# Life Sciences Grade 12 NW June 2025 Question Paper (English)

> Grade 12 Life Sciences question paper from the NW June Exam 2025 (English), 16 pages. Read online or get the free PDF download, memo linked when available.

- Page: https://www.hlayiso.com/library/grade-12-life-sciences-2025-nw-june-exam-question-paper-english/86e54c15-e11f-4f25-a0f9-d7dfa34e2c88
- Updated: 2026-09-28
- Subject: Life Sciences
- Grade: Grade 12
- Language: English
- Document type: Question paper
- Year: 2025
- Exam period: NW June Exam
- Curriculum: CAPS
- Pages: 16

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## About this document

Life Sciences · Grade 12 · NW June Exam · 2025 · English. Question paper, 16 pages. Read online or download the PDF.

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### Page 1

PROVINCIAL ASSESSMENT

                                  GRADE 12

                                 LIFE SCIENCES
                                    JUNE 2025

MARKS: 150

TIME: 2½ hours

                     This question paper consists of 16 pages.

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### Page 2

Life Sciences                               2                                NW/June 2025
                                          Grade 12

INSTRUCTIONS AND INFORMATION

 Read the following instructions carefully before answering the questions.

 1.        Answer ALL the questions.

 2.        Write ALL the answers in the ANSWER BOOK.

 3.        Start the answers to EACH question at the top of a NEW page.

 4.        Number the answers correctly according to the numbering system used
           in this question paper.

 5.        Present your answers according to the instructions of each question.

 6.        Do ALL drawings in pencil and label them in blue or black ink.

 7.        Draw diagrams, flow charts or tables only when asked to do so.

 8.        The diagrams in this question paper are NOT necessarily drawn to
           scale.

 9.        Do NOT use graph paper.

 10.       You must use a non-programmable calculator, protractor and a
           compass where necessary.

 11.       Write neatly and legibly.

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### Page 3

Life Sciences                               3                                 NW/June 2025
                                          Grade 12

 SECTION A

 QUESTION 1

 1.1     Various options are provided as possible answers to the following
         questions. Choose the answer and write only the letter (A–D) next to the
         question numbers (1.1.1 to 1.1.10) in the ANSWER BOOK,
         e.g. 1.1.11 D.

        1.1.1    What will the percentage of thymine be in a DNA molecule, if
                 35% of the nitrogenous bases are guanine?

                 A      35%
                 B      30%
                 C      70%
                 D      15%

        1.1.2    Which ONE of the following can occur during meiosis I?

                 A      Chromatids separate to move to opposite poles
                 B      Identical haploid cells form
                 C      Non-disjunction
                 D      Alleles of a gene fuse together

         1.1.3 The diagram below shows the structure of the sperm cell.

                                            Y            Z

                                                     X

                 Which ONE of the following combinations is correct?

                 A      X – Tail        Y – Mitochondria      Z – Nucleus
                 B      X – Flagellum   Y – Middle piece      Z – Acrosome
                 C      X – Tail        Y – Acrosome          Z – Head
                 D      X – Cilium      Y – Mitochondria      Z – Acrosome

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### Page 4

Life Sciences                                   4                                  NW/June 2025
                                              Grade 12

         1.1.4   The hormone responsible for secondary sexual characteristics
                 in males is ...

                 A         luteinising hormone.
                 B         testosterone.
                 C         progesterone.
                 D         oxytocin.

         1.1.5       In a dihybrid cross, an animal with long ears (L) and red fur (R)
                     was crossed with an animal with short ears (l) and black fur (r).

                     Which ONE of the following could represent the genotypes of
                     the parents?

                     A      LLRR × llrr
                     B      LlRr × LlRr
                     C      llRR × llrr
                     D      Llrr × LLRr

         1.1.6       The chances of having a male child in humans are ...

                     A      25%
                     B      50%
                     C      75%
                     D      100%

         1.1.7       The scientist that bred pea plants to investigate the priniciples
                     of genetics:

                     A      James Watson
                     B      Maurice Wilkins
                     C      Rosalind Franklin
                     D      Gregor Mendel

         1.1.8       DNA and RNA are examples of ...

                     A      amino acids.
                     B      proteins.
                     C      nucleic acids.
                     D      enzymes.

