Cell cycle
What are the three phases of the cell cycle?
Interphase, Mitosis, Cytokinesis
What happens during cytokinesis?
The cell pinches in around the middle of the cell. The cytoplasm divides and the cell splits in two. Each daughter of the cell gets half of the organelles.
What happens during interphase?
The cell grows, makes a copy of it DNA, and prepares to divide.
What happens to the cell nucleus during mitosis?
It divides into two new nuclei during 4 phases
When does replication begin?
When 2 sides of the DNA molecule unwind and separate (like a zipper unzippering)
What is replication?
the cell makes an exact copy of the DNA in its nucleus
What is different about cytokinesis in animal cells?
The cell membrane squeezes togethers around the middle of the cell. The cytoplasm pinches into 2 cells. Each daughter cell gets about half of the organelles.
What happens during the first part of interphase?
the cell grows to full size and produces structures it needs
(cells make new ribosomes and produce enzymes)
(copies are made of both mitochrondria and chloroplasts)
What happens at the end of cytokinesis?
the cell enters interphase and the cell cycle begins again
Where do the molecules separate?
between the paired nitrogen bases
What happens during Mitosis?
One copy of the DNA is distributed into each of the daughter cells
How is cytokinesis different in plant cells?
A plant's rigid wall cannot squeeze together in the same way that a cell membrane can. Instead, a cell plate forms across the middle of the cell. The cell plate gradually develops into new cell membranes between the 2 daughter cells. New cell walls forms around the cell membranes.
What is the cell ready to do at the end of interphase?
the cell is ready to divide
What happens during prophase?
the threadlike chromatin in the nucleus condenses to form double rod structures called CHROMOSOMES
What do the nitrogen bases pair up with?
the bases on each half of the DNA molecule
Why is the cell cycle important?
Enables organisms to grow and develop by creating new cells
What is the role of the spindle fibers during cell division?
spindle fibers attach to chromosomes and pull them apart to opposite poles of the cell, ensuring that each new daughter cell receives an equal set of chromosomes during mitosis and meiosis; essentially, they are responsible for the accurate segregation of genetic material during cell division.
Why is replication important?
Each daughter must have a complete set of DNA to survive
What happens during metaphase?
The chromosomes line up across the center of the cell. Each chromosome attaches to a spindle fiber at its centromere.
What happens as a result of them pairing with each other?
the order of the bases in each new DNA molecule EXACTLY matches the order in the original DNA molecule
How long does it take a cell to complete one cell cycle? Which stage takes the longest?
It depends on the cell but growth and DNA replication take the longest. Mitosis and cytokinesis take the shortest.
What are the two sides of a DNA ladder made up of?
Molecules called nitrogen bases
(A,T,C,G)
What other cylindrical structures are copied during interphase?
centrioles
What happens during anaphase?
The centromeres split. Two chromatids separate and each becomes a new chromosome. The new chromosomes move to opposite ends of the cell. The cell stretches out as the opposite ends are pushed apart.
During DNA replication, which base pairs with guanine? Which base pairs with Adenine?
guanine- cytosine
adenine- thymine