Life Sciences Examination Guidelines Grade 12

The Curriculum and Assessment Policy Statement (CAPS) for Life Sciences presents the nature and purpose of the subject, guiding teaching and assessment philosophy in Grade 12.
The purpose of the Examination Guidelines is outlined as follows:
- Provide clarity on the content depth and scope to be assessed in the Grade 12 National Senior Certificate (NSC) Examination in Life Sciences.
- Assist teachers in adequately preparing learners for the examinations.
Focuses on final Grade 12 external examinations and does not deeply discuss School-Based Assessment (SBA).
Essential documents to read in conjunction:
- National Curriculum Statement (NCS) CAPS: Life Sciences.
- National Protocol of Assessment regarding programs and promotion requirements for Grades R–12.
- Amendments to the Grade 12 Abridged CAPS Section 4 (Effective from January 2021).

Three broad subject-specific aims in Life Sciences correlate with the purposes of learning science:
- Specific Aim 1: Focuses on knowing subject content.
- Specific Aim 2: Focuses on undertaking science or practical work and investigations.
- Specific Aim 3: Highlights understanding the applications of Life Sciences in daily life, acknowledging scientific developments and indigenous knowledge relationships.
It is crucial to address these aims in both teaching and assessments.

Assessment must accommodate various learner abilities by encompassing a spectrum of cognitive levels and difficulty degrees.
Assessment planning and development should integrate subject content, specific aims, and skill ranges.

Cognitive levels weightings for assessment tasks are:
- Knowledge: 40%
- Comprehension: 25%
- Application: 20%
- Analysis, Synthesis and Evaluation: 15%

Degrees of difficulty classified as follows:
- Easy (30%): Accessible to the average learner.
- Moderately challenging (40%): Requires analytical thought for the average learner.
- Difficult (25%): High challenge for average learners.
- Very difficult (5%): Requires advanced problem-solving abilities for level 7 learners.
Difficulty categories include:
- Content difficulty
- Stimulus difficulty
- Task difficulty
- Expected response difficulty.

Examinations consist of two question papers, each lasting 2½ hours and worth 150 marks:
- SECTION A: Short answer questions (multiple-choice, terminology, columns/statements, and matching items) worth 50 marks.
- SECTION B: A variety of two questions worth 50 marks each, divided into subquestions totaling 100 marks.

TOPIC	WEIGHTING (%)	MARKS
Reproduction in Vertebrates	5	8
Human Reproduction	27	41
Responding to the Environment (humans)	36	54
Responding to Environment (plants)	9	13
Endocrine and Homeostasis in Humans	23	34
TOTAL	100%	150

PAPER 2:

INTRODUCTION:
- Revise cell structure emphasizing ribosome, cytoplasm, and nucleus.
- Two nucleic acids: DNA and RNA consist of nucleotides.
- DNA Location, Structure, and Functions:
- Location:
  - Nuclear DNA makes up genes on chromosomes.
  - Mitochondrial DNA and chloroplast DNA in plants.
- Historical Context: Watson & Crick, Franklin & Wilkins.
- Structure: DNA's double helix shape composed of nucleotides.
- Components of DNA Nucleotide:
  - Nitrogenous bases bonded by hydrogen bonds: A, T, C, G (A: T and G: C pairing).
  - Sugar (deoxyribose) and phosphate components.
- Functions of DNA:
  - Gene composition carrying hereditary information, coded instructions for protein synthesis.
DNA Replication:
- Overview of when, where, and how replication occurs, emphasizing its significance.
DNA Profiling:
- Understand uses and interpretation of DNA profiles.

LOCATION: mRNA in nucleus forming on ribosome; tRNA in the cytoplasm.
STRUCTURE: Single strand of nucleotides.
RNA NUCLEOTIDE COMPONENTS:
- Nitrogenous bases: A, U (instead of T), C, G.
- Sugar (ribose) and phosphate component.
FUNCTION: Primarily involved in protein synthesis.

Involvement of DNA and RNA:
- Transcription:
- DNA unwinds, strands separate; one strand serves as a template for mRNA formation using free RNA nucleotides, yielding mRNA that transmits the coded message.
- Translation:
- tRNA brings specific amino acids to ribosome matching anticodons with mRNA codons, protein synthesis via peptide bonds formed among amino acids.
Diagrams: Illustrate transcription and translation processes.

INTRODUCTION:
- Revise cell structure with emphasis on nuclear parts and cytoplasm.
- CHROMOSOME STRUCTURE:
- Consists of DNA and protein; characteristic chromosome number of organisms (humans have 46).
- Chromosomes transition from single to double chromatid at replication.
- DIFFERENTIATE: Haploid vs. diploid, sex cells vs. somatic cells, sex chromosomes vs. autosomes.
DEFINITION OF MEIOSIS:
- Continuous process, divided into phases for convenience.
- INTERPHASE EVENTS: DNA replication occurs.
MEIOSIS I PHASES:
- Events of Prophase I (including crossing over), Metaphase I, Anaphase I, Telophase I with diagrams.
MEIOSIS II PHASES:
- Events outlined similarly to Meiosis I.
IMPORTANCE OF MEIOSIS:
- Production of haploid gametes, maintenance of chromosome number, genetic variation mechanisms.
ABNORMAL MEIOSIS:
- Discuss non-disjunction and consequences, e.g., Down syndrome resulting from extra chromosome 21.
COMPARISON TO MITOSIS:
- Highlight similarities and differences between both processes.

DIVERSITY OF REPRODUCTIVE STRATEGIES:
- Discuss external vs. internal fertilization, ovipary, ovovivipary and vivipary, amniotic eggs, developmental strategies, and parental care with examples.