UNIT 2 past paper questions

• Which is a feature of cellulose molecules?

  form microfibrils
• Which molecule contains magnesium ions?

  chlorophyll
• Name one tissue that gives the plant support and is also involved in the transport of water through the plant.

  xylem
• Name one fibre that gives the plant support but is not involved in the

  transport of water through the plant.

  sclerenchyma or tracheids
• Describe the information the scientists would have used to classify M. smithii into the Archaea domain.

  no presence of nucleus

  presence of cell wall
• Explain how the scientists could confirm that M. smithii and M. oralis are different species of Archaea.

  analysis of molecular evidence

  analysis of phenotype

  comparison of biological molecules
• Describe what will happen to these chromosomes when they enter the

  interphase stage of the cell cycle.

  uncoiling of chromosomes used in DNA replication
• Name the stage of meiosis in which crossing over begins.

  Prophase I
• Which structure in the cell would become radioactive first?

  ribosomes
• In which stage of the cell cycle would the number and size of the Golgi apparatus increase?

  interphase
• Suggest why the number and size of the Golgi apparatus change during the cell cycle.

  due to mitosis therefore size of golgi has to increase in interphase to provide enough organelles for two daughter cells because increased gene expression will occur
• Compare and contrast the structure of this fungal cell and a plant cell.

  Similarities

  both have a cell wall

  both have membrane bound organelles

  Differences

  cell wall for fungi is made of chitin and cell wall for plant is made of cellulose

  plants have chlorophyll
• Explain how cortical granules ensure that the egg cell is diploid after fertilisation.

  Cortical granules are released from the egg and fuse with the egg cell membrane it then releases enzymes to cause the hardening of the zona pellucida so only one sperm cell enters the egg cell
• Golgi apparatus

  orange: cisterne

  blue: cis face

  yellow: lumen

  purple: trans face

  green:secretory vesicles

  
• Describe how the scientists could calculate the heterozygosity index for a population of Sehuencas water frogs.

  {analyse the DNA of (.)/ determine the population size of (.)(1)

  • divide the number of heterozygotes by the total number of

  (.)
• state the function of a nucleolus


  produces ribosome
• Explain the importance of magnesium ions to plants

  without magnesium the leaves wont be able to form chlorophyll for photosynthesis
• structures is involved in transporting substances both up and down the plant stem


  phloem
• structures is involved in transporting calcium ions from the stem to the leaves


  xylem
• have secondary thickening in the cell walls

  xylem vessels and sclerenchyma fibres
• Describe the events that occur after a sperm cell enters an egg cell, until a zygote is formed

  cortical releases enzyme and fuse with the egg cell surface membrane zona pellucida hardens to prevent more than one sperm from entering the egg the two haploids form a diploid
• Explain how the silver trumpet tree produces seeds that are genetically different from each other.

  due to meiosis, random assortment and cross over of alleles

  each male and female egg are genetically different from each other
• function of mitochondria


  provides ATP, aerobic respiration and protein synthesis
• Explain the conditions needed for increased bacterial growth.

  glucose and oxygen for respiration, optimum pH and tempurature

  for faster enzyme reaction
• organ system 


  a group of organs working together to form a specific function
• tissue


  a group of similar cells working together to perform a specific function
• compare and contrast the stuctures of phloem tubes and xylem vessels.

  Similarities

  • both have tubular structures
  • both have no nucleus
  • both contain cellulose

  Differences

  • phloem tubes are not hollow
  • phloem are not lignified xylem have lignin
• locus


  the location of genes or a gene on a chromosome
• Suggest why a fertilised egg cell has three nuclei.

  polyspermy has occurred, there are two extra sperm nuclei

  when a sperm enters the egg the cortical granules release enzymes and harden the zona pellucida which should prevent polyspermy

  polyspermy occurred because zona pellucida had damaged areas so didn’t harden
• structure found in the cytoplasm of both eukaryotic and prokaryotic cells

  ribosomes and cell membrane
• why fungi is eukaryote

  has cell wall

  has 80s ribosomes

  has mitochondria and nucleus
• role of secretory vesicles from golgi

  they move from the golgi to the cell membrane, the vesicle fuses with the cell membrane by exocytosis
• compare the structure of bacterial cell to a yeast cell

  similarities

  both have ribosomes

  both have cell wall

  differences

  bacterial cells have plasmids and yeast has linear DNA

  bacterial cells do not have membrane bound organelles
• ribosomes are found in

  eukaryotic and prokaryotic cells
• amyloplasts are found in

  plant cells only
• mitochondia are found in

  eukaryotic cells
• centrioles are found in

  animal cells only
• function of golgi apparatus

  modifies proteins with the addition of carbohydrates and packages them into vesicles
• difference between the structure of tissue and that of a organ

  tissue are group of similar cells, organs are a group of tissues
• organelles with single membrane

  golgi, vacuole, lysome,