Cell Cycle
What is the cell cycle, and why is it important?
The series of stages a cell goes through as it grows, copies its DNA, and divides. It allows organisms to grow and replace damaged or old cells.
During which stage do chromosomes line up in the middle of the cell?
Metaphase.
How does mitosis help an organism grow?
It increases the number of cells in the organism.
Which molecule stores the genetic instructions that must be copied before cell division?
DNA.
What is the correct order of biological organization from smallest to largest: organ, cell, organism, tissue?
Cell → tissue → organ → organism.
During which stage of the cell cycle is DNA copied?
S phase of interphase.
During which stage do sister chromatids separate and move to opposite ends of the cell?
Anaphase.
How does mitosis help repair a cut on your skin?
It produces new cells to replace damaged or lost cells.
DNA belongs to which group of biological macromolecules: carbohydrates, lipids, proteins, or nucleic acids?
Nucleic acids.
What is the difference between a unicellular and a multicellular organism?
A unicellular organism consists of one cell, while a multicellular organism consists of many cells.
What are the three stages of interphase?
G1, S, and G2
Put the four stages of mitosis in order.
Prophase, metaphase, anaphase, telophase
What disease can develop when cells divide uncontrollably?
Cancer.
Which organelle contains most of a eukaryotic cell's DNA?
The nucleus.
A group of similar cells works together to repair damaged muscle. What level of organization do these cells form?
Tissue.
A cell has 10 chromosomes before DNA replication. How many chromosomes does it have after DNA replication?
10 chromosomes. Each chromosome now consists of two sister chromatids.
What is the difference between mitosis and cytokinesis?
Mitosis divides the nucleus and its chromosomes. Cytokinesis divides the cytoplasm, forming separate daughter cells.
Why is it important for cells to have controls that regulate the cell cycle?
These controls help cells divide at the appropriate time and prevent damaged or abnormal cells from dividing uncontrollably.
What are the building blocks, or monomers, of proteins?
Amino acids.
Why do cells need to exchange materials with their environment to maintain homeostasis?
They need to take in needed materials, such as nutrients and oxygen, and remove wastes to maintain stable internal conditions.
Why must a cell copy its DNA before dividing?
So each daughter cell receives a complete set of genetic information.
A body cell has 16 chromosomes. How many chromosomes should each daughter cell have after normal mitosis and cytokinesis?
16 chromosomes.
A mutation affects a gene that normally stops a cell from dividing when it should. How could this contribute to cancer?
The cell may continue dividing when it should stop, potentially producing a mass of abnormal cells.
Which cell structure controls what enters and leaves the cell, helping maintain homeostasis?
The cell membrane.
A scientist observes a cell with DNA but no nucleus. Does this automatically mean the cell is a virus? Explain.
No. Prokaryotic cells, such as bacteria, have DNA but no nucleus. Viruses are not cells and cannot reproduce independently.