In 1953, _____ noted that DNA consists of two polynucleotide strands, running in opposite directions and coiled around each other in a double helix

Strands are held together by ______ between specific pairs of bases

The strands of DNA are complementary because of

The primary structure of a nucleic acid is the ______

The nucleotides in nucleic acids are joined by ______

The 3’-OH group of the sugar in one nucleotide forms an ______ to the phosphate group on the 5’-carbon of the sugar of the next nucleotide

A ________ has a free 5’-phosphate group at one end and a free 3’-OH group at the other end The sequence is read from the free 5’-end using the letters of the bases This example reads 5’—A—C—G—T—3’

In DNA, A, C, G, and T are linked by________ between deoxyribose and phosphate

is described from 5' end, identifying the bases in order of occurrence, using the abbreviations A for adenosine, G for guanosine, C for cytidine, and T for thymine (or U for uracil in RNA) A typical sequence is written as

Properties of a DNA double helix

Secondary Structure

In DNA there are two strands of nucleotides that wind together in a double helix - the strands run in ______ - the bases are are arranged in ______ - the base pairs are held together by _______

The pairing of the bases from the two strands is very specific. The complimentary base pairs are A-T and G-C Each pair consists of a purine and a pyrimidine, so they are the same width, keeping the two strands at equal distances from each other

The model was developed by Watson and Crick in 1953.

Watson and Crick received a nobel prize in _____ for their work.

The dna model looks like a twisted ladder – ______

- Columbia University, NY -Investigated the composition of DNA -His findings by 1950 strongly suggested the base-pairings of A-T & G-C

Met with Watson and Crick in _____ and shared his findings

A = T & C = G

First determined by Watson & Crick in 1953

Shape and size is uniform for all life (i.e. DNA is identical)

Without parallel base pairing this conformation could not exist

Nucleic acid structure consists of

are critical for binding proteins that regulate DNA function

The paired strands are coiled into a spiral called

[normally] exists as a single stranded polymer

exists as a double stranded polymer

DNA double strand is created by _______ between nucleotides

Nucleotides always bind to

1. Before a cell divides, the DNA strands unwind and separate 2. Each strand makes a new partner by adding the appropriate nucleotides 3. The result is that there are now two double-stranded DNA molecules in the nucleus. When the cell divides, each nucleus contains identical DNA

STEP 1: Hydrogen bonds between base pairs are broken by the ________ and DNA molecule unzips. DNA molecule separates into complementary halves

Cell division involving ______ produces 2 daughter cells that are genetically identical to each other and genetically identical to the parent cell

Remember that for this (replication) to happen, DNA in the parent cell must be replicated (copied) before the cell divides – this process occurs during ______ in the cell cycle

STEP 2: ______ match up with complementary bases. Free nucleotides abundant in nucleus

Nucleotides are linked into 2 new strands of DNA by the enzyme, ________—_______ also proofreads for copying errors

occur when copying errors cause a change in the sequence of DNA nucleotide bases

In eukaryotic cells (animals, plants, fungi) DNA is stored in the nucleus, which is separated from the rest of the cell by a

The DNA is only organized into _______ during cell replication

Between replications, the DNA is stored in a compact ball called ______, and is wrapped around proteins called ________ to form nucleosomes

When a eukaryotic cell divides, the process is called _____ - the cell splits into two identical daughter cells - the DNA must be replicated so that each daughter cell has a copy

DNA replication involves several processes: 1. - first, the DNA must be _____, separating the two strands

DNA replication involves several processes: 2. - the ______ then act as templates for synthesis of the new strands, which are complimentary in sequence

DNA replication involves several processes: 3.- bases are added one at a time until two new DNA strands that exactly duplicate the _______ are produced

A process where one strand of each daughter DNA comes from the parent DNA and one strand is new

The energy for the synthesis of the new strands comes from _______ of phosphate groups as the phosphodiester bonds form between the bases

Schematic representation of the strand separation in duplex DNA resulting from its

unwinds several sections of parent DNA

open DNA section, called a

_____ catalyzes the formation of 5’-3’ester bonds of the leading strand

The _______, which grows in the 3’-5’ direction, is synthesized in short sections called ______

The Okazaki fragments and ______ are joined by to give a single 3’-5’ DNA strand