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THE CELL CYCLE, MITOSIS AND CANCER BIOL2
Fichas del conjunto (46)
- 1What are the two main stages of cell division?Nuclear division followed by cell division
- 2What are the two types of nuclear division?Mitosis and meiosis
- 3What is the name given to the method of DNA replication that is universally accepted?Semi-conservative replication
- 4What are the 4 requirements for semi-conservative replication to take place?1. The four types of nucleotide (and bases) must be present
2. Both strands of the DNA must act as a template for the attachment of the nucleotides
3. The enzyme DNA polymerase is needed to catalyse the reaction
4. A source of chemical energy is required - 5In the semi-conservative method, which enzyme acts first and what does it do?DNA helicase breaks the h-bonds linking the base pairs of DNA
- 6What does this result in?The double helix separates into two individual strands and unwinds
- 7What do these polynucleotide strands than act as?A template to which free nucleotides are attracted to (attracted to their complementary base)
- 8What is required to activate these free nucleotides?Energy
- 9How are the activated nucleotides jointed to their complementary base pair?DNA polymerase
- 10What does this form?The 'missing' polynucleotide strand on each of the two original strands of DNA
- 11So, what do each of the new DNA molecules contain?One original strand and one new strand - this is why its called semi-conservative
- 12Which two scientists conducted an experiment to test the hypothesis of the semi-conservative method?Meselsohn and Stahl
- 13Which three facts did they base their work on?1. All the bases contain nitrogen
2. Nitrogen has two isotopes (14 and 15 - 15 is heavier)
3. Bacteria will incorporate nitrogen from their growing medium into any new DNA that they make - 14They reasoned that bacteria growing on a medium containing 14N would be _______than bacteria grown on a medium containing 15NLighter
- 15They labelled the 'old' DNA by _______ __ __ _ _______ __ ____Growing it on a medium of 15N
- 16Where did they then transfer the bacteria and what did they allow it to do?Transferred it to a medium of 14N and allowed it to replicate once (for one generation)
- 17What would the mass of each new DNA molecule depend on?Which method of DNA replication had taken place (conservative or semi-conservative)
- 18How did they separate the different DNA types?They extracted the DNA and centrifuged it
- 19Where did the ligher DNA collect and where did the heavier DNA collect?Lighter DNA - nearer the top
Heavier DNA - nearer the bottom - 20What is the definition of mitosis?Nuclear division producing two daughter nuclei that have the same number of chromosomes as the parent cell and as each other
- 21In which rare event may the daughter cells NOT have identical DNA to the parent cell?Mutation
- 22What is name given to the period of time before mitosis in which the cell is not dividing?Interphase
- 23What important process occurs during interphase?DNA replication
- 24Mitosis is continuous process but it can be divided into 4 stages. What are these four stages?Prophase
Metaphase
Anaphase
Telophase - 25What happens during prophase?The chromosomes become visible and the nuclear envelope disappears
- 26What happens during metaphase?The spindle forms and chromosomes line up on the center of the cell
- 27What happens during anaphase?Spindle fibres attach to the chromatids and contract
Chromatids are pulled appart to opposite poles - 28What reforms during telophase?The nuclear envelope
- 29And then what follows?Division
- 30What are the three main reasons mitosis is important?- Growth
- Differentiation
- Repair - 31What are the three stages of the cell cycle?Interphase
Nuclear division
Cell division - 32Interphase occupies most of the cell cycle. What are the three parts of interphase?G1
S
G2 - 33What is G1?First growth phase - when the proteins from which cell organelles are made are produced
- 34What happens during S phase?When DNA is replicated
- 35What happens during G2 phase?Organelles grow and divide and energy stores are increased
- 36What happens during nuclear division?The nucleus divides
- 37By what process does the nucleus divide into 2?Mitosis
- 38How many does the nucleus divide into during meiosis?4
- 39What is cancer?A group of diseases caused by a growth disorder of cells
- 40Cancer is result of damage to what?Genes that regulate mitosis and the cell cycle
- 41What does this lead to?Uncontrolled growth of cells - an abnormal group of cells (tumor) develops and expands in size
- 42How do drugs used to treat cancer (chemotherapy) disrupt the cell cycle?- Preventing DNA from replicating
- Inhibiting the metaphase stage of mitosis by interfering with spindle formation - 43What drugs can be used to prevent DNA from replicating?Cisplatin
- 44What drug can be used to inhibit metaphase by interfering with spindle formation?Vinca alkaloids
- 45What is the problem with such drugs?They also disrupt the cell cycle of normal cells
- 46However why are cancer cells damaged to a greater degree than normal cells?Because they have a fast rate of division
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- A-Level AS AQA BIOLOGY Fichas sobre THE CELL CYCLE, MITOSIS AND CANCER BIOL2, creado por ashiana121 el 25/05/2015.
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