# Life Sciences Grade 12 P2 NSC November 2022 Memo (English)

> Grade 12 Life Sciences Paper 2 memorandum from the NSC November Exam 2022 (English), 11 pages. Read online or download the free PDF.

- Page: https://www.hlayiso.com/library/life-sciences-p2-nov-2022-mg-eng/0867aa1a-14ea-4df1-b5b2-4d0abccca11f
- Updated: 2026-10-29
- Subject: Life Sciences
- Grade: Grade 12
- Document type: Memorandum
- Year: 2022
- Exam period: NSC November Exam
- Paper: 2
- Curriculum: CAPS
- Pages: 11

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## About this document

Life Sciences · Grade 12 · NSC November Exam · 2022. Memorandum. Read online or download the PDF.

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## Document text

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                                   NATIONAL
                              SENIOR CERTIFICATE

                                      GRADE 12

                                  LIFE SCIENCES P2

                                   NOVEMBER 2022

                               MARKING GUIDELINES

MARKS: 150

                      These marking guidelines consist of 11 pages.

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Life Sciences/P2                               2                          DBE/November 2022
                                    NSC – Marking Guidelines

PRINCIPLES RELATED TO MARKING LIFE SCIENCES

1.    If more information than marks allocated is given
      Stop marking when maximum marks is reached and put a wavy line and 'max' in
      the right-hand margin.

2.    If, for example, three reasons are required and five are given
      Mark the first three irrespective of whether all or some are correct/incorrect.

3.    If whole process is given when only a part of it is required
      Read all and credit the relevant part.

4.    If comparisons are asked for, but descriptions are given
      Accept if the differences/similarities are clear.

5.    If tabulation is required, but paragraphs are given
      Candidates will lose marks for not tabulating.

6.    If diagrams are given with annotations when descriptions are required
      Candidates will lose marks.

7.    If flow charts are given instead of descriptions
      Candidates will lose marks.

8.    If sequence is muddled and links do not make sense
      Where sequence and links are correct, credit. Where sequence and links are
      incorrect, do not credit. If sequence and links become correct again, resume
      credit.

9.    Non-recognised abbreviations
      Accept if first defined in answer. If not defined, do not credit the unrecognised
      abbreviation, but credit the rest of the answer if correct.

10. Wrong numbering
    If answer fits into the correct sequence of questions, but the wrong number is
    given, it is acceptable.

11. If language used changes the intended meaning
    Do not accept.

12. Spelling errors
    If recognisable, accept the answer, provided it does not mean something else in
    Life Sciences or if it is out of context.

13. If common names are given in terminology
    Accept, provided it was accepted at the national memo discussion meeting.

14. If only the letter is asked for, but only the name is given (and vice versa)
    Do not credit.

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Life Sciences/P2                               3                           DBE/November 2022
                                    NSC – Marking Guidelines

15. If units are not given in measurements
    Candidates will lose marks. Marking guidelines will allocate marks for units
    separately.

16. Be sensitive to the sense of an answer, which may be stated in a different
    way.

17. Caption
    All illustrations (diagrams, graphs, tables, etc.) must have a caption.

18. Code-switching of official languages (terms and concepts)
    A single word or two that appear(s) in any official language other than the learner's
    assessment language used to the greatest extent in his/her answers should be
    credited, if it is correct. A marker that is proficient in the relevant official language
    should be consulted. This is applicable to all official languages.

19. Changes to the marking guidelines
    No changes must be made to the marking guidelines. The provincial internal
    moderator must be consulted, who in turn will consult with the national internal
    moderator (and the Umalusi moderators where necessary).

20. Official marking guidelines
    Only marking guidelines bearing the signatures of the national internal moderator
    and the Umalusi moderators and distributed by the National Department of Basic
    Education via the provinces must be used.

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Life Sciences/P2                             4               DBE/November 2022
                                  NSC – Marking Guidelines

SECTION A

QUESTION 1

1.1       1.1.1       B
          1.1.2       B
          1.1.3       A
          1.1.4       C
          1.1.5       C
          1.1.6       A
          1.1.7       B
          1.1.8       D
          1.1.9       B                                              (9 x 2)     (18)

1.2       1.2.1       (Biological) evolution
          1.2.2       Hydrogenbonds
          1.2.3       Centromere
          1.2.4       Cytokinesis
          1.2.5       Crossing over
          1.2.6       Centrosomes/Centrioles
          1.2.7       Homologousstructures
          1.2.8       Interphase
          1.2.9       Ribosome                                        (9 x 1)     (9)

1.3       1.3.1       B only
          1.3.2       A only
          1.3.3       B only                                        (3 x 2)      (6)

1.4       1.4.1       3/Three                                                     (1)

          1.4.2      (a) H                                                        (1)

                     (b) Rr                                                       (1)

                     (c) Cand F                                                  (2)
                                                                                   (5)

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Life Sciences/P2                                 5                 DBE/November 2022
                                      NSC – Marking Guidelines

1.5       1.5.1      5/Five                                                             (1)

