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66 Cards in this Set
- Front
- Back
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anaphase
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Of mitosis, stage when sister chromatids of each chromosome move to opposite spindle poles. During anaphase I (meiosis), each duplicated chromosome and its homologue move to opposite poles. During anaphase II, sister chromatids of each chromosome move to opposite poles.
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bipolar mitotic spindle
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dynamic array of microtubles that move across chromosomes in precise directions during mitosis or meiosis.
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cancer
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malignant neoplasm; mass of cells that divide abnormally and can spread in the body
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cell cycle
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Series of events from one cell division to the next. Interphase, mitosis, and cytoplasmic division constitute one cycle.
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cell plate
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in a dividing plant cell, a disk-like structure that becomes a crosswall with new plasma membrane on both sides
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cell plate formation
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mechanism of cytoplasmic division in plant cells
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centriole
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organelle that organizes formation and direction of cilia, flagella, and spindles
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centromere
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Constricted part of a chromosome to which spindle microtubules attach.
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centrosome
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Cell region where microtubules are produced.
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chromosome
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A coherent structure consisting of a DNA molecule and associated proteins. .
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chromosome number
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Sum of all chromosomes in a given type of cell.
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cleavage
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Early stage of animal development. Mitotic cell divisions divide a fertilized egg into many smaller, nucleated cells; original volume of egg cytoplasm does not increase.
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cytokine
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Signaling molecules of the immune system (e.g., interferons, interleukins).
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diploid number
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Total chromosome number in cells that have a pair of each type of chromosome characteristic of the species.
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growth
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Of multicelled species, increases in the number, size, and volume of cells. Of bacteria, increases in cell number.
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interphase
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Cell cycle interval between nuclear divisions; a cell grows in mass and roughly doubles the number of cytoplasmic components. DNA replication occurs during the interphase that precedes mitosis.
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karyotype
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Preparation of an individual’s metaphase chromosomes sorted by length, centromere location, and shape
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meiosis
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Only nuclear division process that halves the chromosome number of a parental cell, to the haploid number. Forms gametes in animals and spores in plants.
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metaphase
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Of meiosis I, stage when all pairs of homologous chromosomes have become positioned at the spindle equator. Of mitosis or meiosis II, all duplicated chromosomes are positioned at the spindle equator.
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microtubule
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Cytoskeletal element; consists of tubulin subunits. Contributes to cell shape, growth, and motion; constituent of spindles
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mitosis
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Nuclear division mechanism that maintains the parental chromosome number for forthcoming daughter cells. Basis of growth, tissue repair, and often asexual reproduction of eukaryotes.
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neoplasm
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Mass of cells (tumor) that have lost control over growth and division.
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nucleosome
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A small stretch of eukaryotic DNA wound around histone proteins.
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prophase
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Of mitosis, a stage when duplicated chromosomes start to condense, a spindle forms, and the nuclear envelope starts to break up. Duplicated pairs of centrioles move to opposite spindle poles. In prophase I of meiosis, crossing over also occurs.
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proto-oncogene
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A gene that, when mutated or overexpressed, helps turn a normal cell into a cancerous one.
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sister chromatids
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Two identical DNA molecules (and associated proteins) attached at the centromere until they are separated from each other at mitosis or meiosis; each is then a separate chromosome.
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telophase
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Of meiosis I, a stage when one member of each pair of homologous chromosomes reaches a spindle pole. Of mitosis and of meiosis II, the stage when chromosomes decondense into threadlike structures and daughter nuclei form.
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Name the 4 stages of mitosis:
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prophas
metaphase anaphase telophase |
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What happens to the cytoplasm of an animal cell after nuclear division?
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it is simply pinched in two
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What happens to the cytoplasm of a plant cell after nuclear division?
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a cross wall forms in the cytoplasm and divides it.
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How do tumors form?
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when the surveillance mechanisms that monitor and control the timing and rate of cellular division fail.
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What does the continuity of life depend on?
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reproduction.
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What is mitosis?
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mitosis is a nuclear division mechanism that occurs in somatic cells (body cells) of multicelled eukaryotes
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What is meiosis?
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this is a nuclear division mechanism that only occurs in sexual reproduction. This precedes the formation of gametes.
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What is a chromosome?
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a molecule of DNA and its proteins. (one strand)
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What are sister chromatids?
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a strand of chromosome and its copy that stay attached to each other.
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What do histone proteins look like?
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like beads on a string.
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What is a nucleosome?
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a unit of structural organization.
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What is a centromere?
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the point where sister chromatids are attached to each other.
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What is a cell cycle? When does it start and when does it end?
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a series of events from one cell division to the next. It starts when a new daughter cell forms by mitosis, and ends when the cell divides.
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Name the three stages of interphase.
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G1, S, and G2
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What happens in G1?
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Interval "Gap" of cell growth and functioning before the onset of DNA replication.
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What happens in the S phase of interphase?
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Time of "synthesis" (DNA replication) - chromosomes are duplicated.
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What happens in G2?
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It is the second interval "gap" after DNA replication. It is when the cell prepares for division.
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What is a chromosome number?
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the sum of all chromosomes in cells of a given type.
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What is 2n?
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diploid number.
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What is a diploid number?
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2n. a "diploid" number of chromosomes. There are two of each type.
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There are 2 sets of 23 chromosomes. What chromosome number does this result in?
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as a result there is a chromosome number of 46 in humans.
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How many stages does mitosis have?
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4 stages. prophas, metaphase, anaphase, and telophase.
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What is a bipolar mitotic spindle?
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this is a dynamic structure that is made of microtubles that grow or shrink as tubulin subunits are added or lost from their ends.
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What is the first stage or mitosis? and what happens in this stage?
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Prophase. The Chromosomes are already duplicated, and the sister chromatids are joined at the centromere.
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What is a centrosome?
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A centrosome is a site where microtubules originate.
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What do microtubules eventually form?
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it eventually forms the bipolar spindle.
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What happens in prophase?
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mitosis begins. and the duplicated chromosomes begin to condense.
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What is cleavage?
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a mechanism that pinches cytoplasm into two.
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What is cell plate formation?
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when tiny vesicles packed with wall building materials fuse with one another and eventually bridge te cytoplasm.
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What is a form of cytoplasmic division in animal cells?
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cleavage
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What is a form of cytoplasmic division in plant cells?
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the formation of a cross wall between the new plasma membranes of adjoining daughter cells.
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What is a kinase?
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enzymes that phosphorylate other molecules, and act as checkpoint gene products. When DNA is broken or incomplete, they activate other proteins so they can ultimately stop the cell cycle or induce cell death.
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What are tumor suppressors?
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checkpoint genes that inhibit mitosis.
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What are oncogenes?
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oncogenes are checkpoint genes that stimulate mitosis. (mutations that affect oncogene products or at the rate in which they form help transform a normal cell into a tumor cell.)
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Give examples of neoplasms.
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moles and tumors.
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What is a neoplasm?
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abnormal masses of cells that lost controls over how they grow and divide.
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What are cancers?
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cancers are abnormally growing and dividing cells of malignant neoplasm. Cancers disrupt surrounding tissues physically and metabolically.
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Give 4 characteristics of cancer cells.
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1.) they grow and divide abnormally.
2.)the cytoplasm and plasma membrane of the cancer cells become grossly altered. 3.)weakend capacity for adhesion. Therefore they cannot stay anchored in proper tissues. 4.) cancer cells may have lethal effects. |
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What is metastasis?
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metastasis is the name for the process of abnormal cell migration and tissue invasion.
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