Plant BIo 42 Geary Exam 3

Pregunta	Respuesta
What is the cell cycle? What are stem cells? What is differentiation? What is totipotency?	1) a series of events that takes place in a cell as it grows and divides. 2) a simple cell in the body that is able to develop into any one of various kinds of cells. 3) development from the one to the many, the simple to the complex, or the homogeneous to the heterogeneous. 4) The ability of cells such as an embryonic stem cell to differentiate into any type of body cell.
What is interphase? What is M phase? How is nuclear division different from cytokinesis? What problem does the cell wall pose for plant cells that are dividing?	1) is the phase of the cell cycle in which the cell spends and performs the majority of its time, its the step prior to cell division. 2) cell division. 3) Mitosis is a process of NUCLEAR division in which the duplicated chromosomes separate to form two genetically identical daughter nuclei. Cytokinesis is CYTOPLASMIC, which means during cytokinesis, the cytoplasm of a cell is physically divided to form two daughter cells housing the newly formed nuclei. 4) the cell wall would enlarge and expand bc the cells are glued in with the cell wall so the plant cells cannot divide without the cell wall.
What is G1? What happens during G1? Do all cells finish G1 and move on to the next phase(s)? Why or why not?	1) the first of four phases of the cell cycle that takes place in the eukaryotic cell division. . 2) In this part of interphase the cell grows in size and synthesizes mRNA and proteins in preparation for mitosis. 3 & 4) NO not all cells will finish. the G1 checkpoint ensures that the cell is large enough to divide and that enough nutrients are available to support the resulting daughter cells. So basically if a cell receives a go-ahead signal from G1 it will usually continue w/ the cell cycle BUT if they don't receive the go-ahead signal the cell will have to exit the cell cycle and switch to a nondividing state called G0.
What is the S phase? What happens during S phase? What form is DNA in during this phase? What are histones? What is the centromere? What is endoreplication & where might you expect to find it happening?	1) DNA synthesis. 2) genetic material replicates and is double checked. So during the S phase the Chromatids are replicated, so you get the chromatid and it's sister chromatid, which together make a Chromosome. The chromosomes are supercoiled and condensed, read and double checked for any errors from replication.. if there did happen to be an error it would either end up with mutation or cancer, because if not read right, the cell could divide as many times as possible ending up with a cancer cell. 3) replication. 4) a group of basic proteins found in chromatin. 5) the constricted region joining the 2 sister chromatids that make up an X-shaped chromosome. 6) endoreplication is when cells undergo interphase but do not divide. You can find endoreplication occurring in tissues in either animals or commonly in plants.
What is G2? What happens during G2? What is the spindle/what is it made of?	1) the pre-mitotic phase or the 3rd phase of the cell cycle. 2) a safety gap during which a cell can check to make sure that the entirety of its DNA and other intracellular components have been properly duplicated. 3) a collection of tiny fibers composed of microtubules which are important for cell division.
What is chromatin? Where is it found? How is it different from chromosomes? What is the purpose of chromosomes? What are chromatids & what process do they originate from?	1) its a mass of genetic material composed of DNA and proteins that condense to form chromosomes. 2) nucleus. 3) chromosomes are composed of condensed chromatin fibers and chromatin are composed of nucleosomes. 4) carries genetic information in the form of genes. 5) chromatid is 1 copy of a duplicated chromosome which is generally joined to its other copy by 1 centromere. they come from a replication of a single chromosome.
What are homologous chromosomes? Where does the original cell of an organism get each of its homologous chromosomes? How are alleles different from genes?	1) 1 mom & 1 dad chromosome pair up w/ each other inside a cell during meiosis. 2) from mom and dad. 3) mom has XX & dad has XY
What is/are the overall function(s) of mitosis? What is produced by mitosis? How many cells? How do the daughter cells compare genetically to each other & to the original parent cell?	1) growth and repair. 2) daughter cells. 3) 2. 4) the daughter cells are genetically identical to each other and to their original parent cells.
What are the four steps of mitosis? What happens in each one?	1)prophase, metaphase, anaphase and telophase. 2) prophase:chromosomes become more defined, the nucleic envelope breaks down metaphase: sister chromatids meet up in the middle anaphase: the pairs move apart telophase: new cells begin to develop
When does cytokinesis occur? What is its function? How are the cell walls of the new daughter cells formed?	1) telophase 2) forms daughter cells. 3) process during which the cytoplasm of the cell is divided approx. equal as the cell membrane pinches off forming 2 daughter cells in animals but in plants a cell plate forms.
What is a gamete? How do gametes compare to the parent cells they originated from? What is a zygote? How does it compare (genetically) to the gametes that it forms from? How does the zygote compare to the original parent cells that produced the gametes?	1) sex cell (sperm and egg) 2) gametes are haploid whereas the parent cells are diploid. 3) a cell formed when 2 gamete cells are joined by occurrence of sexual reproduction. 4) zygote is diploid and gamete is haploid. 5) the zygote came from the parent cells.
