gene mutations regulation of gene expression – part iii spring 2013 - althoff reference: mader...
TRANSCRIPT
![Page 1: Gene Mutations Regulation of Gene Expression – Part III Spring 2013 - Althoff Reference: Mader & Windelspecht Ch. 13) Lec 20](https://reader036.vdocument.in/reader036/viewer/2022062423/56649f005503460f94c1625a/html5/thumbnails/1.jpg)
• Gene Mutations
Regulation of Gene Expression – Part IIISpring 2013 - Althoff Reference: Mader & Windelspecht Ch. 13)
Lec20
![Page 2: Gene Mutations Regulation of Gene Expression – Part III Spring 2013 - Althoff Reference: Mader & Windelspecht Ch. 13) Lec 20](https://reader036.vdocument.in/reader036/viewer/2022062423/56649f005503460f94c1625a/html5/thumbnails/2.jpg)
• A gene mutations is __________ change in the _____________________ in DNA
• The “change” can result in a) no effect on protein activity to b) complete inactivity
• A ____________________ is one that occurs in _______________ and can be passed to subsequent generations.
• A ____________________ is one that occurs in ___________—and therefore may only affect a small number of cells in a tissue
• Somatic mutations _________ passed on to future generations
Gene Mutations
![Page 3: Gene Mutations Regulation of Gene Expression – Part III Spring 2013 - Althoff Reference: Mader & Windelspecht Ch. 13) Lec 20](https://reader036.vdocument.in/reader036/viewer/2022062423/56649f005503460f94c1625a/html5/thumbnails/3.jpg)
Causes – 2 basic types• ________________ mutations = happen for no apparent
reason…a result of abnormalities in normal biological processes
• ___________ mutations = induced by ____________ ______________. They may result from exposure to
a) toxic chemicalsb) radiation c) other?
These “exposures” “induce/cause” changes in base sequences of DNA
![Page 4: Gene Mutations Regulation of Gene Expression – Part III Spring 2013 - Althoff Reference: Mader & Windelspecht Ch. 13) Lec 20](https://reader036.vdocument.in/reader036/viewer/2022062423/56649f005503460f94c1625a/html5/thumbnails/4.jpg)
Spontaneous Mutations• Again, associated with “normal” biological processes• Example: moveable piece of DNA, termed a
___________, may “jump” from location to another, disrupting one or more genes…leading to an abnormal product
Interrupted DNA sequence
![Page 5: Gene Mutations Regulation of Gene Expression – Part III Spring 2013 - Althoff Reference: Mader & Windelspecht Ch. 13) Lec 20](https://reader036.vdocument.in/reader036/viewer/2022062423/56649f005503460f94c1625a/html5/thumbnails/5.jpg)
Spontaneous Mutations…con’t• Again, associated with “normal” biological processes• Example: On rare occasions, a base in DNA can undergo a
_________________ that leads to a mispairing during replication…a subsequent base pair change may be carried forth in future generations
• This ↑example is a rare occurrence because…._______________—the enzyme that carries out replication—__________ the new strand againstthe old strand and ________ mismatched nucleotides…and _______ it with the correct one
• Estimates: only ___ mistake in every ___________ nucleotide pair replications
![Page 6: Gene Mutations Regulation of Gene Expression – Part III Spring 2013 - Althoff Reference: Mader & Windelspecht Ch. 13) Lec 20](https://reader036.vdocument.in/reader036/viewer/2022062423/56649f005503460f94c1625a/html5/thumbnails/6.jpg)
Induced Mutations • Are known as _____________• Those mutagens known to cause cancer are also known as
_______________• Sources for chemical mutagens include: a)
food we eat i) AF-2 once used in Japan – now banned ii) Safrole flavoring agent once used in root beer – now banned iii) Acrylamide—a natural product found in French fries—suspected mutage b) industrial chemicals & tobacco smoke
i) tobacco changes several known organic chemicals known as carcinogens
