RNA and Protein Synthesis
Lesson 13.1 – RNA
Comparing RNA and DNA
The sugar in RNA is __________________________ instead of ___________________________.
RNA is generally ______________________________________________, not double-stranded.
RNA contains __________________________________ in place of thymine.
The Role of RNA
The roles played by __________________ and _______________________ molecules in directing protein production are like the two types of plans builders use:
________________________________________________
________________________________________________
Types of RNA
The three main types of RNA are:
Messenger RNA
An _________________________________ molecule is a __________________ of the portion of DNA that will be used to make a protein.
After being made in the ___________________, mRNA travels to the ___________________, the site of protein synthesis.
Ribosomal RNA
Protein synthesis occurs on ______________________, which are made up of two subunits.
These subunits consist of several molecules of ________________________________________ and as many as 80 different proteins.
Transfer RNA
During protein synthesis, __________________________________ RNA molecules (tRNA) carry amino acids from the _____________________ to the mRNA.
RNA Synthesis: Transcription
In ____________________________________, segments of DNA serve as ________________________ to produce _____________________________________ mRNA molecules.
RNA Synthesis: Promoters
______________________________________________ binds only to regions of DNA that have specific base sequences. These regions are called ____________________________________.
RNA Synthesis: RNA Editing
New RNA molecules sometimes require a bit of ______________________________ before they are ready to be read.
Lesson 13.2 – Ribosomes and Protein Synthesis
The Genetic Code
RNA has four bases: adenine, cytosine, guanine, and ______________________________. These bases form a “language”: __________________________________.
The Genetic Code: Codons
The genetic code is read in three-letter groupings called __________________________.
A ______________________________ is a group of three _____________________________ bases in messenger RNA that specifies a particular amino acid.
Genetic Code Table
There are _______________________ possible three-base codons in the genetic code.
Reading Codons
Start at the ________________________________ of the circle with the first letter of the codon and move ________________________.
Start and Stop Codons
The methionine codon ______________________________ serves as the “_______________________” codon for protein synthesis. There are three “_______________________” codons.
Translation
Transcribed mRNA directs the ________________________________ process.
Translation is the process that produces ______________________________ by decoding the sequence of mRNA codons.
Translation: Transfer RNA
Translation starts when a ________________________________ attaches to an ___________________ molecule. Then, ______________________________________________ molecules, carrying amino acids with them, bind to mRNA _________________________________.
Translation: The Polypeptide Assembly
The _____________________________________ helps form a peptide bond. It breaks the _________________ holding the first tRNA molecule to its amino acid.
Translation: Completing the Polypeptide
The ribosome reaches a _________________________________________ codon, releasing the newly synthesized _________________________________________ and the mRNA molecule, completing the process of _____________________________.
Roles of RNA in Translation
All three major forms of RNA—_________________________________________________—are involved in the process of translation.
The Molecular Basis of Heredity
The __________________________________________________________ of molecular biology is that information is transferred from __________________________________________________________.
Gene Expression
When a ______________________________________________ (segment) of DNA code is used to build a protein, scientists say that gene has been __________________________________________.
Lesson 13.3 – Mutations
Mutations
________________________________ are _______________________ changes in genetic information.
Types of Mutations
Mutations fall into two basic categories:
_________________________________________
_________________________________________
Gene Mutations: Point Mutations
A ______________________________ mutation is a change in a single nucleotide.
There are three types of point mutations:
Point Mutations: Substitutions
In a ____________________________________, one base is changed to a different base.
Point Mutations: Insertions and Deletions
___________________________________ mutation: when a single extra base is added into the code
___________________________________ mutation: when a single base is removed from the code
Chromosomal Mutations
Effects of Mutations
Mutations can ___________________________________________________________ on an organism.
Some mutations arise from ______________________—chemical or physical agents in the environment.
Effects of Mutations: Harmful
Some of the most __________________________________ mutations are those that dramatically change protein structure or gene activity.
Effects of Mutations: Beneficial
Mutations often produce proteins with new or __________________________________ functions that can be ___________________________ to organisms in different or changing environments.
Lesson 13.4 – Gene Regulation and Expression
Prokaryotic Gene Regulation
DNA-binding proteins in _______________________ regulate genes by controlling _________________.
One of the keys to gene transcription in bacteria is the organization of genes into __________________.
The Lac Operon
When lactose is __________________present, the lac genes are turned ________________________ by regulatory proteins that bind to DNA and _____________________ transcription.
Promoters and Operators
Located in front of the operon’s three genes are two regulatory regions:
__________________________
__________________________
The Lac Repressor Blocks Transcription
When the lac repressor binds to the _____________________, RNA _____________________________ cannot reach the lac genes to begin _________________________________.
Lactose Turns On the Operon
When lactose is ________________________________ to the medium, it diffuses into the cell and ____________________________ to the lac repressor.
Eukaryotic Gene Regulation
A typical eukaryotic gene has a ____________________________ box.
Transcription Factors
By binding DNA sequences in the _____________________________________ regions of eukaryotic genes, ___________________________________________ control the expression of those genes.
Cell Specialization
Complex __________________________________ in eukaryotes is what makes ___________________ and specialization possible.
RNA Interference
Small RNA molecules that ___________________________________ to any of the major groups of RNA play a powerful role in regulating gene expression.
They do so by _____________________ with mRNA.
The small interfering RNA molecules fold into double-stranded _____________________________. The dicer enzyme ____________________ the double strands into __________________________ (miRNA).
The two strands of the loops ________________________.
One of the miRNA pieces attaches to a cluster of proteins, forming a ____________________________ complex.
____________________________________ gene expression by means of an miRNA silencing complex is known as __________________________________________.
The Promise of RNAi Technology
The discovery of ____________________________ has made it possible for researchers to_______________ genes on and off at will, simply by inserting double-stranded RNA into cells.
It may provide new ways to treat and perhaps even cure ___________________________
Genetic Control of Development
____________________________________ gene expression is important in shaping how a multicellular organism develops.
Each of the ________________________________________ cell types found in the adult originates from the same ______________________________ egg cell.
Homeotic, Homeobox, and Hox Genes
___________________________________ regulate organ development.
___________________________________ code for transcription factors.
___________________________________ determine the identities of each body segment.
Environmental Influences
___________________________________ can affect gene regulation.
___________________________________________ is an example of how organisms can regulate gene _________________________________ in response to change in their environment
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