# Life Sciences Grade 11 P1 Eastern Cape November 2015 Memo

> Grade 11 Life Sciences Paper 1 memorandum from the Eastern Cape November 2015 (English), 7 pages. Read online or download the free PDF.

- Page: https://www.hlayiso.com/library/life-sc-p1-gr11-memo-eng-nov2015/d6186b0b-3956-4132-a8d4-6cd198e43c24
- Updated: 2026-09-27
- Subject: Life Sciences
- Grade: Grade 11
- Document type: Memorandum
- Year: 2015
- Exam period: Eastern Cape November
- Paper: 1
- Curriculum: CAPS
- Pages: 7

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Life Sciences · Grade 11 · Eastern Cape November · 2015. Memorandum, 7 pages. Read online or download the PDF.

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### Page 1

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                          NATIONAL
                     SENIOR CERTIFICATE

                           GRADE 11

                      NOVEMBER 2015

                     LIFE SCIENCES P1
                      MEMORANDUM

MARKS:   150

                   This memorandum consists of 7 pages.

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2                                  LIFE SCIENCES P1                  (EC/NOVEMBER 2015)

 SECTION A

 QUESTION 1

 1.1   1.1.1    D 
       1.1.2    A 
       1.1.3    C 
       1.1.4    C 
       1.1.5    C 
       1.1.6    D 
       1.1.7    D 
       1.1.8    A 
       1.1.9    B 
       1.1.10   B                                                 (10 x 2)    (20)

 1.2   1.2.1    Chlorophyll 
       1.2.2    Blue-black 
       1.2.3    Deoxyribonucleic acid/DNA 
       1.2.4    Oxygen 
       1.2.5    Cristae 
       1.2.6    Kreb’s cycle                                         (6 x 1)   (6)

 1.3   1.3.1    A only 
       1.3.2    None 
       1.3.3    Both A and B 
       1.3.4    B only 
       1.3.5    Both A and B 
       1.3.6    A only                                              (6 x 2)   (12)

 1.4   1.4.1    A - Renal capsule 
                B - Collecting tubules 
                C - Ureter                                                     (3)
       1.4.2    Ureter/C                                                       (1)
       1.4.3    Renal artery  - D                                             (2)
       1.4.4    E or Renal vein                                                (1)

 1.5   1.5.1    Obesity is an imbalance between energy intake and
                expenditure  such that excess energy is stored in fat cells
                which enlarge/ increase in number                              (2)
       1.5.2    13 127                                                         (1)
       1.5.3    Men are physically more active than women                      (1)
       1.5.4    Hypertension                                                   (1)
                                                           TOTAL SECTION A:     50

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(EC/NOVEMBER 2015)                    LIFE SCIENCES P1                                      3

 SECTION B

 QUESTION 2

 2.1 2.1.1      Census                                                               (1)

       2.1.2    B                                                                    (1)

       2.1.3    The base of the age pyramid is wide but it narrows towards the
                top. 
                This indicates a high proportion of individuals in the younger age
                group.  When they grow up and reproduce the population will
                increase in size.  The narrowing of the pyramid towards the top
                also indicates a high death rate with increasing age.                (4)

       2.1.4    The population size at each of the age groups remains almost
                equal.  This indicates that the birth and death rates are almost
                the same.  Therefore, the population will remain more or less the
                same.                                                                (3)

       2.1.5    Stable population                                                    (1)

 2.2 2.2.1      (a)    Community
                       A community consists of populations of different species 
                       that live and interact in the same place  at the same
                       time.                                                         (2)
                (b)    Ecological niche
                       The ecological role of a species within the structure and
                       function of a community.                                      (2)

       2.2.2    Tribolium confusum 
                100 survived in bottle 6 when the temperature was 24 °C and the
                relative humidity was 30%.                                           (2)

       2.2.3    Density independent factors                                          (1)

       2.2.4    Since there are two different species involved it can be regarded
                as an interspecific competition.                                     (1)

 2.3 2.3.1      Exponential/Geometric/J-shape growth form                            (1)

