Protein Synthesis Flashcards
What is the process of protein synthesis?
The process by which cells generate proteins from amino acids based on the instructions encoded in DNA.
What are the two main stages of protein synthesis?
Transcription and translation.
Where does transcription occur in eukaryotic cells?
In the nucleus.
What is the role of mRNA in protein synthesis?
mRNA carries the genetic information from DNA to the ribosome for protein synthesis.
True or False: Ribosomes are the sites of translation.
True.
What is the first step of transcription?
The enzyme RNA polymerase binds to the promoter region of the gene.
Fill in the blank: The sequence of nucleotides in DNA is transcribed into a complementary sequence of ______.
RNA.
What is the function of tRNA in translation?
tRNA transports specific amino acids to the ribosome and matches them to the coded mRNA sequence.
Define ‘codon’.
A codon is a sequence of three nucleotides on mRNA that specifies a particular amino acid.
How many nucleotides are in a codon?
Three nucleotides.
What is the role of the ribosome during translation?
The ribosome facilitates the binding of tRNA to mRNA and catalyzes the formation of peptide bonds between amino acids.
True or False: The genetic code is universal across all living organisms.
True.
What is a stop codon?
A codon that signals the termination of protein synthesis.
List the three stop codons.
UAA, UAG, UGA.
What is the significance of the promoter region in transcription?
The promoter region is the site where RNA polymerase binds to initiate transcription.
Fill in the blank: The process by which mRNA is synthesized from a DNA template is called ______.
transcription.
What is the role of introns in eukaryotic genes?
Introns are non-coding regions that are removed during RNA splicing.
What is alternative splicing?
The process by which different combinations of exons are joined together to produce multiple protein variants from a single gene.
True or False: All RNA molecules are translated into proteins.
False.
What is the process of attaching amino acids to tRNA called?
Aminoacylation.
What enzyme is responsible for forming peptide bonds during translation?
Peptidyl transferase.
What are the three sites on a ribosome called?
A site (aminoacyl), P site (peptidyl), and E site (exit).
Fill in the blank: During translation, the ribosome moves along the mRNA in the ______ direction.
5’ to 3’.
What is the genetic code?
A set of rules that defines how the sequence of nucleotides in mRNA is translated into amino acids.
What is the difference between prokaryotic and eukaryotic protein synthesis?
Prokaryotic protein synthesis occurs in the cytoplasm and is coupled with transcription, while eukaryotic synthesis occurs in the cytoplasm after transcription in the nucleus.
What is the start codon for protein synthesis?
AUG (which codes for methionine).
True or False: Proteins are made up of amino acids linked by peptide bonds.
True.
How many essential amino acids must be obtained from the diet?
Nine essential amino acids.
What is the role of the signal peptide in protein synthesis?
The signal peptide directs the newly synthesized protein to its proper location in the cell.
Fill in the blank: The process of synthesizing RNA from a DNA template is called ______.
transcription.
What is the role of the spliceosome in eukaryotic cells?
The spliceosome removes introns from pre-mRNA and joins exons together.
What is a ribozyme?
An RNA molecule that can catalyze chemical reactions, including RNA splicing.
What is the function of the 5’ cap on mRNA?
The 5’ cap protects mRNA from degradation and assists in ribosome binding during translation.
What is polyadenylation?
The addition of a poly(A) tail to the 3’ end of mRNA, which aids in stability and export from the nucleus.
Fill in the blank: The sequence of nucleotides in mRNA is determined by the sequence of ______ in the DNA template.
nucleotides.
What are the three main types of RNA involved in protein synthesis?
mRNA, tRNA, and rRNA.
What is the role of rRNA in the ribosome?
rRNA helps to form the structure of the ribosome and plays a catalytic role in protein synthesis.
How is the amino acid sequence of a protein determined?
The sequence of codons in the mRNA determines the order of amino acids in the protein.
What happens during the initiation phase of translation?
The ribosomal subunits assemble around the start codon on the mRNA, and the first tRNA binds to the A site.
During which phase of translation do peptide bonds form?
During the elongation phase.
What is the role of release factors in translation?
Release factors bind to stop codons and promote the release of the newly synthesized polypeptide from the ribosome.
