Cell Cycle and DNA Replication Flashcards
Anchorage Dependence
Cells must be anchored to a surface before they may grow/divide
Density Dependence
Cells produce proto-oncogens when they are not touching other cells, and then produce tumor suppressors once they touch other cells
Antiparallel Synthesis
The idea that strands of DNA are replicated in a complementary fashion. 5’ to 3’ DNA matches up with the other strand 3’ to 5’.
Semi-Conservative Replication
The two new DNA molecules produced through DNA replication are each made up of one newly synthesized DNA strand and one old DNA strand.
Diploid
A cell that contains two chromosomes for each trait.
Somatic Cells
Body cells (including skin, heart, and liver cells), which are diploid
Proto-oncogens
Molecules that promote cell growth and encourage division
Tumor Suppressors
Molecules that inhibit cell division and growth
Cell Cycle Arrest - Apoptosis
Cell “Suicide”, in which a cell destroys itself by bursting all of its lysosomes, releasing all of its digestive enzymes to digest itself.
Centrioles and Spindle Fibers
Centrioles are organelles that produce spindle fibers, and they do so to pull together sister chromatids and thus produce two distinct sets of chromosomes.
Centromeres
The point at which sister chromatids are “glued” together. Sister chromatids are pulled apart when spindle fibers attach here.
Kinetochores
The specific points on each side of the centromeres that the spindle fibers attach to to pull the DNA apart.
Cell Regulation Check Points
Points in the cell cycle where the cell has monitoring proteins to check on the cell’s progress through the cell cycle. If an error is detected, the cell will stop progressing until the error is fixed. If it can’t be fixed, the cell will undergo apoptosis.
P53
A checkpoint protein that detects mismatched DNA during G1 phase. If it detects an error, it triggers an inhibitor that will stop cyclin, preventing the activation of S phase proteins.
CDK
Cyclin-Dependent Kinase, the molecule that, when activated, adds a phosphate onto other, specific enzymes in order to activate them and progress the cell cycle.
Cyclin
The molecule that is easy for the cell to make and destroy that activates kinase in its function of activating other enzymes. The cell makes cyclin only when it is ready to progress to the next phase of the cell cycle.
Kinase
The enzyme that is always present in the cell that must have cyclin added to it in order to be activated.
Chromatin
A loose form of DNA in which it is tangled
Chromosomes
The condensed form of DNA that forms during prophase. The DNA is now coiled tightly around proteins called histones, and is visible under a microscope.
Sister Chromatids
The two copies of DNA that pair together, attached at the centromere.
Cleavage Furrow
The final phase that is formed during telophase in animal cells. The cell membrane pinches in as the cell elongates and the cell splits into two.
Cell Plate
The final phase that is formed during telophase in plant cells. An extension of the cell wall is created by the golgi body and several vesicles.
Leading Strand (Continuous Synthesis)
The strand that is made as DNA Polymerase trails right behind DNA Helicase, following it and traveling in the same direction.
Lagging Strand (Discontinuous Synthesis)
The strand that is made as DNA Polymerase travels in the direction opposite from the one DNA Helicase is traveling in. Therefore, DNA Polymerase has to replicate this strand in parts.
Okazaki Fragments
The parts of the lagging strand that are replicated one at a time.
Excision Repair (Mutations)
The process during which DNA Polymerase, at the end of DNA replication, replaces any incorrect sequences in the newly synthesized strand of DNA.
DNA Polymerase
The enzyme that brings in DNA nucleotides complementary to those on the DNA strand being replicated and puts them in place.
DNA Helicase
The enzyme that initially separates the DNA strands before and during DNA replication through a twisting motion. It attaches to DNA at the origin of replication and starts unraveling going outwards. Therefore, it is always at the replication fork.
DNA Ligase
The enzyme that follows behind DNA Polymerase. It attaches all of the DNA nucleotides that DNA Polymerase lays down through dehydration synthesis, forming the sugar - phosphate bonds.
RNA Polymerase
The enzyme that, starting at the origin of replication, adds in a few RNA nucleotides across from the separated DNA. This is the RNA Primer.
RNA Primer
The set of a few RNA nucleotides that RNA Polymerase lays down at the origin of replication. The RNA Primer is what the DNA nucleotides that DNA Polymerase lays down are able to attach to initially.
Prophase
DNA condenses into chromosomes/chromatids. The nucleus breaks apart and the nucleolus disappears. Centrioles move to opposite poles of the cell and begin creating spindle fibers.
Metaphase
The spindle fibers extend and connect to each side of the sister chromatids at the kinetochores. The chromosomes are then lined up in the middle of the cell.
Metaphase Plate
The imaginary middle of the cell, at which the chromosomes line up during metaphase.
Anaphase
Enzymes dissolve the centromeres that connect each pair of sister chromatids. The spindle fibers tug on the sister chromatids until they come apart and move to an opposite end of the cell.
Telophase
The spindle fibers disappear and the fragments from the nucleus re-form around each set of chromosomes. The cell membrane pinches in as the cell elongates. The chromosomes loosen back into chromatin and the nucleolus reappears in each nucleus.
Cytokinesis
The final step in cell division. The cytoplasm of the cell splits to form 2 daughter cells, each identical to the parent cell. In animal cells, this occurs through a cleavage furrow, while a cell plate forms in plant cells.
Cell Cycle
The process that a body cell goes through in order to grow and divide.
Interphase
The part of the cell cycle including G1, G0, S, and G2.
G0
The part of the cell cycle occurring towards the end of G1 in which the cell can stay and stop progressing through the cell cycle.
Restriction Point
A point in the cell cycle immediately following G0 that, if the cell passes, it must either complete the cell cycle or undergo apoptosis.
G1
The stage of the cell cycle during which the cell undergoes initial growth.
G2
The stage of the cell cycle during which the cell grows again and prepares for cell division.
S Phase
The stage of the cell cycle during which the cell’s DNA is replicated.
M Phase
The stage of the cell cycle that includes mitosis and cytokinesis. During this stage, the cell divides.
Mitosis
The stage of the cell cycle in which the cell undergoes division of the nucleus and DNA into two separate parts.
Cytokinesis
The stage of the cell cycle immediately following mitosis in which the cytoplasm of the cell divides finally into two, forming two individual daughter cells.
