Chapter 7: From DNA to Protein: How Cells Read the Genome Flashcards
(32 cards)
Define the following terms:
Gene Expression:
RNA Polymerase II:
Transcription:
RNA Processing:
Start Site:
Start Codon:
Translation:
Codon:
Anticodon:
Gene Expression: The process by which a gene makes a product that is useful to the cell or organism by directing the synthesis of a protein or an RNA molecule with a characteristic activity.
RNA Polymerase II: Enzyme that catalyzes the synthesis of an RNA molecule from a DNA template using ribonucleoside triphosphate precursors.
Transcription: Process in which RNA polymerase uses one strand of DNA as a template to synthesize a complementary RNA sequence.
RNA Processing: Broad term for the modifications that a precursor mRNA undergoes as it matures into an mRNA. It typically includes 5′ capping, RNA splicing, and 3′ polyadenylation.
Start Site: is the location where transcription starts at the 5’-end of a gene sequence from the end of termination.
Start Codon: is the initiation signal for translation that is found on a messenger RNA (mRNA) strand usually the triplet codon is AUG that starts the process close to TATA box.
Translation: Process by which the sequence of nucleotides in a messenger RNA molecule directs the incorporation of amino acids into protein.
Codon: Group of three consecutive nucleotides that specifies a particular amino acid or that starts or stops protein synthesis; applies to the nucleotides in an mRNA or in a coding sequence of DNA.
Anticodon: Set of three consecutive nucleotides in a transfer RNA molecule that recognizes, through base-pairing, the three-nucleotide codon on a messenger RNA molecule; this interaction helps to deliver the correct amino acid to a growing polypeptide chain.
What is the Central Dogma of Molecular Biology?
The central dogma of molecular biology describes the flow of genetic information from DNA to RNA, RNA to protein. The central dogma follows the two step process, transcription and translation. The process is given below.
DNA → RNA → Protein
The information in the DNA of every cell is converted into small portable RNA messages in transcription. During translation, the RNA messages travel from the DNA to the ribosomes to make specific proteins.
Protein Conformation Primary Structure-? Secondary Structure-? Tertiary Structure-? Quaternary Structure-?
order of amino acids alpha helix, beta sheet lowest energy folded state protein complexes
How many different amino acids are commonly used in making proteins?
20
Which parts of amino acids are involved in a peptide bond?
amino group of one amino acid and carboxyl group of the other
Which part of an amino acid gives it its unique properties
side chain
What is the best type of model visualizing the surface of a protein
space-filling
What are two types of β sheets?
parallel and anitparallel
What does the primary structure of a protein refer to?
the linear amino acid sequence of the protein
Consider the thermodynamic properties of chemical reactions. Even though enzymes do not affect the overall energy of the reactants or the products (i.e., the thermodynamics), they alter the speed of the reaction. Enzymes accomplish this by doing which of the following?
Reducing the activation energy of a reaction.
RNA Polymerase RNA Pol1 makes-? RNA Pol2 makes-? RNA Pol3 makes-?
rRNA mRNA rRNA, tRNA, snRNA
RNA Pol II is a protein complex that ___ DNA into ___
RNA Pol II is a protein complex that transcribes DNA into mRNA
Transcriptional Control (TF)
Bind to gene’s promoter by DNA-binding domain Regulate Transcription.
2 major types of Transcription Factors
- General Transcription Factors 2. Specific Transcription Factors
General Transcription Factors
Required for TXN at all genes. At every gene that is being transcribed.
Specific Transcription Factors
Activators and Repressors Required for TXN only at some genes AND regulate TXN of those genes.
Regulated genes
- Cell type specific 2. Expressed during development and differentiation. 3. Expressed in response to environmental changes.
What Translation requires?
mRNA transcript Many tRNA One Ribosome
Transcription ->(?) -(?)-> (?) -> (?)
Transcription -> Primary mRNA -(RNA processing) -> Mature mRNA transcript -> Translation
What makes one type of cell different from another type of cell, even if they have the same genome?
It has to do with the expression of the gene although they are comprised of the same gene, and DNA as it is expressed differently from one another.
How is DNA different from RNA? (Name four ways that they are different.)
Various ways DNA and RNA is different:
-DNA is double stranded and RNA is single stranded.
-DNA has deoxyribose and RNA has ribose sugars.
-DNA has adenine, Guanine, cytosine and thymine bases.
-RNA has adenine, guanine, cytosine and uracil bases.
-DNA and RNA both has sugar phosphate backbones, the difference is in the type of the sugar they have. DNA has deoxyribose and RNA has ribose sugar.
-DNA is immense in bulk and has a larger strand while RNA is much smaller in comparison.
Define the following:
mRNA:
tRNA:
rRNA:
snRNA:
mRNA: RNA molecule that specifies the amino acid sequence of a protein.
tRNA: Small RNA molecule that serves as an adaptor that “reads” a codon in mRNA and adds the correct amino acid to the growing polypeptide chain.
rRNA: RNA molecule that forms the structural and catalytic core of the ribosome.
snRNA: RNA molecule of around 200 nucleotides that participates in RNA splicing.
Describe Transcription. What is needed for Transcription to happen? How does Transcription begin? How does Transcription end?
Process in which RNA polymerase uses one strand of DNA as a template to synthesize a complementary RNA sequence. Transcription begins when RNA polymerase binds to a promoter sequence near the beginning of a gene (directly or through helper proteins). RNA polymerase uses one of the DNA strands (the template strand) as a template to make a new, complementary RNA molecule. Transcription ends in a process called termination.
Describe the three parts of RNA processing. (What happens to make a primary transcript into a mature transcript?)
Splicing, adding of the cap and tail, and the exit of the mRNA from the nucleus.
A 5’ cap is added to the beginning of the RNA transcript, and a 3’ poly-A tail is added to the end.
In splicing, some sections of the RNA transcript (introns) are removed, and the remaining sections (exons) are stuck back together.
Some genes can be alternatively spliced, leading to the production of different mature mRNA molecules from the same initial transcript.
