DNA replication and cell division Flashcards
(28 cards)
What is the name of the process that copies DNA?
DNA replication.
When does DNA replication occur?
During the S phase of the cell cycle.
What is meant by semi-conservative replication?
Each new DNA molecule contains one original strand and one new strand.
What enzyme breaks hydrogen bonds between DNA strands?
DNA helicase.
What happens after DNA helicase separates the strands?
The strands act as templates for complementary base pairing.
Which enzyme forms phosphodiester bonds between nucleotides?
DNA polymerase.
In which direction does DNA polymerase work?
From the 5’ to the 3’ end of the new strand.
What type of bond is formed between bases in a DNA molecule?
Hydrogen bonds.
What type of bond is formed between nucleotides in a DNA strand?
Phosphodiester bond.
What provides the energy for DNA replication?
Hydrolysis of activated nucleotides.
What is the role of DNA polymerase?
To join adjacent nucleotides and build the new DNA strand.
How was semi-conservative replication proven?
By the Meselson-Stahl experiment.
What are the two main types of cell division?
Mitosis and meiosis.
What is the purpose of mitosis?
Growth and repair and asexual reproduction.
What is the result of mitosis?
Two genetically identical diploid daughter cells.
What are the stages of the cell cycle?
Interphase and mitosis and cytokinesis.
What happens in interphase?
DNA replication and cell growth and organelle synthesis.
What are the stages of mitosis?
Prophase and metaphase and anaphase and telophase.
What happens in prophase?
Chromosomes condense and spindle fibres form and nuclear envelope breaks down.
What happens in metaphase?
Chromosomes align along the equator of the cell.
What happens in anaphase?
Sister chromatids are pulled apart to opposite poles.
What happens in telophase?
Nuclear envelopes reform around each set of chromosomes.
What is cytokinesis?
The division of the cytoplasm into two daughter cells.
What is the result of meiosis?
Four genetically different haploid cells.
