| A | B |
|---|
| difficulties cell faces as it increases in size | demands on DNA, less efficient in moving materials across membrane |
| cell division | process in which cell divides into 2 daughter cells |
| asexual reproduction | genetically identical offspring from single parent |
| sexual reproduction | offspring inherit genetic info from each parent |
| chromosomes | packages of DNA |
| prokaryotic cell | contains a single, circular DNA chromosome |
| eukaryotic cell | contains more DNA than prokaryotic cell |
| role of chromosomes in cell division | make it possible to separate DNA precisely during division |
| complex of chromosome & histone (protein) | chromatin |
| cell cycle | series of events in which cells grow and divide |
| main events of the cell cycle | growth, preparation for division, , forms 2 daughter cells |
| binary fission | results in the production of two genetically identical cells |
| interphase | divided into 3 parts; G1, S, & G2 |
| G1 phase | cell growth |
| G1 | cell increases in size, synthesizes new proteins and organelles |
| S phase | chromosomes are replicated and new DNA synthesized |
| S Phase | at the end of this phase, cell contains twice as much DNA as it had in the beginning |
| G2 phase | preparing for cell division |
| G2 phase | many of the organelles and molecules required for division are produced |
| M phase | Cell division |
| M phase | 2 daughter cells are produced |
| mitosis | first stage of cell division |
| mitosis | cell nucleus is divided during this stage |
| cytokinesis | second stage of cell division |
| cytokinesis | division of cytoplasm takes place |
| prophase | first and longest stage of mitosis |
| prophase | duplicated chromosomes become visible |
| prophase | spindle begins to form outside the nucleus |
| centromere | region of a chromosome where the two sister chromatids attach |
| chromatid | DNA strand in the duplicated chromosome |
| centrioles | structure in an animal cell that helps to organize cell division |
| metaphase | second and shortest stage of mitosis |
| metaphase | duplicated chromosomes line up across center of cell |
| metaphase | spindle fibers connect centromere of each chromosome to the two poles of spindle |
| anaphase | third phase of mitosis |
| anaphase | chromosomes separate and move to opposite ends of cell |
| telophase | fourth and final stage of mitosis |
| telophase | distinct chromosomes spread out into tangle of chromatin |
| telophase | nuclear envelope forms around and nucleolus becomes visible in each daughter nucleus |
| cytokinesis | splits one cell into two-completes cell division process |
| cyclin | protein that regulates the cell cycle |
| internal regulators | respond to events occuring inside the cell |
| external regulators | respond to events outside the cell - speed up or slow down cell cycle |
| growth factors | stimulate growth and division of cells |
| apoptosis | process of programmed cell death |
| cancer | disorder in which body cells lose ability to control growth |
| cancer | occurs in multicellular organisms |
| tumor | mass of cancer cells |
| embryo | developing stage of a multicellular organism |
| differentiation | process by which cells become specialized |
| stem cells | unspecialized cells from which differentiated cells develop |
| totipotent cell | can develop into any type of cell in the body |
| blastocyst | hollow ball of cells with cluster of cells inside (human embryo) |
| pluripotent cell | can develop into most, but not all cell types |
| pluripotent cell | cannot form tissues surrounding the embryo |
| multipotent cell | can develop into many types of diffentiated cells |
| adult stem cells | multipotent |
| stem cells | offer potential benefit of using undiff. cells to repair or replace badly damaged cells and tissues |
