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Bio Test 6
Cell Division and Replication
| Question | Answer |
|---|---|
| What is the continuity of life based upon? | Based on the reproduction of cells or cell division |
| How do unicellular organisms reproduce? | By cell division |
| What is an example of a unicellular organism? | Amoebo, bacteria...etc. |
| What are the three things multicellular organisms depend on cell division for? | Development from a fertilized cell, growth, repair |
| What does cell division result in? | Genetically identical daughter cells |
| What do cells do before they divide? | They ensure that each daughter cell receives an exact copy of DNA; they duplicate DNA |
| Genome: | Cell's endowment of DNA |
| Prokaryotic Genome: | Single long DNA molecule |
| Eukaryotic genome: | Has a number of DNA molecules |
| What is the DNA in a human cell: | 2 m DNA, 250,000 greater than diameter |
| Where is all the DNA in a cell located? | In chromosomes |
| Every eukaryotic species has how many chromosomes? | A characteristic number |
| Somatic Cells: | All body cells except reproductive cells |
| Reproductive cells and what's anothe rname for it: | Ova, sperm, eggs, (gametes) |
| What many chromosomes are in somatic cells? | 46 chromosomes (2 sets of 23) (1 inherited from each parent) |
| Chromatin: | Is in eukaryotic chromosomes and is a complex of DNA and protein that condenses during cell division |
| How many chromosomes are in gametes? | 23 chromosomes |
| What does the cell do to prepare for division? | DNA is replicated and the chromosomes condense |
| What does each duplicated chromosome have? | 2 sister chromatids |
| What does each chromatid contain? | An identical DNA molecule |
| How are chromatids (INITIALLY) attached to cell? | adhesive proteins |
| What does eukaryotic cell divison consist of? | Mitosis, and cytokenisis |
| Mitosis: | The division of the nucleus or dna |
| cytokinesis: | The division of the cytoplasm |
| What is meiosis and what about the daughter cells in this process? | When sex cells are produced after a reduction in chromosome number--the daughet cells are going to be non-identical and have only 23 chromosomes |
| Where, specifically (in males and females) does meiosis occur? | gonads--ovaries and testes |
| Fertilization: | Fuses two gametes together and returns the chromosome number to 46 |
| What does the cell cycle consist of? | Mitotic phase or M phase, and interphase |
| Mitotic phase: | Usually the shortest part of the cell cycle where mitosis and cytokinesis occurs |
| Interphase (what percent of cell cycle does it cover?) | accounts of 90% of cell cycle |
| what does Interphase consists of? Which phases? | Gap 1 phase, synthesis phase, and gap two phase |
| What occurs in the S phase? | chromosomes are duplicated |
| How does the cell grow in interphase? | By producing proteins and cytoplasmic organelles like mitochondria and ER |
| What are the five stages of mitosis? | Prophase, prometaphase, metaphase, anaphase, telophase |
| What happens in the latter stages of Mitosis? | cytokinesis overlaps with them to complete the mitotic phase |
| What happens to the chromatic fibers in prophase? | They become more tightly coiled, condensing into discrete chromosomes observable with a light microscope |
| What happens to the nucleoli in prophase? | it disappears |
| How does the chromosome appear in prophase? | as 2 identical sister chromatids joined together |
| What begins to form in prophase? | mitotic spindles, composed of the centrosomes and the microtubles that extend from them |
| Asters: | Radial arrays of shorter microtubules extending from the centrosome |
| What happens to the centrosomes in prophase? | They move away from each other--propelled by the lengthening microtubules between them |
| What happens to the nuclear envelope in prometaphase? | it fragments |
| What can the microtubules of the spindle do in prometaphase? | They can invade the nuclear area and interact with the chromosomes which have become more condensed |
| What do the microtubules do in prometaphase? | Extend from each centrosome toward the middle of the cell |
| What does each of the two sister chromatids have in prometaphase? | has a kinetochore |
| Kinetochore: | Specialized protein structure located at the centromere |
| What do some of the microtubules do in prometaphase? | attach to kinetochores to become (Kinetochore micro) and jerk the chromosomes back and forth |
| Nonkinetochore microtubules do what in prometaphase? | interact with those from the opposite pole of the spindle |
| What is the longest phase in mitosis and how long does it take? | metaphase (20mins) |
| Where are the centrosomes located in metaphase? | opposite ends of the cell |
| Where do the centrosomes gather in metaphse? | At the metaphase plate |
| what is a metaphase plate? | an imaginary plane that is equal distance between the spindle's 2 poles |
| What lies on this plate? | chromosome's centromeres |
| For each chromosome in metaphase, what about the kinetochores of the sister chromatids | They are attached to the kinetochore microtubules coming from opposite poles |
| Spindle: | Entire apparatus of microtubules, it is called spindle because of its shape |
| What is the shortest phase of mitosis? | Anaphase (few mins) |
