DNA
Replication
Replication
What is the purpose of DNA Replication?
The purpose is to create an identical copy of DNA so that that every new cell has the same genetic material.
What is the final product of DNA replication?
2 identical double-stranded DNA molecules.
What is produced by transcription?
Messenger RNA (mRNA)
What is transcription And where does it occur?
Transcription is the process of making an mRNA copy of a gene from DNA, which occurs in the nucleus.
What is the purpose of translation?
To synthesize proteins from mRNA instructions, that perform essential functions in the cell.
Where in the cell does DNA Replication happen?
In the nucleus (of eukaryotic cell).
What role do nucleotides play in DNA replication?
Theyβre building blocks to create new DNA strands by pairing with complementary bases on the template strand.
What is the purpose of transcription?
To create an mRNA copy of a gene that can be used to make a protein.
What is the purpose of transcription?
To copy a gene's DNA sequence into RNA for protein production.
Where does translation take place in a cell?
On ribosomes in the cytoplasm
Which enzyme opens the DNA double helix?
Helicase
What is a replication fork?
A Y-shaped region where the DNA is being unwound for replication.
What enzyme carries out transcription?
RNA polymerase
How does transcription occur?
RNA polymerase binds to the promoter region of a gene, unwinds the DNA, and builds an mRNA strand by using the DNA template strand.
What is needed for translation to occur and what is produce?
Ribosomes, tRNA, mRNA and amino acids are needed. A polypeptide chain is produced, which folds into a functional protein.
What is the role of DNA polymerase during the replication?
It adds complementary DNA nucleotides to the growing strand and checks it for errors.
Describe the difference between the leading and the lagging strands.
The leading strand is synthesized continuously; the lagging strand is made in short fragments called Okazaki fragments.
How does RNA polymerase know where to start transcribing?
It binds to the promoter region on the DNA
Given the following template DNA strand:
3β TGC AAT CCG TAG 5β
What is the mRNA sequence?
5β ACG UUA GGC AUC 3β
How does translation happen and how does the ribosome know where to start translating?
Ribosomes read the mRNA codons, it starts at the start codon (AUG) on the mRNA. Then tRNAs bring the correct amino acids to build a protein chain.
If a mutation causes DNA polymerase to lose its ability to proofread during replication, what would be consequences for the cell that could occur?
There would be an increased number of errors in the newly synthesized DNA, which leads to mutations that could affect the function of proteins and potentially cause diseases like cancer.
Why are the two new DNA strands formed in opposite directions?
Because DNA polymerase can only add nucleotides in the 5β to 3β direction, so one strand is made continuously (leading) and the other in fragments (lagging).
What would happen if a geneβs promoter region was deleted?
Transcription would not begin because RNA polymerase wouldnβt βknowβ where to bind.
What is the difference between the template strand and the coding strand in transcription?
The template strand is used to build the mRNA and the coding strand has the same sequence as the mRNA (it just has T instead of U).
Describe how codons and anticodons work together during translation.
Codons on mRNA pair with complementary anticodons on tRNA to ensure correct amino acid sequence.