2.3 NUCLEIC ACIDS Flashcards
Key Event in 1865
Mendel’s Law of Heredity
Key Event in 1866
Johanns Miescher, Purification of DNA
Key Event in 1949
Sickle Cell Anemia mutation was first studied
Key Event in 1953
Watson and Crick’s DNA structure
Key Event in 1970
Recombinant DNA technology
Key Event in 1977
DNA sequencing
Key Event in 1985
In vitro amplification of DNA (PCR)
Key Event in 2001
The human genome project
The building blocks of DNA and RNA
Nucleic Acids
3 functional groups of nucleotides
Nitrogenous Base
Pentose Sugar
Phosphate groups
Nucleic acids are made up of?
Long chains or strands or monomers of Nucleotides
Main function of Nucleic acids
store and transmit the genetic information from the DNA to become protein
Two types of Nucleic Acids
Deoxyribonucleic acid
Ribonucleic acid
Two types of nitrogenous bases
Purine Pyrimidine
Nitrogenous base made up of double ring structures
Purine
Purine examples
Guanine and Adenine
Nitrogenous base made up of single ring structures
Pyrimidines
Pyrimidine examples
Cytosine
Thymine
Uracil
Nitrogenous base found only in DNA
Thymine
Nitrogenous base found only in RNA
Uracil
Building block of the nucleic acid
Pentose sugar
Purpose of the 1st carbon in the pentose sugar
Hold the nitrogenous bases
Purpose of the 2nd carbon in the pentose sugar
Determines whether it is Deoxyribose or Ribose
What accessory is attached to the second carbon if the pentose sugar is a Deoxyribose?
Hydrogen group (H)
What accessory is attached to the second carbon if the pentose sugar is a Ribose?
Hydroxyl group (OH)
Purpose of the 3rd carbon in the pentose sugar
Attaches to the succeeding nucleotides with the phosphodiester bond
How to check if it is a deoxyribose or ribose other than the attachment
difference of nucleotide to nucleoside
If it is phosphorylated
Phosphorylated sugar is a monomer of
Nucleotide
Unphosphorylated sugar is a monomer of
Nucleoside
This end of the DNA always end with a free phosphate group
5’
This end of the DNA is the free sugar
3’
Usually found in nucleus and are found in the mitochondria
Macromolecule of carbon, nitrogen, oxygen, phosphorous, and hydrogen atoms
DNA
Rule that base pairs follows
Chargaff’s rule
Chargaff’s rule states that
Adenine with Thymine
Cytosine with Guanine
The formation of hydrogen bonds between two complementary strand of DNA is called
hybridization
More stable pair in the base pairs
Guanine and cytosine
Mechanisms of nitrogenous bases in order to prevent water
Decrease
Bond which joins the two strands
Hydrogen bond
Direction of reading DNA pairs
5’ to 3’
Enzyme responsible for polymerizing the nucleotide chains
DNA polymerase
How do we read the template strand
3’ to 5’
This unzips the DNA strand
Helicase
This will bind to the strand in order to prevent rebinding of unwound strands
Single Stranded Binding Proteins
Site where the helicase separates the strand
Replication Fork
Placed in front of the replication fork that prevents the supercoiling of the DNA
Topoisomerase
Important to produce RNA primer
It is only possible if it toward the replication fork
Primase
Primase activates what
DNA polymerase 3
Responsible for adding the nucleotide bases to the daughter strand
DNA polymerase 3
Helps to connect okazaki fragments
DNA ligase
Direction of daughter strand synthesis
5’ to 3’
Enzymes for degradation of DNA
Restriction enzymes
Types of restriction enzymes
Nucleases/ DNAses
Types of Nucleases
Exonucleases and Endonucleases
It degrades the DNA from its end, either the 5’ to 3’
Exonucleases
Degrades in the middle, it is used if you want to insert a new sequence or cut them in the middle part. And to identify a recognition site of endonuclease
Endonuclease
Attacks specific sequence of DNA
Restriction enzymes
Restriction enzyme endonucleases types
1-3
Action of type 1 restriction enzyme endonucleases
Random Cut
Important for molecular studies
Type 2 restriction endonucleases
Type 3 Restriction endonuclease action
Non specific cut
Type 2 Restriction endonuclease action
Specific cut
Adds methyl group to self nucleic acid so that it wont be degraded by Restriction enzymes
Methyltransferase enzyme
Mixture and assembly of new genetic combinations
Recombination (sexual reproduction)
Recombination of asexual organisms
Conjugation
Transduction
Transformation
Needs contact to have genetic exchange
Conjugation
Uses carrier to give genetic material from donor to receiver
Transduction
Useful in modern day recombination techniques
Transformation
Double stranded circles of 2,000-100,000 bp in size
carry genetic information
were found to be a source of resistant phenotypes in multidrug bacteria
carry antibiotic-resistant gene
very short sequence
Plasmids
Single stranded whose main purpose is to translate the dna to become proteins
Ribonucleic acid
Nitrogen bases in RNA
Adenine
Cytosine
Guanine
Uracil
Types of RNA
Ribosomal RNA
Messenger RNA
Transfer RNA
Small nuclear RNA
Largest component of the cellular RNA 80%-90% of total cellular RNA
Ribosomal RNA
Three rRNA in prokaryotes
16s 23s 5s (sedimentation coefficient)
rRNA species in prokaryotes that is considered as the pre-ribosomal RNA
catalytic routes and structural routes
Single 45s precursor RNA
In prokaryotes, mRNA are simultaneously synthesized and translated into protein and it is also termed as
polycistronic
Eukaryotic mRNA is
monocistronic
In eukaryotes, synthesis and translation of mRNA are separated with
Nuclear membrane barrier
Translation of information from nucleic to acid to protein requires reading of mRNA by ribosomes, using adaptor molecules also called as
Transfer RNA
tRNA size
73-93 bases
24,000-31,000 MW
Responsible for carrying individual amino acids to the ribosome where they will be joined together by peptide bonds to make protein
contains UAG
tRNA
function in splicing in eukaryotes
sediment in a range of 6-8S
found only in nucleus
catalytic or structural only
Small Nuclear RNA
Unsaturated RNA molecules
sRNAs
non coding RNA
ncRNA
This is the copying of information from DNA to mRNA
Transcription
copying of one strand of DNA into RNA by a process of similar to that of DNA replication
Gene expression
Three types of RNA polymerase
pol I-III
most useful coding RNA polymerase
pol II
cellular location of pol I
Nucleolus
cellular location of pol II
Nucleus
cellular location of pol III
Nucleus
Products of pol I
18s
5.8s
28s
rRNA
Products of pol II
mRNA
snRNA
Products of pol III
tRNA
5s
rRNA
a-Amanitin of pol I
Insensitive
a-Amanitin of pol II
Inhibited
a-Amanitin of pol III
Inhibited by high concentration
Other RNA metabolizing enzymes
Ribonucleases:
Endoribonucleases - middle
Exoribonucleases - end
RNA helicases
catalyze the unwinding of double stranded DNA
RNA helicases
DNA double helix that carries genes seen during cell division
Chromosomes
chromosome structure usually observed in cells
Chromatin threads
chromosome structure observed in dividing cell
X shapes
Individual collection of the chromosomes used to check abnormalities
Karyotype