Structure of DNA Flashcards
What do nucleic acids form from?
Nucleotides polymerize into chains to form DNA or RNA molecules.
What are the primary, secondary, and tertiary structures of nucleic acids similar to?
They are similar to protein structure.
What forms the primary structure of nucleic acids?
Covalent bonding of nucleotide monomers to make the backbone.
What composes the backbone of DNA?
Alternating deoxyribose and phosphate groups linked through covalent bonds.
What composes the backbone of RNA?
Ribose and phosphate groups.
What do the 5’ and 3’ ends refer to in nucleic acids?
The 5 and 3 carbons on the pentose.
Where do bases extend from in DNA and RNA?
From the pentose groups and are not part of the backbone.
How is the nucleotide chain written?
From the 5’ end to the 3’ end, left to right.
What is an oligonucleotide?
A chain of 50 or fewer nucleotides.
What is the secondary structure of nucleic acids?
Any stable structure taken up by some or all of the nucleotides.
What is the secondary structure of DNA called?
Double helix.
Who determined the double helix structure of DNA?
James Watson and Francis Crick.
What did Erwin Chargaff conclude about DNA?
The base composition varies between species and A=T, G=C.
What holds the two polynucleotide chains of DNA together?
Hydrogen bonds.
What is the significance of complementary base pairing in DNA?
A binds to T and G binds to C through hydrogen bonds.
How many hydrogen bonds do A and T form?
Two hydrogen bonds.
How many hydrogen bonds do G and C form?
Three hydrogen bonds.
What are the two strands of DNA written to highlight?
The interactions between complementary strands.
What is the most common form of DNA?
B form of DNA.
What are the three forms of DNA?
A-form, B-form, and Z-form.
What distinguishes the Z-form of DNA?
It has a left-handed twist to the helix.
What is the function of DNA?
To store genetic information that contains the sequence of proteins.
What is a gene?
A chromosomal segment of DNA that contains a specific base sequence.
What is a codon?
A sequence of three adjacent nucleotides that encodes for an amino acid.
How many nucleotides are needed to encode a 100 amino acid protein?
300 nucleotides.
What is needed to make a protein from the stored genetic information in DNA?
RNA.
