BIOL 243 Midterm Notes Exam With
Complete Solutions
Define genetics, genes, and molecular genetics - ANSWER -genetics: study of HEREDITY AND
VARIATION in cells, individuals, and populations
-gene: the FUNCTIONAL UNIT of heredity and variation (on DNA)
-molecular genetics: study of the STRUCTURE AND FUNCTION OF GENES at the molecular
level
Define gene, alleles, genotype, phenotype, and genome - ANSWER -gene: the DNA sequence
involved in making RNA and protein
-allel: VARIANTS of a gene caused by DIFFERENCES IN DNA SEQUENCES
-genotype: the GENE INHERITED by an organism
-phenotype: VISIBLE TRAITS of the individual
-genome: ENTIRE DNA SEQUENCE (ACGT) of an individual
Genes are found on ___________ and are parts of the ________________ that encodes _____________
and _________. What is gene expression? What is the difference between coding and
non-coding RNA and what is the function of each? - ANSWER found on CHROMOSOMES and
are parts of the genome that encode RNA and PROTEIN
-gene expression: TURNING ON a gene to produce RNA and protein
-coding: RNA that makes protein, mRNA
,-non-coding: doesnt make proteins, tRNA or rRNA
What ultimately determines the phenotype of a cell and why? How do alleles contribute to
phenotypic variation? - ANSWER -proteins because they control every reaction in the cell
(enzymes, structural proteins, signalling proteins) (although DNA is the information molecule
that directs protein expression)
-alleles are different forms of a gene caused by different DNA sequences resulting in variation
in protein expression and therefore the phenotype
What is protein expression? What is the difference between enzymes, structural proteins, and
signalling proteins? - ANSWER -protein expression: the type and abundance of proteins in the
cell
-enzymes: catalyze the synthesis and transformation of all biomolecules
-structural proteins: maintain the cell shape
-signalling proteins: such as hormones and receptors
Why do we sequence genomes? How is studying molecular genetics important to:
-human health
-forensics (DNA fingerprinting)
-agriculture
-environment
-evolutionary biology - ANSWER to understand how the types and abundance of RNA and
proteins result in the phenotype of the organism (identify all the genes in the genome)
,-human health: understand human diseases so we can better diagnose and treat
-forensics (DNA fingerprinting): crime, paternity tests, organ donors, finding source of food
poisoning outbreak
-agriculture: creating superior crops and livestock, and "pharm" animals (insulin in cows)
-environment: molecular ecology (identify species, .diagnosis for conservation) genetic
engineering microbes for bioremediation/cleaning
-evolutionary biology: phylogenetics and phylogenomics
In general, what are the three classical experiments that established DNA as the hereditary
molecule? - ANSWER -Griffith: found a substance that could genetically transform
streptococcus pneumonia (mouse)
-Avery, MacLeod, & McCarthy: identified DNA as the molecule that transforms rough S.
pneumonia to the ineffective form (DNAse)
-Hershey and Chase: found the final evidence establishing DNA as the hereditary molecule
(32P in DNA and 35S in proteins)
What is the procedure and findings of Griffith's experiments? - ANSWER Procedure
-When injecting S strain mouse died, R strain mouse lived, S and R mouse died, and dead S
and R mouse died, suggesting that something released from dead S transformed R to S
Conclusion
some molecule, called the "transforming principle" released when S cells were killed could
transform R cells to the virulent S form causing pneumonia, this transformation was
permanent and heritable such that the progeny were also S strain
, What is streptococcus pneumonia? What are the 2 types? - ANSWER bacterial pathogen that
causes pneumonia
1. smooth strain (S): bacterium surrounded by a polysaccharide capsule that protects it from
the immune system thereby allowing infection (virulence)
2. rough strain (R): no capsule, cant evade the immune system (non-virulent)
What were the hypothesis, experiment, and findings of Avery, MacLeod, & McCarthy's
experiments? - ANSWER Hypothesis: the transforming principle could be protein, DNA, or
RNA
Experiment: put in RNAse, Protease, or DNAse to destroy each, kill S cells, and see if R cells
are transformed to S in each
Findings: when DNAse destroyed DNA such that only RNA and protein were left, R remained
as R so that DNA is the transforming principle that plays a role in converting R strain to
virulent S strain
What is the life cycle of a virus (bacteriophage) including the 2 cycles? Which cycle can
become the other? - ANSWER -the viral bacteriophage docs on the surface of the bacteria and
injects viral DNA into the bacteria
-here it can either enter the lytic cycle or the lysogenic cycle
Lytic cycle: virus DNA mass replication separately from bacterial chromosome, resulting in
host cell lyses
Lysogenic cycle: viral DNA is integrated into the bacterial chromosome, lays dormant, as
bacterial DNA replicates, viral DNA is passed onto the progeny cells
Lysogeny can become lytic if the viral DNA is excised from the bacterial chromosome
