Question paper and memo

Limpopo Life Sciences Grade 12 Pre June 2023 QP and Memo

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Downloaded from Stanmorephysics.com _LIDAP Oro PROVINCIAL GOVERNMENT REPUGLIC OF SOUTH AFRICA CEPARTMENT OF EDUCATION MOGALAKWENA DISTRICT NATIONAL SENIOn® CCORTIFICATE TOTAL MARKS: 150 TIME: 2,5 HOURS This question paper consists of 17 pages including the cover page.

Rosweeaded frompdiapmerapahyss tesssG@KtyGR12 — Mogalakwena: May 2023 NSC INSTRUCTIONS AND INFORMATION Read the following instructions carefully before answering the questions. 1. iét ALL the questions. 2. WAH@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. Make ALL drawings in pencil and label them in blue or black ink. 7. Draw diagrams, tables or flow charts 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. Page 2 of 17

Bosuelaaded fromp:Skcupinesapahyss tesssG@KtycR 12 — Mogalakwena: May 2023 NSC SECTION A QUESTION1 1.1 | Various options are provided as possible answers to the following questions. Choose the correct answer write only the letter (A to D) next to the question number (1.1.1 to 1.1.10) in the WER BOOK, for example 1.1.10 D 1.1.1 | Durin, ich of the following phases does DNA replication take place? 2 ophase phase C. Interphase D. Metaphase 1.1.2 | The term that describes nuclear division is known as... 2 A. Gametogenesis B. Cytokinesis C. Karyokinesis D. Cytoclosis 1.1.3 Which part of the human brain controls balance and equilibrium? 2 A Cerebrum B_ Cerebellum C Medulla oblongata D_ Corpus callosum 1.1.4 | A learner conducted an investigation to determine the percentage 2 of people that are long-sighted. The factor that is LEAST likely to affect such an investigation is the ... light intensity of the room in which the test was conducted. height of the people. age of the people in the sample. distance between the tool used to test the sight and the person being tested. 9000>F Page 3 of 17

Rosweleaded frompSitcupnessaphys iesssG@Ont/Gr 12 — Mogalakwena: May 2023 NSC 1.1.5 The data below represents the results of an investigation used to 2 determine how the thickness of the lens changed as a pencil was moved away from the eye. =S> ISTANCE FROM EYE | THICKNESS OF LENS im (cm) (mm) 10 40 = 20 3,6 30 3,2 50 2,9 100 2,6 150 2,6 200 2,6 [Adapted from Complete Biology, 2000] The general conclusion that can be made from the data is that ... Aas the distance from the eye increased up to 100 cm, the thickness of the lens increased, after which it remained constant. Bas the distance from the eye decreased, the thickness of the lens remained constant. Cas the distance from the eye increased up to 100 cm, the thickness of the lens decreased, after which it remained constant. D_ the thickness of the lens increased with an increase in distance Questions 1.1.6 and 1.1.7 refer to the information below. 2 In pea plants yellow seed colour (Y) is dominant over green seed colour (y). Smooth seed texture (S) is dominant over wrinkled seed texture (s). A student crossed a plant which had yellow wrinkled seeds with a plant which had green smooth seeds. 1.1.6 | Which ONE of the following shows possible alleles present 2 in a gamete that is produced by the plant with yellow wrinkled seeds? A YYss B yySS z E D Ys my Page 4 of 17

Rosweneaded frompdtapmernapphys tessse@Krycr 12 Mogalakwena: May 2023 NSC 1.1.7 Which ONE of the following is a possible representation of the 2 genotypes of the P1 generation? A xX yyss B x yySs Cc x yySs D x YySs 1.1.8 | The gland that acts as both exocrine and endocrine is the... 2 A Pancreas B Thyroid gland C Adrenal gland D Mammary gland 1.1.9 | Which of the following CORRECTLY represents the events involved inthe | 2 secretion and action of ADH( antidiuretic hormone)? WATER LEVEL AMOUNT OF AMOUNT OF WATER IN BLOOD ADH REABSORBED BY RELATIVE TO PRODUCED KIDNEYS NORMAL RELATIVE TO NORMAL A Increase Increase Decrease B Increase Decrease Increase Cc Decrease Increase Increase D Decrease Decrease Decrease 1.1.10 | Eggs or ova are produced in the... 2 A Fallopian tubes B ovaries C uterus D_ vagina (10 X 2) | (20) 1.2 Give the correct biological term for each of the following descriptions. Write only the term next to the question number (1.2.1 to 1.2.8) in the ANSWER BOOK. 1.2.1. | Mutual exhange of genetic information between homologous chromosomes | 1 at the chiasma 1.2.2 | The bag that contains the testes 1 1.2.3 | The inner wall of the uterus which is richly supplied with blood 1 1.2.4 | Site where sperms are stored in the male pool 1 1.2.5 | A chromosome number twice that of a gamete of a given Species 1 1.2.6 | The type of cell division during which reduction of chro mes takes place 1 1.2.7__| Arapid involuntary response to a stimulus 1 1.2.8 | Membrane like structures that surround the brain and spinal chord 1 (8 X 1) | (8) Page 5 of 17

