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chapter 8 bio test
| Term | Definition |
|---|---|
| cell division | reproduction at the cellular level |
| what does cell division produce | two daughter cells that are genetically identical to each other and to the original cell |
| unicellular cell division | used for reproduction of the species |
| multicellular cell division | used for growth, repair, and replacement |
| asexual reproduction | produces offspring that are identical to the original cell or organism(involves inheritance of all genes from one parent) |
| sexual reproduction | produces offspring that are similar to the parents but show variations in traits |
| what type of chromosomes duplicated with each duplication | eukaryotic |
| chromatin | unwound segments of DNA, DNA is in this form when the cell is not dividing |
| chromatin characteristics | composed of DNA and proteins that help maintain chromosome structure and function |
| what form is DNA in before cell division | chromatin |
| chromosomes | wound up segments of DNA that contain genes, only in this form during cell division |
| somatic cells | any body cell(skin, muscle, not a sex cell) |
| how many chromosomes do somatic cells have | 46 |
| gene | unit of information that controls for a trait |
| how many genes do humans have | 21,000 |
| what pair do chromosomes come in | homologous pairs |
| homologous pairs | a pair of chromosomes that are the same size, shape, and contain the same genes |
| diploid number(2n) | both members of a homologous pair(somatic cells) |
| haploid number(n) | only one member of a homologous pair(gamete cells) |
| sister chromatids | two exact genetic copies, original chromosome and its exact genetic copy |
| when do chromosomes replicate into sister chromatids | prior to cell division |
| centromere | hold together sister chromatids |
| the cell cycle | the life of a cell, from the time a cell is formed until it divides again |
| what are the two stages of the cell cycle | interphase and the mitotic phase |
| interphase | period of growth and preparation for division |
| G1 stage of interphase | growth, increase in cytoplasm |
| S stage of interphase | duplication of chromosomes |
| G2 stage of interphase | growth, preparation for division |
| Mitosis | division of the nucleus(PMAT) |
| what are the 4 stages of mitosis | prophase, metaphase, anaphase, and telophase |
| cytokinesis | division of the cytoplasm |
| internal and external signals | stimulate or inhibit the cell cycle |
| internal signals | genes/proteins |
| external signals | limiting factors |
| checkpoints in the cell cycle | can stop an event or signal an event to proceed(G1, G2, and M) |
| G1 checkpoint | looks for wound up DNA, chromatid --> chromosomes |
| G2 checkpoint | looks for every chromosome to be replicated(sister chromatids) |
| M checkpoint | looks for the correct number of chromosomes |
| apoptosis | programmed cell death, stops body from passing on bad cells |
| cancer | uncontrolled cell growth, cancer cells divide excessively and invade other tissues of the body |
| characteristic of cancer cells | immortal, lack differentiation, abnormal nuclei, form tumors, undergo metastasis |
| differentiation | the cells do not look like the tissue they were removed from |
| tumor | a mass of abnormally growing cells within otherwise normal tissue |
| benign tumor | remain at the original site but may disrupt certain organs if they grow in size |
| malignant tumor | can spread to neighboring tissues and invade other parts of the body |
| metastasis | the spread of cancer cells beyond their original site |
| causes of cancer | mutations in the genes involved in the cell cycle, inherited forms, and environmental |
| proto-oncogenes | normal genes that promote cell division(gas pedal) |
| what do mutations to proto-oncogenes cause | create cancer causing oncogenes that often stimulate cell division |
| tumor-suppressor genes | normally inhibit cell division or function in the repair of DNA damage(break) |
| what do mutations do to genes | inactivate the genes and allow uncontrolled division to occur |
| heredity | cancer can run in families if an individual inherits a mutated proto-onco or tumor suppressor gene |
| are most cancers heredity | no |
| how does your environment cause cancer | viruses, carcinogens, lifestyle choices |
| ways to treat cancer | surgery, radiation, chemotherapy, and personalized medicine |
| radiation | pinpointed treatment towards a tumor |
| chemotherapy | drug concoction in bloodstream, goes everywhere |
| personalized medicine | find mutations, use others information for treatment |
| how are chromosomes matched | homologous pairs |
| in humans, how many chromosomes and homologous pairs do somatic cells have | 46 chromosomes and 23 homologous pairs |
| during fertilization what do parents give | one member of each homologous pair |
| autosome | non-sex determining chromosome, contain the same genes(22 homologous pairs) |
| sex chromosomes | sex determining chromosome may not contain the same genes, X and Y(1 pair) |
| what type of chromosomes do females pass on | XX |
