BIOL 133 EXAM 3 QUESTIONS WITH
100% CORRECT ANSWERS LATEST
VERSION 2025/2026.
Epigenetics - ANS "above the gene"
Epigenetic changes - ANS - DO NOT ALTER DNA SEQUENCE
- result in changes to chemical groups that associate with DNA
- changes can sometimes be passed to a new generation
Epigenetics example - ANS - 2 groups of rats
- 1 group was "loved" other was neglected
- NR3C1 is gene that plays role in regulating stress
- Loved rats: blood pressure and stress hormones within normal - NR3C1 activity strong
- Neglected rats: blood pressure and stress hormones high - NR3C1 activity silenced by
additional methyl groups
Globin chain switching - ANS - hemoglobin: carries oxygen, made up of 4 subunits
- subunits differ in embryo, fetus & adult (EZGAB))
Embryo - ANS epsilon & zeta
1 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
,Fetus - ANS alpha & gamma
Adult - ANS alpha & beta
Blood plasma composition - ANS - plasma contains many different types of proteins (~40,000)
- plasma protein profile changes when individual becomes sick
- blood tests look for levels of proteins that indicate disease
Proteomics - ANS - study of function of all expressed proteins
- 1 gene - 1 protein does not work
- gene expression changes over time (developing fetus has different gene expression than adult)
Human genome - ANS ~20,000 genes
~100,000 mRNAS
~ 1 million proteins
Control of gene expression, how do we turn genes off and on? - ANS - promoter regions -
RNA polymerase and transcription factors must bind promotor
Histones - ANS - proteins around which DNA entwines
- expose DNA to allow transcription
Chromatin remodeling - ANS - acetyl groups bind lysine
- methyl groups bind and turn off transcription
MicroRNAs - ANS - microRNAs bind mRNAs and prevent translation
2 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
, Maximizing genetic info - ANS - only 1.5% base pairs code for proteins
- we have ~ 20,000 genes but 1 million different proteins
Alternate splicing - ANS exons can be shuffled into unique arrangements to produce different
proteins
Protein modification - ANS different chemical groups (sugars and lipids) added to base
protein
Protein splicing - ANS a single protein is cut into two
Noncoding DNA - ANS - most of the human genome does not encode proteins!!!
- viral DNA (~8% of our genome is viral (human endogenous retroviruses)
- Noncoding RNAs (tRNA, rRNA, snoRNA)
- psuedogenes
- repeats
- introns
- promoters
Mutation - ANS change in nucleotide base sequence of a gene (genotype)
Mutant - ANS change in phenotype
"loss of function" mutations - ANS recessive
3 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
100% CORRECT ANSWERS LATEST
VERSION 2025/2026.
Epigenetics - ANS "above the gene"
Epigenetic changes - ANS - DO NOT ALTER DNA SEQUENCE
- result in changes to chemical groups that associate with DNA
- changes can sometimes be passed to a new generation
Epigenetics example - ANS - 2 groups of rats
- 1 group was "loved" other was neglected
- NR3C1 is gene that plays role in regulating stress
- Loved rats: blood pressure and stress hormones within normal - NR3C1 activity strong
- Neglected rats: blood pressure and stress hormones high - NR3C1 activity silenced by
additional methyl groups
Globin chain switching - ANS - hemoglobin: carries oxygen, made up of 4 subunits
- subunits differ in embryo, fetus & adult (EZGAB))
Embryo - ANS epsilon & zeta
1 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
,Fetus - ANS alpha & gamma
Adult - ANS alpha & beta
Blood plasma composition - ANS - plasma contains many different types of proteins (~40,000)
- plasma protein profile changes when individual becomes sick
- blood tests look for levels of proteins that indicate disease
Proteomics - ANS - study of function of all expressed proteins
- 1 gene - 1 protein does not work
- gene expression changes over time (developing fetus has different gene expression than adult)
Human genome - ANS ~20,000 genes
~100,000 mRNAS
~ 1 million proteins
Control of gene expression, how do we turn genes off and on? - ANS - promoter regions -
RNA polymerase and transcription factors must bind promotor
Histones - ANS - proteins around which DNA entwines
- expose DNA to allow transcription
Chromatin remodeling - ANS - acetyl groups bind lysine
- methyl groups bind and turn off transcription
MicroRNAs - ANS - microRNAs bind mRNAs and prevent translation
2 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
, Maximizing genetic info - ANS - only 1.5% base pairs code for proteins
- we have ~ 20,000 genes but 1 million different proteins
Alternate splicing - ANS exons can be shuffled into unique arrangements to produce different
proteins
Protein modification - ANS different chemical groups (sugars and lipids) added to base
protein
Protein splicing - ANS a single protein is cut into two
Noncoding DNA - ANS - most of the human genome does not encode proteins!!!
- viral DNA (~8% of our genome is viral (human endogenous retroviruses)
- Noncoding RNAs (tRNA, rRNA, snoRNA)
- psuedogenes
- repeats
- introns
- promoters
Mutation - ANS change in nucleotide base sequence of a gene (genotype)
Mutant - ANS change in phenotype
"loss of function" mutations - ANS recessive
3 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
