10.6-10.16: the flow of information from DNA to RNA to protein

What is the enzyme which "reads" this strand and produces a new RNA strand?

*RNA polymerase*

The first steps of transcription are _____. Describe this step.

*binding* and *initiation* involves the attachment of RNA polymerase to the promoter

The next step of transcription is _____, in which the ___ _____ continues to grow.

*elongation* RNA strand

What are the non-coding sequences (that are removed)? What are the coding sequences (that remain, and are eventually expressed)

*introns* *exons*

A specific nucleotide sequence (called a _____) acts as a binding site for RNA polymerase, determining where transcription begins.

*promoter*

What are the structures within the cytoplasm *that coordinate the functioning of mRNA and tRNA* to catalyze the synthesis of polypeptides?

*ribosomes*

For example, a _____ is added to the 5' end, and a _____ is added to the 3' end.

*small cap* (modified form of G nucleotide) *long tail* (chain of 50-250 A nucleotides)

The final step in transcription is _____, in which RNA polymerase reaches the _____ sequence, and _____ from the newly-made RNA strand.

*termination* terminator sequence detaches

RNA polymerase adds RNA nucleotides until it reaches a sequence of DNA bases called the _____, which signals the end of the gene.

*terminator*

How many amino acids are there?

20

How many binding sites do ribosomes contain?

3 (A, P, and E)

How many nucleotides are there?

4

How many codons are there? (hint, codons contain 3 nucleotides, and there are 4 different nucleotides)

64

What is the start codon?

AUG (methionine)

Genes (which are segments of ___) are transcribed into ___, and eventually translated into _____.

DNA RNA proteins

Messenger RNA is transcribed from ___, and the information in the mRNA is then translated into ________.

DNA polypeptides (not an entire protein)

However, a gene does not build a protein directly. Instead, it uses ______ to relay a genetic message, which is eventually turned into a protein.

RNA

Another type of RNA processing is made necessary in eukaryotes by nonding streches of nucleotides that interrupt the nucleotides that actually code for amino acids. What is this form of processing called?

RNA splicing

*The flow of genetic info from DNA to RNA to protein*

These are fill-in-the-blank flashcards pulled straight from a Bio1210 textbook. Review them in the correct order, or they will not make sense.

What are the phases of translation?

Translation can be divided into the same phases as transcription: binding/initiation elongation termiantion

What are the stop codons?

UAA, UAG, UGA

What is the "language" of proteins?

amino acids

A single-stranded loop at one end of the folded tRNA molecule contains a special triplet of bases called an _____.

anticodon

Translation occurs in the _____.

cytoplasm

Define *degenerate*.

each amino acid can be associated with more than one codon

Define *unambiguous*.

each codon specifies only one amino acid

Each amino acid is joined to the correct tRNA by a specific _____.

enzyme

What is the purpose of the 5' cap and 3' tail?

facilitate export of mRNA from nucleus protect mRNA from degradation by cellular enzymes help ribosomes bind to the mRNA

True or False? Genes build proteins themselves.

false

True or False? Transcription is entirely identical between eukaryotes and prokaryotes.

false

True or False? Eukaryotic mRNA leaves the nucleas immediately after it has been formed.

false Eukaryotic mRNA transcripts are modified/processed in several ways before leaving the nucleus.

True or False? The differences mentioned above have no impact on medical treatments.

false The differences are medically significant. Certain abx drugs can inactivate bacterial ribosomes while leaving eukaryotic ribosomes unaffected.

True or False? It is up to the ribosomes to accurately match the amino acids to the appropriate codons to form the new polypeptide.

false it is up to the tRNAs

True or False? This is a single enzyme which serves to bind the appropriate amino acid to its related tRNA molecule.

false there is a family of 20 versions of these enzymes, one enzyme for each amino acid *each enzyme specifically binds one type of amino acid to all tRNA molecules that code for that amino acid*

Where are the *ribosomes* found?

free-floating in the cytosol, or bound to the rough ER or the nuclear envelope

Whereas eukaryotes have a nuclear membrane, prokaryotes do not. Where does transcription occur in eukaryotes?

in the nucleus

The process of initiation brings together which molecules?

mRNA tRNA (bearing amino acids) the two ribosomal subunits

The kind of RNA that encodes amino acid sequences is called _________________ because it conveys genetic messages from DNA to the translation machinery of the cell.

messenger RNA (mRNA)

What is the "language" of DNA and RNA made up of?

nucleotide sequences

Transcription occurs in the _____.

nucleus

During transcription, how many of the DNA strands are used as a copy to make an mRNA molecule?

one strand

In order to do this, tRNAs much carry out two important functions. What are they?

picking up the correct amino acids recognizing the appropriate codons in the mRNA

Once an amino acid is attached to its appropriate tRNA, it can be incorporated into a growing ________ ________. This occurs within the _______, which are the structures responsible for the synthesis of proteins.

polypeptide chain ribosomes

RNA splicing also provides a means to produce multiple _____ from a single _____.

polypeptides gene

Genes provide the instructions for making specific _____.

proteins

In other words, _____(s) are the link between an organism's genotype and phenotype.

proteins

What does the *anticodon* do?

recognizes a particular codon on the mRNA by using base-paring rules

Each of these subunits are made up of a special kind of RNA, called ________.

ribosomal RNA (rRNA)

Translation requires two heavy-duty components. What are they?

ribosomes transfer RNA (tRNA)

In bacteria (which lack nuclei), transcription and translation occur (simultaneously/at different times), and occur in the _____.

simultaneously cytoplasm

What is *tRNA*?

tRNA is transfer RNA, it carries amino acids to the ribosomes during translation

What is the name of this strand?

the *template strand*

What is the molecular connection between these two?

the DNA inherited by an organism specifies its traits by dictating the synthesis of its proteins

The genetic code is both *degenerate* and *unambiguous*.

the following flashcards will discuss these terms

Define *triplet code*.

the genetic code is a sequence of three nucleic acid bases, each sequence being called a *codon*. each codons codes for a single amino acid

Define *genotype*.

the genetic makeup of an organism

Define *phenotype*.

the physical traits of an organism

Define *genes*.

the portions of DNA that actually carry instructions and regulatory sequences for protein synthesis

What is *RNA splicing*?

the process by which non-coding sequences are removed from the pre-mRNA molecule.

Define *translation*.

the process of assembling a protein using the message carried by mRNA

Define *transcription*.

the process of copying the genetic code from DNA into the form of mRNA

What is the binding site for RNA polymerase?

the promoter

Define *genetic code*.

the set of rules that determines how a nucleotide sequence is converted into the amino acid sequence of a protein

What are *ribosomes*

the sites of protein synthesis

True or False? Although all tRNA molecules are similar, there is a slightly different variety of tRNA for each amino acid.

true

True or False? An mRNA molecule is longer than the genetic message it carries.

true

True or False? The genetic code is nearly universal, being shared by organisms from the simplest bacteria to the most complex plants and animals.

true

True or False? The ribosomes of bacteria and eukaryotes are very similar in function, but those of eukaryotes are slightly larger and different in composition.

true

True or False? There are nucleotide sequences at the end of the mRNA molecule which help it to bind to the ribosome.

true

A ribosome is made up of how many subunits?

two (a large and a small subunit)