DNA Structure and Function Flashcards

Flashcards on DNA Structure and Function based on lecture notes.

What contributions did Darwin and Mendel make to modern genetics?

Evolution and inheritable properties.

According to P. Levene, what do nucleic acids consist of?

NAs consist of sugars, phosphates, and 4 nitrogen-containing bases: Adenine (A), Guanine (G), Cytosine (C), and Thymine (T).

What are Chargaff's rules?

GC% varies between different species, and A=T; G=C, base-pairing of complementary nucleotides.

What is the overall structure of DNA, as determined by Watson & Crick?

DNA is organized in an anti-parallel double helix.

What are nucleic acids?

Linear polymers of nucleotides

What is the backbone of DNA and RNA made of?

Sugar and phosphate

What are the 4 different nitrogen bases in DNA and RNA?

Adenine (A), Guanine (G), Cytosine (C), Thymine (T) / Uracil (U)

How are nucleotides linked in the primary structure of nucleic acids?

Nucleotides are linked via a phosphodiester bond with a 5'P-3'OH orientation.

How do nucleotides pair in the secondary structure of DNA?

Specific pairs of nucleotides can form hydrogen bonds: A and T; G and C.

What is the function of ribozymes?

Catalytic function

What is the central dogma of gene expression?

Transcription: DNA → RNA and Translation: RNA → protein.

Describe transcription.

Copy genetic information stored in DNA into mRNA.

What are the 3 important steps of mRNA processing?

Attachment of modified G at 5’ end of primary mRNA (Capping), Attachment of Poly-A tail at 3' end, Excision of non-coding regions (intragenic regions; introns) from primary mRNA and coupling of coding or expressed regions (exons) (Splicing)

Describe translation.

Translation of information in mRNA into AA sequence by ribosome.

What is the translation initiation?

Association of small ribosome subunit with mRNA and “initiator tRNA” with first AA of the peptide in the P-site, then association with large subunit.

What is the translation elongation?

New AA-tRNA binds into A site, formation of peptide bond and translocation ribosome to next codon.

What is the translation termination?

Stopcodon in A site, binding of Release Factors, disassociation of ribosome subunits.

Define a gene.

Unit of genetic information; DNA region that enables transcription in a functional RNA (protein-encoding or not).

Define gene expression.

Process in which the information in a gene effectively gives rise to the formation of a functional product (protein or functional RNA molecule).

What is the role of the promoter in gene expression?

Regulatory region in the DNA that determines how efficient RNA Polymerase binds, where transcription starts, and determines whether and how much transcription will take place.

What is epigenetic regulation?

Change in gene expression caused by change in environmental factors, not due to changes in DNA sequence.