Term
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Definition
| A cellular stucture carrying genetic material, found in the nucleus of eukaryotic cells. Each chromosome consists of one very long DNA molecule and associated proteins. |
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Term
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Definition
| the complex of DNA and protiens that makes up eukaryotic chromosomes, When the cell is not dividing chromatins existis in its despersed form, as a mass of very long, thin firbers that are not visible with the light microscope. |
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Term
| What is a stomatic cell ? |
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Definition
Any cell in a multicullular organism except a sperm or egg or thier precursors
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Term
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Definition
| Reproductive cells, sperm and eggs have half as many chromosome as somatic, or one set of 23 chromosomes in humans. |
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Term
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Definition
| The first gap or growth phase of the cell cycle, consisting of the portion of interphase before DNA synthesis begins. |
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Term
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Definition
| An ordered sequence of events in the life of a cell, from its orgin in the division of a parent cell untill its own division into two . The eukaryotic cell cylce is composed of interphase ( including G1 2 G2 subphases) and M phase ( including mitosis and cytokinesis) |
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Term
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Definition
| the second gap, or growth phase of the cell cycle, consisting of the portion of interphase after DNA synthesis occurs |
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Term
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Definition
| a nondiving state occupied by cells that have left the cycle, sometimes reversibly. |
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Term
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Definition
| the synthesis phase of the cell cycle, the portion of interphase during which DNA is replicated |
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Term
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Definition
| the phase of the cell cylce that includes mitosis and cytokinesis |
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Term
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Definition
| The period in the cell cycle when the cell is not dividing. During interphase , cellular metabolic activity is high, chromosomes, and organelles are duplicated and cell size may increase. Interphase often accounts for about 90% of the cell cycle. |
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Term
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Definition
| a procces of nuclear division in the eukaryotic cells conventionally divided into five stages, prophase, prometaphase, metaphase, anaphase, and telophase. Mitosis conserves chromsome number by allocating replicated chromosomes equally to each of the daugther nuclei. |
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Term
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Definition
| The first stage of mitosis, in which the chromatin condenses into discrete chromosomoes visible with a light microscope, the mitotic spindle begins to form, and the nucleous disapears but the nucleus remains intact |
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Term
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Definition
| the second stage of mitosis, in which the nuclear envelope fragments and the spinde microtubals attach to the kinetochores of the chromosomes |
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Term
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Definition
| The third stage of mitosis, in which the spindle is complete and the chromosomes, attached to microtubules at thier kinetochores, are all aligned at the metaphase plate. |
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Term
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Definition
| The fourth stage of mitosis, in which the chromatidis of each chromosome have speareted adn the daughter chromosomes are movings to the poles of the cell. |
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Term
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Definition
| the fifth and final stage of mitosis, in which daughter nuclei are forming and cytokensis has typically begun. |
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Term
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Definition
| the division the cytoplasm to form two separate daughter cells immediately after mitosis, meiosis I, or meisosis II. |
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Term
| What is the mitotic spindle? |
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Definition
| A assemblage of micortubules and associated protteins that is involved in the movement of chromosome during mitosis. |
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Term
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Definition
| a stucture of protiens attached to the centromere that links each sister chromatid to the mitotic spindle |
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Term
| How does a cell control the cell cycle? |
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Definition
| a cyclically operationing set of meolcules in the eukaryotic cell that both triggers and coordinates key events in the cell cycle. |
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Term
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Definition
| a control point in the cell cycle where stop and go-ahead signals can reulate the cycle. |
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Term
| What events take place in the cell cycle check points? |
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Definition
| The G1 checkpoint - dubbed the restiction point. IF the cell recieves the go ahead signal at g1 checkpoint than it will usually complete the G1 S G2 and M phase and divide. If it does not recievbe a go-ahead signal at that point it will exit the cycle, switching into a nondividing state called G0 phase. |
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Term
| How does cyclin regulate the cell cycle? |
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Definition
| When the time for mitosis approaches the levels of cyclins go up in the cell, Cyclin form a mpf - mitotic promoting factors- gives the go single for mitosis |
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Term
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Definition
| a cellualr protien that occurs in a cyclically fluctuating concentration and plays an important role in regulating the cell cycle. |
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Term
| What is a cyclin-dependent kinase (cdk) |
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Definition
| a protien in kinase that is active only when attached to a particular cyclin. |
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Term
| What is density dependent inhibition? |
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Definition
| the phenonmenon observed in normal animal cells that causes them to stop dividing when they come into contact with one another. |
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Term
What is the anchorage dependence?
