What is RNA short for?
Ribonucleic Acid
How is RNA similar to DNA?
RNA is made up of a 5-carbon surgar, a phosphate group, and a nitrogenous base
How is RNA different from DNA?
(1) the sugar in RNA is ribose; (2) RNA is single-stranded;(3) RNA contains uracil in place of thymine
Why are the chemical differences between RNA and DNA important?
they make it easier for enzymes in the cell to tell DNA and RNA apart
What is the principal job of RNA?
Protein synthesis, or the assembly of amino acids into proteins.
What are the 3 types of RNA?
Messenger RNA (mRNA), Ribosomal RNA (rRNA), and Transfer RNA (tRNA).
What is the function of mRNA?
carries copies of the genetic instructions from DNA to other parts of the cell.
What is the function of rRNA?
form important part of both subunits of ribosome
What is the function of tRNA?
transfers each amino acid to the ribosome
Most of the work of making RNA occurs during what phase of protein synthesis?
Transcription.
What happens during transcription?
segments of DNA serve as templates to produce complementary RNA molecules.
What are the steps in the process of transcription?
1. RNA polymerase unwinds the two DNA strands.
2. RNA polymerase copies the genectic instructions to form a strand of mRNA.
3. The mRNA carries the genetic instructions through the nuclear por complex into the cytoplasm to a ribosome subunit.
4. The mRNA
How does protein synthesis differ in prokaryote cells and eukaryote cells?
In prokaryote cells, RNA synthesis and protein synthesis take place in the cytoplasm. In eukararyotes, RNA is produced in the cell's nucleus and then moves to the cytoplasm to play a role in the production of protein.
What is the difference between transcription and translation?
Transcription
- process of transforming DNA into mRNA
- can happen in the nucleus
Translation
- process of going from mRNA to a polypeptide or protein
- always happens in the cytoplasm
What enzyme does transcription require?
RNA polymerase.
What is RNA polymerase?
an enzyme that binds to DNA during transcription and separates or unwinds the DNA strands.
What is the function of RNA polymerase in transcription?
RNA polymerase binds to DNA, separates the strands, then uses one of the strands as a template from which to assemble nucleotides into a complementary RNA strand
Why is RNA polymerase important?
its ability to copy a single DNA sequence into RNA makes it possible for a single gene to produce hundreds or even thousands of RNA molecules.
How does RNA polymerase know where to start and stop making a strand of mRNA?
RNA polymerase binds only to promoters, which are signals in the DNA molecule that show RNA polymerase exactly where to start making mRNA. Similar signals in DNA cause transcription to stop when a new mRNA molecule is complete.
What are introns?
pre-mRNA molecules that have pieces cut out of them before they go into action
What are exons?
The remaining pieces of pre-mRNA that are spliced together to form the final mRNA.
What are polypeptides?
Long strands of amino acids.
What determines the properties in proteins?
The specific amino acids in a polypeptide and the order in which they are joined.
What influences the shape of a protein?
The sequence of amino acids, which in turn influences the function.
What are the 4 different nitrogenous bases in RNA?
The four different bases in RNA are: adenine (A), cystosine (C), guanine (G) and uracil (U).
What is the genetic code for RNA?
ACGU.
How is the genetic code for RNA read?
The genetic code is read three "letters" at a time, so that each "word" is three bases long and corresponds to a single amino acid.
What is a codon?
The three-letter word in mRNA. It consists of three consecutive bases that specify a single amino acid to be added to a polypeptide chain.
How many possible three-base codons are there in RNA?
64, because there are 4 different bases.
What is an anticodon?
An anticodon is the three unpaired bases on a tRNA that is complementary to one mRNA.
What is the role of Ribosomes in Translation?
Ribosomes use the sequence of codons in mRNA to assemble amino acids into polypeptide chains.
Where does translation occur in eukaryotic cells?
Translation is carried out by ribosomes after the transcribed mRNA enters the cell's cytoplasm.
What are the steps in the process of translation?
1. mRNA attaches to ribosome subunit; second ribsome subunit attaches to first forming a functional ribosome
2. tRNa brings amino acids into ribsome
3. each tRNA has an anticodon (complementary to the codon on the mRNA strand); ribosome places start codon
How do all three major forms of RNA come together in in the ribosome during translation?
The mRNA carries the coded message that directs the process tRNA delivers exactly the right amino acid called for by each codon on the mRNA. The tRNA are adaptors that enable the ribosome to read the mRNA's message accuarately and to get the translation j
What are Ribosomes composed of?
Ribosomes are composed of roughly 80 proteins and 3 or 4 different rRNA molecules.
What is the function of rRNA?
rRNA molecules help hold ribosomal proteins in place and help locate the beginning and end of the mRNA message. They may also carry out the chemical reaction that joins amino acids together.