RNA Unit

BIO QUIZ

VOCAB:

DNA- (deoxyribonucleic acid) has two strands of nucleotides

RNA- (ribonucleic acid) has one strand of nucleotide 

Messenger RNA (mRNA)- created by “scribing” the line of code needed to make the protein

Transcription- the act of scribing the line of code

RNA Polymerase- the enzyme responsible for the copying (“scribing”)

Initiation- RNA polymerase binds and unzips the DNA at the promoter

Elongation- Copies into a single-stranded RNA

Termination- Zips the DNA back up

Promoters- regions of DNA that have a specific base sequence.

Introns- unnecessary pieces cut out(rna editing)

Exons- remaining pieces are spliced back together(rna editing)

Translation- “Translating” the code to make the protein (polypeptide chain of amino acids)

Protein- a chain of amino acids (called a polypeptide chain)

rRNA- building block of the ribosome

Codons- a sequence of three consecutive nucleotides in a DNA or RNA molecule that codes for a specific amino acid.

tRNA- reads the mRNA and transfers the correct amino acid. each tRNA has a 3-base anticodon that matches the codons on the mRNA

Mutations- Any change to the genetic information of a cell

Mutagens- factors in the environment that damage DNA (more frequent)

Point mutation- (Substitution) One nitrogenous base is changed to another

Silent mutation- no difference

Nonsense mutation- changes the amino acid to a stop

Missense mutation- changes the amino acid

Insertion- An extra nitrogenous base is added

Deletion- A nitrogenous base is taken out

TYPES OF RNA:

mRNA: the blueprint code message to make the protein

rRNA: building block of the ribosome

tRNA: transfers the correct amino acids together to make the polypeptide chain

KEY POINTS: 

6.3- DNA and RNA are both nucleic acids with some common features and some differences. Within a cell, DNA acts as the molecule of heredity by directing the production of RNA, which in turn directs the production of proteins.

6.4- Genetic information flows from DNA to messenger RNA in the nucleus through the process of transcription. At the ribosomes in the cytoplasm, each mRNA codon is translated into an amino acid of a protein.

6.5- During transcription, the DNA double helix separates, and one strand is used to generate a molecule of RNA. The RNA is processed to become messenger RNA, which then exits the nucleus via a nuclear pore.

6.6- Translation is accomplished by ribosomes, made from rRNA and protein. Ribosomes use two kinds of RNA to produce a string of amino acids. The genetic code dictates the correspondence between RNA triplets and amino acids.

6.7- Translation begins when a ribosome assembles from its subunits at the start codon of an mRNA. Elongation then proceeds, adding one amino acid at a time to the mRNA. When a stop codon is reached, the ribosome machinery disassembles, releasing the protein and the mRNA.

6.10- Mutations, changes to the nucleotide sequence of DNA, can occur spontaneously or be caused by mutagens. Point mutations affect a single mRNA codon, whereas insertions and deletions can affect many codons.