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.