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### Page 5

Life Sciences                                   5                                NW/June 2025
                                              Grade 12

         1.1.9       What is illustrated in the diagram below?

                     A      tRNA molecules transferring amino acids during
                            translation.
                     B      Transcription taking place on the DNA template inside
                            the nucleus.
                     C      DNA nucleotides attaching to the template strand during
                            DNA replication.
                     D      The mRNA molecule leaving the nucleus.

         1.1.10 Where in the human body will you find the structure illustrated
                in the diagram below?

                     A      Cerebellum
                     B      Spinal cord
                     C      Brain
                     D      Effector muscle                                (10 x 2)     (20)

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### Page 6

Life Sciences                                6                                   NW/June 2025
                                           Grade 12

 1.2     Give the correct biological term for each of the following descriptions.
         Write only the term next to the question numbers (1.2.1 to 1.2.9) in the
         ANSWER BOOK.

         1.2.1   A genetic cross that involves the inheritance of a single
                 characteristic

         1.2.2   The hormone responsible for repairing the endometrium after
                 menstruation

         1.2.3   The division of the cytoplasm during the process of meiosis

         1.2.4   The neuron that transports impulses towards the effector

         1.2.5   The bonds found between the monomers of a protein

         1.2.6   Structures in the testes responsible for providing the mother cells
                 for spermatogenesis

         1.2.7   The type of dominance where neither alleles of a gene are fully
                 expressed, and the phenotype shows an intermediate state

         1.2.8   The part of the brain that controls the breathing rate

         1.2.9   A representation showing all the nuclear chromosomes in a cell
                                                                        (9 x 1)          (9)

 1.3     Indicate whether each of the statements in COLUMN I apply to A ONLY,
         B ONLY, BOTH A AND B or NONE of the items in COLUMN II. Write
         A only, B only, both A and B, or none next to the question numbers
         (1.3.1 to 1.3.3) in the ANSWER BOOK.

                    COLUMN I                                 COLUMN II
         1.3.1 Process(es) involved in          A:    DNA replication
               protein synthesis                B:    Transcription
         1.3.2 Diploid cells are being          A:    Meiosis
               produced                         B:    Oogenesis
         1.3.3 Part of the central nervous      A:    Cranial nerves
               system                           B:    Spinal cord
                                                                            (3 x 2)     (6)

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Life Sciences                                 7                             NW/June 2025
                                            Grade 12

 1.4     The diagram below represents a molecule found in a cell.

                                Q
                                               W

                                                                     R
                                                  A
                                                                     S
                                              W

                                                  G

                                                                     V

                                                       C

                                                  A

                                                  G

                            Strand 1                   Strand 2

         1.4.1 Identify:

                (a)    Unit Q                                                     (1)

                (b)    R                                                          (1)

                (c)    S                                                          (1)

                (d)    The full name of V                                         (1)

                (e)    W                                                          (1)

         1.4.2 Identify the molecule in the diagram above.                        (1)

         1.4.3 Give ONE visible reason for your answer to QUESTION 1.4.2.         (1)

         1.4.4 Write down the sequence of the nitrogenous bases for strand 1
               from the top to the bottom.                                        (2)

         1.4.5 Besides the nucleus, name ONE other location in an animal cell
               where DNA can be found.                                            (1)
                                                                                  (10)
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Life Sciences                                  8                                  NW/June 2025
                                             Grade 12

 1.5     The diagram below represents the side view of the male reproductive
         system.

                A                                                             D

                                                                              E

                B
                                                                              F
                C

         1.5.1 Give the LETTER and the NAME of the ...

                    (a)   structure where sperm cells are temporarily stored to           (2)
                          mature.

                    (b)   structure that provides sperm cells with fructose sugar.        (2)

         1.5.2 Identify part A.                                                           (1)
                                                                                          (5)

                                                              TOTAL SECTION A:            50

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### Page 9

Life Sciences                                  9                                   NW/June 2025
                                             Grade 12

 SECTION B

 QUESTION 2

 2.1     The diagram below represents a developing foetus in the uterus.

                                                 A
                                                 B

                              C

                              D
                                                                     E

                                                                     F

         2.1.1       Give the LETTER of the part where:

                     (a)    fertilisation usually occurs                                  (1)

                     (b)    ova are produced                                              (1)

                     (c)    a mucus plug forms during gestation                           (1)

         2.1.2       Give TWO functions of part C.                                        (2)

         2.1.3       Describe ONE structural adaptation of part E for gestation.          (2)

         2.1.4       Explain how the development of the foetus would be affected
                     if a tumour starts growing in part D, pushing on the blood
                     vessels inside.                                                      (4)

