DNA heredity Flashcards
what is genetics?
study of heredity and variation in cells, individuals and population
what is a gene?
functional unit of heredity variation
what is molecular genetics?
study of structure and function of genes at the molecular level
what is an allele and what is it caused by?
various forms of a gene caused by differences in DNA sequence
what is a genotype?
genes inherited by an organism
what is a phenotype?
visible traits
what is a genome?
entire DNA sequence of an organism
what is a gene in terms of DNA?
DNA sequence involved in RNA and protein formation
where are genes found?
on chromosomes
what is gene expression?
tuning on a gene so that it has an effect
has to be a coding gene
what is a coding gene?
a gene that gets converted to protein
what is a non coding gene?
a gene that does not get converted to protein
what is protein expression?
the type and abundance of proteins in the cell
how does protein determine phenotype?
protein determines and controls every reaction in the cell
what does an enzyme do?
catalyses the synthesis and transformation of all biomolecules
what do structural proteins do?
maintenance of cell shape
what are signalling proteins?
hormones and receptors
what two things make individuals different from eachother?
different alleles
different regulation of gene and protein expression
why do we sequence genomes?
to understand the type and abundance of RNA and protein that result in the phenotype of the organism
what do we need in order to sequence genomes?
identify all the genes in the genome
what are 5 reasons studying molecular genetics is important?
human health
forensics (DNA fingerprinting)
agriculture
environment
evolutionary biology
what does human health entail?
better understanding of human diseases resulting in new therapeutics and diagnostics
what does forensics entail?
crime, paternity tests, matching
organ donors, authenticate consumables, source of food poisoning outbreaks, Covid-19 variants
what does agriculture entail?
superior crops and livestock; “pharm”
animals
what does environment entail?
molecular ecology (species identification and diagnosis for conservation and species-habitat relationships); genetic engineering microbes for bioremediation
what does evolutionary biology entail?
phylogenetics and phylogenomic
what are the 3 experiments that established DNA as the hereditary molecule?
Griffith
Avery, MacLeod & McCarthy
Hershey and Chase
what was the Griffith experiment?
found a substance that could genetically transform streptococcus pneumonia
what was the Avery, MacLeod & McCarthy experiment?
identified DNA as the molecule that transforms rough s. pneumonia to the ineffective form
what was the Hershey and Chase experiment?
found the final evidence establishing DNA as the hereditary molecule
what is Streptococcus pneumoniae?
Bacterial pathogen that causes pneumonia in mammals
what is the smooth strain of Streptococcus pneumoniae?
bacterium is surrounded by a polysaccharide capsule
capsule protects strain from the immune system allowing infection (virulence)
what is rough strain streptococcus pneumoniae?
lacks polysaccharide capsule, cannot evade the immune system, therefore, non-virulent
what is Griffiths conclusion (the transformation principle)?
some molecules released when S. cells were killed could transform living R cells genetically to the virulent S form
-transformation was permanent and heritable
What is the chemical nature of the transforming principle? (Avery, MacLeod & McCarthy)
if the type of protein is missing and transformation doesn’t occur, that molecule is the transforming principle
what is the experimental approach for Avery’s experiment
eliminate each type of molecule in s cells one at a time and see whether transformation of R cells into the S virulent form still occurs
what is the transforming principle?
DNA
what is the lytic cycle?
massive reproduction of virus resulting in host cell lysis (virulent)
what is the lysogeny cycle?
replication of viral genome (latent).
when can lysogenic cycle change to lytic cycle?
if viral DNA is excised from bacterial chromosome
what is one characteristic of the lytic cycle?
viral DNA replicates separately from bacterial chromosome
what is one characteristic of the lysogenic cycle?
viral DNA is integrated into the bacterial chromosome
what were the results of the hershey experiement?
no 35s in cells, 35s found in detached bacteriophages= no 35s in progeny bacteriophage (not HERITABLE)
32p in cells, no 32p found in detached bacteriophages = 32P in progeny bacteriophage (HERITABLE).
what was Hershey’s experimental process?
label bacteriophages, DNA, and protein with radioactive isotopes 32p and 35s
-allow infection of E. coli with radioactive bacteriophages
-separate attached bacteriophages and E.coli
-assay presence of 32P (DNA) and 35S (protein) in detached bacteriophage, E. coli cells and progeny bacteriophage