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Definition
| the requirement that a cell must be attached to a substratum in orrder to initate cell division |
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Term
| Growth and metastasis of malignant breast tumor |
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Definition
| The cells of malignant tumors grow in an uncrontrolled way and can spread to neighboring tissues via lypmph and blood vessles, to other parts of the body. the spread of cancer cells beyond thier orginal site is called meastasis. |
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Term
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Definition
| the spread of cancer cells to locations distanct from thier original site |
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Term
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Definition
| A discrete unit of herediatry information consisting of a specific nucleotide squence in DNA |
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Term
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Definition
| The transmission of traits from one generation to the next |
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Term
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Definition
| a specifici place along the length of a chromosome where a given gene is located |
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Term
what is asexual reproduction?
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Definition
| the generation of offspring from a single parent that occurs without the fusion of gametes ( by budding, diviion of a single cell, or divion of the entire orgainsm into towo or more parts. In most cases the offspring are genetically identical to the parent. |
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Term
| What is sexual reproduction |
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Definition
| a type of reproduction in wich two parents give rise to offspring that have unique combinations of genes inheritated from both parents via the gametes. |
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Term
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Definition
| a display of the chromsome pairs of a cell aranged by size and shape |
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Term
| What is a homologous chromosome? |
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Definition
| a pair of chromosomes of the same length, centromere positon, and staining pattern that posses geners for the same characters at correspoding loci. Once homologous chromosome is inherited from the organism's father the other from the mother. Also called homologs or homologous |
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Term
| What are sex chromosomes? |
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Definition
| a chromosome responsibel for determing the sex of an individual |
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Term
| What are somatic chromosomes? |
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Definition
| any chromosome that is not a sex chromosome; appear in pairs in body cells but as single chromosomes in spermatozoa |
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Term
| What are sister chromatids |
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Definition
| two copies of a duplicated chromosome attached to each other by proteins at the centromere and, sometimes, along the arms. While joined, two sister chromatids make up one chromsome. Chromatids are eventually sperated during mitosis or meiosis II |
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Term
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Definition
| a cell containing only one set of chromosomes (n) |
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Term
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Definition
| A cell containing two sets of chromsomes (2n), one set inherited from each parent. |
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Term
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Definition
| the union of haploid gametes to produce a diploid zygote |
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Term
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Definition
| The diploid cell producred by the union of haploid gametes during fertiliztion; a fertilized egg. |
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Term
| How are gametes produced? |
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Definition
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Term
| What process produces gametes? |
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Definition
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Term
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Definition
| In the life cycle of a plant or alga under going alternation of generations, a haploid cell produced in the sporophyte by meiosis. A spore can divide by mitosis to develope into a multicellular haploid indiviula, the gametophyte without fusing with another cell. |
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Term
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Definition
| In fugi a haploid cell, produced either sexually or asexually, that produces a mycellium after germenation. |
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Term
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Definition
| a diplodi cell, also know as a spore mother cell, that undergoes meiosis and generates haploid spores. |
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Term
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Definition
| in orgaisms ( plants and some algae) that have alternation of generations, the multicellular haploid form that produces haploid gametes by mitosis. The haploid gametes untie and develop into sporphytes. |
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Term
| What is the alternation of generations? |
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Definition
| a life cycle in wich there is both a multicellular diplopid form, the sporophyte, and a multicellular haploid form, the gametophyte; characteristiscs of plants and some algae |
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Term
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Definition
| the first division of a two stage prosses of cell dividon in sexually reproducing organisms that result in cells with half the number of chromsome set as the original cell. |
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Term
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Definition
| The second division of a two-stage process of cell division in sexually reproducing organisms that resuls in cells with half the number of chromsomes sex as the original cell. |
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Term
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Definition
| the reciprocal exchenge of genetic material between nonsister chromatids during prophase I of meiosis |
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Term
| What is the differences in mitosis and meiosis |
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Definition
1.In Meiosis synapsis and crossing over occurs in prophase I, in mitosis synapsis and crossing over normally do not occur during prophase of miotosis.
2. Homologous paris at the metaphase plate. At metaphase I of meiosis, chromosomes are positioned at the metaphase plate as pairs of homologs, rather than indivual chromosomes, as in metaphase.
