Cell cycle
What’s the point of the cell cycle?
The point of the cell cycle is for the cell to grow and develop and eventually split to form two identical cells through mitosis and cytokinesis.
When do sister chromatids form?
S phase
What is the relationship between nitrogenous bases and nucleotides?
Nitrogenous bases are part of a nucleotide, along with a deoxyribose sugar and phosphate group.
Structure of DNA 3d
Double Helix
% of the DNA strand that is purines = __%
% of the DNA strand that is pyrimidines = __%
% of the DNA strand that is purines = 50%
% of the DNA strand that is pyrimidines = 50%
In which phase do cells spend the most time?
G1
What process forms sister chromatids?
Replication
What is the relationship between nucleotides and DNA?
Nucleotides are the building block monomers of DNA.
Replicated DNA
Sister Chromatins
If 22% of a DNA strand is Guanine, what are the amounts of the following?
Cytosine = __%
Adenine =__%
Thymine = __%
Cytosine = 22%
Adenine =28%
Thymine = 28%
Why might this make sense that cells spend the most time in G1
New cells have just formed through the mitotic phase. They need to grow and develop
Are sister chromatids identical? Explain.
Yes, DNA replication copies DNA exactly and two sister chromatids form.
What is the relationship between DNA and genes?
A segment of DNA is called a gene. Genes code for specific proteins.
Mitosis
Cell division In somatic cells
_____is an enzyme that breaks the hydrogen bonds between nitrogenous bases, allowing the two strands to separate
helicase
How is the cell different in G1 versus G2? What has happened to the DNA?
The DNA replicated in the S phase.
When does chromatin condense to form chromosomes?
Just before cell division
What is the relationship between DNA and chromosomes?
Chromosomes are composed of condensed DNA.
S phase
Phase when DNA replicates
DNA is built in the _’ to _’ direction
After the daughter cells are created, do they necessarily need to go through their own cell cycle? Explain.
No, some cells do not begin a new cell cycle when they are created. A good example of this is a nerve cell. Cells that do not enter the cell cycle will enter G0 phase.
Condensed DNA
Chromosomes
# of chromosomes in a human cell
46
Free
Free
One side of the new DNA is built in a continuous process and it is called the ____ . The other strand needs to be built in sections called okazaki fragments, and it is called the ___.
leading strand, lagging strand