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Flashcards in Lecture 7 Deck (64):
1

parents pass on to their offspring -- later known as genes that are responsible for inherited traits

discrete heritable factors

2

Mendel's first law of inheritance explains

3:1 F2 phenotype ratio

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threadlike structures in the nucleus of a eukaryotic cell that become visible when cell begins to divide

chromosome

4

entire genetic info for flies are on --

4 pairs of chromosomes

5

Thomas Morgan 1908

eye color gene in Drosophila on the X chromosome

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1860s: Mendel presents studies on -- in peas

heredity

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1869: Miescher isolated large substance in nucleus of white cells in pus from surgical bandages

slightly acidic, sugar, and rich in phosphorous; called it "nuclein"

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genetic materials are in chromosomes, which are in --

nucleus

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chromosomes contain a variety of -- in addition to DNA

proteins

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-- made using killed microorganisms which could be injected into patients to elicit the immune response of live cells without the risk of disease

vaccines

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1928: Griffith stumbled on a demonstration of the transmission of genetic instructions by a process we now call the

"transformation principle"

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1929: Levene determined the chemical composition and structure of the

DNA building blocks

13

Avery's lab discovered how to transform R strain into S strain --

in vitro

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Avery's two conclusions

1) molecules that can carry heritable info are in S strain
2) molecule that carries the heritable info is DNA

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When extracts of heat killed S strain + R stain were treated with DNase -->

no cells transformed to infective form

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1944: Avery, Macleod, and McCarty concluded that DNA was the

"S substance" but there were still doubters

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people finally accepted that DNA is the genetic material after whose experiment

1952: Hershey and Chase

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How can the info to specify an organism be carried in chemical form?

DNA is a linear polymer of 4 different monomers, strung out in a defined sequence like the letters of a document written in an alphabetic script

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How can DNA be duplicated and copied from generation to generation?

each strand of the double helix can serve as a template

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-- are the building blocks of DNA

nucleotides

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to maximize the efficiency of base-pair packing, the 2 sugar-phosphate backbones wind around each other to form a right handed double helix, with one complete turn every --

10 base pairs

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DNA is negatively charged because of

phosphate

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DNA strands are complementary and run in -- direction

antiparallel

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the chain of nucleotides in a DNA strand, being both -- and --, can be read as letters on a page

directional and linear

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most stable form of DNA

double helix

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purines (A, G) have -- rings

2 rings

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pyrimidine --, --, --, have 1 ring each

cytosine, thymine, uracil

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base pairing between -- and --

purines and pyrimidines

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2 H bonds between

A and T

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3 H bonds between

C and G

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each base pair is of similar width and thus hold the -- at a constant distance apart along the DNA molecule

sugar-phosphate backbones

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the -- and -- of the bases allow hydrogen bonds to form efficiently only between A and T and between C and G

shapes and chemical structures

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bases can only pair if the two polynucleotide chains that contain them are -- to each other

antiparallel

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the coiling of the two DNA strands around each other creates two -- in the double helix

grooves

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5' end usually shown carrying the

phosphate group

36

Chargaff's Rule

% A = %T
%G = % C
purines = pyrimidines

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usually, only the -- strand is presented in the 5' to 3' direction

top

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only one strand can serve as a template for one particular gene during --

transcription

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for transcription, usually given -- which has the exact sequence of mRNA (except for U)

non-template strand

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DNA is often measured in

bp or kb

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1 bp (base pair) = -- Daltons

660

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only -- code for proteins

exons

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exons are -- % of DNA

1.5%

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Franklin and Wilkins showed that DNA is helical from --

x-ray diffraction

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Franklin's data showed

1) backbone on the outside
2) provided insight that allowed Watson and Crick to determine that the strands were antiparallel
3) provided the best evidence of the helical nature of DNA

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each turn of DNA is about

10.5 base pairs

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bases of DNA are stabilized by

hydrogen bonds

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the double helix is stabilized by

base pairing and base stacking

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the -- groove is rich in chemical information

major

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minor groove has same arrangement of

hydrogen acceptors and donors

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major groove provides --

specificity

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DNA has many --

forms

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most common form of DNA (and was discovered by Watson and Crick)

B DNA

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double helix goes to the -- depending on environment

lowest energy state

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protein alpha helices have h bonds that are -- to the axis of the helix

parallel

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proteins are rigid, --, and --

short, and connected by turns

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double-stranded DNA helix have H bonds that are -- to the axis

perpendicular

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DNA can be -- by protein

bent

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DNA can be -- around proteins to fit in nucleus

tightly packed

60

DNA bases point

IN

61

Protein R groups point

OUT

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protein turns =

3.6 amino acids

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DNA backbone

phosphodiester bond

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protein backbone

peptide bond