M2 - Central Dogma Flashcards
What three functions must genetic material be able to perform?
- The Genotypic Function
- The Phenotypic Function
- The Evolutionary Function
What is the Genotypic Function?
- Replication, (Each cell must be replicated from a single cell into daughter cells)
What is the Phenotypic Function?
- Gene expression, (Genes control shape and colour)
What is the Evolutionary Function?
- Mutation. (Through mutations different colours are achieved)
In three points, describe chromosomes?
- DNA, protein and sometimes RNA
- A unit of inheritance
- Where genes are usually located
What are the four different nucleotide bases?
- Adenine
- Thymine
- Guanine
- Cytosine
What are the structural components of nucleic acids?
- Nucleic acids are composed of repeating sub units called nucleotide’s.
- Each nucleotide is composed of three units: Phosphate group, Five-carbon sugar, Nitrogen containing base
Why is the Phosphate Group important in nucleotide’s?
- Phosphate group can form strong covalent bonds
What is the difference in bases between DNA and RNA?
DNA:
- Adenine (A) and Guanine (G) which are Purines
- Thymine (T) and Cytosine (C) which are Pyrimidines
RNA:
- Uracil (U) instead of T
What is a Deoxyribonucleotide?
It is a nucleotide in the DNA instead of the RNA
What are the Pyrimidine Deoxyribonucleotide’s?
- Deoxythymidine monophosphate, dTMP
- Deoxycytidine monophosphate, dCMP
What are the Purine Deoxyribonucleotide’s?
- Deoxyadenosine monophosphate, dAMP
- Deoxyguanosine monophosphate, dGMP
What is the structure of a polynucleotide chain?
- DNA always read from 5ʹ to 3ʹ ends.
- DNA always transcribed, replicated 5ʹ to 3ʹ
- These numbers refer to the chemical bonds.
- It gives directionality to the sequence.
What is the Central Dogma?
- Transcription and translation: DNA → RNA → protein.
Draw and fill in the Central Dogma flow chart
https://docs.google.com/document/d/1Nzo4FTzXCbwOZjpoc_J_4IF3gsOXPcoyC2BowELmx0U/edit?usp=sharing
What is a gene?
- A gene is the “unit factor” that controls a specific phenotypic trait (Mendel)
What are some examples of refinements on Mendel’s discovery of Genes?
One Gene-One Enzyme:
- Garrod (inherited disease of metabolism)
- Mutations in genes encoding enzymes produce metabolic block
- Example (Phenylketonuria is caused by the absence of phenylalanine hydroxylase)
- Beadle & Tatum (experiments with Neurospora)
Overlapping and genes within-genes (1960’s), and sequencing of eukayotic genes shown to be interrupted by introns (1970’s)
What did Morgan and William Sutton prove?
- They proved genes exist on
chromosomes
What substances are chromosomes made of?
- Chromosomes contain proteins and nucleic acids.
- The nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).
What are some refinements on genes that have been found and who were they discovered by
- Sia and Dawson (following on from Griffith)-Transformation principle
- Avery, MacLeod and McCarty – DNA is the transforming agent
- Hershey and Chase – DNA is the genetic material
- Fraenkel-Conrat – RNA can also act as genetic material
What are the Sia and Dawson Experiments?
- Frederick Griffith’s discovered transformation in Streptococcus pneumoniae
- Heat-killed Type IIIS bacteria (virulent when alive) & live Type IIR (avirulent) injected into mice → Many mice died → live Type IIIS bacteria isolated
- Sia & Dawson performed the same experiments in vitro
What was discovered from the Sia and Dawson Experiments?
- The “Transforming Principle”
What is the Transforming Principle?
- The term given to the substance that could be transferred from non living cells to living cells, causing the living cell to show characteristics of the non living cell.
What was the Transforming Principle in the Sia and Dawson Experiments?
- Avery, Macleod and McCarty showed that “transforming principle” is DNA
- This was seen when the Type IIR cells were added to the IIIS cells in the serum that precipitates IIR cells from mixture
- Once they were added the DNA from the heat-killed IIIS cells was transferred to the living Type IIR cells and hence they were able to kill the mice.
