Life Sciences Exam Notes

General Examination Instructions

  • Answer ALL questions in the provided answer book.
  • Each answer should start on a NEW page.
  • Number answers in accordance with the question paper numbering.
  • Drawings must be done in pencil and labeled in blue/black ink.
  • Submit diagrams, tables, or flow charts only upon request.
  • Do NOT use graph paper.
  • A non-programmable calculator, protractor, and compass are permissible.
  • Round all calculations to two decimal places.

Section A: Various Choice Questions

  • 1.1.1: Monomers of proteins are A. amino acids.
  • 1.1.2: When blood sugar rises, the pancreas secretes D. insulin.
  • 1.1.3: Nerve cells transmitting impulses to the brain are C. sensory neurons.
  • 1.1.4: Connection between axon of one neuron to another is a B. synapse.
  • 1.1.5: Plant hormone for elongation of internodes is C. gibberellins.
  • 1.1.6: Percentage of heterozygous offspring from a black and white rabbit is B 100.
  • 1.1.7: Malfunctioning endocrine gland causing disorder in the image is the C. pancreas.
  • 1.1.8: Autonomic nervous system B. consists of sympathetic and para-sympathetic systems.
  • 1.1.9: Description of reproductive strategy represented as B Altricial development.

Biological Terms

  • 1.2.1: Cataract.
  • 1.2.2: Mechanoreceptors.
  • 1.2.3: Alleles.
  • 1.2.4: Stem cells.
  • 1.2.5: Auxins.
  • 1.2.6: Pituitary gland.
  • 1.2.7: Leydig cells.

Statements Application

  • 1.3.1: A only - Incomplete dominance.
  • 1.3.2: A only - Geotropism.
  • 1.3.3: A only - Sickle cell anaemia.
  • 1.3.4: A only - Ovipary.
  • 1.3.5: B only - Allantois.
  • 1.3.6: A only - Concave lens.

Rabbit Genotypes Analysis

  • 1.4.1:
    • (a) Grey fur and red eyes.
    • (b) White fur and black eyes.
    • (c) White fur and red eyes.
    • (d) Grey fur and black eyes.
  • 1.4.2: Offspring statistics from the Punnett square results.
    • (a) 4: Grey fur and black eyes.
    • (b) 4: Grey fur and red eyes.
    • (c) 0: White fur and black eyes.
    • (d) 0: White fur and red eyes.

Homeostatic Processes

  • 1.5.1: Volume at A decreases.
  • 1.5.2: Gland at B: Pituitary gland.
  • 1.5.3: Hormone C: Antidiuretic hormone.
  • 1.5.4: Reabsorption occurs in organ D's nephrons.
  • 1.5.5: Quantity of water E is less lost in urine.

Section B: Various Studies and Analyses

  • 2.1.1: Identify processes as Replication and Transcription.
  • 2.1.2: Replication occurs before cell division.
  • 2.1.3: Resulting impact of not replicating before division can lead to cellular malfunction.
  • 2.1.4: Specific name for errors: Mutations.
  • 2.1.5: Causes of mutations: Radiation & Chemical exposure.

Biotechnology in Agriculture

  • 2.2.1: Identify biotechnological process as Selective Breeding.
  • 2.2.2: Selective Breeding involves choosing specific plants or animals to reproduce in order to enhance desired traits.
  • 2.2.3: Sheep X inherits traits from Sheep A.
  • 2.2.4: Reasoning based on genetic lineage or preferred traits.

Alcohol and Reaction Time Study

  • 2.3.1: Independent variable: Blood Alcohol Concentration.
  • 2.3.2: Control could be: Reaction time without alcohol.
  • 2.3.3: Ways to improve validity: Control environmental factors & varied participant demographics.

Diagram Interpretation on Alcohol Influence

  • 2.3.4: Identify parts: A: Eyes; B: Brain.
  • 2.3.5: Alcohol increases reaction time by slowing neurotransmitter processing in the brain.

Menstrual Cycle Insights

  • 3.1.1 (a): Source of Oestrogen Ovaries.
  • 3.1.1 (b): Source of Progesterone Corpus luteum.
  • 3.1.2 (a): Increase in oestrogen thickens the uterine wall.
  • 3.1.2 (b): Drop in progesterone may lead to shedding of the uterine lining.
  • 3.1.3: High progesterone after day 28 indicates possible pregnancy.
  • 3.1.4: IUD does not stop menstrual cycle as it prevents implantation of the fertilized egg due to the presence of cytokines.

Exchange of Substances Between Mother and Foetus

  • 3.4.1: Identify parts: A: Amniotic sac; B: Placenta; D: Umbilical cord.
  • 3.4.2: Premature breaking of part C risks fetal development due to lack of amniotic fluid.
  • 3.4.3: Placenta produces progesterone.
  • 3.4.4: Nutrients and gases exchanged via diffusion across placental membranes.

Meiosis Errors

  • 3.3.1: Identify phase of meiosis: Anaphase I.
  • 3.3.2: Failure to separate homologous chromosomes indicates malfunction during the Anaphase.
  • 3.3.3: Name the error: Nondisjunction.
  • 3.3.4: Draw of metaphase I with proper alignment of chromosomes.

Sugar Tax Discussion

  • 3.4.1: Objectives: Reduce sugar consumption; Generate healthcare funds.
  • 3.4.2: Diabetes harms productivity due to health complications leading to reduced work capacity and increased medical expenses.