Unit 2, part 2 Flashcards
What is the primary reason DNA needs to be replicated?
Whenever a cell divides, the two new daughter cells must contain the same genetic information as the parent cell.
What type of process is DNA replication?
It is a semiconservative process.
What are the three main steps of DNA replication?
- Initiation & unwinding
- Elongation
- Termination
What is the significance of multiple starting points in eukaryotic DNA replication?
Eukaryotic DNA replication has multiple starting points (origins of replication) to facilitate faster replication.
What components are required for DNA replication?
- Template to copy: Single-stranded DNA
- Machinery to do the copying
- Enzymes to read the template & build the new strand
- Substrates (dNTPs)
Fill in the blank: New DNA is always made _____ to _____.
5’ to 3’
What enzyme is responsible for unwinding DNA during replication?
Helicase.
What are Okazaki fragments?
Short fragments of DNA synthesized on the lagging strand.
True or False: DNA replication occurs in a unidirectional manner.
False.
What is the role of telomerase in DNA replication?
Telomerase synthesizes nucleotides at the end of the chromosome to prevent shortening.
What happens when replication forks meet during DNA replication?
Replication stops.
What is fidelity in the context of DNA replication?
Fidelity refers to how exact (or perfect) something is copied or reproduced.
What is the function of proofreading polymerases?
To correct incorrect nucleotides inserted during DNA replication.
Fill in the blank: DNA structure is critical because it is _____ and _____
Complementary and anti-parallel.
What happens if a mistake in DNA replication is not caught by proofreading?
The structure of the DNA molecule near the incorrect nucleotide will be slightly altered.
What is the average rate of DNA replication in humans?
Cells can replicate ~50 bp/second.
How long would it take to replicate one chromosome from end to end?
Over a month.
What is the consequence of the last RNA primer not being replaced at the end of a chromosome?
The chromosome gets a little shorter with each division.
Which type of cells typically contain telomerase?
Germline cells, embryonic cells, and a few somatic cells that divide a lot.
What are the two types of DNA polymerases mentioned?
- Polymerase for synthesizing new DNA strands
- Polymerase for replacing RNA primers with DNA
In DNA replication, what is the role of ligase?
Seals the backbone of the DNA.