| what type of chromosomes do males pass on | XY |
| how many chromosomes do gametes have | a single set of chromosomes |
| gametes | reproductive cells |
| when are gametes formed | during a process of cell division known as meiosis |
| what type of cells are gametes | haploid(n) |
| how many homologous pairs does each gamete have | one member of each homologous pair |
| what types of chromosomes are in human gametes | 22 autosomes and 1 sex chromosomes(23 total) |
| what is the female gamete | the egg and it is made in the ovaries |
| what is the male gamete | the sperm and is made in the testis |
| what does meiosis do to the chromosome number | it reduces the chromosome number from diploid to haploid |
| meiosis | a type of cell division that produces haploid gametes in diploid organisms |
| what is the significance of meiosis | produces haploid gametes, two haploid cells may then combine in fertilization to restore the diploid state in the zygote |
| meiosis description | meiosis goes through the process of cell division twice resulting in 4 haploid daughter cells |
| meiosis 1 | separates the homologous pairs |
| meiosis 2 | separates the sister chromatids |
| when does independent assortment occur | during metaphase 1 and "mixes" the chromosomes that are in each gamete |
| description of independent assortment | each pair of homologous chromosomes align independently at the equator, each time a cell goes through meiosis the alignment can change |
| what is the result of independent assortment | more genetic variation in the gametes |
| 2^n description of each | 2 - the number of ways a homologous pair of chromosomes can align to the n - number of homologous pairs |
| 2^n | the number of genetically different kinds of gametes one diploid cell can produce |
| when does crossing over occur | during prophase 1 and "mixes" the genes, resulting in even more genetic variation in the gametes |
| description of crossing over | an exchange of genetic material between non-sister chromatids of a homologous pair |
| what is the result of crossing over | even more genetic variation in the gametes |
| fertilization | random fertilization is the combination of each genetically unique sperm with each genetically unique egg |
| what is the result of fertilization | an increase in genetic variation of the offspring |
| in humans how many genetically different offspring could one couple produce based on independence assortment alone | 2^n X 2^n |
| human life cycle | an organism's life cycle is the sequence of stages leading from the adults of one generation to the adults of the next generation |
| what does the human life cycle involve | fertilization, mitosis, and meiosis |
| process of fertilization in cycle of life | the cycle begins when a haploid sperm cell fuses with a haploid egg cell, zygote formed by fertilization is now a diploid cell |
| process of mitosis in cycle of life | mitosis of the zygote generates all the somatic cells into the adult form |
| process of meiosis in cycle of life | at puberty gametes will begin to form in males and females, these cells are haploid cells needed to start the process again |
| what is the alterations of chromosomes number & structure called | nondisjunction |
| nondisjunction | the failure of chromosomes/chromatids to separate normally during meiosis, results in gamete with an altered number of chromosomes |
| when can meiosis occur | during meiosis 1 (anaphase 1) or meiosis 2 (anaphase 2) |
| karyotype | ordered display of an individual's chromosomes arranged in pairs |
| what are karyotype used for | to determine homologous pairs, chromosome number and chromosome structure(shows extra, missing chromosomes, etc, cannot show cancer) |
| how can cells be obtained for a karyotype | from an adult via blood or tissue sample |
| how can cells be obtained for a karyotype from a fetus | amniocentesis |
| examples of alterations in chromosome number | trisomy 21- down syndrome, monosomy- one copy of a chromosome, abnormal number of sex chromosomes, XXY- Klinefelter syndrome, XO- turner syndrome, XXX- trisomy X |
| similarities and differences between mitosis and meiosis | mitosis goes through the cell cycle once- meiosis twice a, mitosis is used for growth, repair, and asexual reproduction- meiosis is used for creation of gametes for sexual reproduction, |
| similarities and differences between mitosis and meiosis products | mitosis produces two genetically identical diploid somatic cells-meiosis produces four genetically unique haploid gametes |
| genetic continuity | duplicates chromosomes in interphase and separates them in meiosis |
| genetic variation | daughter cells are different from the parent, crossing over and independent assortment ensures this |
| advantages of sexual reproduction | increase genetic variation,- population has variation, variation protects from entire population from being wiped out be disease and allows for evolution |
| advantages of asexual reproduction | you don't need a partner, ensures that species can carry on, relatively quick |
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annatribuno