         2.1.5       Explain the chance of fertilisation taking place in the diagram
                     above.                                                               (4)
                                                                                          (15)

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### Page 10

Life Sciences                                10                                NW/June 2025
                                           Grade 12

 2.2     Describe the process of oogenesis.                                            (5)

 2.3     Read the extract below.

         Monotremes are a very unique group of mammals that lay eggs. The
         duck-billed platypus is a well-known example, but is just one of five
         species of monotremes. The other four species are all types of echidnas,
         also known as spiny anteaters. They resemble hedgehogs, having quill-
         covered bodies, but possess much longer snouts.

         The mating behaviour of echidnas is extremely intricate and scientists
         have struggled to discover the mechanism, as echidnas do not seem
         interested in mating while in captivity. Females lay one egg with a soft
         leathery shell 22 days after mating with a male. She has a pouch, similar
         to a kangaroo’s, and will immediately desposit her egg in the pouch until
         it hatches ten days later. Once hatched the young hairless echidna
         starts feeding on milk produced by the mother, while staying in the
         pouch.

         2.3.1   What type of fertilisation occurs in echidnas?                        (1)

         2.3.2   Give TWO advantages of the type of fertilisation mentioned in
                 QUESTION 2.3.1.                                                       (2)

         2.3.3   Which reproductive strategy is found in echidnas?                     (1)

         2.3.4   Provide TWO reasons to show evidence of parental care in
                 echidnas.                                                             (2)

         2.3.5   Do these mammals show precocial, or altricial development?            (1)

         2.3.6   Give ONE characteristic of the echidna to support your answer
                 to QUESTION 2.3.5.                                                    (1)
                                                                                       (8)

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### Page 11

Life Sciences                             11                            NW/June 2025
                                        Grade 12

 2.4     The two diagrams below represent two phases of meiosis.

                                A                          B

         2.4.1 Identify the phases represented by:

                 (a)    A                                                      (1)

                 (b)    B                                                      (1)

         2.4.2 Explain why both cells (A and B) show non-disjunction.          (3)

         2.4.3 Tabulate TWO differences between mitosis and meiosis.           (5)
                                                                               (10)

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### Page 12

Life Sciences                                  12                               NW/June 2025
                                             Grade 12

 2.5     The pedigree diagram below shows the inheritance of a type of night
         blindness in a family. This disorder is sex-linked and is caused by a
         recessive allele (n). Having normal night vision is caused by a dominant
         allele (N).

                             1           2

             Normale manA3                                                  4
         :                   A

                                                                 5
             Key

                     Unaffected manA                         Unaffected woman

                     Affected manA                           Affected womanA

                                 Inheritance of night blindnessA

         2.5.1 What is meant by a sex-linked disorder?                                 (1)

         2.5.2 How many of the male descendents of parents 1 and 2 are
               unaffected?                                                             (1)

         2.5.3 Give the genotype of:

                   (a)    Individual 2                                                 (2)

                   (b)    Individual 5                                                 (2)

         2.5.4 If individual 5 has children with an unaffected man, what
               percentage of her daughters will have an allele for night
               blindness, but is NOT affected?                                         (2)

         2.5.5 Name TWO genetic disorders, except for night blindness, that
               are sex-linked.                                                         (2)

         2.5.6 Explain how it was possible for individuals 1 and 2 to have an
               affected child, while both of them are unaffected.                      (2)
                                                                                       (12)
                                                                                       [50]

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### Page 13

Life Sciences                                 13                                   NW/June 2025
                                            Grade 12

 QUESTION 3

 3.1      Read the extract below.

                        The Development and Shaping of the Brain

          The making of the human brain from the tip of a 3 millimeter neural tube
          is a marvel of biological engineering. To arrive at the more than 100
          billion neurons found in a newborn baby, the brain must grow at the rate
          of about 250 000 nerve cells per minute, on average, throughout the
          course of pregnancy. But it is not the volume of growth alone that makes
          the production of a human brain so exceptional compared to other
          organs. The brain has many functions, and how the functions are
          specifically assigned to each location in the brain, are stunning in their
          complexity; yet the feat of growing a human brain occurs in hundreds of
          millions of individuals each year.

