Bio Midterm Mitosis Flashcards
Basic unit of living organisms. Different _____ have different functions in the human body. For example, a muscle contracts to help us move, and an immune cell helps to fight disease.
Cell
These are bacterial cells, they have a very simple structure and lack a nucleus. DNA is concentrated in an area called a nucleoid that has no membrane around it. There are no membranes around any of its cell parts/organelles
Prokaryotic Cell
These are plant, animal, fungi, and protist cells. They have a true nucleus in which DNA is enclosed by a membrane, as well as other more complex membrane bound organelles
Eukaryotic Cell
Is surrounded by a membrane called the nuclear membrane. It is the control centre of the cell. The _______ contains chromatin which is composed of smaller units called genes. Genes are made up of molecules of DNA (deoxyribonucleic acid). Genes control the day by day activities of the cell by producing enzymes which control every chemical reaction in the cell. During cell reproduction the chromatin condenses to form chromosomes.
Nucleus
Is a segment of a DNA located on a chromosome. Each ____ codes for a particular protein that has some function or creates some structure in our body. Different _____ have different locations on the chromosome.
Gene
Coiled up and condensed DNA and associated proteins (histones)
Chromosome
DNA when it exists as long thin threads, before it coils up into a chromosome.
Chromatin
The twisted ladder shape of a DNA molecule
DNA double helix
Cells reproduce through a continuous sequence of growth and division called the ___ _____. There are 2 phases
- Growth and division called Interphase
- Division which involves mitosis and cytokinesis
The Cell Cycle
The cell cycle is faster for some cells than others, depending on the type of cell and environment. Some cells, such as those of the immune system may have to divide, grow and mature in a much shorter time frame. (Hours). Stomach cells last days whereas some brain cells last 30 - 50 years.
Time Frame for the Cell Cycle
Organisms grow and get larger by increasing the number of cells in their bodies
Functions of the cell cycle
Growth
When an organism’s body becomes damaged or injured, mitosis regenerates the injured area. Some organisms can even regenerate entire body parts (star fish).
Regeneration
Certain cells have to be continuously replaced because they die. For example red blood cells which transplant carbon dioxide and oxygen die by the millions each day and therefore need to be replaced.
Maintain Body Function
Mitosis is a type of cell division that occurs in somatic cells (body cells). During mitosis a cell chromosome replicates. The two daughter cells produced receive an identical copy of the chromosomes. Two identical diploid cells are produced from the original diploid cell. This ensures that every body cell produced recieves an exact copy of the DNA and the same number of chromosomes. Mitosis is divided into 4 stages: Prophase, Metaphase, Anaphase, and Telophase. The period is between these stages called Interphase.
What is Mitosis?
This is a period of growth when the cell undergoes normal day to day activities including protein synthesis, and DNA replication (spends the most time in this stage) divided into G-1, S, and G-2 phases. Genetic material exists as long thin twisted threads called chromatin. Chromatin replicates. Nuclear membranes and nucleolus are present and visible. Centrioles replicate to form two pairs.
Interphase
Pairs of centrioles move to opposite ends of the cell. Nuclear membrane and nucleolus disintegrate.(Disappear). Chromatin condenses into short thick rods called chromatids. Each chromatid is joined to it’s Identical sister chromatid that is replicated during interphase. They are joined at the centromere. (Visible as x-shaped chromosomes). Microtubules form star-shaped asters around centrioles, they form continuous strands between pairs of centrioles and they will eventually connect centrioles to the disc-shaped kinetochores on each chromatid. This entire framework of microtubules is called the mitotic spindle.
Prophase
