PowerPoint Slides for Chapter 1: Heritable Material by A. Malcolm Campbell, Laurie J. Heyer, & Christopher Paradise 1.4 How does DNA’s shape affect its

PowerPoint Slides for Chapter 1:Heritable Material

by A. Malcolm Campbell, Laurie J. Heyer, & Christopher Paradise

1.4 How does DNA’s shape affect its function?

Integrating Concepts in Biology

Title Page Copyright © 2015 by AM Campbell, LJ Heyer, CJ Paradise. All rights reserved.

Biology Learning Objectives• Draw the structure of DNA showing the double helix

and base pairings.• Demonstrate how DNA replication is

semiconservative.• Evaluate experimental design and analyze data from

research on DNA as molecular information.

Bio-Math Exploration Learning Objectives• Estimate the amount of DNA in a sample by finding

the area under a curve.• Determine the number of generations that have passed

in a population of cells.

Copyright © 2015 by AM Campbell, LJ Heyer, CJ Paradise. All rights reserved.

Fig.1.9

Nucleotide Structures

You should be able to distinguishdeoxyribonucleic acid (DNA) from ribonucleic acid (RNA),


You should be able to distinguishdeoxyribonucleic acid (DNA) from ribonucleic acid (RNA),

Fig. 1.9



DNAdATP

RNAATP

Fig. 1.9



Fig. 1.9

rotate 90°

2’ carbondATP




Fig. 1.9

ATP or dATP?


Watson and Crick DNA Model

Fig. 1.10 from Watson and Crick, 1953








Fig. 1.10

Can you spot their error?from Watson and Crick, 1953


Fig. 1.10

Can you spot their error?from Watson and Crick, 1953


Fig. 1.10

phosphate

should be anti-parallel strandsfrom Watson and Crick, 1953

Chemical Bonds

Fig. 1.11 Copyright © 2015 by AM Campbell, LJ Heyer, CJ Paradise. All rights reserved.

Chemical Bonds

Fig. 1.11

You should be able to match these representations with the appropriate chemical bonds.


Chemical Bonds


Chemical Bonds


Chemical Bonds

Fig. 1.11

Match the chemicalrepresentations withthe appropriate bonds.


Chemical Bonds


Chemical Bonds


Chemical Bonds

Fig. 1.11

Describe the generalrules for each bond type found in biologicalexamples.


Chemical Bonds


Chemical Bonds

Fig. 1.11

(N or O) and H

bases (+) and acids (-)

any element, often

C – C, C – O, C – N, C – H


Maurice Wilkins’ data Rosalind Franklin’s data

X-ray Diffraction of DNA

Fig. 1.12 from Wilkins, et al., 1953 and from Franklin and Gosling, 1953.

Maurice Wilkins’ data Rosalind Franklin’s data

X-ray Diffraction of DNA

Fig. 1.12 from Wilkins, et al., 1953 and from Franklin and Gosling, 1953.

Watson & Crick Base Pairs

Fig. 1.13

Find their mistake.

modified from Watson and Crick. 1953b


Fig. 1.13

Find their mistake.



Fig. 1.13

missed H-bond



Fig. 1.13 too far for H-bond modified from Watson and Crick. 1953b


Fig. 1.13

pyrimidines

1

1



Fig. 1.13

purines

12

12


Always Three Rings Wide

Fig. 1.13

12

12


3

3

3 Models of DNA Replication

Fig. 1.14modified from Meselson and Stahl. 1958.


Fig. 1.14

all old DNA

What are the implications for each model?

modified from Meselson and Stahl. 1958.


Fig. 1.14

half old

half new

semi-conservative



Fig. 1.14

all old

all new

conservative



Fig. 1.14

all stands half new

mosaic



Fig. 1.14

all stands half new

mosaic

all old

all new

conservative

half old

half new

semi-conservative


Meselson & Stahl Experiments

high concentration of salt(high density)

low concentration(low density)

Fig. 1.15Afrom Meselson and Stahl. 1958.


