NU 318 Genetics Exam 3 With
Complete Solution
Define Epigenetics - ANSWER the study of environmental influences on gene
expression that occur WITHOUT a DNA change
- they are chemical or environmental modifications
ex: parental diet and environmental toxins
What are the components of the epigenome? - ANSWER 1. methylation
2. micro RNA
3. histone modification
Define methylation - ANSWER Addition of a chemical tag that turns off gene
expression from a parent
- DNA sequence AND methyl tag are passed down to offspring
Histone modification - ANSWER changes in the structure of histones that
make it more or less likely that a segment of DNA will be transcribed
- chemical tags are attacked to the tails of histones
- when histones are too tightly wound then parts of DNA segments will not
be available for transcription
What are micro-RNA? - ANSWER - small single stranded RNA that bind to
mRNA and make it double stranded
- they prevent translation, and therefore protein synthesis
,What is a microbiome? - ANSWER the microorganisms in a particular
environment (including the body or a part of the body).
- unique to every person
What was the Dutch Hunger Winter? - ANSWER - a super cold winter that
prevented shipments of food
- people survived on 30% of normal intake
- babies malnourished during the LAST few months of gestation remained
SMALL
- babies malnourished in FIRST months of gestation had more OBESITY and
health problems in the future
What is the relationship between epigenetics and cancer? - ANSWER WE
KNOW:
a. cancer represents changes in gene expression
b. damage or loss of expression of suppressor genes can permit expression
of cancer genes
c. damage or mutation of an oncogene can make it less susceptible to control
by suppressor products
What is the relationship between methylation and cancer? - ANSWER - this is
the most studied epigenetic mechanism in cancer
- areas around oncogenes are often hypomethylated (increase expression)
- areas around tumor suppressor genes are hypermethylated (decrease
expression)
, What are cancer preventions and/or therapy research that have been found?
- ANSWER THE FOLLOWING HELP PREVENT CANCER
1.) There are compounds to PREVENT methylation of suppressor genes
2.) There are compounds to CAUSE oncogenes to be methylated
3.) There are drugs that inhibit enzymes that increase methylation or change
in histone influence
4.) Antioxidant influence
Name 2 environmental toxins and why are they toxic? - ANSWER 1. Biphenol
A (BPA)
2. Phthylates
- these change cell structure and therefore influence future generations
What was the experiment with the Agouti Mice? - ANSWER - mice with two
copies of dominant Agouti gene: yellow and obese
- when the Agouti gene was methylated:
a.) They became brown
b.) They developed a normal appetite
What is the primary risk factor for having a mentla disorder? - ANSWER
having a close family member who had the disorder
What is true about Schizophrenia, Bipolar disorder, & Autism - ANSWER all
three of these have a higher heritability than Parkinsons and Breast Cancer
What are the pharmacogenetics for mental disorders? - ANSWER - only some
psychotropic medications are helpful for some individuals
Complete Solution
Define Epigenetics - ANSWER the study of environmental influences on gene
expression that occur WITHOUT a DNA change
- they are chemical or environmental modifications
ex: parental diet and environmental toxins
What are the components of the epigenome? - ANSWER 1. methylation
2. micro RNA
3. histone modification
Define methylation - ANSWER Addition of a chemical tag that turns off gene
expression from a parent
- DNA sequence AND methyl tag are passed down to offspring
Histone modification - ANSWER changes in the structure of histones that
make it more or less likely that a segment of DNA will be transcribed
- chemical tags are attacked to the tails of histones
- when histones are too tightly wound then parts of DNA segments will not
be available for transcription
What are micro-RNA? - ANSWER - small single stranded RNA that bind to
mRNA and make it double stranded
- they prevent translation, and therefore protein synthesis
,What is a microbiome? - ANSWER the microorganisms in a particular
environment (including the body or a part of the body).
- unique to every person
What was the Dutch Hunger Winter? - ANSWER - a super cold winter that
prevented shipments of food
- people survived on 30% of normal intake
- babies malnourished during the LAST few months of gestation remained
SMALL
- babies malnourished in FIRST months of gestation had more OBESITY and
health problems in the future
What is the relationship between epigenetics and cancer? - ANSWER WE
KNOW:
a. cancer represents changes in gene expression
b. damage or loss of expression of suppressor genes can permit expression
of cancer genes
c. damage or mutation of an oncogene can make it less susceptible to control
by suppressor products
What is the relationship between methylation and cancer? - ANSWER - this is
the most studied epigenetic mechanism in cancer
- areas around oncogenes are often hypomethylated (increase expression)
- areas around tumor suppressor genes are hypermethylated (decrease
expression)
, What are cancer preventions and/or therapy research that have been found?
- ANSWER THE FOLLOWING HELP PREVENT CANCER
1.) There are compounds to PREVENT methylation of suppressor genes
2.) There are compounds to CAUSE oncogenes to be methylated
3.) There are drugs that inhibit enzymes that increase methylation or change
in histone influence
4.) Antioxidant influence
Name 2 environmental toxins and why are they toxic? - ANSWER 1. Biphenol
A (BPA)
2. Phthylates
- these change cell structure and therefore influence future generations
What was the experiment with the Agouti Mice? - ANSWER - mice with two
copies of dominant Agouti gene: yellow and obese
- when the Agouti gene was methylated:
a.) They became brown
b.) They developed a normal appetite
What is the primary risk factor for having a mentla disorder? - ANSWER
having a close family member who had the disorder
What is true about Schizophrenia, Bipolar disorder, & Autism - ANSWER all
three of these have a higher heritability than Parkinsons and Breast Cancer
What are the pharmacogenetics for mental disorders? - ANSWER - only some
psychotropic medications are helpful for some individuals
