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