Cellular Growth/Cell Cycle
How many pairs of chromosomes do humans have?
23
What are sister chromatids and where do they attach?
Two identical copies of a chromosome combined at the centromere.
What is the product of mitosis?
Two identical daughter cells.
What is cytokinesis?
Splitting of the cytoplasm to form 2 new cells.
What are checkpoints?
Checkpoints: points in the cycle when the cell considers whether or not to move forward through the cycle.
Define surface area and volume in relation to a cell.
Surface area: area covered by the plasma membrane.
Volume: space taken up by the inner contents of a cell.
Distinguish between diploid and haploid cells.
Diploid: two copies of each chromosome
Haploid: one copy of each chromosome
What are the four phases of mitosis, in order?
Prophase
Metaphase
Anaphase
Telophase
In which phase of mitosis are chromosomes lined up in the middle of the cell?
Metaphase
What are the two types of stem cells? Where are each found?
Embryonic stem cells: found in embryonic tissue
Adult stem cells: found in various adult body tissues
What is the difference between chromatin and chromosomes?
Chromatin: DNA+histones, decondensed.
Chromosome: condensed, separate, linear pieces of DNA.
What are the two major phases of the cell cycle? Briefly describe each.
Interphase: cell growth and DNA replication
Mitosis: Cell division to produce 2 identical daughter cells
What is the name of the location where animal cells pinch off to form two new daughter cells during cytokinesis?
Cleavage furrow
What phase must a cell go through in between each round of mitosis/cytokinesis?
Interphase
What causes cancer? Be specific.
Carcinogens cause DNA mutations, which result in uncontrollable cell growth by allowing the cell to divide faster, avoid apoptosis, or bypass checkpoints.
How does surface area:volume ratio influence cell size?
Cells with a higher surface area: volume ratio can sustain themselves more easily, so they tend to be smaller as it is more efficient.
Why is DNA in a decondensed form during most of a cell's life? In what circumstances does DNA need to be condensed?
Chromatin is decondensed most of the time, meaning that is is unraveled. This gives cell machinery easy access to the DNA strand.
It condenses in preparation for cell division.
Which phase of mitosis is the longest? What happens during this phase?
Prophase: chromatin condenses into chromosomes, forming sister chromatids attached at the centromere. The spindle apparatus forms, attaching to the centromeres of sister chromatids.
Describe what happens during anaphase. Include what happens to the spindle apparatus.
Chromatids are pulled apart to opposite poles of the cell, separating sister chromatids. The spindle apparatus shortens.
What protein/enzyme complex is responsible for controlling the rate and timing of the cell cycle in animal cells?
Cylin/cyclin-dependant kinases (CDKs)
What is the mitotic spindle composed of?
Centrioles: organelles involved in cell division
Give the 3 steps of interphase and describe what happens in each.
G1: cell growth, organelles are copied
S: DNA replication
G2: cell growth, production of proteins/organelles, preparation for mitosis
Describe what you would see when looking at a plant cell undergoing telophase under a microscope.
You would see two nuclei filled with decondensed chromatin. You might start to see the separation of cells with a new cell wall.
How does cytokinesis differ between plant and animal cells?
Animal cells split completely to form two new cells.
Plant cells form a cell plate in between the two new cells, which forms between the daughter nuclei.
When do each of the four checkpoints occur during the cell cycle?
After each stage of interphase (G1, S, G2), and during mitosis (metaphase).