       2.3.2    Accelerated/ exponential growth phase                                (1)

       2.3.3         Increases in food production and distribution
                     Improvement in public health (water and sanitation)
                     Advancement in medical technology (antibiotics and
                      vaccines)
                     Education and awareness leading to more health conscious
                      population                                                     (4)

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4                                    LIFE SCIENCES P1                       (EC/NOVEMBER 2015)

      2.3.4   The human population has almost reached the carrying capacity
              of the planet earth and therefore begin to experience
              environmental resistance such as:
                  Competition for food, water and living space leading to war
                   and crime rate escalate.
                  New diseases (e.g. HIV and Aids; Ebola, etc.)
                  Greater awareness and education                   (Any 2 x 1)      (2)

      2.3.5   (a)      Might lead to extinction of human species                  (1)
              (b)         Educate and organise awareness programmes to
                           highlight the consequences of unchecked population
                           growth
                          Tax incentives for smaller families
                          Introduction of family planning programmes(Any 1 x 1) (1)

 2.4 2.4.1    The plant was placed in a dark box/darkroom for at least 48
              hours.                                                                  (1)

      2.4.2         In the dark box, the potted plant was not exposed to sun
                     light 
                    and therefore, no photosynthesis takes place. 
                    In the absence of photosynthesis, no glucose will become
                     available as a source of energy. 
                    Therefore, the plant starts converting stored starch in to
                     glucose continuously until it is no longer present.              (4)

      2.4.3         Boil the leaf in water for 3–4 minutes. 
                    Boil the leaf in alcohol for about 2 minutes. 
                    Rinse the leaf in cold water. 
                    Spread the leaf on a tile and add few drops of diluted iodine
                     solution. 

      2.4.4

                                                                                       (3)
                                                                                      [40]

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(EC/NOVEMBER 2015)                    LIFE SCIENCES P1                                         5

 QUESTION 3

 3.1 3.1.1      The rate of photosynthesis increases  as the light intensity
                increases  therefore, the mean mass of lettuce plants increase. 
                                                                        (Any 2 x 1)      (2)

       3.1.2    Carbon dioxide 
                Temperature                                                             (2)

       3.1.3    They raised the level of CO2 to an optimum level of 4%  and
                temperature to 25 °C  as they increased the light intensity to
                8 arbitrary units.                                                      (3)

       3.1.4          The rate of photosynthesis will drop  drastically
                      because at higher temperature the protein molecules of
                       the enzymes become denatured 
                      and therefore, become functionless.                              (2)

 3.2 3.2.1      A      Stomach
                B      Pancreas 
                D      Gall bladder                                                     (3)

       3.2.2    Name: Liver 
                Letter: C                                                               (2)

       3.2.3          Neutralises the acidic chyme from the stomach 
                      Emulsifies fat 
                      Provides an alkaline pH for the functioning of enzymes
                       found in the pancreatic juice 
                      Acts an antiseptic and prevents decomposition of food            (4)

       3.2.4    Diabetes mellitus                                                       (1)

       3.2.5    When the blood sugar level rises:
                     (Beta cells) of the islets of Langerhans  in the
                       pancreas  secrete insulin  which regulates blood sugar
                       level.
                     It facilitates absorption of glucose from blood into the cells
                       and glucose level of blood is lowered. 
                     It increases the rate of glucose utilisation in cells. 
                     It stimulates the conversion of excess glucose into
                       glycogen in the liver and muscles.                    (max 4)
                When the blood sugar level drops:
                     (Alpha cells) of the islets of Langerhans in the pancreas
                       secrete glucagon  which regulates blood sugar level.
                     It stimulates the conversion of stored glycogen into
                       glucose. 
                     and increases the level of glucose in the blood. 
                High concentration of glucose inhibits the secretion of glucagon
                but stimulates the secretion of insulin. Similarly, low
                concentration of glucose inhibits the secretion of insulin but
                stimulates the secretion of glucagon. This is known as negative
                feedback mechanism.                                           (max 4)   (8)
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6                                   LIFE SCIENCES P1                         (EC/NOVEMBER 2015)