          1.5.2      Gonosomes/Sex chromosomes                                          (1)

          1.5.3      (a)   Down syndrome/Trisomy 21                                     (1)

                     (b)   Non-disjunction                                              (1)

          1.5.4      Male                                                               (1)
                                                                                         (5)

1.6       1.6.1      Dihybridcross                                                      (1)

          1.6.2      (a)   Brown fur and long ears                                     (2)

                     (b)   bbee                                                        (2)

                     (c)   Be be                                                       (2)
                                                                                         (7)

                                                                 TOTAL SECTION A: 50

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Life Sciences/P2                                6                          DBE/November 2022
                                     NSC – Marking Guidelines

SECTION B

QUESTION 2

2.1       2.1.1      Nucleus/nucleoplasm                                                         (1)

          2.1.2      (a)   Deoxyribose                                                           (1)

                     (b)   Uracil/U                                                              (1)

          2.1.3                 Transcription                      DNA replication
                       Only one strand acts as a           Both strands act as
                       template                           templates
                       (Free) RNA nucleotides are         (Free) DNA nucleotides are
                       complementary                       complementary
                       Adenine complements                 Adenine pairs with thymine/
                       uracil/(A complements U)           (A pairs with T)
                       A mRNA molecule is formed          Two identical DNA molecules
                                                           are formed
                       Only a short section of DNA        The whole DNA molecule is
                       is used                             used
                       DNA unwinds and unzips              DNA unwinds and unzips
                       partially                          completely
                     (Mark first TWO only)                    1 mark for table + (Any 2 x 2)      (5)
                                                                                                  (8)

2.2       2.2.1      Gene mutation                                                               (1)

          2.2.2      - There is a change in the sequence (of nitrogenous bases) from
                       CCG to CUG                                                                (1)

          2.2.3      (a) 5/Five                                                                  (1)

                     (b) UAU                                                                     (1)

                     (c) -     The codon CCG changed to CUG/ 4th codon has
                               changed
                           -   The anticodon/tRNA sequence changed
                           -   The amino acid proline
                           -   was replaced by leucine
                           -   This resulted in a different protein/no protein being
                               formed                                                   Any       (4)
                                                                                                  (8)

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Life Sciences/P2                                7                             DBE/November 2022
                                     NSC – Marking Guidelines

2.3       2.3.1      (a) 20                                                                        (1)

                     (b) 50                                                                        (1)

          2.3.2       -   A sperm cell is a gamete
                      -   formed by meiosis
                      -   and must be haploid
                      -   to overcome the doubling effect of fertilisation                         (4)

          2.3.3      -    Anaphase I                                                               (1)

          2.3.4      -    Spindle fibres shorten/contract
                     -    Chromosome pairs separateand
                     -    move to the opposite poles                                               (3)
                                                                                                    (10)

2.4       2.4.1       954 000                                                                      (1)

          2.4.2       1 800 000 – (954 000 + 180 000 + 54 000)
                      = 612 000people

                                                       OR
                      1 800 000 - 1 188 000
                       = 612 000people
                                                       OR

                           x 1 800 000 = 612 000people                                           (3)

          2.4.3       -   The alleIe for blood group A/ IA is inherited from one parent
                          and
                      -   the alleIe for blood group B/ IB is inherited from the other
                          parent therefore
                      -   the child has blood group AB/genotype IAIB                               (3)
                                                                                                    (7)

2.5       2.5.1      Heila and Leo                                                                (2)
                     (Mark first TWO only)

          2.5.2      -    All of the (DNA) bands from Heila and Leo
                     -    match with the (DNA) bands of the mother and the father
                                                       OR
                     -    None of the (DNA) bands from Priya
                     -    match with the (DNA) bands of the mother and the father                  (2)

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Life Sciences/P2                                 8                                DBE/November 2022
                                      NSC – Marking Guidelines

          2.5.3      - Tracing missing persons
                     - Identification of genetic disorders
                     - Identification of suspects in a crime
                     - Matching tissues for organ transplants
                     - Identifying dead persons                                                  Any   (3)
                     (Mark first THREE only)                                                            (7)
2.6       2.6.1       -   Males have only one X chromosome/The Y-chromosome
                          does not have this allele and
                      -   have to inherit only one recessive allele to have white teeth
                      -   whereas females have two X chromosomes and have to
                      -   inherit two recessive alleles to have white teeth                            (4)

          2.6.2      P1              Phenotype     Male with brown             Female with
                                                   teeth                     x white teeth

                                     Genotype      XBY                          b b
                                                                             x XX
                     Meiosis
                                     G/gametes        XB,        Y           x      Xb,       Xb

                     Fertilisation

                     F1              Genotype          XBXb,         XBXb,        XbY, XbY

                                     Phenotype     1 female with brown teeth: 1 male with
                                                   white teeth*
                     P1 and F1
                     Meiosis and fertilisation
                                                            *1 compulsory mark + Any 5
                                                         OR
                     P1              Phenotype     Male with brown             Female with
                                                   teeth                     x white teeth

                                     Genotype      XBY                          b b
                                                                             x XX