| When does the anaphase begin? and what happens to the chromatids at this point? | When two sister chromatids of each pair suddenly part-each chromatid then becomes a full fledged chromosome |
| What happens as kinetochore microtubules shorten in anaphase? | the two liberated chromosomes begin moving to opposite ends of the cell |
| When does the cell elongate in anaphase? | When the nonkinetochore microtubules lengthen |
| At the end of anaphase, what do the two ends have? | equal and complete collections of chromosomes |
| What begins to form in telophase? | 2 daughter nuclei begin to form and the nuclear envelope develops from fragments |
| What happens to the chromosomes in telophase? | they become less condensed |
| What is the specific definition of Mitosis, and when does it end? | The division of 1 nucleus into two identical nuclei ends at mitosis |
| What is usually underway by late telophse? | The division of cytoplasm--so that the two daughter cells appear shortly after the end of mitosis |
| What does a cleavage furrow do in animal cells: | pinches the cell in two and initiates cytokinesis |
| What happens in plant cells, during cytokinesis? | a cell plate forms |
| The cell cycle is regulated by what? | a molecular control system |
| The frequency of cell division varies with | the type of cell |
| These cell cycle differences result from what? | regulation at the molecular level |
| How are the sequential events of the cell cycle directed? | by a distinct cell cycle control system, which is similar to a clock |
| This clock has specific checkpoints and what happens at those points? | the cycle stops until a go-ahead signal is received |
| What are the two types of regulatory proteins involved in the cell cycle control? | Cyclins and cyclin-dependent kinases (phosphorylation) |
| Where do the protein kinases give the go-ahead signals? | at the G1 and G2 points |
| What must be done to the kinases? | The kinases must be activated even though they are at costant concentrations in the cell |
| How are the kinases activated? | by the attachment of a cyclin |
| cyclins | Get their name from their cyclically fluctuating concentration in the cell |
| What is important to note about cyclins in the cell? | 1) Fluctuate during cell cycle |
| What was the first CDK complex to the discovered? | MPF--maturation promoting factor or "m-phase promoting factor |
| What does the MPF do? | Triggers the cell's passage past the G2 checkpoint into M phase |
| Why are cyclin CDK complexes activated? | So this complex can phosphorylate other proteins and send a cell into the mitotic phase (cell division) |
| What is important about CDK and cyclin: | CDK is inactive unless cyclin is bound to it |
| REMEMBER SLIDE 36 | PRINT SLIDE |
| Both internal and external signals | control the cell cycle checkpoints |
| growth factors | stimulate cells to divide |
| density-dependent inhibition | crowded cells stop growing |
| anchorage dependent cell growth | cells must be attached to some substratum in order for them to divide |
| What is used to hold the anchorage | plastic |
| What do cancer cells exhibit (or not) | neither density-dependant inhibition nor anchorage dependence (uncontrolled) |
| Cancer cells don't respond to | Don't respond normally to body's control mechanisms |
| Cancer cells divide | out of control |
| What does the cancer cell division cause/ | a tumor |
| When does cancer begin? | when a single cell in a tissue undergoes transformation |
| When a transformed cell evades destruction | In can divide and form a tumor |
| Benign tumor: | when cancer cells remain at the original site; they don't cause problems and are simply removed via surgery |
| Malignant tumors: | Become invasive...impair the function of organs, they divide quickly and form tumors or metastasize |
| metastasis: | spread of cancer cells to distant locations from original site |
| When the cancer cells leave the benign location | they can spread and create more tumors in other parts of the body (secondary tumors) |
| How are living organism distinguished? | By their ability to reproduce their own kind |
| Heredity: | Transmission of traits from one generation to the next |
| Variation | Shows the offspring differ somewhat in appearance from parents and siblings |
| Genetics | the scientific study of heredity and hereditary variation |
| How can genetics be studied? What are the three ways? | Organism, cell, molecule |
| How do offsprings acquire genes from parents? | inheriting chromosomes |
| Genes are two things...what? | Units of heredity and segments of DNA |
| Each gene in an organism's DNA is located where? | in a specific locus (location) on a certain chromosomes |
| What is an example of something that undergoes asexual reproduction? | Hydra |
| What is asexual reproduction? | One parent produces gentically indentical offspring by MITOSIS |
| Sexual reproduction: | When two parents' offspring that have unique combinations of genes inherited from two parents |
| What alternates in sexual life cycle? | Fertilization and meiosis |
| A life cycle is what? | Generation to generation sequence of stages in the reproductive history of an organism from conception to production of its own offspring |
| Karyotype: | An ordered visual representation of the chromosomes in a cell |
| Homologous chromosomes (3 things about them, third thing is another name for them) | two chromosomes composing a pair, have the same characteristcs, autosomes |
