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15 Cards in this Set
- Front
- Back
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What are the advantages of being multi- over uni- cellular
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Organism is larger
Cell differentiation Organisms can be more complexed |
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What do multicellular organisms need to have organisms for
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Communication between cells → nervous system circulatory system
Supplying the cells with nutrients → digestive system Controlling exchanges with the environment → respiratory system, excretory system |
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What type of cells are body cells
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Diploid
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Why do chromosomes need to be copied
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So that new cells can be produced for:
Growth Repair to damaged tissue Replacement of worn out cells Asexual reproduction (which involves only one parent) |
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When is mitosis used
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cell division
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Explain the process of mitosis
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1. Chromosomes in the nucleus are copied
2. Chromatids pulled apart and moved towards the poles 3. Chromosomes separate 4. Cell divides |
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What does human reproduction involve
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Two parent
Sexual intercourse Offspring that are unique |
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What type of cells are gametes
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Haploid
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What are the adaptations of a sperm cell
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Tail - to move them towards the egg
Increased amount of mitochondria Acrosome - releases enzymes to digest the egg membrane |
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How are gametes produced
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Meiosis
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What is a haploid
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Contains only one just one of the chromosomes from each pair and half of the genetic material of a body cell
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Why does fertilization lead to genetic variation
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2 Gametes combine to form a diploid zygote
Genes on chromosomes combine to control the characteristics of the zygote |
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Explain the process of DNA replication
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The DNA 'unzips' to form single strands
Free nucleotides lock on to bases - complementary base pairing New double strands |
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Explain the process of meiosis
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Chromosomes make a identical copies of themselves, whilst they're in the parent cell
Similar chromosomes pair up Sections of DNA get swapped Pairs of chromosomes divide - into diploid cells They then split - creating haploid cells |
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What must happen before mitosis can occur
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DNA repication
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