Cell Division and Inheritance Pt. 1 Final Flashcards
What is cancer
The uncontrolled growth and division of cells
Normal cells of the body spend most of their time in interphase
Cancer results from the G1 phase of the cell cycle being affected, the cells are much smaller than normal, the time necessary for the cell cycle shortens
How are cancer cells different from regular cells?
They spend less time in interphase
They have uncontrolled mitosis –
They grow faster than normal cells
They can break away from groups of cells and travel to other places in the body.
They have a different physical structure – often with parts that allow them to grip
and grab onto other cells and tissues
One way that cancer cells are physically different from normal cells
gripping structures
How do you end up dying of cancer?
Mutated cells keep reproducing at a high rate, causing the body to put lots of energy into their production and upkeep. All of this energy being devoted to these cancer cells causes other normal cells to suffer and can ultimately lead to death.
Different possible causes of cancer
Chemicals, UV radiation, virus such as the HPV virus, x-rays, and genetics
All of these items increase the likelihood of cells becoming mutated which means that cells may not repair and follow a proper cell division cycle
what is a tumor?
Cluster of cells going through uncontrolled mitosis.
types of tumors
Benign Tumors – these tumors have cells that do NOT migrate to other parts of the body and do not harm other parts of the body
Malignant Tumors – these tumors have cells that can migrate to other parts of the body, potentially causing the cancer cells to spread in the body
What happens if the body is going through metastasis?
When a tumor or cancer cells have spread from their original source, this is called metastasis.
what is a biopsy?
In a biopsy, the doctor removes a sample of the cells from the tumor to analyze under a microscope to determine whether the cells are cancerous
phases of the cell cycle
G1,S,G2, M
M includes mitosis and cytokinesis
interphase is everything else
Cancer treatments
surgery - removing the tumor
chemotherapy - To kill cancer cells in the body, doctors can inject powerful drugs into the body. This is usually done as an injection of drugs into the blood. These drugs kill cells quickly and aggressively. These drugs will also kill many normal cells in the body.
radiation - directing radiation at the tumor, radiation willl kill the cells in the tumor, hopefully causing it to shrink and die
Interphase parts
G1
Cell growth
Cells increase in size and synthesize new proteins and organelles
S
DNA replication
New DNA is synthesized when the chromosomes are replicated
Cell at the end of the S phase contains twice as much DNA as it did at the beginning
G2
Preparing for cell division
Many of the organelles and molecules required for cells division are produced
phases of cell division
Prophase
Metaphase
Anaphase
Telophase
cytokinesis
prophase
Nuclear envelope breaks down
Chromatin condenses into chromosomes
spindle fibers attach
centrosomes moves to opposite poles
Metaphase
Chromosomes line up in the center of the cell, spindle fibers fully form, nucleus is gone
Anaphase
sister chromatids are split, pulled apart by spindle fibers, move to opposite sides of cell
Telophase
Nucleus reforms
chromosomes unwind and turns back into chromatin
cytokinesis begins
cytokinesis
cytoplasm splits, fully making parent cell into two new cells
If sister chromatids did not like up correctly during metaphase
DNA would not be split correctly , so neither of the cells would have the correct amount of DNA. Might be hard for spindle fibers to connect, might draw entire chromosome to one side, would cause an imbalance in the DNA
G0
Cells spend much more time in interphase than in cell division (mitosis and cytokinesis)
Occasionally cells stop dividing and enter another phase, G0
Not dividing cells are staying in G0 long term and will not do any more mitosis
Sometimes cells are in G0 only for a little bit and do not stay there permanently
Cells split of into G0 coming off from G1, cell has maybe grown a little bit, but not fully grown, hasn’t really begun dividing yet
what happens to mutated cells
Apoptosis - Cell cycle has a regular system of checks and balances that prevents damaged or mutated cells from proceeding to the next phase. One way an organism deals with the problems is to kill the damaged cell before it passes on the problem to its daughter cells.
Sometimes instead of being killed, damaged or mutated cells in an organism enter G0, which stops them from copying and making other damaged cells, but also gives the body an opportunity to potentially fix the damage
mitosis in plant vs. animals cells
Cytokinesis
In animal cells, cytokinesis occurs by a process known as cleavage, forming a cleavage furrow, a shallow groove in the cell surface. Cell membrane is drawn inward until the cytoplasm is pinched into two nearly equal parts
In plant cells, a cell plate forms during cytokinesis, which gradually develops into cell membranes that separate the two daughter cells, a cell wall then forms in between the two new membranes
plant cells also don’t have centrioles
homologous pairs
matching genes - one from female parent and one from male parents
alleles
different genes for the same trait
amount of chromosomes in cells
Ex. humans have 46 chromosomes or 23 pairs
One set from dad - 23 in sperm
One set from mom - 23 in egg
Genotype
Combination of genes an organism has (actual gene makeup)
phenotype
physical appearance resulting from gene makeup
Where does an organism get its unique characteristics?
Organisms inherit their set of characteristics from their parents or parent
An individual’s characteristics are determined by factors that are passed from one parental generation to the next
How are different forms of a gene distributed to offspring?
During gamete formation, the alleles for each gene segregate from each other, so that each gamete carries only one allele for each gene
How to allele segregate when more than one gene is involved?
Independent assort, genes for different traits segregate independently during the formation of gametes
What did Mendel contribute to our understanding of genetics? (4 concepts!)
Traits are determined by genes, which are passed from parent to offspring
Principle of dominance, some alleles are dominant and others are recessive
Each adult has two copies of each gene–one from each parent
Segregation, During gamete formation, the alleles for each gene segregate from each other, so that each game carries only one allele for each gene
Independent assortment, genes for different traits can segregate independently during the formation of gametes, inheritance of one trait has no effect on the inheritance of another trait
