Genetics PCB 3063 Exam 3
Rosalind Franklin and Maurice Wilkins - ✔️✔️DNA is a multiple-stranded fiber of 20 A
thickness. Groups spaced 3.4 A along the fiber and a repeating unit every 34 A.
Purines - ✔️✔️Two fused heterocyclic rings
A, G
Pyrimidines - ✔️✔️One single heterocyclic ring
T, U, C
Nucleotide Sugars - ✔️✔️Ribose
Deoxyribose (Base is always attached to C-1' of the sugar.
Phosphates - ✔️✔️Can be attached to the C-5' of the sugar.
Deoxyribonucleo-side - ✔️✔️Base + Sugar
Deoxyribonucleo-tide - ✔️✔️Base + Sugar + Phosphate
Adjacent nucleotides are linked by... - ✔️✔️5'-3' Phosphodiester Bonds
A nucleotide has what on each end? - ✔️✔️A free 5' phosphate
A free 3' hydroxyl
Erwin Chargaff - ✔️✔️A=T
C=G
Nucleotide - ✔️✔️Repeating structural unit of DNA and RNA. Composed of a
nitrogenous base, a sugar, and a phosphate.
DNA is a helical structure that is not a single strand and consists of about 10 base pairs
per complete turn.
Watson and Crick - ✔️✔️Solved DNA structure
The Double-Helix - ✔️✔️Two anti-parallel strands.
Sugar-phosphate backbone on the outside.
Nitrogenous bases "stacked" on the inside.
, The double-helix has how many bp per complete twist? - ✔️✔️10
Which direction does the double-helix turn? - ✔️✔️Right-handed / Clockwise
The two strands of the double-helix are held together by... - ✔️✔️Hydrogen bonds
between complementary bases.
A=T two hydrogen bonds
C=G three hydrogen bonds
B-DNA - ✔️✔️10bp/turn
Biologically favored.
Parallel bases.
A-DNA - ✔️✔️11bp/turn; 23 A diameter
Prevalent under high salt concentrations/low water conditions.
Doubtful to occur under biological conditions.
C-DNA - ✔️✔️9.3bp/turn; 19A diamether
Prevalent under great dehydration conditions
Doubtful to occur under biological conditions.
Z-DNA - ✔️✔️Prevalent in vitro in C-G containing DNA.
Left-handed.
12bp/turn; 18 A diameter
Zig-Zag conformation
May be involved in regulating gene expression in vivo.
RNA Structure - ✔️✔️Ribose
A=U
C=G
Usually single stranded, but can form short ds regions.
RNA Double Helix - ✔️✔️Right handed
A form. 11-12 base pairs per turn.
What is the structural difference between the sugar found in RNA and the sugar found
in DNA? - ✔️✔️The presence of a 2' hydroxyl.
What order of atoms correctly describes the backbone of a DNA strand? - ✔️✔️3'C-O-
P-O-5'C
What aspect of the sugar is unique to RNA? - ✔️✔️It contains an OH group on the
number 2' carbon of the pentose sugar.
Rosalind Franklin and Maurice Wilkins - ✔️✔️DNA is a multiple-stranded fiber of 20 A
thickness. Groups spaced 3.4 A along the fiber and a repeating unit every 34 A.
Purines - ✔️✔️Two fused heterocyclic rings
A, G
Pyrimidines - ✔️✔️One single heterocyclic ring
T, U, C
Nucleotide Sugars - ✔️✔️Ribose
Deoxyribose (Base is always attached to C-1' of the sugar.
Phosphates - ✔️✔️Can be attached to the C-5' of the sugar.
Deoxyribonucleo-side - ✔️✔️Base + Sugar
Deoxyribonucleo-tide - ✔️✔️Base + Sugar + Phosphate
Adjacent nucleotides are linked by... - ✔️✔️5'-3' Phosphodiester Bonds
A nucleotide has what on each end? - ✔️✔️A free 5' phosphate
A free 3' hydroxyl
Erwin Chargaff - ✔️✔️A=T
C=G
Nucleotide - ✔️✔️Repeating structural unit of DNA and RNA. Composed of a
nitrogenous base, a sugar, and a phosphate.
DNA is a helical structure that is not a single strand and consists of about 10 base pairs
per complete turn.
Watson and Crick - ✔️✔️Solved DNA structure
The Double-Helix - ✔️✔️Two anti-parallel strands.
Sugar-phosphate backbone on the outside.
Nitrogenous bases "stacked" on the inside.
, The double-helix has how many bp per complete twist? - ✔️✔️10
Which direction does the double-helix turn? - ✔️✔️Right-handed / Clockwise
The two strands of the double-helix are held together by... - ✔️✔️Hydrogen bonds
between complementary bases.
A=T two hydrogen bonds
C=G three hydrogen bonds
B-DNA - ✔️✔️10bp/turn
Biologically favored.
Parallel bases.
A-DNA - ✔️✔️11bp/turn; 23 A diameter
Prevalent under high salt concentrations/low water conditions.
Doubtful to occur under biological conditions.
C-DNA - ✔️✔️9.3bp/turn; 19A diamether
Prevalent under great dehydration conditions
Doubtful to occur under biological conditions.
Z-DNA - ✔️✔️Prevalent in vitro in C-G containing DNA.
Left-handed.
12bp/turn; 18 A diameter
Zig-Zag conformation
May be involved in regulating gene expression in vivo.
RNA Structure - ✔️✔️Ribose
A=U
C=G
Usually single stranded, but can form short ds regions.
RNA Double Helix - ✔️✔️Right handed
A form. 11-12 base pairs per turn.
What is the structural difference between the sugar found in RNA and the sugar found
in DNA? - ✔️✔️The presence of a 2' hydroxyl.
What order of atoms correctly describes the backbone of a DNA strand? - ✔️✔️3'C-O-
P-O-5'C
What aspect of the sugar is unique to RNA? - ✔️✔️It contains an OH group on the
number 2' carbon of the pentose sugar.
