluster?
Turns ‘on’ all enzymes are made, turns ‘off’ no enzymes are made
4 kinds
What are the different kinds of DNA point mutations?
Substitutions, deletions/insertions, inversions
What are the two kinds of chromosomal mutations?
Aneuploidy: irregular number of a particular chromosome (Down Syndrome - 3 copies of no. 21 chromosome)
Polyploidy: more than the normal 2 complete sets of chromosomes (wheat has this) caused by issues separating during meiosis
Is mutation random?
Yes, but it can be increased by factors such as high energy particles such as UV light, gamma rays, cigarettes, viruses and grilled meat
What are mutagens?
Chemical factors - different chemical that reacts with parts of the DNA molecule
What are the 3 impacts of mutations?
Neutral - the change does not make a difference (e.g. a point mutation that does not change the amino acid)
Negative - The change alters an amino acid and the protein functions differently (e.g. sickle cell anemia)
Positive - A mutation occurs that does make a difference, but provides genetic advantage (camouflage)
What are structural genes?
Genes that produce proteins that become part of structure and function of the organism
What are regulator genes?
They determine whether other genes are active or not and the rate at which products are made
What is an operon?
A cluster of genes under the control of 1 promoter transcribed as a group - typically code for functionally related proteins (e.g. a group of enzymes all involved in making an amino acid)
What do operons contain?
A promoter region, regulatory genes, operator region
What is the promoter region?
Short section of DNA where RNA polymerase binds to begin transcription
What is the operator?
A section of DNA where a repressor can bind if the enzyme (in this case lacZ, Y and A - for breaking down lactose) is not needed (generally if there is glucose around)
What is lacI?
The regulatory gene at the beginning of the operon that codes for the repressor to be made (it also has it’s own promoter)
What are the three lac enzymes made in the lac operon?
Lac A, Z and Y
What is lactose broken into by the three lac enzymes?
Monosaccharides (single unit sugars for glycolysis)
What is the CAP?
Catabolite Activator Protein (positive regulatory site)
How is the CAP activated?
by the cAMP (cyclic AMP) which is a ‘hunger signal’ made when glucose levels are low
How does cAMP work?
By binding to the CAP, changing its shape and making it able to bind DNA and promote transcription
How does the repressor work?
By attaching to the operator and preventing RNA polymerase from making enzymes
What is allolactose?
A type of lactose that binds to the repressor when lactose is present, allowing RNA polymerase to pass and make lac enzymes Z, Y and A for lactose digestion
What does it mean to be a specialized cell?
In multicellular organisms, cells work together, with each cell having its own specific function
What can specialized cells differ in?
Size, shape, number/type of organelles
What is an example of a specialized plant and animal cell?
Animal: red blood cells
Plants: Xylem cells
How do cells end up different if they all have the same DNA?
Specialization happens during a cells development when exposure to complex biochemicals direct which sections of DNA are used. This is gene regulation
Define Totipotent
Can turn into all cell types
Define Pluripotent
Can turn into most cell types