Complete Solutions
Define genetics, genes, and molecular genetics - ANSWER -genetics: study of HEREDITY AND
VARIATION in cells, individuals, and populations
-gene: the FUNCTIONAL UNIT of heredity and variation (on DNA)
-molecular genetics: study of the STRUCTURE AND FUNCTION OF GENES at the molecular
level
Define gene, alleles, genotype, phenotype, and genome - ANSWER -gene: the DNA sequence
involved in making RNA and protein
-allel: VARIANTS of a gene caused by DIFFERENCES IN DNA SEQUENCES
-genotype: the GENE INHERITED by an organism
-phenotype: VISIBLE TRAITS of the individual
-genome: ENTIRE DNA SEQUENCE (ACGT) of an individual
Genes are found on ___________ and are parts of the ________________ that encodes _____________
and _________. What is gene expression? What is the difference between coding and
non-coding RNA and what is the function of each? - ANSWER found on CHROMOSOMES and
are parts of the genome that encode RNA and PROTEIN
-gene expression: TURNING ON a gene to produce RNA and protein
-coding: RNA that makes protein, mRNA
,-non-coding: doesnt make proteins, tRNA or rRNA
What ultimately determines the phenotype of a cell and why? How do alleles contribute to
phenotypic variation? - ANSWER -proteins because they control every reaction in the cell
(enzymes, structural proteins, signalling proteins) (although DNA is the information molecule
that directs protein expression)
-alleles are different forms of a gene caused by different DNA sequences resulting in variation
in protein expression and therefore the phenotype
What is protein expression? What is the difference between enzymes, structural proteins, and
signalling proteins? - ANSWER -protein expression: the type and abundance of proteins in the
cell
-enzymes: catalyze the synthesis and transformation of all biomolecules
-structural proteins: maintain the cell shape
-signalling proteins: such as hormones and receptors
Why do we sequence genomes? How is studying molecular genetics important to:
-human health
-forensics (DNA fingerprinting)
-agriculture
-environment
-evolutionary biology - ANSWER to understand how the types and abundance of RNA and
proteins result in the phenotype of the organism (identify all the genes in the genome)
,-human health: understand human diseases so we can better diagnose and treat
-forensics (DNA fingerprinting): crime, paternity tests, organ donors, finding source of food
poisoning outbreak
-agriculture: creating superior crops and livestock, and "pharm" animals (insulin in cows)
-environment: molecular ecology (identify species, .diagnosis for conservation) genetic
engineering microbes for bioremediation/cleaning
-evolutionary biology: phylogenetics and phylogenomics
In general, what are the three classical experiments that established DNA as the hereditary
molecule? - ANSWER -Griffith: found a substance that could genetically transform
streptococcus pneumonia (mouse)
-Avery, MacLeod, & McCarthy: identified DNA as the molecule that transforms rough S.
pneumonia to the ineffective form (DNAse)
-Hershey and Chase: found the final evidence establishing DNA as the hereditary molecule
(32P in DNA and 35S in proteins)
What is the procedure and findings of Griffith's experiments? - ANSWER Procedure
-When injecting S strain mouse died, R strain mouse lived, S and R mouse died, and dead S
and R mouse died, suggesting that something released from dead S transformed R to S
Conclusion
some molecule, called the "transforming principle" released when S cells were killed could
transform R cells to the virulent S form causing pneumonia, this transformation was
permanent and heritable such that the progeny were also S strain
, What is streptococcus pneumonia? What are the 2 types? - ANSWER bacterial pathogen that
causes pneumonia
1. smooth strain (S): bacterium surrounded by a polysaccharide capsule that protects it from
the immune system thereby allowing infection (virulence)
2. rough strain (R): no capsule, cant evade the immune system (non-virulent)
What were the hypothesis, experiment, and findings of Avery, MacLeod, & McCarthy's
experiments? - ANSWER Hypothesis: the transforming principle could be protein, DNA, or
RNA
Experiment: put in RNAse, Protease, or DNAse to destroy each, kill S cells, and see if R cells
are transformed to S in each
Findings: when DNAse destroyed DNA such that only RNA and protein were left, R remained
as R so that DNA is the transforming principle that plays a role in converting R strain to
virulent S strain
What is the life cycle of a virus (bacteriophage) including the 2 cycles? Which cycle can
become the other? - ANSWER -the viral bacteriophage docs on the surface of the bacteria and
injects viral DNA into the bacteria
-here it can either enter the lytic cycle or the lysogenic cycle
Lytic cycle: virus DNA mass replication separately from bacterial chromosome, resulting in
host cell lyses
Lysogenic cycle: viral DNA is integrated into the bacterial chromosome, lays dormant, as
bacterial DNA replicates, viral DNA is passed onto the progeny cells
Lysogeny can become lytic if the viral DNA is excised from the bacterial chromosome
