Download Ch. 13.3 13.4 notes mutations

Notes: Chapter 13: Mutations and Gene Expression
Mutations: Changes in ______________________ information that can be __________________________
Gene Mutations: changes in one or a few _________________ along a _______________
•
Point mutations – occur at a single point in the _____________________________________________
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_________________________ – one base is changed to a different base (CCC to CCA)
•
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Sometimes these affect only one _____________________. Sometimes they have no effect at
all.
Frameshift mutations – the “reading frame” of the genetic code has been shifted by either
__________________________________________ a base. These can change every
____________________________ following the point of mutation.
– Insertions – a base is ___________________
– Deletions – a base is _______________________
• Sometimes a protein is altered so much from these mutations that they cannot perform their
function.
Chromosomal Mutations – a change in the ______________________ or ___________________________ of a
chromosome, the location of a ______________ on a chromosome, or the number of ______________ of some genes
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Deletion – ________________________________________ on a chromosome
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Duplication – _________________________________________ on a chromosome
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Inversion – ___________________________________________ on a chromosome
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Translocation – genes from one chromosome are __________________________________________
that wouldn’t ordinarily carry those genes
Mutagens: Chemical or physical agents that give rise to some ______________________________
Examples:
Mutations can have harmful effects, no effect, or can be helpful.
Harmful effects: a defective ________________ is produced; gene function is _________________; example: sickle cell
disease in humans
Helpful effects: a protein is produced that enables the organism to
_____________________________________________________________________________; example: resistance of
insects to pesticides; example: _____________________ – having extra sets of chromosomes leads to larger, stronger
plants (3N)
Chapter 13.4 Gene Regulation and Expression
Prokaryotic Gene Regulation
•
Operon – a group of genes that are __________________________ (turned on or off) together – these genes
usually have a related function
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Example: lac operon – 3 genes in E. coli that must be turned on together before this bacterium can use lactose
as a food
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The breakdown of lactose by E. coli is completed by proteins coded for on the lac operon. If lactose is
not the immediate food source then the lac operon is not needed and these genes are turned off.
Eukaryotic Gene Regulation
•
TATA box – a segment before a _____________________ - that helps position
__________________________________________
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Transcription factors – ____________________ that bind to DNA that ensure that transcription of a gene is used
at the right __________________ and that proteins are made in the right _____________________
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Guide and stabilize the binding of ______________________________________
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Regulatory proteins that control the rate of ______________________________________
Hox Genes
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Homeobox (Hox) genes: determine the ____________________________________ of an organism at the
zygote level
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Tell the cells of the body how to ___________________________________________ as the body grows
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The order of these _____________________ on the chromosome matches the order of the traits in the
organism
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Discovered in fruit flies but are found in all animals including humans
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The order of these genes is the same throughout a ____________________________
•
A _______________________________ in the Hox genes of fruit flies has yielded wings or legs in areas that they
otherwise would not be
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A mutation in the Hox genes of humans could lead to ______________________________________________
Do muscle cells and nerve cells contain the same genes? __________________
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Every cell in the body has the same ____________ (except gametes)
DNA regulation is important in cell __________________________________.
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Cells of different types have different genes _____________________________________________________
RNA interference (RNAi): silencing a gene by way of small RNA segments (microRNA or miRNA)bound to a protein – a
“silencing complex”
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Silencing complex _______________________________________________ segments of mRNA that correspond
to the sequence on the miRNA thus preventing the translation of that section of mRNA
Huntington’s Disease: Caused by a single _____________________________________________________ gene
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Genotype: ___________
•
This mutant gene produces a ___________________________ that causes nerve cells to become damaged and
areas of the brain to deteriorate. This will then interfere with
_________________________________________________________________________________________
How might RNAi technology be used to treat Huntington’s disease?