Cell Cycle
What are the two main stages of the cell cycle?
interphase and mitosis
How many daughter cells result from mitosis?
2 identical daughter cells
How many daughter cells are produced at the end of meiosis?
4 haploid, unique daughter cells
What happens when the cell cycle is not properly regulated?
Cells divide uncontrollably, forming tumors.
What is the main difference between somatic and gametic cells?
Somatic cells are body cells (diploid); gametic cells are reproductive (haploid).
During which phase of the cell cycle does DNA replication occur?
s phase
What happens to chromosomes during metaphase?
they line up on the cell's equator and attach to spindle fibers
What type of cells are produced by meiosis?
gametes (sperm or egg)
What is a tumor?
A mass of abnormally dividing cells.
What structure holds sister chromatids together?
centromere
What happens during the G1 and G2 phases of interphase?
growth, every day functions, productions of organelles and proteins for mitosis prep
During which phase of mitosis do sister chromatids separate?
anaphase
What process during meiosis increases genetic variation by exchanging DNA segments
crossing over during prophase 1
Tumor suppressor genes, such as BRCA1, control the cell cycle checkpoints. What would need to occur to BRCA1 for a tumor to form?
it would need to be mutated / have the wrong protein structure to not work
What happens if nondisjunction occurs during meiosis?
Gametes end up with the wrong number of chromosomes (e.g., Down syndrome).
What is the purpose of cell cycle checkpoints?
to ensure the cell is ready to move to the next phase and prevent mutations.
What structure helps organize and separate chromosomes during mitosis?
the spindle fibers and centrioles
Explain the difference between homologous chromosomes and sister chromatids.
Homologous chromosomes come from different parents but have the same genes; sister chromatids are identical copies of one chromosome.
What other regulations do cells have to avoid becoming cancerous?
apoptosis if the DNA cannot be fixed, stops growing if area is too crowded, stops diving after a certain number of divisions
DAILEY DOUBLE:
In which stage(s) of the cell cycle is DNA in the form of chromatin?
During interphase (when the cell is not dividing)
List out all phases of the cell cycle in order
G1, S, G2, M, cytokenesis
Describe two ways mitosis is important for multicellular organisms.
growth, repair of tissues, regeneration, and asexual reproduction
Compare the outcomes of meiosis I and meiosis II.
Meiosis I separates homologous chromosomes (reduces chromosome number); Meiosis II separates sister chromatids (produces 4 haploid cells).
What gene type normally prevents uncontrolled cell growth but can cause cancer when mutated?
Tumor suppressor genes (e.g., p53)
Explain why meiosis is necessary for maintaining chromosome number across generations.
it halves the chromosome number so fertilization restores the diploid number.