Chapter 8: Mitosis Flashcards
Compare asexual and sexual reproduction.
Asexual is replicating its genetic material and splitting the contents of one cell into two.
Sexual reproduction in contrast, is the production of off-spring whose genetic makeup comes from two parents.
Define cloning.
Asexual reproduction
Which organisms uses sexual reproduction and which uses asexual.
Sexual reproduction is used by humans
Asexual reproduction is used by bacteria, archaea, multicellular eukaryotes, and protist
Define meiosis?
It is the specialized type of cell division that gives rise to these sex cells.
Define gametes.
Sex cell
Define fertilization?
It is the union of the sperm and the egg cell.
Define mitosis.
Divides eukaryotic cell’s genetic information into two identical daughter cells.
Define apoptosis.
It is a cell death that is a normal part of development.
What does apoptosis accomplish?
It shapes new structures.
Compare meiosis and mitosis.
In the life cycle of humans and many other organism adults produce gametes by meiosis. Fertilization unites sperm and egg, and then mitotic cell division accounts for the growth of the new offspring.
Why must DNA replicate prior to cell division?
In DNA replication, the cell copies all of this information letter by letter from the genome. Without these instructions a new cell will die.
Define genome?
Consists of all the cells genetic material.
What is the role of DNA polymerase and ligase in replication?
DNA polymerase binds nucleotides to form new strands.
Ligase joins Okazaki fragments and seals nicks in sugar phosphate backbones
Why is DNA replication considered semiconservative?
DNA strands unwind and separate.
New nucleotides from complementary base pairs with each exposed strand.
The process ends with two identical double-stranded DNA molecules.
Define chromosome.
It is a single molecule of DNA and it’s associated proteins.
Define chromatin.
Which is a collective term for all of the cell’s DNA and it’s associated proteins.
Define Chromatid.
One of two identical attached copies that make up a replicated chromosome.
Define centromere.
A small part of a chromosome that attaches sister chromatids to each other.
How does the cell both have access to DNA and move DNA to new cells?
Eukaryotic chromosomes consists of chromatin, which is a collective term for all of the cell’s DNA and it’s associated proteins. These proteins include the many enzymes that help replicate the DNA and transcribe it to a sequence of RNA
Define cell cycle.
It is the events that occur from one cell division until the next.
Define interphase.
The cell is not dividing.
Define cytokinesis.
It is the splitting of the cell itself.
What happens during prophase?
Chromosomes condense and become visible. Spindle forms as centrosomes move to opposite poles.
What happens during prometaphase?
Nuclear envelope breaks up. Spindle fibers attach to kinetochores on chromosome.
What happens during metaphase?
Chromosome align along equator of cell.
What is anaphase?
Centrosomes split as sister chromatids separate and move to opposite poles of cell.
What happens during telophase?
Nuclear envelope and nucleolus form at each pole. Chromosome decondense. Spindle disappears.
What happens during cytokinesis?
Division of the cytoplasm into two cells.
Why is interphase not a resting stage for the cell?
Interphase is a very active time this is when the cell carries out its basic functions, from muscle contraction to insulin production to bone formation. DNA replication also takes place during this stage.
What is the role of the mitotic spindle?
The spindle aligns chromosomes. The spindle fibers push and pull to align the chromosomes. It coordinates the chromosome movements.
When does the spindle first appear?
In the prophase
When does the spindle disappear?
In the telophase.
What do the chromosomes do during mitosis?
Chromosomes divide during mitosis.
What does the mitotic spindle do during mitosis?
The spindle aligns chromosomes.
What does the cytoplasm do during cytokinesis?
The cytoplasm splits in cytokinesis.
During which stage of mitosis does cytokinesis occur?
Telophase
Compare cell plate and cleavage furrow.
Cleavage furrow is an indentation in cell membrane of an animal cell undergoing cytokinesis
Cell plate is materials that forms the beginnings of the cell wall in a plant cell undergoing cytokinesis
Both undergo cytokinesis
Cleavage furrow occur in animal cell the cell plate in plant cell.
Define tumor.
An abnormal mass of tissue.
What is benign tumor?
Usually slow growing and harmless, unless they become large enough to disrupt nearby tissue organs.
What is a malignant tumor?
Invades adjacent tumors
Define cancer?
Is a class of diseases characterized by malignant cells.
How does cancer begin?
Cancer begins when a single cell accumulates genetic mutations that cause it to break through its death and division control. Cancer arises when cells divide out of control.
How do cancer cells differ from normal cells?
First is its look,
second unlike normal cells, many cancer cells are essentially Immortal, ignoring the clock that limits normal cells to 50.
Third difference between normal cells and cancer cells lies in growth factors.
Fourth, normal cells growing in culture exhibit contact inhibition. Cancer cells lack contact inhibition so they tend to pile up I’m culture.
Also cancer cells lack anchorage dependence.
Define metastasize?
Meaning that it’s cells can break away from the original mass and travel in the bloodstream or lymphatic system to colonize other area s of the body.
Define contact inhibition?
Meaning that they stop dividing when they touch one another.
Compare benign and malignant.
Benign is usually harmless tissue but if it grows large enough it can affect other tissue.
Malignant invades adjacent tissue.
Compare oncogenes and tumor suppressor genes.
Oncogenes are mutated variants of genes that normally stimulate cell division.
Tumor suppressor genes encode proteins that normally block cancer development.
During which phase of mitosis would you expect to see chromosomes consisting of two chromatids within the nucleus?
Prophase
In a cell with 4 chromosomes, how many sister chromatids are visible during telophase?
None
What is independent assortment
Rearrangement of chromosomes during meiosis
What is nondisjunction
Failure of chromosome or sister chromatid to separate during meiosis.
Meiosis is called reduction division. When does the reduction in chromosomes number occur?
Anaphase 1
Mitosis occurs where?
Somatic cells
During which stage of the cell cycle does growth occur?
Interphase