What is meiosis? What is the overall function of meiosis? How many cells are produced by the meiosis of one original cell, and how do these daughter cells compare to each other & to the original parent cell?	1) male and female gametes fuse during fertilization creating a diploid cell w/ a complete set of paired chromosomes. 2) reproduction and genetic diversity in next generation 3) in meiosis you start w/ 2 haploids you end w/ 4 daughter cells which are haploid
What are the stages in the first half of meiosis? What happens in this first half that is very different from what happens in mitosis? What do the homologous chromosomes do? Why is this important?	1) meiosis I: prophase I, metaphase I, anaphase I & telophase I. 2) this is the step the generates genetic diversity. DNA replication precedes the start of meiosis I. 3) this is when mom and dad chromosomes pair up in the cell in the same location w/ possibly different alleles, during meiosis. 4) to ensure genetic variation for the next generation.
What is synapsis? What is crossing over? Why is it important?	1) the pairing of 2 homologous chromosomes that occurs during meiosis. 2) the reciprocal exchange of genetic material between nonsister chromatids during synapsis of meiosis I. 3) to ensure genetic variation for the next generation.
What controls which chromosomes end up together in gametes?	through DNA translation and transcription. http://learn.genetics.utah.edu/content/pigeons/geneticlinkage/
Does meiosis always produce 4 daughter cells? Why or why not? What would be an example of an exception?	Needs Answer
What does the term “coenocytic” mean?	a multinucleate cell that is caused by multiple nuclear divisions w/o their accompanying cytokinesis.
What is alternation of generations?	Image: 7bb37c05-46b5-4a4f-9212-9ab0c9860128 (image/png)
What do the terms haploid & diploid mean? What process makes haploid cells from diploid cells? What is syngamy? What is the result of syngamy?	1) haploid: single set of unpaired chromosomes. diploid: 2 complete sets of chromosomes, 1 from each parent. 2) Meiosis makes diploid and mitosis makes haploid. 3) fusion of 2 cells. 4) zygote.
What is a gametophyte? What do gametophytes produce? By which kind of cell division process? What is a sporophyte? What do sporophytes produce? By which kind of cell division process?	1) haploid multicellular stage in the alternation of generations of plants and algae. 2) haploid gametes. 3) mitosis. 4) diploid multicellular stage in a plant and algae lifecycle. 5) diploid spores. 6) meiosis.
What is the advantage of having a sheltered (rather than a free-living) gametophyte generation?	Increased cross fertilization and great dispersal of the next generation are the advantages of multicellular pollen and seeds. Spores are the way ferns and moss spread longer distances. Spores are single-celled and vulnerable .so dispersal is limited. Being tied to water, as moss & ferns are with flagellated gametes, makes self-fertilization more common so genetic recombination is at a low rate.
What does the term gymnosperm mean? What are the four existing divisions of gymnosperms?	Gymnosperm means naked seed. The four divisions of gymnoperms are the conifers, cycads, gingkos, and the gnetophytes
What does the term heterosporous mean? What are megaspores & what develops from them? What are microspores & what develops from them? What process gives rise to megaspores & microspores?	1) Heterosporous means that the plant make two different kinds of spores. 2) Megaspores are female gametophytes and the make egg cells. 3) Microspores are male gametophytes and they make sperm cells. 4) The process that makes Micro/megaspores is mitosis (?)
What is a sporophyll? What are megasporophylls & microsporophylls?	1) A sporophyll is a leaf that bears sporangia. 2) Megasporophylls are sperm producing sporophylls while megasporophylls are egg producing.
In seed plants, where does the megagametophyte form? (What is the other term/phrase for the megagametophyte?) Does the megagametophyte develop into a more or less separate plant that is visible outside the sporangium? Where does production of and fertilization of the egg take place?	!) In the megasporangium. 2) Into a cone or flower in seed plants. 3) In the carpal.
In seed plants, where does the microgametophyte form? What do the microgametophytes produce?	1) In the microsporangium. 2) They producesperm cells.
What are some of the characteristics of division Coniferophyta? Do members of this division have vessels in their wood? Do members of this division have swimming sperm?	1) Leaves arranged spirally, wind-pollinated, produce cones. 2) They have no vessels. 3) They do not have swimming sperm, use the pollen tube.
In the Coniferophyta, what structure contains megasporophylls?	In the cones
What is the integument? What is the micropyle? What is the ovule? Is the ovule composed of haploid cells, diploid cells, or both?	The outermost layer of the ovule. The opening in the ovule which the pollen tube goes through to fertilize the egg cell. The structure which contains the female reproductive cells. The ovule largely consists of diploid cells except in the megagametophyte which is haploid.
What member of the Aracauriaceae was recently discovered, and where?	Wollemi pine which was thought to be extinct was found in Australia in 1994
What are some of the characteristics of cycads? What does the term dioecious mean? Are cycads more or less dependent on moisture in their environment compared to Coniferophyta? Why?	1) Have a stout woody trunk with a crown of evergreen leaves on top, no branches. 2) Having separate sexes. 3) They are less dependent on moisture in the environment since they are very good at storing water in their leaves.
What are the three genera of the gnetophyta? Where would you find these three kinds of plants?	1) Ephedra, Gnetum, and Welwitschia. 2) In small parts of the western-south US, Angola and surrounding area, and Malaysia
What are some of the characteristics within the gnetophyta that they share with flowering plants? What kind of evidence has been used to evaluate the relationship between gnetophytes & flowering plants? What conclusion was reached from this work?	They have trachied and vessel elements like flowering plants and are pollinated by insects (some not all), sperm are not motile, double fetilization. This has lead to people thinking that this group is the most closely related to and may have given rise to angiosperms.

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