Unit lV - Part 1

Question 1

Who first identified DNA?

Answer 1

Friedrich Miescher

Question 2

While Friedrich Miescher studying white blood cells – molecule is slightly acidic, high percentage of phosphorous, later he called it “____”, changed to _________- deoxyribonucleic acid or DNA.

Answer 2

nuclein
nucleic acid

Question 3

much higher phosphorous content and resistance to proteolysis (protein digestion)

Answer 3

Nuclein

Question 4

__________ - nuclein

Answer 4

Friedrich Miescher (1869)

Question 5

He discovered the three major components of a single nucleotide

Answer 5

Phoebus Levene
(Phosphate, sugar,base)

Question 6

He said that nucleotide composition of DNA varies among species
(other DNA molecule)

Answer 6

Erwin Chargaff

Question 7

x-ray crystallography

Answer 7

Rosalind Franklin and Maurice Wilkins

Question 8

__________ - double stranded DNA, Nature in April 1953

______ : Nobel Prize in Physiology and Medicine

Answer 8

James Watson and English physicist Francis Crick (1950)

1962

Question 9

The first scientists to formulate an accurate description of this molecule’s complex (DNA), double-helical structure

Answer 9

James Watson and Francis Crick

Question 10

How did scientists determine that DNA is the hereditary material?

Answer 10

Groundbreaking experiments by Griffith, Avery, Hershey, and Chase disproved the notion that proteins were genetic material.

Question 11

This process kills the virulent S-strain bacteria

Answer 11

Heating

Question 12

A chemical substance from dead cells can transform living cells, true or false?

Answer 12

TRUE

Question 13

They showed that DNA is the substance that Transforms Bacteria

Answer 13

Avery, MacLeod, and McCarty

Question 14

Experimental principle used by Avery, MacLeod, and MacCarty to identify the _______

Answer 14

Transforming principle

Question 15

_______ and ______ Provided Evidence that DNA is the Genetic Material of T2 Phage

Answer 15

Hershey and Chase

Question 16

It is a substance that transforms bacteria

Answer 16

DNA

Question 17

 most of the 35S isotope was found in the supernatant (sulfur found in protein)

 By comparison, only about 35% of the 32P was found in the supernatant ( Phosphate- found in DNA)

 Therefore, most of the DNA was located within the bacterial cells in the ________

Answer 17

pellet

Question 18

 ______: DNA “Saga” began when Swiss biochemist _________ isolated Nuclein

Answer 18

1868
Friedrich Miescher

Question 19

 ______: __________ - Tetranucleotide Hypothesis

Answer 19

1910
Phoebus Levene

Question 20

 _______: _________ - Transforming Principle

Answer 20

1928
Griffith

Question 21

 ________: ___________ - DNA is Transforming Principle

Answer 21

1944
Avery, MacLeod & McCarty

Question 22

 ________: _________ - A=T, G=C

Answer 22

1950
Chargaff’s Rules

Question 23

 _________: __________ - Blender Experiment

Answer 23

1952
A.D. Hershey & Martha Chase

Question 24

 _______: __________ - A Structure for DNA

Answer 24

1953
James Watson & Francis Crick

Question 25

_________________________ King’s College, London Initially a nuclear physicist 1950: X-ray diffraction work on ram sperm and DNA from With grad student _______ produced x-ray photographs of DNA showing crystalline structure These photographs, shown at a conference in Naples, sparked James Watson’s interest in DNA

Answer 25

Maurice Wilkins Raymond Gosling

Question 26

______________ • King’s College, London “We realized that if DNA was the gene material, then we had just shown that genes could crystalize…”

Answer 26

Raymond Gosling

Question 27

_____________ Late 1950: Randall arranged for a three-year research fellowship that would fund Rosalind Franklin in his laboratory ● Needed expertise in interpreting x-ray images ● English physical chemist and xray crystallographer expert ● Previously worked on x-ray diffraction patterns in coal and carbon fiber technology in Paris • Franklin was given Gosling as a grad student as well as Singers DNA • She discovered 2 forms of DNA: A form (dehydrated) and B form (hydrated). • opposed the idea of model building

Answer 27

● Rosalind Franklin

Question 28

In ______, _______ solved basic mathematics of ________ and proposed Wilkin's x-ray diffraction data indicates a helical structure of DNA.

