Intro to DNA Flashcards
Structure, how we know it contains genetic information, providing the mechanism for heredity, genome and chromosomes.
How can we combat climate change?
Increase carbon storage in plants.
How can we help the aging population?
Understanding the molecular basis of healthy aging.
How can we help food poverty?
Grow more resilient and nutritious crops.
How can we help with infection and disease?
Understanding and treating pathogenic/genetic diseases e.g. cancer.
How can we help biodiversity?
Monitoring the size and fitness of a population.
What has been used for 2000 years by Chinese herbal medicine practitioners?
Artemisia annua / sweet wormwood / ginghao
In 1956, what did Li Shizhen (herbalist) recommend?
Patients with a fever soak wormwood in water, squeeze out the juice and drink it all.
In 1960-70, what did Tu Youyou discover and isolate?
Qinghaosu/Artemisinin = active anti-malarial compound from sweet wormwood.
What caused Artemisinin production to reduce from 1.5 years to 3 months?
When synthesised from yeast rather than extracted.
In 1868, what did Friedrich Miescher do?
Isolated ‘nuclein’ from white blood cells present in human pus using a crude nuclear fraction = later renamed nucelic acid.
(Crude nuclear fraction = portion of WBCs containing the nucleus and its associated components e.g. nuclear envelope and nucleolus).
Give the characteristics ‘nuclein’ was found to have
Had high molecular weight, was acidic and contained appreciable amounts of phosphorous.
Other than human pus, how else is ‘nuclein’ obtained?
From nuclei of other animal tissues.
From yeast cells.
In 1944, what did Avery, Macleod and McCarty perform?
Streptococcus pneumoniae transformation experiments.
The researchers prepared an extract from the disease-causing S-strain of pneumococci and showed that the “transforming principle” that would permanently change the harmless R-strain pneumococci into the pathogenic S-strain is DNA.
Why were the Streptococcus pneumoniae transformation experiments significant?
This was the first evidence DNA could serve as genetic material.
Describe how the researchers showed the molecule that carries heritable ‘transforming principle’ is DNA.
S-strain cells extract prepared and fractioned into RNA, protein, DNA, lipid and carbohydrate.
Molecules then tested for ability to transform R-strain cells.
What biological materials are bacteriophages (viruses that infect bacteria) made from?
Only DNA and protein.
Describe the experiment Alfred Hershey and Martha Chase did in 1953?
Labelled DNA with radioactive isotope P(32) and protein with S(35).
Viruses allowed to infect E.coli, viral heads sheared off bacteria, centrifuge.
What was the result?
Only P(32) present in infected bacterial cells and passed onto bacteriophage progeny (offspring).
Give 5 requirements of DNA.
Stable overtime for storage.
Able to be faithfully replicated.
Able to control expression of traits/encode the sequence of proteins.
Able to direct cellular processes.
Able to change in a controlled way (evolution).
In 1953, what did Rosalind Franklin do and conclude?
Used x-ray crystallography to study structure of DNA, concluding its a double helix.
In 1953 what did James Watson and Francis Crick publish?
A paper for describing a model for the structure of DNA.
Concluded complementary bases A,T,C,G pair along the centre of the double helix to hold the two DNA strands together.
In 2007, why was Watson suspended from Cold Spring Harbour Laboratory?
For problematic statements regarding eugenics, race, sexuality, gender and intelligence.
Eugenics - arrange reproduction within a human population to increase the occurrence of heritable characteristics regarded as desirable.
Who is the professor of Human Immunogenetics and founding director of the National Human Genome Center at Howard University?
Dr. Georgia Dunston - explores relationship between immune system and genetics.
What did she examine?
The genetic basis for the difference in how Type 2 diabetes manifests in West African populations compared to those from Finland.
(Understanding genetic variations relevant to the immune system).
How did her process of acquiring, testing and analysing samples from African populations help?
Answered questions about genetic variations across human populations.
Added African representation to the Human Genome Project (HGP).
What is genetics?
The study of the structure and function of genes, genetic variation and heredity in organisms.
What elements does the DNA double helix and sugar phosphate backbone contain?
N, P, O, C, H.
What is the orientation of the helix?
Clockwise/right-handed.
Describe what a nucleotide is?
Ester bond between phosphate and deoxyribose.
(Phosphodiester bonds in sugar-phosphate backbone).
Glycosidic bond between base and deoxyribose.
What is the difference between pyrimidines and purines?
Pyrimidines are six-membered single ring structures and purines are nine-membered, double ring structures.
