Biology Chapter 2: Reproduction Flashcards
Explain the difference between diploid and haploid
Diploid have 2 copies of each chromosome; haploid have one copy
What are the five stages of the cell cycle?
G1, S, G2, M, G0
What are the three stages that make up interphase?
G1, S, G2
What happens during the G1 stage?
cells create organelles for energy and protein production, while also increasing size.
What is the restriction point?
DNA is checked for quality, it must be passed for the cell to move into the S stage.
What happens during the S stage?
DNA is replicated - strands of DNA are called chromatids and are held together at the centromere.
What happens during the G2 stage?
further cell growth and replication of organelles in preparation for mitosis. Another quality checkpoint must be passed for the cell to pass into mitosis.
What happens during the M stage?
mitosis and cytokinesis occur
What happens during the G0 stage?
the cell performs its functions without any preparation for division.
What is p53?
plays a role in the two major checkpoints of the cell cycle (from G1 to S and G2 to M)
What is the significance of cyclins and cyclin-dependent kinases in the cell cycle?
rise and fall during the cell cycle. Cyclins bind to CDKs, phosphorylating and activating transcription factors for the next stage of the cell cycle.
When does cancer occur?
It occurs when cell cycle control becomes deranged, allowing damaged cells to undergo mitosis without regard to quality or quantity of the new cells produced. They may begin to produce factors that allow them to escape their site and invade or metastasize elsewhere.
What is the result of mitosis?
Two identical somatic cells
What are the 4 phases of mitosis?
prophase, metaphase, anaphase, telophase
What happens in prophase?
chromosomes condense, membrane dissolves, nucleoli disappear, centrioles migrate to opposite sides of the cell and the spindle apparatus begins to form. the kinetochore of each chromosome is contacted by a spindle fiber.
What happens in metaphase?
Chromosomes line up along the metaphase plate.
What happens in anaphase?
sister chromatids are separated and pulled to opposite poles.
What happens in telophase?
nuclear membrane reforms, spindle apparatus disappears and cytosol and organelles are split between the two daughter cells through cytokinesis.
Where does meiosis occur?
In gameocytes, germ cells
What does meiosis produce?
up to 4 nonidentical haploid sex cells (gametes)
How many rounds of replication does meiosis have? Division?
1 round of replication and 2 rounds of division (reductional and the equational)
What happens in meiosis I?
homologous pairs of chromosomes are separated from each other
What are homologues?
chromosomes that are given the same number, but are of opposite parental origin