Fig. 1.15A

they wanted the DNA to appear about the same total darkness at each time point

backgroundsvary due to

different photographic

exposure times

from Meselson and Stahl. 1958.


Fig. 1.15A

evenly distributed DNA0



Fig. 1.15A

partially equilibrated DNA15



Fig. 1.15A

fully equilibrated DNA43

36



Fig. 1.15A

density of normal (light 14N) DNA



Fig. 1.15B

mix DNA made of 14N (light)

and15N (heavy)

centrifuge in salt gradient



Fig. 1.15B

density of light(14N) DNA

density of heavy(15N) DNA

mix DNA made of 14N (light)

and15N (heavy)

centrifuge in salt gradient



Fig. 1.15B & C

(15N) DNA

(14N) DNA



Fig. 1.15B & C

(15N) DNA

(14N) DNA

quantifying DNA in each band



Fig. 1.16

experiment performed twice



Fig. 1.16

experiment #1



Fig. 1.16

experiment #2



Fig. 1.16

all cells (DNA) grown in heavy 15N



Fig. 1.16

harvest cells (DNA) at time zero



Fig. 1.16

all cells (DNA) switched to light 14N



Fig. 1.16

harvest cells (DNA) at several time points



Fig. 1.16

separate new DNAby salt gradient



separate mixed DNAby salt gradient



Fig. 1.17

DNA centrifuged

43 hours

high salt densityon right side

all old/heavy (15N)

time = 0(in generations)0



Fig. 1.17

high salt densityon right side

quantify DNAin band



all 15N DNA

half 15N, half 14N DNAFig. 1.17modified from Meselson and Stahl. 1958.


Fig. 1.17

all heavyall light



Fig. 1.17

all heavyall light

DNA replicated

once

half 15N, half 14N DNAmodified from Meselson and Stahl. 1958.


Fig. 1.17

all heavyall light

DNA replicatesat different times



Fig. 1.17

DNA replicated

~ twice

all 15N DNA

50% 15N DNA

what has happened? 1.9

all heavyall light

14N 15N 15N14N



Fig. 1.17

DNA replicated

~ twice

all 15N DNA

50% 15N DNA


all heavyall light

14N 15N 15N14N



all 15N DNA

50% 15N DNA


1.0

0

Fig. 1.17

all heavyall light



all 15N DNA

50% 15N DNA

half DNA is 100% 14N

half DNA is 50% 14N 50% 15N

1.9

1.0

0

Fig. 1.17

all heavyall light



Fig. 1.14

all stands half new

mosaic

all old

all new

conservative

half old

half new

semi-conservative



all 15N DNA

50% 15N DNA

1.9

1.0

0



all 15N DNA

50% 15N DNA

1.9

1.0

0

Fig. 1.17

✓ data



50% 15N DNA

1.9

1.0

0

✓

all 15N DNA


Fig. 1.17

half DNA is 100% 14N



50% 15N DNA

1.9

1.0

0

✓

all 15N DNA


Fig. 1.17

✓ datahalf DNA is 100% 14N



Fig. 1.14

all stands half new

mosaic

all old

all new

conservative

half old

half new

semi-conservative



4

0 & 2

0 & 4

# replications



4

0 & 2

0 & 4

# replications

Fig. 1.17

all heavy

all light



4

0 & 2

0 & 4

# replications



4 = 16 copies

0 = 1 copy+2 = 4 copies

# replicationspercentage

14N mixed 15N

12.587.5 0.0

40.040.0 20.0

7.552.5 40.0 0 = 1 copy+4 = 16 copies



DNA is replicated in a semiconservative

process


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PowerPoint Slides for Chapter 1: Heritable Material by A. Malcolm Campbell, Laurie J. Heyer, & Christopher Paradise 1.4 How does DNA’s shape affect its