DNA and mitosis 3.0 / 5 based on 1 rating ? BiologyDNA, genetics and evolutionASAQA Created by: rayanne vitaliCreated on: 17-02-13 15:51 what are the requirements for semi conservative replication to take place? all four types of nucleotide present, both strands of dna must act as template, DNA polymerase must be present,a source of chemical energy is needed 1 of 20 why is the process of dna replication described as semi conservative ? because half the original dna is built into the new strand 2 of 20 what two enzymes are involved in dna replication and what do they do ? helicase breaks hydrogen bonds keeping base together, polymerase. joins activated nucleotides togther 3 of 20 whats the difference between miosis and mitosis ? in mitosis each two daughter cells have a full set of chromosomes , miosis four daughter cells are produced with half the number 4 of 20 what are the for stages of mitosis ? prophase , metaphase , anaphase , telophase 5 of 20 what happens during prophase ? chromosomes become visible, nuclear envelope disintergrates , nucleolus disappears 6 of 20 what happens during metaphase ? spindle fibres form , chromosomes line up on equator of cell 7 of 20 what happens during anaphase ? spindle fibres attached to chromatids contract , chromosomes are pulled towards poles 8 of 20 what happens during telophase ? chromatids reach poles and become indistinct , nuclear envelope reforms , nucleolus reforms , spindle fibres disintegrates 9 of 20 name three reasons why it is so important to make exact copies of existing cells growth , differentiation and repair 10 of 20 what are the three stages of the cell cycle ? interphase , nuclear division & cell division 11 of 20 what are the three parts that interphase can be divided into first growth where proteins are produced , synthesis phase where dna is replicated , 12 of 20 how dot he drugs used to treat cancer stop the cell cycle ? by preventing dna from replicating, inhibiting the metaphase stage if mitosis 13 of 20 what is a tissue ? a collection of similar cells that perform a specific function 14 of 20 name two examples of tissue ? xylem and epithelial tissue 15 of 20 what is an organ? a combination of tissues that are coordinated to perform variety of functions? 16 of 20 name two examples of organs ? the stomach , a leaf 17 of 20 what are organ systems ? organs that work together as a single unit 18 of 20 name three organ systems ? digestive , circulatory & respiratory system 19 of 20 why is an artery described as an organ but a blood capillary not ? an artery is made up of more than one tissue where blood capillary is only made up of one 20 of 20
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