GN 301 Module 3: DNA, RNA, and Chromatin Structure

DNA

deoxyribonucleic acid

Friedrich Miescher

Identified DNA from white blood cells and called it nuclein, noting it was slightly acidic

Boveri and Sutton

Found chromosomes and proposed the chromosome theory of inheritance

What was thought to be the genetic material prior to determining that it was DNA?

Protein was thought to make up the genetic material because it makes up about 50% of the cell. People thought that because proteins have a lot of variability and are used for many functions.

Avery, McCarty and MacLeod

Showed that DNA can transform the properties of cells by studying how DNA transformed bacteria

Albrecht Kossel

Discovered that DNA was composed of 5 nitrogen bases: adenine, thymine, guanine, cytosine, and uracil

Phoebus Levene

Discovered and named the nucleotide (sugar + base + phosphatase)

Maurice Wilkins and Rosalind Franklin

Came up with x-ray experiment to take pictures of DNA structures, discovering that it was helical

Erwin Chargaff

Researched the percentages of bases present in different animals and compared the ratios

James Watson and Francis Crick

Put together the first DNA replica structure from Wilkins and Franklin’s research

Deoxyribose

has has a hydrogen atom at position 2 (in DNA)

Ribose

has a hydroxyl group at position 2 (in RNA)

single-ringed structure

having a(n) ________ with 5- members and 2 nitrogen atoms.

RNA

________ contains the sugar ribose, while DNA has deoxyribose.

two -ringed structure

having a(n) ________ consisting of a 9- membered molecule with 4 nitrogen atoms.

Phosphate

is connected to 5 carbon of sugar.

Chromatin

found in DNA in the nucleus, where it forms chromosomes in the nucleus.

DNA

________ is double- stranded, while RNA is single- stranded.

Plectonic coil

A type of coiling of a double‐stranded helix in which the two strands are intertwined; they may not be separated without uncoiling.

carbon of sugar

Base is connected to 3 ________.

DNA Components

1 nucleotide = 1 sugar + 1 base + 1 phosphate

Purines

Adenine and guanine

Pyrimidines

Cytosine, thymine, uracil

Describe complementary base pairing: between which bases and how many hydrogen bonds joining each pair?

Adenine and thymine pair up, while guanine and cytosine pair. 2 hydrogen bonds pair adenine and thymine, while 3 bonds pair guanine and cytosine.

Right handed coil

the banister handle is on the right side

Chromatin

complex of DNA (proteins and RNA)

Histone

protein found in chromatin

Complementary strands

DNA copy of a mRNA molecule produced by reverse transcriptase

Antiparallel

Parallel but moving in opposite directions

How many base pairs per turn?

10 1/2

Diameter of helix?

1\.8 nm

Length of 1 turn

3\.4 nm