 3.3 3.3.1    A      Afferent arteriole 
              B      Efferent arteriole 
              C      Glomerulus                                                        (3)

      3.3.2   Ultra-filtration                                                         (1)

      3.3.3   Part labelled B is narrower than part labelled A.  Narrow
              diameter of part labelled B therefore, resist the flow of blood by
              slowing down the rate of blood flow.  This creates higher blood
              pressure  in part labelled C. High blood pressure thus generated
              leads to leakage of blood plasma  with smaller substances such
              as glucose, amino acids, water, urea and other nitrogenous waste
              products through the micro pores  on the capillary network at C.
              Blood cells, plasma proteins and other large solutes are left
              behind in blood.                                                         (6)

      3.3.4   Podocytes                                                                (1)

      3.3.5   Presence of slit pores  between the podocytes act as selective
              filters  allowing only fairly small particles to pass through into the
              capsular space.                                            (Any 2 x 1)    (2)
                                                                                        [40]

                                                              TOTAL SECTION B:          80

 SECTION C

 QUESTION 4

 Mechanism of breathing process
 Inhalation (Inspiration)
    Diaphragm contracts and becomes less convex 
    Abdominal muscles relax 
    External intercostals muscle contractinternal intercostal muscle relax 
    Ribs are raised upwards and outwards 
    Thoracic cavity enlarges in volume 
    and pressure in lungs decreases 
    Air flows through the air passages into lungs 
    Lungs expand                                                       (max 5)        (5)

 Exhalation (Expiration)
   Diaphragm relaxes and return to its convex dome-shaped position
   External intercostals muscles relax and internal intercostals contract
   Ribs and sternum move inwards and downwards
   Volume of thoracic cavity decreases
   Pressure inside thoracic cavity increases
   Pressure on lungs increases and
   air rich in carbon dioxide is forced out of lungs  through the air passages
    into atmosphere                                                       (max 5) (5)

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(EC/NOVEMBER 2015)                    LIFE SCIENCES P1                                      7

 Homeostatic control of carbon dioxide and oxygen
   When the carbon dioxide concentration in the blood increases 
   it is detected by the sensory cells (pH receptors) in the walls of the aorta
    near the heart and brain 
   and at the base of the carotid arteries  and
   afferent sensory impulses are transmitted 
   to the respiratory control centre in the medulla oblongata 
   and the cardio-vascular centre 
   from where efferent impulses are transmitted to the diaphragm 
   and external inter-costal muscles 
   which contract more actively to increase the rate and depth of breathing 
   as a result, more oxygen is inhaled  and
   more carbon dioxide is exhaled 
   the cardiac muscles contract faster  (heart beat rate increases)
   and the carbon dioxide containing blood is pumped faster to lungs 
   and oxygen containing blood faster to the tissue cells 
   the peripheral arterioles contract 
   so that the blood flows faster through the tissues 
   when the carbon dioxide concentration decreases the process slows
    down                                                                  (max 7)    (7)

 Assessing the presentation of the essay
                   Relevance          Logical sequence            Comprehensive
  Criterion
                       (R)                     (L)                       (C)
 Generally All information          Ideas are arranged in        All aspects
             provided is relevant   a logical/cause-effect       required by the
             to the topic.          sequence.                    essay have been
                                                                 sufficiently
                                                                 addressed.
 In this        Only information        The mechanism of         Mechanism of
 essay          relevant to the         breathing process is     breathing process
                Mechanism of            described in the         thoroughly
                breathing process       correct sequence and     discussed with
                and the homeostatic     the homeostatic          homeostatic
                control of carbon       control of respiratory   control of
                dioxide and oxygen.     gases are described      respiratory gases.
                                        in the correct logical
                                        sequence.
 Marks                   1                          1                    1

                                                                         Content:     17
                                                                        Synthesis:    3

                                                             TOTAL SECTION C:          20
                                                                GRAND TOTAL:          150

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