ENVIROMENTAL HEALTH SCIENCE FINAL EXAMS
WITH VERIFIRED ANSWERS PAPER 5-YEAR 2024-
2025
What is the microbiome?
The microbiome are the microbial organisms that live within the intestines, skin,
and within mucus membranes.
How does the microbiome prevent disease?
The microbiome can impact how toxicants are absorbed (or not absorbed) into
the body and impact our susceptibility to disease.
Define: Environmental response gene
This dictates a person's response to certain environmental exposures, but
without exposure it has no health consequence.
Explain how environmental factors influence genetic expression.
Epigenetics - heritable changes in the phenotype without changes in the DNA
structure (genotype). The environment can change what genes are expressed
and when. Epigenetics determines which genes are expressed (turned on or off).
,Central Dogma of DNA to Protein
DNA - Transcription - RNA - Translation - Protein
Types of Genetic Mutations (two big categories)
1. Microlesions
2. Macrolesions
Types of Microlesions (genetic mutations) - Two Types
1. Base-pair substitution
2. Frameshift Mutations
Types of Macrolesions (genetic mutations) - Two Types
1. Chromosome Aberrations
2. Changes in chromosome number (aneuploidy, polyploidy)
Explain base-pair substitution
Changes the sequence of the genetic base pairs (AT/GC) due to an interaction
with an outside chemical structure. Point mutations. Does not always change
the function (but can)
, Explain frameshift mutations
Insertion or deletion of one or more bases (AT/GC) in the sequence. Changes the
reading frame. Almost always get an altered protein, often leads to non-
functional.
Explain Chromosome Aberrations
Change in chromosome structure via deletion, duplication, inversion,
translocation. Benzene, ionizing radiation can cause it.
Explain changes in chromosome number (two types)
1. Aneuploidy - increase in number of one or more chromosomes (usually
sperm/eggs). Odd number of chromosomes in gamete (trisomy/monosomy)
2. Polyploidy - increase in a whole set of chromosomes
Name the 4 types of chromosomal aberrations (macrolesion)
1. Deletion
2. Translocation
3. Duplication
4. Inversion
Define chromosomal deletion
A chromosome segment is lost completely
WITH VERIFIRED ANSWERS PAPER 5-YEAR 2024-
2025
What is the microbiome?
The microbiome are the microbial organisms that live within the intestines, skin,
and within mucus membranes.
How does the microbiome prevent disease?
The microbiome can impact how toxicants are absorbed (or not absorbed) into
the body and impact our susceptibility to disease.
Define: Environmental response gene
This dictates a person's response to certain environmental exposures, but
without exposure it has no health consequence.
Explain how environmental factors influence genetic expression.
Epigenetics - heritable changes in the phenotype without changes in the DNA
structure (genotype). The environment can change what genes are expressed
and when. Epigenetics determines which genes are expressed (turned on or off).
,Central Dogma of DNA to Protein
DNA - Transcription - RNA - Translation - Protein
Types of Genetic Mutations (two big categories)
1. Microlesions
2. Macrolesions
Types of Microlesions (genetic mutations) - Two Types
1. Base-pair substitution
2. Frameshift Mutations
Types of Macrolesions (genetic mutations) - Two Types
1. Chromosome Aberrations
2. Changes in chromosome number (aneuploidy, polyploidy)
Explain base-pair substitution
Changes the sequence of the genetic base pairs (AT/GC) due to an interaction
with an outside chemical structure. Point mutations. Does not always change
the function (but can)
, Explain frameshift mutations
Insertion or deletion of one or more bases (AT/GC) in the sequence. Changes the
reading frame. Almost always get an altered protein, often leads to non-
functional.
Explain Chromosome Aberrations
Change in chromosome structure via deletion, duplication, inversion,
translocation. Benzene, ionizing radiation can cause it.
Explain changes in chromosome number (two types)
1. Aneuploidy - increase in number of one or more chromosomes (usually
sperm/eggs). Odd number of chromosomes in gamete (trisomy/monosomy)
2. Polyploidy - increase in a whole set of chromosomes
Name the 4 types of chromosomal aberrations (macrolesion)
1. Deletion
2. Translocation
3. Duplication
4. Inversion
Define chromosomal deletion
A chromosome segment is lost completely
