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Lesson Overview Fermentation
Objectives 13.1RNA
-Contrast RNA and DNA.
-Explain the process of transcription.
Lesson Overview Fermentation
What is RNA???
RNA, like DNA, is a nucleic acid that consists of a long chain of nucleotides.
RNA stands for RiboNucleic Acid, while DNA stands for DeoxyriboNucleic Acid.
RNA uses the base sequence copied from DNA to direct the production of proteins.
Lesson Overview Fermentation
Comparing RNA and DNA Each nucleotide in both DNA and RNA is made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base.
There are three important differences between RNA and DNA: (1) The sugar in RNA is ribose instead of deoxyribose.
(2) RNA is generally single-stranded and not double-stranded.
(3) RNA contains uracil in place of thymine.
Lesson Overview Fermentation
DNA vs RNA…
Lesson Overview Fermentation
Types of RNA
The three main types of RNA are:1. messenger RNA (mRNA)2. ribosomal RNA (rRNA)3. transfer RNA (tRNA).
Lesson Overview Fermentation
Messenger RNA (mRNA)
The RNA that carries copies of the DNA instructions are known as messenger RNA (mRNA).
They carry information from DNA to the ribosome.
Lesson Overview Fermentation
Ribosomal RNA (rRNA)
Proteins are assembled on ribosomes.
The ribosome is made up of several ribosomal RNA (rRNA) molecules and as many as 80 different proteins.
Lesson Overview Fermentation
Transfer RNA (tRNA)
For a protein to be built, a transfer RNA (tRNA) molecule must transfer each amino acid to the ribosome by matching the mRNA’s CODON to the tRNA’s ANTICODON.
Lesson Overview Fermentation
Transcription
Most of the work of making RNA takes place during transcription. During transcription, segments of DNA serve as templates to produce a complementary strand of RNA.
Lesson Overview Fermentation
Where does transcription take place?
Prokaryotes - cytoplasm.
Eukaryotes - nucleus and then protein synthesis happens on the ribosomes in the cytoplasm.
Lesson Overview Fermentation
RNA Editing
RNA molecules sometimes require bits and pieces to be cut out of them.
The portions that are cut out and discarded are called introns or “junk DNA”.
The remaining pieces, known as exons, are then spliced back together to form the final mRNA.
Lesson Overview Fermentation
True or False1. The three types of RNA are messenger RNA, transfer RNA, and
ribosomal RNA. _________________________2. DNA molecules stay in the nucleus; RNA molecules leave the
nucleus and move through the cytoplasm to the ribosomes. _________________________
3. During DNA replication, only one strand of DNA serves as a template. _________________________
Lesson Overview Fermentation
Answers1. The three types of RNA are messenger RNA, transfer RNA, and
ribosomal RNA. true2. DNA molecules stay in the nucleus; RNA molecules leave the
nucleus and move through the cytoplasm to the ribosomes. true3. During DNA replication, only one strand of DNA serves as a
template. False, RNA replication
