DNA Biology and Technology Flashcards
What is DNA?
- Stands for Deoxyribonucleic acid
- Genetic material
- It’s the master copy of our genes
RNA
- Stands for Ribonucleic acid
- Working copy. Created from master copy (so that DNA is less subject to damage)
DNA must be able to…
- Replicate
- Store information (Does so through genetic code)
- Undergo change (to create variation in our species)
What form is DNA in?
- Double helix (because there are two strands of twisted molecules)
Building Blocks of DNA
- Nucleotides (phosphate, deoxyribose [sugar], nitrogeneous base [adenine, cytosine, guanine, thymine])
Purines and Pyramidines of Nitrogenous base in DNA
Purines (larger molecules than pyramidines) = Andenine & Guanine
Pyramidines= Cytosine & Thymine
What are the rails in the “DNA latter” composed of?
Sugar and phosphate
What are the rungs in the “DNA latter” composed of, and how are they held together?
- Composed of nitrogenous bases adenine (A), thymine (T), cytosine (C), and guanine (G)
- Held together by complementary base pairing
Complementary Base Pairing
- Adenine always binds to Thymine and Guanine always binds with Cytosine
- Held together by hydrogen bonds
- This is to ensure that the width of DNA remains consistent
What is DNA Replication
- Copying DNA for cell division
- Semiconservative process
- Errors that occur in the process are called mutations
Which phase of meiosis is DNA replicated?
The S phase
DNA helicase’s function in DNA replication
- unzips DNA by breaking down the weak hydrogen bonds between the paired bases
DNA Polymerase
- makes new DNA
- fits new nucleotides into place onto the split strand of DNA (but can only add them to the 3 end)
- they usually catch the errors they make when they the wrong nucleotides
- They need energy to add nucleotides, which they GET from the nucleotides
Lagging Strand vs Leading Strand
Leading Strand:
- Once the primer gives the starting point for the unzipping of the helicase, DNA is added to the leading strand continuously
- Replicated in ´3- ´5 direction
Lagging Strand
- Made in small pieces called okazaki fragments
- Replicated in ´5- ´3 direction
RNA Primase
Primase is an enzyme that synthesizes short RNA sequences called primers.
Messenger RNA
- also called mRNA
- produced in nucleas
- DNA serves as a template for it´s formation. DNA is transcribed into mRNA durring transcription
- Acts as messenger between DNA and protien production. Acts as messenger because DNA can´t leave the nucleas
Ribsomal RNA
- Produced in eukaryotes
- Produced using a DNA template
- ribosomal RNA (rRNA), molecule in cells that forms part of the protein-synthesizing organelle known as a ribosome and that is exported to the cytoplasm to help translate the information in messenger RNA (mRNA) into protein.
Transffered RNA
- Folds onto itself to form a ´t´ shape
- Brings amino acids together durring translation to form the growing peptide change
RNA Primer
- Starters of DNA synthesis
- Start at specific spots (the origins of replication) that are recognized by their specific sequence
- short stretch of nucleic acid complementary to the template, that provides a 3’ end for DNA polymerase to work on
- Usually about 5-10 nucleotides long
Single Stranded Binding Proteins
- Bind to the DNA and hold the 2 separated strands of it apart so that it doesn´t rejoin itself again
Okazaki Fragments
- The fragments that the lagging strand is made in
- Around 100-200 nucleotides long
Messenger RNA
- produced in nucleas
- carries genetic info from DNA to ribosomes where protien synthesis occurs (because DNA can´t leave the cell)
Ribosomal RNA
- Produced using a DNA template
- Joins with specific protiens to form the large and small subunits of ribosomes
- Durring protien sythesis: rRNA binds amino acids brought in by tRNA with the help of peptide bonds and thus helps in the protein synthesis
Transfer RNA
- In the shape of a T
- Produced in nucleus
- tRNA transfers amino acids to ribosomes
- t RNA carries only one type of amino acid, so there must be at least 20 different tRNA molecules functioning in a cell for the 20 types of amino acids.
Gene
The linear sequence of DNA that may code for a protein, ribosomal RNA, transfer RNA, or microRNA
Process of Transcription
- makes an RNA copy of DNA
- Occurs in the nucleas
Process of Translation
- makes protein from RNA
- Occurs at the ribosomes
Initiation: mRNA binds to the smaller subunit of the ribosome.
Elongation: The mRNA within the proteins helps match the nucleotides (by the process of complementary base pairing) to code for a polypeptide. The polypeptide lengthens.
Termination: The polypeptide chain stops growing when the codon tells it to.
What are proteins and polymers composed of?
- amino acids
How many amino acids are found in most proteins?
20
Cause of variation in proteins
Number and order of the amino acids. The sequence of amino acids in a protein leads to a particular shape.
