chapter 8 biology
Terms
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- sarcoma
- cancer of supportive tissues, such as bone, cartilage, muscle
- fertilization
- the union of the nucleus of a sperm cell with the nucleus of an egg cell
- crossing over
- exchange of segments between chromatids of homologous chromosomes during synapis in prophase I of meiosis
- somatic cell
- any cell except a sperm or egg cell or a cell that develops into a sperm or egg cell
- mitosis
- cell divides and produces an exact copy of itself
- mitotic phase
- the part of cell cycle when mitosis divides the nucleus and distributes its chromosomes to the daughter nuclei
- genome
- a complete set of an organism's genes; an organism's genetic material
- chromosome
- a threadlike, gene-carrying structure found in the nucleus of a eukaryotic cell and most visible during mitosis & meiosis. consists of chromatin
- karyotype
- a display of micrographs of metaphase chromosomes of a cell, arranged by size and centromere position.
- metastasis
- spread of cancer cells beyond original site
- gamete
- sex cell; haploid egg or sperm. union of 2 of opposite sex (fertilization) produces zygote
- autosome
- chromosome not directly involved in determining sex. in mammals, any chromosome other than X and Y
- sex chromosome
- chromosome that determines if organism is male or female
- metaphase
- 3rd stage mitosis. cell's duplicated chromosomes are lined up at middle.
- chiasma
- microscopically visible site where crossing over has occurred between chromatids of homologous chromosomes during prophase I of meiosis
- cancer cells
- cells that are not subject to normal cell cycle control mechanisms and that will therefore divide continuously
- growth factor
- a protein secreted by a certain body cells that stimulates other cells to divide
- sister chromatid
- one of the 2 identical parts of a duplicated chromosome
- tumor
- abnormal mass of cells that forms within otherwise normal tissue
- cell plate
- double membrane across midline of dividing plant cell, between which the new cell wall forms during cytokinesis
- cytokinesis
- the division of the cytoplasm to form two separate daughter cells. occurs during telophase
- carcinoma
- cancer that originates in the coverings of the body, like skin or lining of intestinal tract
- anaphase
- 4th stage mitosis. sister chromatids separate. ends when complete set of daughter chromatids are at opposite ends of cell.
- meiosis
- division of single diploid nucleus into 4 haploid daughter nuclei. meiosis and cytokinesis produce haploid gametes from diploid cells in reproductive organs of parents
- haploid cell
- in life cycle of organism that reproduces sexually, a cell containing a single set of chromosomes, an n cell
- cell cycle
- an ordered sequence of events that extends from the time a eukaryotic cell is first formed until its own division into 2 cells
- benign tumor
- abnormal mass of cells that remains at its original site in body
- homologous chromosomes
- 2 chromosomes that make up a matched pair in a diploid cell. same length, centromere position, staining pattern. possess alleles for same genes at corresponding loci. one from mom one from dad.
- locus
- site where a gene is found on chromosome. homologous chromosomes have corresponding gene loci.
- interphase
- the period in the cell cycle when the cell is not dividing
- life cycle
- the entire sequence of stages in the life of an organism, from the adults of one generation to the adults of the next
- duplication
- repetition of part of a chrom. resulting from fusion with a fragment from a homologous chrom.; can result from an error in meiosis or mutagenesis
- zygote
- the fertilized egg, which is diploid, that results from the union of sperm nucleus and egg nucleus
- deletion
- loss of one or more nucleotides from a gene by mutation; loss of a fragment of chrom.
- cleavage furrow
- first sign of cytokinesis during cell division in animal cell, shallow groove in cell surface near the old metaphase plate
- leukemia
- type of cancer of blood-forming tissues, excessive production of white blood cells; cancer of bone marrow cells that produce leukocytes
- malignant tumor
- abnormal tissure mass that can spread into neighboring tissue and to other parts of body. cancerous
- oncogenes
- gene that produces cancer
- prophase
- the first stage of mitosis, during which the chromatin condenses to form structures(sister chromatids) visible with microscope, and the mitotic spindles begin to form. nucleus still intact
- chromatin
- the combination of DNA and proteins that constitutes chromosomes; often refers to the very extended form taken by chromosomes when a eukaryotic cell isn't dividing
- centrosome
- material in cytoplasm that gives rise to microtubules, important in mitosis and meiosis, also called microtubule-organizing center
- Down syndrome
- a human genetic disorder resulting from presence of an extra chrom. 21; characterized by heart & respiratory defects and varying degrees of mental retardation
- telophase
- 5th & last stage mitosis. daughter nuclei form at two poles of cell. occurs together with cytokinesis
- nondisjunction
- accident meiosis or mitosis in which pair of homologous chromosomes or a pair of sister chromatids fail to separate at anaphase
- mitotic spidle
- spindle shaped structure formed of microtubules and associated proteins that is involved in movements of chromosomes during mitosis & meiosis. shaped like football
- inversion
- change in chrom. resulting from reattachment of a chrom. fragment to original chrom., but in a reverse direction. mutagens and errors during meiosis can cause it
- translocation
- change in chrom. resulting from a chromosomal fragment attaching to a nonhomologous chromosome; can occur as a result of an error in meiosis or from mutagenesis
- lymphoma
- cancer of tissues that form white blood cells
- anchorage dependance
- requirement that to divide, a cell must be attached to a solid surface
- prometaphase
- 2nd stage of mitosis, during which the nuclear envelope fragments and spindle fibers attach to kinetochores of sister chromatids
- cell cycle control system
- cyclically operating set of proteins that triggers and coordinates events in the cell cycle
- cell division
- the reproduction of a cell
- diploid cell
- in an organism that reproduces sexually, a cell containing 2 homologous sets of chromosomes, 1 set from each parent, a 2n cell
- density-dependent inhibition
- arrest of cell division that ocurrs when cells grown in a laboratory dish touch one another, generally due to an inadequate supple of growth factors
- centromere
- the region of a chromosome where 2 sister chromatids are joined and where spindle fibers attach during mitosis and meiosis. it divides at the onset of anaphase during mitosis and anaphase II during meiosis
- binary fission
- a means of asexual reproduction in which a parent organism divides into two individuals of about equal size