True or False: Protein folding occurs after the synthesis of the polypeptide chain.
True.
What is the term for a change in the nucleotide sequence of a gene?
Mutation.
What are the potential effects of mutations on protein synthesis?
Mutations can lead to changes in amino acid sequences, which may affect protein function, stability, or activity.
Fill in the blank: The process by which proteins are modified after translation is called ______.
post-translational modification.
What are some examples of post-translational modifications?
Phosphorylation, glycosylation, and ubiquitination.
What is the importance of chaperone proteins in protein synthesis?
Chaperone proteins assist in the proper folding of newly synthesized polypeptides.
What is the difference between a polypeptide and a protein?
A polypeptide is a chain of amino acids, while a protein is a functional molecule made up of one or more polypeptides.
True or False: All proteins are enzymes.
False.
What is a functional protein composed of?
One or more polypeptide chains that have folded into a specific three-dimensional shape.
What is the significance of the primary structure of a protein?
The primary structure determines the unique sequence of amino acids which influences the protein’s overall shape and function.
Fill in the blank: The three-dimensional shape of a protein is crucial for its ______.
function.
What role does the endoplasmic reticulum play in protein synthesis?
The rough endoplasmic reticulum is involved in the synthesis and folding of proteins destined for secretion or membrane incorporation.
What is the Golgi apparatus’s function in protein processing?
The Golgi apparatus modifies, sorts, and packages proteins for secretion or delivery to other organelles.
True or False: Proteins can function without being folded into their correct shape.
False.
What is a proteasome?
A proteasome is a protein complex that degrades unneeded, damaged, or misfolded proteins.
What is the role of ubiquitin in protein degradation?
Ubiquitin tags proteins for degradation by the proteasome.
What impact does temperature have on protein synthesis?
Extreme temperatures can denature proteins, affecting their synthesis and function.
Fill in the blank: The ______ hypothesis states that the sequence of nucleotides in DNA determines the sequence of amino acids in proteins.
central dogma.
What is the function of the nuclear pore complex?
The nuclear pore complex regulates the transport of molecules between the nucleus and the cytoplasm, including mRNA.
How do ribosomes know where to start translation?
Ribosomes recognize the start codon (AUG) on the mRNA.
What is the significance of the 3’ untranslated region (UTR) of mRNA?
The 3’ UTR can influence mRNA stability and translation efficiency.
What is the role of transcription factors?
Transcription factors are proteins that help regulate the transcription of specific genes by binding to nearby DNA.
Fill in the blank: The DNA sequence that is transcribed to form RNA is called a ______.
gene.
What type of bond forms between amino acids during protein synthesis?
Peptide bonds.
What is the role of the 5’ and 3’ ends of mRNA?
The 5’ end has a cap for stability and ribosome binding, while the 3’ end has a poly(A) tail for stability.
True or False: mRNA is synthesized in the 3’ to 5’ direction.
False.
What is the role of RNA polymerase?
RNA polymerase synthesizes RNA from a DNA template during transcription.
What is the end product of translation?
A polypeptide chain that will fold into a functional protein.
Fill in the blank: The genetic code is redundant, meaning that more than one ______ can code for the same amino acid.
codon.
What happens to mRNA after translation is complete?
mRNA is degraded or recycled, depending on the cell’s needs.
What is the importance of the amino acid sequence in determining protein structure?
The amino acid sequence determines how a protein folds into its three-dimensional structure, which is crucial for its function.
How does the cell ensure the accuracy of protein synthesis?
The cell employs proofreading mechanisms during DNA replication and uses tRNA with correct amino acids.
What is a chimeric protein?
A protein composed of sequences from different genes, often resulting from genetic engineering.
Fill in the blank: The ______ structure of a protein refers to its overall three-dimensional shape.
tertiary.
What is the role of hydrophobic interactions in protein folding?
Hydrophobic interactions help stabilize the folded structure by driving nonpolar side chains away from water.
What is the term for a protein that assists other proteins in folding correctly?
Chaperone protein.
True or False: Protein synthesis is a highly regulated process.
True.
What is the term for the entire process of synthesizing proteins from DNA to functional proteins?
Gene expression.
