Topic A Flashcards
Genetics
Study of heredity and variation in cells, individuals and populations
Molecular genetics
The study of structure and function of genes at the molecular level
Gene
DNA sequences involved in making RNA and proteins. A functional unit of heredity and variation in individuals.
Found on chromosomes and are parts of the genome that encode RNA and protein.
Alleles
Variant forms of a gene caused by differences in DNA sequence
Genotype
Genes inherited by a organism
Phenotype
Visible traits
Genome
Entire DNA sequence of an organism (ACGT)
Gene expression
“Turning on” a gene to produce RNA and protein (coding gene)
Coding gene and example
Makes RNA and proteins
Example: messenger RNA
Non coding gene and example
RNA that does not make a protein
Example: ribosome RNA
Transfer RNA
Protein expressions
The type and abundance of protein in the cell
Enzymes
Catalyzing the synthesis and transformation of all biomolecules
Structural proteins
Maintaining the cell shape
Signaling proteins
Hormones and receptors
What makes individuals different?
1) different alleles
2) differential regulation of gene and protein expression
Why is studying molecular genetics important?
- Human health-better understanding
- Forensics (DNA finger prints) -crime, paternity tests
- Agriculture- superior crops and livestock
- Environment- molecular ecology
Griffith experiment
Found a substance that could genetically transform streptococcus pneumonia
Avery, Macleod and McCarthy
Identified DNA as the molecule that transforms rough S. Pneumonia to the infective form
Hershey and chase
Found the final evidence establishing DNA as the hereditary molecule
Streptococcus pneumonia
Bacterial pathogen that causes pneumonia in mammals
Smooth strain (S)
Bacterium is surrounded by a polysaccharide capsule that protects from immune system (virulent)
Rough strain (R)
Lacks polysaccharide capsule, cannot evade the immune system (non virulent)
Griffin’s conclusion
Some molecules (transforming principle) release when S cells were killed could transform living R cells genetically to the virulent S form. This transformation was permanent and heritable.
Avery, MaxLeod & McCarthy experiment
Eliminated each of the type of molecule in the S cell to see whether transformation of R cells into S virulent form still occurred.
Avery, MacLeod & McCarthy conclusion
If type of molecule is a stent and transformation is gone then this molecule is the transforming principle. Found that DNA was the transforming molecule
Lytic cycle
Massive reproduction of virus resulting in host cell lysis (virulent)
Viral dna replicates separately from bacterial chromosome
Lysogenic cycle
Replication of viral genome (latent) no death of host cell
No massive reproduction
Viral dna is integrated into the bacterial chromosome
Hershey and chase experiment
Defining evidence that it is dna that is involved in inheritance
Labeled bacteriophage DNA and proteins with radioactive isotopes 32p and 35s respectively.
Hershey and chase experiment results
No s35 E.coli cells, s35 found in detached bacteriophage
32p in E.coli cell, no 35p found in detached bacteriophage