                     Meiosis
                                                    Gametes                  XB               Y
                     Fertilisation                     Xb               B b
                                                                      X X             XY  b

                                                       Xb             XBXb            XbY

                                                   1 mark for correct gametes
                                                   1 mark for correct genotypes

                     F1              Phenotype     1 female with brown teeth: 1 male with
                                                   white teeth*
                     P1 and F1
                     Meiosis and fertilisation
                                                                 *1 compulsory mark + Any 5             (6)
                                                                                                        (10)
                                                                                                        [50]
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Life Sciences/P2                                9                         DBE/November 2022
                                     NSC – Marking Guidelines

QUESTION 3

3.1       3.1.1       - Embryos
                      - Umbilical cord
                      - Bone marrow                                                             (3)
                      (Mark first THREE only)

          3.1.2       -   Stem cells are undifferentiated
                      -   and have the potential to develop into any type of cell
                      -   to replace affected/defective cells causing a disorder     Any        (2)

          3.1.3       - Heart disease
                      - Spinal injuries                                              Any        (1)
                      (Mark first ONE only)                                                      (6)

3.2       3.2.1       -   A group of organisms of the same species
                      -   occupying the same habitat
                      -   at the same time                                                      (3)

          3.2.2       They produce infertile offspring                                          (1)
                      (Mark first ONE only)

          3.2.3       - Breeding at different times of the year
                      - Species-specific courtship behaviour
                      - Adaptation to different pollinators
                      - Prevention of fertilisation                                  Any        (3)
                      (Mark first THREE only)                                                    (7)

3.3       3.3.1       -   To show a possible common ancestor
                      -   To identify trends in evolution                            Any        (1)

          3.3.2      -    Both have opposable thumbs
                     -    to allow for a power grip/precision grip/ any example thereof         (2)

          3.3.3      -  Humans have small teeth/canines whereas
                        African apes have large teeth/canines
                     - There are no gaps/diastema between the teeth in humans
                        whereas African apes have gaps /diastema between the teeth
                     (Mark first ONE only                                (Any 1 x 2)             (2)
                                                                                                 (5)

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Life Sciences/P2                                10                         DBE/November 2022
                                     NSC – Marking Guidelines

3.4       3.4.1      Phylogenetic tree/cladogram                                               (1)

          3.4.2      2/Two                                                                     (1)

          3.4.3      (a) Homo habilis                                                          (1)

                     (b) (Homo) naledi                                                         (1)

          3.4.4      (Homo) sapiens                                                            (1)

          3.4.5      - Fossilevidence
                     - Cultural evidence
                     - Genetic evidence                                             Any        (2)
                     (Mark first TWO only)

          3.4.6      -    A large cranial capacity in Homo sapiens
                     -    indicates a larger brain
                     -    leading to greater intelligence
                                                         OR
                     -    A small cranial capacityin Australopithecus africanus
                     -    indicates a smaller brain
                     -    leading to lower intelligence                                        (3)

          3.4.7      -    Fossils of Australopithecus spp. were found in Africa only and
                     -    fossils of species X/Homo habilis were found in Africa only
                     -    The oldest fossils of Homo erectus were found in Africa /the
                          younger fossils were found elsewhere
                     -    indicating that modern humans originated in Africa and migrated
                          out of Africa                                                        (4)
                                                                                                (14)

3.5       3.5.1       Ambulocetus                                                              (1)

          3.5.2       It had flipper-like large feet and a tail                               (2)
                      (Mark first ONE only)

          3.5.3       -   They share characteristics/have intermediate characteristics
                      -   of the ancestor/Pakicetus and the present-day species/
                          Balaena
                                                        OR

                      -   They have legs like Pakicetus and
                      -   flippers of the present day Balaena                                  (2)
                      -
          3.5.4       -   Ancestral species of whales all had legs/lived on land
                      -   As more time was spent in the waterin search of food
                      -   the legs were used less and disappeared
                      -   the acquired characteristic was passed on to the next
                          generation                                                  Any      (3)
                                                                                                (8)

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Life Sciences/P2                                11                          DBE/November 2022
                                     NSC – Marking Guidelines

3.6       3.6.1      (a) Probability of developing resistanceto antiretroviral drugs           (1)

                     (b) Number of missed treatments                                           (1)

          3.6.2      Treatment must not be missed                                              (1)

          3.6.3      The probability of HIV developing resistance to antiretroviral drugs
                     increases with the increase in the number of missed treatments

                                                       OR

                     The more the days of missed treatment, the greater the probability
                     of the virus developing resistance to antiretroviral drugs               (2)

          3.6.4      -   There is variation in the resistance of the HI virus to
                         antiretroviral drugs
                     -   Some viruses are resistant to the drugs and
                     -   others are not resistant
                     -   Those that are not resistant do not survive
                     -   When treatments are missed,
                     -   the resistant viruses survive and reproduce
                     -   passing the resistance to their offspring                 Any         (5)
                                                                                                (10)
                                                                                                [50]

                                                                        TOTAL SECTION B: 100
                                                                           GRAND TOTAL: 150

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