DNA stands for deoxyribonucleic acid and is the genetic material of all cells
DNA has a sugar-phosphate backbone with nucleic acid bases: thymine, adenine, cytosine, guanine
The nucleic acid bases form hydrogen bonds with each other and are very specific about which base they will bond with
Adenine bonds with thymine, guanine bonds with cytosine
Two nucleic acid bases held together by hydrogen bonds are called a base-pair
DNA is typically found double-stranded, with complementary strands held together by base-pairs
DNA replication involves separating the strands and using each strand as a template to add a complementary strand
The process of DNA to RNA to protein leads to the expression of traits
RNA stands for ribonucleic acid and is typically single-stranded
RNA has a different sugar than DNA and contains uracil instead of thymine
Messenger RNA (mRNA) carries the protein blueprint from DNA to ribosomes
Transfer RNA (tRNA) carries amino acids to ribosomes
Ribosomal RNA (rRNA) with certain proteins makes up ribosomes
Each tRNA has a specific anticodon and carries a specific amino acid
Transcription is the process of copying a sequence from DNA onto RNA
Translation uses the RNA sequence to direct the production of a protein
RNA processing in eukaryotic cells includes adding a cap and tail to protect the RNA, removing introns, and leaving exons that code for proteins
Mutation is any change in DNA
Mutations may also be the result of errors in DNA replication
Gene regulation is crucial for controlling gene expression, with negative and positive control mechanisms
DNA polymerase is an enzyme that brings nucleotides and adds complementary pairs
DNA polymerase can only build the new strand in the 5' to 3' direction, moving along the old template strand in the 3' to 5' direction
Ligase glues DNA together
DNA strands are anti-parallel, meaning one strand runs 5' to 3' while the other runs 3' to 5'
Substitution: one base is substituted for another
Insertion: one or more nucleotides are inserted into DNA
Deletion: one or more nucleotides are deleted from DNA
Mutagen: something that causes mutation
Insertion and deletion have potential to be especially dangerous
Codon: A sequence of three nucleotides that codes for a specific amino acid. It is located on the mRNA molecule.
Anticodon: The complementary base that matches the codon, and it is located in the tRNA molecule.
Start codon marks the beginning of translation
Stop codon signals for the termination of translation
Transcription:
Initiation: RNA polymerase binds to DNA at a promoter, DNA strands are separated here.
Elongation: RNA polymerase incorporates RNA nucleotides into a strand that is complementary to the DNA template, DNA strands separate only long enough for this to occur.
Termination: RNA polymerase is released from the DNA at the terminator, DNA is double-stranded again.
Translation:
Initiation: The small and large ribosomal subunits form a ribosome around tRNA with an amino acid on the start codon.
Elongation: The next three bases exposed by the ribosome form a codon, tRNA with the complementary anticodon fits into the ribosome and the amino acid it is carrying is added to the chain.
Termination: When the ribosome exposes a stop codon a release factor fits in, resulting in the ribosomal subunits falling off and the chain of amino acids (protein) being released.
A silent mutation is a mutation that does not change the amino acid sequence of a protein.
Mutations occur at random, however there can be factors that make mutations more likely to occur
Not all genes code for proteins and not all genes are turned "on"either
A frameshift mutation in a gene refers to the insertion or deletion of nucleotide bases in numbers that are not in multiples of three
Cells must replicate their DNA before they can divide.