biology: cell cycle and cell division
Vocab:
Benign - not harmful in effect
Oncogene– a group of genetic mutations that may cause cancer.
Tumor suppressor gene– normal genes that slow down cell division or tell cells to die at the right time
Malignant– very virulent or infectious.
Metastasis– spread of cancer cells from the place where they first formed to another part of the bod
Tumor– mass of tissue that forms when cells grow and divide more than they should
Chromosome – A DNA structure that carries genes.
Chromatin – Loose, uncoiled DNA in the nucleus.
Chromatid –one half of a duplicated chromosome.
Centromere – The part that holds two chromatids together.
Centriole – A structure that organizes spindle fiber in cell division.
Facts to know:
Oncogenes increase cell division and tumor suppressor genes reduce cell division
Lack of control of the cell cycle can lead to overgrowth of a cell type and cancer.
Environmental conditions that can increase your chance of developing cancer. These are called “carcinogens”
Replication of DNA creates two identical strands of DNA each with one old strand and one strand made of new nucleotides.
DNA double helix is packaged around histone proteins and condensed to create chromosomes.
Mitosis means nuclear division and that some cells do not follow this process with cytokinesis which leads to cells with multiple nuclei.
How cytokinesis differs in plant and animal cells: plant cells form a cell plate, animal cells form a cleavage furrow
Cell cycle nuclear splitting: takes place during mitosis
Cell cycle splits into 2: Cytokinesis
The structure of DNA and proteins that form cells in the nucleus prior to mitosis is: chromosome
DNA Replication:
Explain why DNA must be replicated in a careful manner before a cell is reproduced.
So that each new daughter cell receives a complete and accurate copy of the genetic information
Describe the basic semi-conservative method of replication of DNA:
the process of making two molecules of DNA from one DNA molecule, each containing one original DNA strand and one newly synthesised DNA strand
The leading strand is synthesized continuously
Enzymes help by unwinding the double helix
Compare prokaryotic and eukaryotic DNA structure.
prokaryotic DNA is typically circular and found freely in the cytoplasm
eukaryotic DNA is linear, organized into chromosomes within a nucleus
Discuss why the cell cycle is important, how the timing of the cycle is different in various cells, what might lead to the cell cycle being initiated, and why it is important that this process is carefully regulated.
It’s important because it ensures the cell grows,replicates DNA, and divides properly. Without the cell cycle, organisms wouldn’t be able to produce new cells to replace damaged ones.
Timing: some are rapidly dividing, some are non-dividing cells (like nerve/muscle cells) and enter G0 phase (after G-1), and cancer cells have uncontrolled timing, leading to rapid, unregulated growth.
What happens in the:
G-1 Phase: growth and development
S Phase: DNA replication
G-2 Phase: prepares for mitosis
Mitosis: mitosis, nuclear division
Cytokinesis: Cytoplasm splits into 2 / cell division
Students will explain that checkpoints are used in the cell cycle and explain what happens if the cell does not carefully complete each stage of the cycle.
Checkpoints in the cell cycle ensure each stage is completed correctly. If errors occur, damaged cells may form, leading to problems like uncontrolled growth or cancer.
Label a single and replicated chromosome.
a single chromosome has a centromere in the middle.
a replicated chromosome has a centromere in the middle and c
Students will describe how spindle fibers and centrioles are involved in the process of mitosis.
Centrioles are on opposite sides of the cell
Form spindle fibers, which connect to the centrioles of chromosomes
Pull sister chromatids apart, ensuring that each new cell gets an equal number of chromosomes.
Students will model and explain the stages of mitosis and why they are important for creating two identical cells.
Prophase - genetic material in the nucleus condenses and the duplicated chromosomes become visible
Metaphase - centromeres of the duplicated chromosomes line up across the center of the cell
Anaphase - chromosomes separate and move along spindle fibers to opposite ends of the cell
Telophase - chromosomes, distinct and condensed, begin to spread out into a tangle of chromatin
Students will explain cytokinesis.
Division of the cytoplasm to form 2 separate daughter cells
final stage in cell cycle / comes after mitosis
Students will describe how the cell cycle is used by some organisms for asexual reproduction.
Some organisms use the cell cycle for asexual reproduction, creating offspring without a mate. Through mitosis, one parent cell divides into two identical cells.
Students will describe what is meant by cell differentiation.
Cell differentiation is when a simple cell changes into a specific type of cell with a special job. For example, a stem cell can turn into a muscle cell, nerve cell, or blood cell. This helps the body form different tissues and organs. Once a cell changes, it usually can’t switch to another type.
Explain the idea of stem cells, differentiating between adult and embryonic stem cells, and describe how gene regulation determines differentiation of cell types.
Stem cells are special cells that can turn into different types of cells in the body.
Embryonic stem cells can become any cell type.
Adult stem cells can only become certain types of cells, like blood or bone cells.
Gene regulation controls what a cell becomes by turning certain genes on or off. This tells the cell what job to do, like becoming a muscle or nerve cell.