DNA Flashcards
What is DNA ligase?
A linking enzyme essential for DNA replication that catalyzes the covalent bonding of the 3’ end of one DNA fragment to the 5’ end of another DNA fragment.
DNA ligase plays a crucial role in joining Okazaki fragments during DNA replication.
What is a nuclease?
An enzyme that cuts DNA or RNA, either removing one or a few bases or hydrolyzing the DNA or RNA completely into its component nucleotides.
Nucleases are important for DNA repair and RNA processing.
What is an Okazaki fragment?
A short segment of DNA synthesized away from the replication fork on a template strand during DNA replication.
Okazaki fragments are joined together to make up the lagging strand of newly synthesized DNA.
What is the function of DNA polymerase?
An enzyme that catalyzes the elongation of new DNA by the addition of nucleotides to the 3’ end of an existing chain.
There are several different DNA polymerases, each with specific roles in DNA replication.
What is the role of helicase?
An enzyme that untwists the double helix of DNA at replication forks, separating the two strands and making them available as template strands.
What is telomerase?
An enzyme that catalyzes the lengthening of telomeres in eukaryotic germ cells.
What is a chromosome?
A cellular structure carrying genetic material, found in the nucleus of eukaryotic cells, consisting of one very long DNA molecule and associated proteins.
What is the leading strand?
The new complementary DNA strand synthesized continuously along the template strand toward the replication fork in the mandatory 5’ → 3’ direction.
What is a somatic cell?
Any cell in a multicellular organism except a sperm or egg or their precursors.
Fill in the blank: DNA _______ is essential for covalent bonding of DNA fragments.
ligase
True or False: Okazaki fragments are synthesized continuously during DNA replication.
False
Okazaki fragments are synthesized discontinuously away from the replication fork.
What are autosomes?
A chromosome that is not directly involved in determining sex, not a sex chromosome.
What is asexual reproduction?
The generation of offspring from a single parent that occurs without the fusion of gametes.
What is a diploid cell?
A cell containing two sets of chromosomes (2n), one set inherited from each parent.
What are telomeres?
The tandemly repetitive DNA at the end of a eukaryotic chromosome’s DNA molecule, protecting the organism’s genes from being eroded during successive rounds of replication.
