Week 1: Nucleic Acids

What carbon of sugar does nitrogenous base attach to? 

"1'"

Oswald Avery

"1944; Identified DNA as ""transforming principle"" (genetic material/substance for heredity)"

What carbon of sugar is different when comparing deoxyribose & ribose? 

"2'"

What carbon of sugar is phosphodiester bond made with? 

"3'"

What carbon of sugar does phosphate group attach to? 

"5'"

Structure of nucleotide

"<img src=""Screen Shot 2022-08-17 at 8.18.00 PM.png"" width=""512"">"

Deoxyribose sugar structure

"<img src=""paste-20af22c3e0e293027d07e58617db387c7e8f10a2.jpg"">"

THYMINE (T) BASE

"<img src=""paste-27c4f7d6150ce1c0a157e677bdaf2fc6dca736fb.jpg"" width=""279""><br><span style=""color: rgb(255, 64, 255);"">PYRIMIDINE</span>&nbsp;<br>Extra methyl group&nbsp;"

ADENINE (A) BASE

"<img src=""paste-47c00c125cf723196fcc65a30a67722b732e857a.jpg""><br><span style=""color: rgb(255, 64, 255);"">PURINE</span>"

GUANINE (G) BASE

"<img src=""paste-9063778d641ebbcfa3dc38c0a23452ba0bc22ded.jpg"" width=""331""><br><span style=""color: rgb(255, 64, 255);"">PURINE</span>"

Ribose sugar structure

"<img src=""paste-a9e8774c944047a5996a35b7fe7a8fc18f604e86.jpg""><br>Hydroxyl group instead of hydrogen&nbsp;"

nucleoside

"<img src=""paste-aa743373a004a0f27d7faffdd9fa2d8896cb352e.jpg"" width=""299""><br><span style=""color: rgb(255, 64, 255);"">Only the base &amp; sugar portion of the nucleotide</span>"

The Central Dogma

"<img src=""paste-acc93030fc1b0558db3c0236b8ae139617d1466d.jpg"">"

CYTOSINE (C) BASE

"<img src=""paste-acee2cf846034df15217cd9afa95a51764b58e93.jpg"" width=""156""><br><span style=""color: rgb(255, 64, 255);"">PYRIMIDINE</span>"

URACIL (U) BASE

"<img src=""paste-e0601564effe663ffa55ca45c79e96126564cdf8.jpg""><br><span style=""color: rgb(255, 64, 255);"">PYRIMIDINE</span>"

polyA polymerase

"Adds polyA tail to 3' end of mRNA"

DNA Polymerase

"Makes new strands in 5'--&gt;3' direction"

Leading strand

"Runs from 3' --&gt; 5' direction"

Template strand

"Runs from 3' --&gt; 5'"

Lagging strand

"Runs from 5' --&gt; 3' direction"

RNA Polymerase

"Works in the 5' --&gt; 3' direction, similar to DNA polymerase"

polyA tail

"at the 3' end, sequence of adenines added to the 3' end after polyadenylation signal<br><br>Protects the mRNA from degradation"

Phosphodiester bond

"formed between 3' hydroxyl on ribose sugar &amp; 5' hydroxyl on phosphate group&nbsp;"

DNA Replication

- each strand serves as a template<br>- occurs during S phase of cell cycle<br>- multiple origins of replication&nbsp;

Identify the structural features of the DNA double helix?

1. Base pairing between two DNA strands<br>2. Strands are antiparallel<br>3. Strands are equidistant<br>4. Strands twist to form a double helix

DNA vs RNA structural differences

1. Double stranded polynucleotide vs. single polynucleotide strand<br>2. deoxyribose sugar vs. ribose sugar&nbsp;<br>3. A, G, C, T vs. A, G, C, U

"DNA's negative charge helps with what?&nbsp;"

1. Stability&nbsp;<br>2. Helps facilitate protein binding&nbsp;<br>3. Helps repel ions

Levene

1919; Discovered nucleic acid is composed of nucleotides & studied the structure of nucleotides

Erwin Chargaff

1950; Discovered base pairing A=T and C=G

Rosalind Franklin & Maurice Wilkens

1952; Photo 51 was an x-ray diffraction image of DNA, allowed the structure of DNA to be illucidated

James Watson & Francis Crick

1953; Published on the complementary structure of DNA

Describe A &amp; T H-bonding

2 H-bonds, 11.1 Angstroms&nbsp;

Describe C&amp;G H-bonding

3 H bonds, 10.8 Angstroms

codon

3 nucleotides which form a unit of genetic code. Translates to a specific amino acid

Purines

A &amp; G

DNA Ligase

Binds any fragments together after DNA polymerase is done copying the parental strand

Pyrimidines

C, T, U

Exons&nbsp;

Coding regions

Phosphate backbone

Consists of the sugar, phosphate groups, and phosphodiester bonds between them. Backbone is always constant&nbsp;<br><br>Gives NAs their negative charge which helps with stability &amp; repels unwanted ions

"5' cap"

Guanine triphosphate added to the end of RNA and then gets mehtylated&nbsp;<br><br>Seals RNA &amp; protects against degradation &amp; allows it to get recognized for translation

Miescher

Isolated white blood cells from bandaid; discovered nuclein (DNA with associated proteins from a cell nuclei)

Where does splicing occur

Nucleus

Promoter region

Region of DNA upstream of a gene where relevant proteins (RNA polymerase &amp; trasncription factors) bind to initiate transcription of that gene

Splicing

Removal of introns during matruation by spliceosome

Topoisomerase

Stabilizes super-coiling (strain caused by helicase unwindind DNA). Does this by breaking and rejoining the phosphodiester bonds

Primase

Synthesizes an RNA primer to give DNA polymerase a place to start from. Is responsible for the Okazaki fragments on the lagging strand

Helicase

Unwainds DNA by breaking H-bonding between 2 DNA strands

Telomerase

When you get to the end of a lagging strand, a primer is removed and you get a shorter strand<br><br>Adds telomeres, short sequences fo repeating bases, to the ends of chromosomes to prevent shortening/lost DNA

gene

coding region in chromsome that generes an RNA/product

Transcription

copying a gene (DNA) to make mRNA