Intro 1_Molecular_Biology_Flashcards
What is molecular biology?
The study of macromolecules and their mechanisms in living organisms.
What are the key focuses of molecular biology?
Molecular nature of genes, gene replication, mutation, and gene expression.
What is the central dogma?
Genetic information flows from DNA to RNA to protein.
What are the two key processes in the central dogma?
Transcription (DNA to RNA) and Translation (RNA to protein).
Who explained the central dogma and emphasized the one-way flow of information?
Francis Crick.
When did molecular biology emerge?
In the 1930s and 1940s.
Who first identified DNA and what was it called?
Friedrich Miescher, called it ‘nuclein’.
Who coined the term ‘molecular biology’?
Warren Weaver in 1938.
What did Chargaff’s rules state?
Ratios of A to T and G to C are equal in DNA.
What major discovery did Watson and Crick make in 1953?
The double helical structure of DNA.
Who discovered mRNA?
Francois Jacob and Jacques Monod in 1961.
What did Francis Crick decipher in 1961?
The triplet codon pattern.
What are the three components of DNA?
Deoxyribose sugar, phosphate group, and nitrogenous bases.
What are the four nitrogenous bases in DNA?
Adenine (A), Thymine (T), Cytosine (C), Guanine (G).
What pairs with A in DNA, and how many bonds?
Thymine (T) with 2 hydrogen bonds.
What pairs with C in DNA, and how many bonds?
Guanine (G) with 3 hydrogen bonds.
What is the orientation of DNA strands?
Antiparallel (5’ to 3’ and 3’ to 5’).
What stabilizes DNA?
Hydrogen bonds, base stacking interactions, and hydrophobic interactions.
Is DNA soluble in water?
Yes, due to hydrophilic phosphate groups.
At what wavelength does DNA absorb UV light?
260 nm.
What is DNA denaturation?
Separation of double strands into single strands by heat or extreme pH.
What is renaturation?
Rejoining of DNA strands when conditions return to normal.
What is the melting temperature (Tm) of DNA?
The temperature at which half of the DNA is denatured.
Why is DNA negatively charged?
Due to phosphate groups in its backbone.
How is DNA packaged in the nucleus?
Using histones to form nucleosomes.
Where is mitochondrial DNA located?
Inside mitochondria.
What is the shape of mtDNA?
Circular, double-stranded.
How many genes does mtDNA contain?
37 genes (2 rRNAs, 22 tRNAs, and 13 for proteins).
How does mtDNA replicate?
Independently of nuclear DNA.
What is the shape of nuclear DNA?
Linear double helix.
What is the shape of mitochondrial and bacterial DNA?
Circular.
Is histone association present in nuclear DNA?
Yes, but absent in mitochondrial and bacterial DNA.
How is mitochondrial DNA inherited?
Maternally.
Where is eukaryotic DNA located?
In the nucleus.
Where is prokaryotic DNA located?
In the cytoplasm.
Are plasmids present in eukaryotic DNA?
No, but often present in prokaryotic DNA.
Are introns present in eukaryotic DNA?
Usually, but absent in prokaryotic DNA.
What is a nucleotide?
A molecule consisting of a sugar, phosphate group, and nitrogenous base.
What is a nucleoside?
A nucleotide without a phosphate group.
What are purines?
Double-ring bases (A and G).
What are pyrimidines?
Single-ring bases (C, T, and U).
What bonds link nucleotides in DNA?
Phosphodiester bonds.
Where does transcription occur?
In the nucleus.
Where does translation occur?
In ribosomes.
What is Chargaff’s Rule?
A = T and G = C in DNA.
What is a nucleosome?
DNA wrapped around histones.
What is DNA base stacking?
Interactions between adjacent bases that stabilize DNA.
What did Friedrich Miescher call DNA?
Nuclein.
What type of bonds hold DNA base pairs together?
Hydrogen bonds.
What feature of DNA ensures genetic stability during replication?
Complementary base pairing.