Gene Expression
Step 1: Transcription:: A strand of mRNA forms complementary to its template DNA
Step 2: Translation:: The strand of mRNA uses the information of the DNA to code for an amino acid
Codon
Three base sequences in the mRNA molecule that correspond to the genetic code
Stop Codons
They stop the protien sythesis
Purpose of Polymerase Chain Reaction (PCR)
- Method of which DNA can be used in biotechnology
- The DNA is amplified so that it can be better studied/analyzed
- PCR can be used for DNA sequencing, DNA fingerprinting
Process of Polymerase Chain Reaction (PCR)
- The sample of DNA is heated to 95 degrees centigrade so that the double helix separates
- Primers Bind To DNA (happens at 55 degrees centigrade)
- Taq DNA polymerase adds conplementary bases (happens at 72 degrees centigrade)
- Process is repeated
Taq DNA Polymerase
- Adds complementary bases in a polymerase chain reaction
- A type of enzyme that comes from a bacterium that can survive at very high temperatures
- Advantage to using this enzyme at this temperature is that the process happens very quickly
DNA Sequencing
- Dye (that can be detected by lasers) is attached to the nucleotides so that an automated sequencing machine can provide a digital representation
- Requires the process of PCR to amplify the DNA
DNA Fingerprinting
- Used to identify samples
1. Short Tandem Repeats (STR) are identified using primers
2. STRs get separated by gel electrophoresis
Short Tandem Repeats
- Segments of DNA with repeated bases
Gel Electrophoresis
- A process of where the DNA segents are put in a gell with a positive and a negative end. The segments then fall onto a certain end based on the number of repeats within them
Purpose of Recombinant DNA Technology
- DNA that contains genetic material from more than one organism
- It is useful for cloning and developing biotechnology products (e.g.) food and medicean,
Steps of Recombinant DNA Technology (example given is combinding Human DNA and bacterial DNA)
- Human DNA and bacterial DNA (in the form of a plasmid) is extracted
- Restriction enzymes chop up the DNA
- DNA ligase seals the fragment of DNA into plasmid
- Bacteria take up recombined plasmid
- Bacteria becomes a transgenic organism and produces a product
Biotechnology Products
- Transgenic organisms produce biotechnology products
- Commonly acquired from bacteria, animals, and plants
DNA Editing
- Involves replacing or removing sequences of DNA
- Recent method is CRISPR
CRISPR
- finds ¨bad¨ sequences of DNA, memorizes them, and then goes off to destroy them. The DNA is either naturally rebuilt (which is the cause for a lot of mutations) or aided by RNA which uses complementary base pairing to add the desired sequence.
Genomics
- Study of the human genome
Functional Genomics
- The sequence of DNA is determined in order to determine the function of a gene
Comparative Genomics
- Used to compare DNA of different organisms/speices
Proteomics
- Study of the structure, function, and interaction of proteins. This study is assisted by bionformatics.
Bioinformatics
- Using computer technology to collect, store, and analyze genetic info
Gene therapy
- Involves the insertion of genetic material for the treatment of a disorder
- Can occur outside of the body through ex vivo
- Can occur inside of the body through in vivo
Steps of Ex Vivo Gene Therapy
- Remove stem cells from bone marrow
- A retrovirus infects the stem cell, bringing with it, it´s DNA
- The viral rDNA (retroviral DNA) brings the normal gene that we want to insert into the infected stem cell, into the genome
- Stem cell is returned to the patient, and it begins to replicate
Steps of In Vivo Gene Therapy
- The vector is inserted into the human body and binds to its host cell, then inserts the gene that has been missing
Vector
DNA molecule (often a virus or plasmid) used as a vehicle to carry a particular DNA segment into a host cell as part of a cloning or recombinant DNA technique
Recombinant DNA
(rDNA) contains DNA from two different sources. The foreign gene and vecotr DNA are cut by the same restriction enxyme and the foreign gene is sealed into the vector DNA
Nucleic Acid
- The umbrella term for what DNA and RNA is
Building blocks of Nucleic Acids
- Nucleotide
Differences between DNA and RNA
DNA:
- Found in nucleas and mitochondria
- Stores genetic info
- Sugar is deoxyribose
- Bases are A,T,C,G
- Transcribed to produce RNA
RNA:
- May be found throughut the cell
- Assits the processing of genetic info
- Sugar is ribose
- Bases are A,U,C,G
- Single-stranded
- Involved in gene regulation and is translated to procedure proteins
Gene
- Short segments of DNA
- Location: Within genetic material of DNA, organized into chromosomes
Genome
- All the genes of an individual
Phenome
- All the proteins of an individual
Steps of Protein synthesis
1: Transcription
2: Translation
Introns
- Portions of DNA that don´t code, and get taken out durring RNA sythesis
Exons
- Coding regions of RNA
How many codons are there?
64
(60 code for amino acids)
(3 codons for stop)
(1 code on for start)
- The # 64 was found because 20 different amino acids are used to build proteins. If a protein consisted of just a single base then protein synthesis then 16 amino acids would be covered. The use of 3 bases allows for 64 possible codons.
- Each amino acid is not limited to a single corresponding codon
Anticodon
- tRNA complementary to the mRNA that helps form a polypeptide chain
Mutations
- Misformations in the change of orignal structure of DNA during replication or division.
- Gene expression
- Pretranscriptional control: DNA serves as a template for mRNA
- Transcriptional control: pre RNA becomes processed to become RNA
- Posttranscriptional control: mRNA moves into cytoplasm and becomes associated with ribosomes
- Translational control: tRNA with anticodons carry amino acids to mRNA
- Posttranslational control: Anticodon-codon complementary base pairing occurs
- Polypeptide sythesis takes place one amino acid at a time
Types of biotechnology products that are produced
- ## Organisms that have had a foreign gene inserted into them are called transgenic organisms