          The brain's 100 trillion or so interconnections provide the physical basis
          for its speed and sophistication. But how is such an intricate network
          constructed in the first place? Does the genetic material of the fertilised
          egg already contain a full set of building specifications for the human
          brain, in which every cell is created as a building block in the overall
          design?

                                    [From https://www.ncbi.nlm.nih.gov/books/NBK234146/]

         3.1.1   The extract above mentions interconnections. What is the
                 scientific name for these connections between neurons?                    (1)

         3.1.2   State TWO ways how the production of the brain is exceptional
                 compared to other organs in the human body.                               (2)

         3.1.3   How many brain cells will grow in an hour in a foetus? Show ALL
                 calculations.                                                             (3)

         3.1.4   Which word in the extract hints that the production of brain tissue
                 is encoded in DNA?                                                        (1)

         3.1.5   Which part of the brain will contain the most neurons?                    (1)
                                                                                           (8)

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### Page 14

Life Sciences                                    14                                NW/June 2025
                                               Grade 12

 3.2     An investigation was done to determine the effect of a new hearing aid
         on the hearing quality of middle-aged adults.

         The investigation was conducted as follows:

               300 participants between the ages of 45 and 65 participated
                voluntarily in the investigation.
               Participants had to undergo a hearing test. During the test, a sound
                with a specific frequency would be played, starting at a soft volume
                and then slowly amplifying it over a short period. Participants had to
                signal the moment they could hear the sound for the first time. This
                was done for ten different sounds.
               After this initial test, 250 participants were given the hearing aids
                and had to wear them for a week.
               After a week, while those with the hearing aids were still wearing
                them, all the participants had to repeat the hearing test.

         The table below shows the number of participants with hearing aids and
         the average number of seconds when they started to hear the sounds
         in the hearing test.

                                         NUMBER OF PARTICIPANTS
             Avg. number of        Before wearing the While wearing the
                seconds               hearing aid        hearing aid
                   0–2                     12                134
                  2.1–4                    37                 96
                  4.1–6                   112                 17
                  6.1–8                    77                 2
                 8.1–10                    12                 1

         3.2.1     For this investigation, give:

                   (a)    The dependent variable                                          (1)

                   (b)    The aim                                                         (2)

         3.2.2     Why can this investigation be regarded as reliable?                    (1)

         3.2.3     Suggest a reason why participants with the hearing aids had to
                   wear them for a week before the follow-up hearing test.                (1)

         3.2.4     Explain why 50 participants had to do the follow-up hearing test
                   without having received the hearing aids.                              (2)

         3.2.5     List THREE ways how the validity of the investigation could be
                   ensured.                                                               (3)

         3.2.6     Give a suitable conclusion for this investigation.                     (2)

         3.2.7     Draw a double bar graph to present the data in the table.              (6)
                                                                                          (18)

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### Page 15

Life Sciences                               15                                NW/June 2025
                                          Grade 12

 3.3     The diagram below represents the structure of the human eye.

         3.3.1 Identify part:

                 (a)   A                                                            (1)

                 (b)   C                                                            (1)

         3.3.2 Michael pranks his friend Karabo by using the flashlight on his
               phone and unexpectantly flashing it into his eyes.

                 Describe how structure B will change in Karabo’s eyes.             (3)

         3.3.3 Make a labelled drawing of the cell in D that transports
               impulses towards the brain.                                          (6)
                                                                                    (11)

 3.4     A man with blood group A marries a woman with blood group O. They
         have two children with the blood groups A and O.

         3.4.1 By using a genetic cross, show the genotypes and phenotypes
               of the parents and children.                                         (6)

         3.4.2 Explain why using blood groups is not an accurate method for
               paternity testing.                                                   (2)
                                                                                    (8)

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### Page 16

Life Sciences                                  16                                NW/June 2025
                                             Grade 12

 3.5    The diagram below shows the main steps used during cloning.

                             A

                                                 B

                                                                       C

                      D

        3.5.1        Write down the LETTER that represents each of the following:

                     (a)    An ovum’s nucleus is being removed                         (1)

                     (b)    A somatic cell is removed from animal tissue of the
                            animal that is to be cloned                                (1)

                     (c)    A nucleus of the animal being cloned is inserted into an
                            ovum                                                       (1)

        3.5.2        State TWO benefits of cloning animals.                            (2)
                                                                                       (5)
                                                                                       [50]

                                                              TOTAL SECTION B:         100
                                                                 GRAND TOTAL:          150

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