![Page 7: Gene Mutations Regulation of Gene Expression – Part III Spring 2013 - Althoff Reference: Mader & Windelspecht Ch. 13) Lec 20](https://reader036.vdocument.in/reader036/viewer/2022062423/56649f005503460f94c1625a/html5/thumbnails/7.jpg)
Induced Mutations…con’t • Forms of radiation known to cause mutations:
X-rays gamma raysUltraviolet (UV) radiation
• UV - absorbed by pyrimidines in DNA
• UV - if 2 thymine molecules next to one another, UV radiation may cause them to bind together…forming _______________. Result: kink in the DNA. They can sometimes be repaired/removed by ____________ enzymes
![Page 8: Gene Mutations Regulation of Gene Expression – Part III Spring 2013 - Althoff Reference: Mader & Windelspecht Ch. 13) Lec 20](https://reader036.vdocument.in/reader036/viewer/2022062423/56649f005503460f94c1625a/html5/thumbnails/8.jpg)
Mutations effect on Protein Activity
• ____________________– change in a ________ DNA nucleotide, and, therefore, possible change in a specific amino acid ex. What results in the cell sickled red blood cell
• ____________________– occur most often when 1 or more nucleotides are either a) inserted or b) deleted from DNA. Result: a completely new sequence of codons and nonfunctional protein. Ex. THE CAT ATE THE RAT. If “C” is deleted, the framework shifts resulting in… THC ATA TET HER AT
![Page 9: Gene Mutations Regulation of Gene Expression – Part III Spring 2013 - Althoff Reference: Mader & Windelspecht Ch. 13) Lec 20](https://reader036.vdocument.in/reader036/viewer/2022062423/56649f005503460f94c1625a/html5/thumbnails/9.jpg)
Mutations Can Cause Cancer
• Current estimate: ________ people will develop cancer at some time in their lives --of the affected: 1/3 of the women will die 1/4 of the males will die
• 3 deadliest forms of cancer: a) lungb) colon and
rectal c) breast• Cancer results from a series of accumulated mutations as
noted earlier this semester (see Lab 9 & text Chapter 9)
![Page 10: Gene Mutations Regulation of Gene Expression – Part III Spring 2013 - Althoff Reference: Mader & Windelspecht Ch. 13) Lec 20](https://reader036.vdocument.in/reader036/viewer/2022062423/56649f005503460f94c1625a/html5/thumbnails/10.jpg)
Cancer…con’t
• __________________ genes ordinarily act as brakes on cell division…especially if abnormalities detected.
• _______________ stimulate cell division but are turned off in fully differentiated , non-dividing cells.
• When proto-oncogenes mutate, they become _______________ that are ______________________.
• The result of 2 and 3: cell division occurs _____________ because a ______________ pathway that reaches from the plasma membrane to the nucleus is non-functional.
1
2
3
4
![Page 11: Gene Mutations Regulation of Gene Expression – Part III Spring 2013 - Althoff Reference: Mader & Windelspecht Ch. 13) Lec 20](https://reader036.vdocument.in/reader036/viewer/2022062423/56649f005503460f94c1625a/html5/thumbnails/11.jpg)
Cell Signaling Pathway that Stimulates a _______________ TUMOR SUPPRESSOR GENE
![Page 12: Gene Mutations Regulation of Gene Expression – Part III Spring 2013 - Althoff Reference: Mader & Windelspecht Ch. 13) Lec 20](https://reader036.vdocument.in/reader036/viewer/2022062423/56649f005503460f94c1625a/html5/thumbnails/12.jpg)
Cell Signaling Pathway that Stimulates an _______________________
![Page 13: Gene Mutations Regulation of Gene Expression – Part III Spring 2013 - Althoff Reference: Mader & Windelspecht Ch. 13) Lec 20](https://reader036.vdocument.in/reader036/viewer/2022062423/56649f005503460f94c1625a/html5/thumbnails/13.jpg)
Cancer…con’t
• Recall ____________________from last lecture (#19)…
• One of the 5 ways to control gene expression
• Transcription factors are fundamental to
a) DNA replication & repair
b) cell growth & division c) __________________
d) __________________