3. Seperation of homologs. At anaphas I of meiosis the duplicated chromosomes of each homologous pair move toward the opposite poles, but the sister chromatids of each duplicated chromsome remain attached. In anaphase of mitosis, by contrast the sister chromatids separate. |
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Term
Key differences in mitosis and meiosis
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Definition
| Meiosis reduces the number of chromosomes sets from two diploid to one haploid whereas mitosis conserves the number of chromsosmes sets. Therefore meiosis produces cells that differ gentetically and mitosis produces identical cells. |
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Term
| What is independent assortment? |
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Definition
| Independent assortment is the random assortment of chromosomes during the production of gametes, the results are genetically unique individual gametes. |
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Term
| What is genetic variation |
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Definition
| differences among indiviuals in the composition of thier genes or other DNA segments. |
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Term
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Definition
| the division of the cytoplasm to form two separate daughter cells immediatly after mitosis, meisos I, or meiosis |
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Term
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Definition
| a monk that documented a particaluate mechanism for inheritance |
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Term
| What was Mendels experimental approach? |
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Definition
| Mendle used the scientific approach to identify two laws fo inheritance. Mendel discovered the basic princples of heredity by breading gardn peas in carefully planed experiments |
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Term
Why did Mendel use peas for his study
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Definition
His experimental organisms were garden peas which proved to have many advantages over other possible organisms:
- They were easy to grow.
- They were available in many easily distinguishable varieties.
- Strict control over mating was possible (small bags over flowers prevented cross-pollination; immature stamens could be removed to prevent self-pollination) to insure the parentage of new seeds.
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Term
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Definition
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Term
| What is a true breeding variety |
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Definition
Mendel worked with his plants until he obtained true-breeding plants (varieties which always produced offspring with the same traits as the parents when the parents were self-fertilizing). He hybridized (cross-pollinated) these true-breeding varieties in experimental crosses.
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Term
| What is Mendel's Law of Segregation? |
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Definition
| When Mendel crossed contrasting true-breeding white and purple flowered pea plants, all of the F1 hybrids were purple. When Mendel crossed the F1 hybrids many of the F2 plants had purple flowers but some had white. Medel discovered a ratio of about three to one, purple to white flowers in F2 generation |
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Term
| What is the Law of segregation |
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Definition
| Mendel's first law, stating that the two alleles in a pair segregate (separate from each other) into different gametes during gamete formation. |
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Term
| What is the law of independent assortment? |
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Definition
| mendels second law stating that each pairs of alleles segregates, or assorts, independently of each other pair during gamete formation; applies when genes for two charcters are located on different pairs of homologous chromsomes or when they are far enough apart on the same chromosome to behave as though they are on different chromsomes |
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Term
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Definition
| any alternative versions of a gene that may produce distinguishable pheontypic effects |
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Term
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Definition
| an allele that is fully expressed in the pheonotype of a heterozygote |
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Term
| What is a recessive allele? |
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Definition
| an allele whose pheonotype effect is not observed ina herozygote |
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Term
| What is Mendels first concept? |
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Definition
| The first concept is that alternative versions of genes account for variations in inhertited characters |
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Term
| What is Mendels 2nd Concept |
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Definition
| The second concept is that for each characteristics an organism inhertis two alleles, one from each parent. |
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Term
| What is the third Concept? |
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Definition
| If two alleles at a locus differ, then one ( the dominant allele determines the organism's appearence, and the other recessive allele has no noticeable effect on apperance. |
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Term
| What is Mendels 4th concept? |
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Definition
| states that two alleles for a hertiable chracter separate during gamete formation and end up in different gametes |
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Term
| What is a homozygous alleles? |
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Definition
| Having two identical alleles for a given gene. |
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Term
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Definition
| Having two differnet alleles for a given gene |
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Term
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Definition
| Breeding an organism of unkown genotype with a homozygous recessive indiviuals to determine the unkonwn genotype. The ratio of pheonotypes in the offspring reveals the unknown genotype. |
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Term
| What is complete dominance? |
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Definition
| The situation in which the pheonotypes of the heterozygote and dominant homozygote are indistinguishable |
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Term
| What is incomplete dominance? |
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Definition
| the situation in which the pheonotype of heterozygotes is intermediate between the pheontypes of indivuals homozygous for either allele |
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Term
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Definition
| The genetic makeup, or set of alleles, of an organism. |
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Term
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Definition
| The observable physical and physiological traits of an organism, which are determined by its genertic makeup |
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Term
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Definition
| the ability of a single gene to have multiple effects. |
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Term
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Definition
| a type of gene interaction in which the phenotypic expression of one gene alters that of another indpendently inhearitable gene. |
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Term
| What is polygenic inheritance? |
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Definition
| an additive effect of two or more genes on a single phenotypic character. |
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Term
| Why are humans not good for genetic research? |
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Definition
| Live too long, Long gesation periods, and not ethichal |
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Term
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Definition
| two dominant alleles affect the pheontype in separate distinguishable ways |
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Term
| What is a example of multiple alleles |
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Definition
| The four phenotypes of the AB blood group in humans are determined by there alleles for the enzyme I that attaches or B carbohydrates to red blood cells. |
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Term
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Definition
| A diagram of a family tree with conventional symbols, showing the the occurence of heritbale character in parents and offspring over multiple generations. |
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Term
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Definition
| In genetics, an indiviual whi is herterzygous at a given genetic locus for a reccesive inderited disorder. The heterozygote is generally pheotypically normal for the disorder but can pass on the ressive allele to offspring. |
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Term
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Definition
| A human genetic disorder caused by a recessive allele for a chloride channel protien; charcterized by an excessive secretion of mucus and consquently vulnerability to infection; fatal if untreated. |
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Term
What is sickle-cell disease?
