DNA & RNA Basics
What are similarities of RNA and DNA?
-They are both nucleotides (sugar + phosphate + nitrogenous base)
-They both share the bases adenine, cytosine and guanine
- They both have a sugar-phosphate backbone
What is Helicase?
Helicase unwinds DNA strands, which breaks the hydrogen bonds between bases
What are Operators?
Operators are segment of DNA where a repressor can bind
What is Transcription?
Transcription results in one mRNA strand that can be translated into three different enzymes
What is Substitution?
Substitution is a single nucleotide in the DNA sequence that is replaced with another
What are ways RNA differs from DNA?
1.) RNA is single stranded (DNA is a double helix)
2.) RNA has ribose (DNA has deoxyribose)
3.) RNA uses Uracil instead of Thymine
What is Topoisomerase?
Topoisomerase relieves the tension where the two strands are separated in front of the helicase. It prevents super coiling
What is a Promoter?
-A promoter is an area where RNA polymerase can bind
-DNA polymerase binds to start transcription
What is Translation?
mRNA synthesizes polypeptide chain. The main purpose is to read the mRNA sequence in code and amino acid sequence
What is Insertion?
Insertion is when an extra nucleotide is added, shifting the reading and potentially altering every amino acid
What are the base pairs in DNA?
Adenine pairs with Thynine = 2 bonds
Cytosine pairs with Guanine = 3 bonds
What are Telomeres?
Telomeres do not code for genes, but they do protect the genetic info
Telomeres become shorter the older you get
What are Operons?
Operons can either be inducible or repressible, depending whether they are turned on or off
Tryptophan levels low = operon on
Tryptophan levels high = operon off
What are differences between Transcription and Translation?
Transcription: Transcription happens first, It is located in the nucleus, It's base pairs are A,T,C,G, It is a DNA template, The product results in all RNA
translation: Translation happens second, It is located in the cytoplasm, It's base pairs are A,U,C,G, It is an mRNA template, The product is a protein(polypeptide chain)
What is Deletion?
Deletion is when a nucleotide is removed, shifting the reading and potentially altering the amino acid
What are Purines and Pyrimidines?
Purines: Adenine and Guanine (2 rings)
Pyrimidines: Thymine, Uracil and Cytosine (1 ring)
What are Single-Stranded Binding Proteins?
SSBPs bind to the separated DNA strands to prevent them from binding back together
What is a Repressor?
-A repressor is a small regulatory molecule that inhibits gene expression by binding to DNA and preventing transcription
-The repressor attaches to operator
What are the Steps of Transcription?
-Initiation = RNA polymerase binds to the promoter
-Elongation = RNA polymerase moves along the DNA template strand,breaking the hydrogen bonds
-Termination = Transcription stops when RNA polymerase reaches a termination sequence in the DNA
What is Frameshift Mutation?
Frameshift mutation occurs when nucleotides are inserted into or deleted from the DNA sequence, altering the reading of the genetic code
What is the Structure of Chromosomes?
1.) Prokaryotic chromosomes are circular. The plasmids are found in the cytosol. They are bacteria cells, Only 1
2.) Eukaryotic chromosomes are linear. The plasmids are found in the nucleus. They are animal and plant cells. There's many of them
What is Semi-Conservative?
Each of the two new DNA molecules contain one original strand and one new strand
What is Lactose?
-Lactose is absent = repressor protein binds to the operator preventing transcription by blocking RNA polymerase
-Lactose is present = converted into allolactose, which binds to the repressor inactivating it. This allows transcription
What are the Steps of Translation?
-Initiation = Translation begins with the assembly of the ribosome on the mRNA
-Elongation = The stage where the polypeptide chain is formed
-Termination = This happens when the ribosome reaches a stop codon (UAA,UAG, or UGA) on the MRNA
What is Gel Electrophoresis?
Gel Electrophoresis is a technique that is used to separate DNA fragments based on their size and electric charge. The smaller the fragment, the faster and farther it moves