| Sex chromosomes: | Distinct from each other in their characteristics |
| How are sex chromosomes represented? | X and Y |
| What sex chromosomes do you need to have to be female...Male? | XX XY |
| What is used to represent the number of chromosmes in a single set? | n |
| what's another name for a diploid cell? | Somatic cell |
| Haploid cells: | one set of chromosomes |
| Diploid cell | has two sets of each of its chromosomes, |
| : give a representation of chromosomes in humans | 2n = 46 |
| What are examples of haploid cells? | Sperm, egg, gametes |
| In humans, give an example of the representation of chromosomes in gametes | 23 n |
| What happens at sexual maturity? | ovaries and testes produce haploid gametes by meiosis |
| In fertilization | these gametes, sperm and ovum, fuse, forming a diploid zygote |
| Zygote | develops into an adult organism |
| Meiosis reduces: | the number of chromosome sets from diploid to haploid |
| what are the two sets of divisions of meiosis? | Meiosis I and II |
| Meiosis I reduces what, with respect to chromosomes | reduces the number of chromosomes from diploid (46) to haploid (23) |
| Meiosis II produces how many haploid daughter cells | four |
| What's important about mitosis: | conserves the number of chromosome sets, produces daughter cells gentically identical to their parent cell and to each other |
| How many events are unique to meiosis, and where do they occur? | 3 events, occur in meiosis one |
| What are the three eventss? | Synapsis and crossing over, tetrads on the metaphase plate, seperation of homologues |
| Where does the first event take place? | Prophase 1: homologous chromosomes physically connect and exchange genetic info |
| Where does the second event take place? | metaphase I: paired homologous chromosomes (tetrads) are positioned on the metaphase plates |
| Where does the third event take place? | at anaphase I, homologous pairs move toward opposite poles of the cell; in anaphase II, the sister chromatids seperate |
| What contributes to evolution? | genetic variation produced in sexual life cycles |
| What produces genetic variation? | reshuffling of gentic material in meiosis |
| What are recombinant chromosomes and when are they produced? what do they carry? | new chromosomes, they are produced in chrosing over, they carry genes derived from two different parents |
| What will the fusion of gametes provide? | produces a zygote with any of about 64 trillion diploid combinations |
| Where are genes located? | Chromosomes |
| How does mendalian inheritance have its physical basis? | in the behavior of chromosomes |
| What accounts for Mendel's laws? | behavior of chromosmes during meiosis |
| What are mendel's two laws made of? | segregation and independant assortment |
| What accounts for the segregation and independent assortment of teh allelles for seed color and shape? | Arrangement of chromosmes at metaphase I of meiosis |
| Each cell that undergoes meiosis in a F1 plant produce how many kinds of gametes? | Two |
| F1 plants produce equal numbers of how many kinds of gametes...and why? | Four kinds, and because the alternative chromosome arrangements at metaphase I are equally likely |
| Peas have how many chromosome pairs? | Seven |
| What did thomas hung morgan provide? | convincing evidence that chromosomes are the location of mendel's heritable factors |
| What did morgan work with & why (3 reasons)? | Fruit flies, because they breed at a high rate, a new generation every two weeks, they only have four pairs of chromosomes |
| Wild type: | Normal phenotypes |
| What did he call alternative traits to the wild type? | mutant phenotypes |
| What does morgan's experiment with white eyes and red eyes tell us? Which chromosome? | Sex-linked atraits, this was the first evidence indicating that a specific gene associated with a specific chromosome exists (X-chromosome) |
| Sister Chromatid: | Replicated forms of chromosome joined together by the centromere and separated druing mitosis or meiosis II. |
| Loci or location: | Location of a gene on a chromosome |
| Chromatid: | Each of the two daughter strands joined at centromere during Mtiosis or Meiosis |
| What laws do chromosomes follow during meisosis? | Laws of mendelian genetics |
| What does the segregation law imply? | Two allelles of a gene separate during meiosis (gamete formation), so that a sperm or an egg carries only one allele of each pair. |
| What if 2 alleles of a gene are different? | Dominant over recessive |
| True-breeding: | Having the same two alleles (homozygous) |
| What doeas the second law imply? | Each pair of alleles segregates into gametes independently of other pairs |
| What is the most lethal genetic disease in the U.S.? | Cystic Fibrosis |
| Cellular level of lethal disease? | Lack working chloride channel in plasma membrane of certain cells (lungs, G1 tract), so choride ions outside the cell increases, affects osmosis. Mucous that coates cell becomes thicker, favors infections |
| Character: | hertitable features, flower color, height, or lung function |
| Trait: | A variant of character, purple or white, tall or short, function or dysfunctional |
| Phenotype: | Observable |
| Genotype: | Entire genetic identity that is not observable |
| Homozygous: | two identical alleles |
| Heterozygous: | Unidentical alleles |
| Dominant: | Overpowers other traits |
| Recessive: | Masked |
Created by:
talkglitter2486