Vocabulary
A group of disease that result from a breakdown in the usual control mechanisms that regulate cell division; certain cells divide uncontrollably and form tumors, from which cells may break away and form secondary tumors in other areas of the body (metastasis)
What are cancers?
A substance or environmental factor that can cause cancer
What is a carcinogen?
A relatively unspecialized cell that retains the ability to divide an unlimited number of times, and which has the potential to become a specialized cell (such as a blood cell or muscle cell)
What is a stem cell?
The sequence of events that takes place from one cell division until the next; it is made up of interphase, mitosis and cytokinesis
What is the cell cycle?
Repetitive sequence of DNA at the end of a chromosome that protects genes from the chromosome shortening that happens at each cell division
A random change in the base sequence (structure) of DNA (a gene mutation), or in the structure and / or number of chromosomes ( a chromosome mutation)
What is a mutation?
The production of new individuals of a species by a single parent organism; not involving gametes and fertilization
What is asexual reproduction?
The division of a nucleus (nuclear division) into two so that the two daughter cells have exactly the same number and type of chromosomes as the parent cells
What is mitosis?
One of two identical parts of a chromosome, held together by a centromere, formed during interphase by the replication of the DNA strand; referred to as sisters
What is a chromatid?
Basic protein (rich in the amino acids arginine and lysine) that forms the nucleosome scaffolding of chromosome; interact with DNA to provide a way to package a very long molecule into a very small space
What is histones?
The making of a new copy of an existing molecule
What is replication?
Mutated gene that causes cancer; a gene carried by a tumor virus or cancer cell, which is responsible for the formation of a tumor; many oncogenes are altered versions of normal cellular genes
What is an oncogene?
An organelle consisting of two centrioles, situated near the nucleus in animal cells and involved in the formation of the spindle prior to nuclear division; acts as a microtubule organizing center (MTOC)
What are centrosomes?
Visible in appropriately stained cells at nuclear division, each chromosome consists of a long thread of DNA package with protein (histone). Chromosomes replicate prior to division into chromatids . The contents of the nucleus appears as granular chromatin between divisions
What are chromosomes?
Constriction of the chromosome ; the region that becomes attached to the spindle prior to nuclear division
What is a centromere?
The period in the cell cycle between one mitosis and the next and during when DNA is replicated
What is interphase?
Stage in mitosis where the chromosomes move to opposite poles of the spindles. Sister chromatids move apart, pulled by the microtubules at the centromere
What is anaphase?
The division of the cytoplasm and cell into two genetically identical cells by constriction from the edges of the cell or the formation of a new cell wall
What is cytokinesis?
Nuclear envelope disappears, chromosomes condense, centriole duplicate and move toward the pole, spindle begins to form, two identical chromatids
What is prophase?
Occurs after a cell has finished its previous division. Molecules are made in preparation for replication and protein synthesis; cell grows in size and synthesizes mRNA and proteins in preparation for subsequent steps leading to mitosis
What is Gap 1 - G1?
DNA replication, making of a new copy of an existing molecule; DNA is replicated in the nucleus so that each chromosome consists of 2 identical chromatids
What is synthesis - S?
Nucleolus re-forming nuclear membrane reforming; sister chromatids reached the poles of the spindle now uncoil again, spindle disappears
What is telophase?
Chromosomes line up across the equator of the spindle. they are attached by their centromeres to the spindle;
What is metaphase?
Cell continues to grow and the new DNA that was made in S phase is checked. Errors are repaired prior to mitosis
What is Gap 2 - G2?
Material containing protein, it is present in the nucleus of eukaryotic cells at interphase and forms into chromosomes during mitosis and meiosis
What is chromatin?