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Definition
| a recessively inherited human blood disorder in which a single nucleotide change in the B globin gene causes the hemoglobin to aggregate, changing red blood cell shape and causing multiple symptons in afflicted individuals. |
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Term
What is huntingtons disease?
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Definition
| a human genetic disease casued by a dominant allele; characterized by uncontrollable body movements and degeneration of the nervous system; usually fatal 10 to 20 years after the onset of symptons. |
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Term
| What are dominant inheritated disorders? |
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Definition
anchondroplastic- a form of dwarfism that occurs in one and every 25000 people.
Huntingtons disease
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Term
| What are multifactorial disorders? |
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Definition
Referring to a phenotypic charcter that is infulenced by multiple genes and environmental factors.
ie. Heart Disease and Diabetes, Cancer, alcholism |
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Term
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Definition
| To see if parents are carriers of a disease before consimating. |
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Term
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Definition
Amnioncentesis- can determine wheter the developing fetus has tay-scahs
Chronic villus sampling- a technique associtated with prenatal dignosis in which a small sample of the fetal portion of the placenta is removed for analysis to detect certan gentetic and congential defects in the fetus. |
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Term
What are hereditary factors?
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Definition
| were a purely abstract concept when he proposed their existence in 1860. are located along chromsomes. |
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Term
| What is chromsome theory of inheritance? |
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Definition
| a basic principle in biology stating that genes are located at specific positons (loci) on chromosomes and that the behavior of chromsomes during meiosis accounts for inheritance patterns. |
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Term
| How genes can be seen on chromosomes? |
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Definition
| by tagging isolated chromsomes with flourescent dye |
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Term
| what are sex-linked genes? |
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Definition
| a gene located on either sex chromosome- human genes are on larger X chromsome |
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Term
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Definition
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Term
| inheritance of sex-linked genes. |
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Definition
| AS female needs 2 copies of the alleles, male need one copy |
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Term
| X inactivation in female mammals |
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Definition
| only 2X chromsomes in each cells randomlyt inactived during embryonic development - Barr Body- She will be a mosaic for that character |
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Term
| What are linked genes and how are they inheritated? |
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Definition
| genes located on the same chromosome that tend to be inhereitated togerther (located near same chromsome) |
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Term
| How unlinked genes undergo recombination and when? |
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Definition
| a inheritance process most sometimes break the physical connection between genes on the same chromosome. |
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Term
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Definition
| The mechanism is crossing over of homologus chromsopmes |
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Term
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Definition
| an ordered list of genetic loci on along a particular chromosomes. |
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Term
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Definition
| a genetic map based on frequences of recombination between markers during crossing over of homologous chromosomes. |
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Term
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Definition
| a error in meiosis or mitosis in which members of a pair of homologous chromsomes or a pair of sister chromatids fail to separate properly from each other. |
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Term
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Definition
| fertilization of games in nondijunction occurs abnormal number of a particular chromsome |
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Term
| what is a monosomic zygote? |
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Definition
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Term
| monozygote with one copy of a particual chromosome. |
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Definition
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Term
| what is a trisomic zygote? |
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Definition
| a zygote that has three copies of a particular chromosome. |
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Term
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Definition
| a condition in whihch organisms has more than two complete sets of chromosome plants mostly not animals |
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Term
| How can the structure of a chromosome be altered |
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Definition
| Deletion- removal of chromosome segment, Duplicaiton- repeats, Inversion- reverses a segment, Translocation- moves a segment from one chromsome to another. |
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Term
| What is human disorders due to chromsomal alterations |
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Definition
| cri du chat, chronic myelogenous lukemia |
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Term
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Definition
| a aneuploid condion that resuls from three copies of chromsome 21 |
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Term
What is genetic imprinting
? |
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Definition
| involes the scielencing of certian genes that are stamebed with a imprint druing gamete production |
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Term
| What is aneuploidy of sex chromosomes? |
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Definition
| nondisjunction of sex chromosomes that produces a variety of aneuploid conditions. Most of these conditons appear to upset the genetic balance less than aneuploid conditions involving autosomes |
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Term
| How organelle genes are inherited |
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Definition
| Mitochondria genes are inherited by the egg. Random cell divide, cellular structure breaks apart the mitochondria stick at the sides at a random fashion. |
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