Answer 28

November 1951 Alec Strokes helical diffraction theory

Question 29

__________ • Taken by Raymond Gosling in ______ under Franklin's instruction • in _________ James Watson visited King's College and was shown this image by Wilkins. • image pointed to a helical structure of B-form of DNA

Answer 29

Photograph 51 March 1952 1953

Question 30

Unlike Franklin and Watson who favored data collection, measurable results and interpretation, Watson and Crick utilized the _____________.

Answer 30

model building approach

Question 31

_____________ ● American chemist, biochemist, peace activist ● Contributions to science include discovery of alpha helix and beta sheet structure of proteins, quantum chemistry resonance work and the discovery of sickle cell anemia as a molecular disease ● “The Nature of the Chemical Bond” ● Considered to be one of the 20 greatest scientists of all time.

Answer 31

Linus Pauling

Question 32

In early _____, Linus Pauling announced that he had discovered the structure of DNA

Answer 32

1953

Question 33

He proposed a 3-chain helix with a sugar phosphate backbone core and nucleic acid bases facing outward.

Answer 33

Linus Pauling

Question 34

Watson and Crick were bubbling at the fact that they had another chance to find out the structure of DNA  Photograph of the double helix was shown to Watson by Wilkins Spring 1953 Watson and Crick was given official orders to work structure of DNA again They needed more information, they needed to figure out how the four components of DNA went together. _________ was the key.

Answer 34

Erwin Chargaff

Question 35

He pioneered the paper chromatography of nucleic acids, using this to determine how much of each of the component nucleotides was contained in a DNA sample. He rapidly demolished Levene's Tetranucleotide Hypothesis to discover his rule in ratios.

Answer 35

Erwin Chargaff

Question 36

WATSON AND CRICK'S STRUCTURE 1. • 2 helical chains each coiled around the same ______ • both chains are right handed • the chains are related by dyad perpendicular to fibre axis • each chains consist of phosphate diester groups 2. • Residues in each chain every ____ A. 3. • _____ between each adjacent residues in the same chain 4. • structure repeats itself after ___ residues. • Open structure with high water content 5. - bases _____ at low water content would compact it

Answer 36

1. axis 2. 3.4 3. 36° 4. 10 5. Tilt

Question 37

Who took the definitive picture of DNA using x-rays?

Answer 37

Rosalind Franklin

Question 38

The name given to the shape of DNA is?

Answer 38

Double Helix

Question 39

Which scientists build a 3-D model of the DNA double helix?

Answer 39

James Watson and Francis Crick

Question 40

_______ is the sugar found in DNA

Answer 40

Deoxyribose

Question 41

DNA monomers are called

Answer 41

Nucleotides

Question 42

Before the divides, it duplicates its DNA in a copying process called ________

Answer 42

Replication

Question 43

 DNA is the “___________”.  chromosomes are made up of thousands of shorter segments of DNA, called ______.  gene stores the directions for making _____

Answer 43

• information molecule • genes • protein

Question 44

 _____ serves as universal information-storage molecule for all forms of life.  DNA molecules are ______.  DNA monomers are called _________.  four nucleotide monomers  Each nucleotide monomer is built from three simple molecular parts:   

Answer 44

• DNA • polymers • nucleotides  Deoxyribose sugar,  phosphate group, and  Nitrogenous base

Question 45

 _________ is a cyclical molecule.  __________ is attached to the fourth carbon of the ring  ________ attached to the third carbon in the ring.

Answer 45

• Deoxyribose • fifth carbon atom • hydroxyl group (-OH)

Question 46

 sugar and acid in all four monomers are the same.  sugar in all four nucleotides is called _______.  _________ is a phosphorous atom with four oxygen atoms bonded to it.  phosphorous atom in phosphate has a marked tendency to bond to other oxygen atoms

Answer 46

• deoxyribose • phosphate group

Question 47

This bonds in DNA polymers connect the 5’ carbon of one nucleotide to the 3’ carbon of another nucleotide

Answer 47

 Phosphodiester bonds

Question 48

__________ orientation and is important for the copying of DNA two strands of the helix run in _______ directions nucleotides forming each DNA strand are connected by ________.

Answer 48

• antiparallel • opposite • hydrogen bonds

Question 49

This creates consistency in the nucleotide sequences of the two DNA polymers that join together to make a chromosome

Answer 49

complementary base pairing

Question 50

 DNA polymers direct the production of other polymers called _________.  A chromosome consists of smaller segments called _______.  Each gene is further divided into three nucleotide subsegments called _______  codon from the original DNA gene is matched with its corresponding ________.

Answer 50

• proteins • genes • codons • amino acid