NCEA Level 1 Science (90188) 2009 — page 1 of 4 Assessment Schedule – 2009 Science: Describe aspects of biology (90188) Evidence Statement Q ONE (a) Achievement Achievement with Merit Correct statement about why a person suffering a viral infection will not suffer effects from toxins (a) Correct explanation why viruses do not produce toxins AND how toxins are produced. (m) Examples: Viruses do not produce toxins as they do not carry out life processes / respiration / excretion / other named life process (ie why not living). Examples: Viruses do not respire / excrete / carry out life processes / are not living. OR Viruses require living cells to reproduce / replicate. Correct statement about how toxins are produced. (a) Examples: Toxins produced as a result of (cellular) metabolism / respiration / excretion / digestion. Achievement with Excellence AND Toxins are a waste product produced when Bacteria / living things digest food / respire / excrete. (DO NOT accept idea that enzymes are toxins.) Toxins are excreted waste. (Not just waste products – must refer to life process.) (b) Correct statements. (a) Eg: Toxins build up as bacteria reproduce / excrete over time. (a) Bacteria reproduce using binary fission / as cell divides in two. (a) Very few bacteria at start / bacteria build up over time (a) Bacteria replicate (fast) in right / warm / moist / nutrient rich conditions (a). Suff. 2 a =A Correct explanation why bacteria increase AND why toxins increase over time. (m) In an initial infection there are very few bacteria. Bacteria reproduce rapidly over 24 hr using binary fission / cell divides in two as quickly as every 20 min, therefore in 24 hr the numbers are very high. AND Toxin amount is dependent on the number of bacteria respiring / excreting, therefore when the numbers are higher after 24 hrs the amount of toxin will be very high. (Must be clear candidates know what a toxin is.) 1m=M Discusses fully why a person would feel unwell after 24 hours by relating symptoms to bacterial life processes. (e) (Must link binary fission AND respiration OR excretion to toxin build up due to large numbers) Eg: Bacteria reproduce by binary fission, which happens rapidly, under optimal conditions (of warmth, moisture, food) leading to high numbers in a short time. Therefore when there are large numbers of bacteria carrying out respiration / excretion after 24 hrs, large amounts of toxin are produced / excreted leading to a person feeling unwell. 1e=E NCEA Level 1 Science (90188) 2009 — page 2 of 4 TWO (a) Identifies THREE parts. (a) Eg: A = spores B = sporangium / spore capsule / case C = (reproductive) hyphae / sporangiophore D = (feeding) hyphae / mycelium TWO correct roles identified. (a) Eg: A - used for reproduction / making new fungi. B -holds / disperses spores C- holds up sporangium D- used for digestion / feeding / how food gets into fungus. (b) Definition of Fermentation. (a) Eg: Anaerobic respiration / release of energy from sugar that takes place without / in the absence of oxygen / respiration without oxygen. OR word / formulae equation acceptable: OR sugar (glucose) carbon dioxide + alcohol (ethanol) (allow yeast and energy to be in equation for A only) ONE correct statement for role of sugar (a) Eg: Sugar is needed for respiration / life processes / food source (NOT fermentation) ONE correct yeast life process described (a) Respiration, excretion, reproduction, nutrition, growth. Suff. 2a=A Explains the role of THREE parts. Parts must be named correctly. (m) Eg: For A: Spores are small / light reproductive parts of the fungus, that disperse . For B: Sporangia are spore sacs / holders for spores which disperse the spores or mature the spores. For C: Reproductive hyphae hold sporangium up so enable better dispersal of spores. For D: (Feeding) hyphae absorb nutrients / produce digestive enzymes / carry out extra cellular digestion. (Do not accept roots / seeds etc as names for parts but analogy okay.) Describes fermentation and explains why sugar is needed OR why yeast is used in bread making. (m) CORRECT word equation needed. Eg: sugar (glucose) carbon dioxide + alcohol (ethanol) (allow energy) AND Anaerobic respiration / fermentation is the release of energy from sugar that takes place in the absence of oxygen. (must be clear that respiration is anaerobic / without oxygen). AND Why sugar is needed: energy molecule broken down in (anaerobic) respiration / provides food / energy supply for yeast to maximize growth / reproduction to increase rate of respiration / faster energy source than flour. Discusses the role of THREE correctly named parts. (e) Eg: For A: Spores are the reproductive units for fungi, they carry the genetic code / DNA to produce another identical fungus OR they are small / light to be carried a distance by wind to land and germinate / start growing on a food source (ie need to link form to function). For B: Sporangia are sacs which carry / produce the spores. When the spores are ripe / mature they burst releasing the spores into the air. For C: The reproductive hyphae are designed to hold up the sporangia to enable the spores to be spread (in the air). For D: The feeding hyphae carry out extra cellular digestion, secreting enzymes to break down food molecules outside of the fungal organism. The nutrients are then absorbed. Describes fermentation and explains why sugar is needed AND the life processes of yeast in bread making. (e) CORRECT word equation needed sugar (glucose) carbon dioxide + alcohol (ethanol) (may include energy) AND Yeast needs sugar as its food / energy supply for respiration / fermentation to release energy needed for growth / reproduction / binary fission. AND Yeast ferments sugar / carries out anaerobic respiration using sugar and produces alcohol and CO2 gas, which causes the bread to rise. Eg: sugar (glucose) carbon dioxide + alcohol Yeast is fermenting, ie anaerobically respiring without using oxygen, using the sugar as easily released energy to grow and reproduce. It excretes CO2 gas as waste which makes bread rise quickly under right conditions of warmth, food, moisture. OR The function of the yeast: Yeast carries out fermentation / (anaerobic) respiration producing CO2 which causes the bread to rise. 1m=M 1e=E NCEA Level 1 Science (90188) 2009 — page 3 of 4 THREE (a) Correct genotype. (a) Accept either ee or homozygous recessive. Correct use of recessive AND allele. (a) Eg: Recessive is an allele which will only be displayed when there is more than one present / no dominant allele present. Correct definition for recessive OR allele (a) Eg: Recessive traits are masked by dominant traits. An allele is an alternative form of a gene. (b) Correct statement. (a) Extra digits (E) is dominant over normal digits (e) so (e) may be present in cats, but stay hidden in Ee. Correct genotype combinations (a). Normal digits (ee) could show up in a Ee Ee cross or a Ee x ee cross. OR Correct Punnett square for either / both of above E e E EE Ee e Ee ee e e E Ee Ee e ee ee Explains the genotype of a normal cat using required terms, allele and recessive. (m) Eg: The cat has two alleles for normal digits. This allele is recessive which means that, in order for it to be displayed, two of the normal alleles are needed. It will be hidden / masked if a dominant allele is present, therefore the genotype is ee (homozygous recessive) as the cat has normal digits. (Must use terms allele and recessive correctly and clearly show that dominant allele will mask / hide and give polydactyl phenotype.) Correct explanation for choice of parent genotypes. (m) Must use terms allele, gene and recessive correctly. Normal digits (ee) could show up in an Ee Ee cross (or Ee ee). It would be impossible if the parents were Ee and EE. OR At least one parent ie heterozygous / Ee / carries dominant and recessive allele for gene. For kitten to not have extra digit it must inherit the recessive allele from both parents. OR 25% or 50% chance will only be displayed in a large sample, not necessarily a single litter. Idea of lower percentage being less likely is clearly explained Correct interpretation of punnet phenotypes (a) Eg 25% chance of normal kitten, 75% polydactyl Discusses how a normal digit kitten can be produced AND links the outcome to the statistical probability of it happening. MUST include Punnett square and use gene / allele correctly. (e) At least one of the parents is heterozygous / Ee / carry dominant and recessive allele for gene. For kitten to not have extra digit it must inherit the recessive allele from both parents. AND Statistically every time an Ee Ee cross is carried out there is 25% chance that offspring would be normal (ee) or 50% for ee x Ee The normal trait may not be expressed at all. PLUS Correct Punnett square. OR Explains both possible parent combinations and outcomes with punnett squares. (e) Eg: At least one of the parents is heterozygous, but the other parent may be homozygous recessive or heterozygous. If the other parent is homozygous recessive, statistically there is a 50% chance that the offspring will inherit both recessive alleles, which will be expressed as normal digits. If the other parent is heterozygous, there is a 25% chance that the offspring will inherit both recessive alleles. e e Suff. 2a=A 1m=M E Ee Ee e ee ee E e 1e=E E EE Ee e Ee ee NCEA Level 1 Science (90188) 2009 — page 4 of 4 FOUR Two correct statements. (2 a) Eg: Variation in meiosis can be caused by crossing over / shuffling / independent assortment. Variation in meiosis can lead to increased survival chances. Mitosis would cause a doubling of chromosome number if used in reproduction. Meiosis halves the number of chromosomes. Cells produced from meiosis lead to the correct number of chromosomes at fertilisation. Diagram or description in words showing the process of mitosis / meiosis. Two correct statements, one explained. (m) Explains fully why meiosis is used for reproduction AND mitosis is not. (e) Eg: Variation in meiosis occurs as a result of crossing over, or “shuffling” meaning that each of the 4 daughter cells produced differs from the rest leading to increased chances of survival. Eg: Cells produced in mitosis are all identical and carry a full set of chromosomes which would mean at fertilisation the chromosome number would double. Whereas in meiosis cells with half the number of chromosomes are produced. Only need half the number of chromosomes as number is restored at fertilisation. Variation in meiosis occurs as a result of crossing over, or “shuffling” meaning that each of the 4 daughter cells produced differs from the rest leading to increased chances of survival due to mixing up / random assortment of the alleles. Cells produced in mitosis are all identical and carry a full set of chromosomes which would mean at fertilisation the chromosome number would double. OR the lack of variation means the offspring are all the same so won’t survive / respond to change. Meiosis is the production of gametes / sex cells, so produces cells with half the number of chromosomes. Only need half the number of chromosomes as number is restored at fertilisation. Correct description of mitosis / meiosis. – eg meiosis makes sex cells / gametes, mitosis is for growth AND repair, mitosis produces daughter cells which are identical / can be used for asexual reproduction. Suff. 2a=A 1 (m) = M 1 (e) = E Judgement Statement Achievement Achievement with Merit Achievement with Excellence 3A OR 2M 1A 2M 1A 2E Lower case a, m, e may be used throughout the paper to indicate contributing evidence for overall grades for questions. Only the circled upper case A, M and E grades shown at the end of each full question are used to make the final judgement.