Bosuetaaded frompStapmnenaphyss kesssG@ntycr 12 NSC Mogalakwena: May 2023 1.3 Indicate whether each of the descriptions in COLUMN | applies 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 number (1.3.1 to 1.3.3) in the ANSWER BOOK. > j,COLUMN | COLUMN 11 1.31. Parto ‘emale reproductive A. Vagina syste! ere fertilisation takes B. Fallopian tube place 1.3.2 Ejaculated from the male during A. Semen copulation B. Amniotic fluid 1.3.3 Cells in the pancreas that secrete A. Thyroid insulin B. Beta cells 1.3.4 Prepares the body for stress A. insulin B. Adrenalin (4 x 2) (8) 1.4 The diagram below represents parts of the endocrine system in humans. Page 6 of 17

Bosuelaaded fromp:Skcupinesapahyss tesssG@KtycR 12 — Mogalakwena: May 2023 NSC 1.4.1 Identify gland: (a) A (b) Tay fal 1.4.2 | Give LETTER and the NAME of the gland that secretes a ho responsible for: (a) Starting puberty in males (b) Stimulating absorption of glucose by cells (c) Making the kidney tubules permeable to water (8) 1.5 The diagram below represents the structure of a neuron. 1.5.1 Name the type of neuron in the diagram above. 1.5.2 Identify part: (a) B (b) F (c) A from the cell body 1.5.3. | Give the LETTER and the NAME of the part that transmits impulses away (6) Page 7 of 17

Roweleaded frompSitaminerahys kessse@ntycr 12 Mogalakwena: May 2023 NSC TOTAL SECTION A | 50 SECTION B QUESTION 2 — 2.1 The diagram shows the process of protein synthesis. — Lx 2.1.1 Identify the following: (a) Molecule X 1 (b) Organelle Y 1 2.1.2 | Identify the nitrogenous base labelled: (a) 1 1 (o) 3 1 2.1.3 | Describe the role of DNA during transcription. 3 21.4 Describe the part of protein synthesis shown as process hich occurs at organelle Y. 4 2.1.5 | Describe the way in which protein synthesis would be feed by a gene 5 mutation (16) Page 8 of 17

Rosweeaded frompdiapmerapahyss tesssG@KtyGR12 — Mogalakwena: May 2023 NSC 2.2 The diagrams below represent a chromosome pair in a female human cell. The cells (A, B and C) show different events in a phase of meiosis, whichare not necessarily in the correct sequence. 2.2.1 How many pairs of chromosomes occur in a normal human cell? 2.2.2 | Give labels for: (a) Structure X (b) Area Y 2.2.3 Name the organ in the human female where meiosis occurs. 2.2.4 | Name the: (a) Process occurring in diagram B (b) Phase represented by the diagrams above (c) Type of cells that would result from meiosis of this cell 2.2.5 Arrange the letters A, B and C to show the correct sequence of the events. (8) Page 9 of 17

Bosuelaaded fromp:Skcupinesapahyss tesssG@KtycR 12 — Mogalakwena: May 2023 NSC 2.3 In rabbits, black fur is produced by the allele (B) and white fur by the allele (b). The table below shows the genotypes of some rabbits. RABBIT GENOTYPE 1 BB 2 Bb 3 bb 2.3.1 What is the phenotype: (a) Produced by the recessive allele 4 (b) Of rabbit 2 1 2.3.2 | Give the NUMBER only (1, 2 or 3) of the rabbit(s) that is/are: (a) Pure-bred 2 (b) Homozygous dominant 4 2.3.3 | Use a genetic cross to show the percentage chance of rabbits 1 and 3 having offspring with white fur. 6 (11) 2.4 A lack of immunity to infections (agammaglobulinemia) is a sex-linked recessive genetic disorder in humans. The dominant allele is represented by XA and the recessive allele is represented by X4. An individual with the disorder is described as affected and an individual without it is described as unaffected. The pedigree diagram below illustrates inheritance of this disorder. Page 10 of 17

Rosweeaded frompdiapmerapahyss tesssG@KtyGR12 — Mogalakwena: May 2023 NSC O ©@ On KEY Unaffected male C) Unaffected female | ae male r Affected female Name the genotypes of individuals: 2.4.1 (a) 1 (b) 2 2.4.2 | What percentage of the males in this pedigree diagram is affected? Show ALL working. 2 2.4.3. | Explain why any son of an affected female will always have this disorder. 3 (9) Page 11 of 17

Roweleaded frompdstagnenephys lesssaentyar 12 NSC Mogalakwena: May 2023 2.5 The diagram below shows one method of cloning sheep. Ox £ 1 Ane ic cell is lb RK aM) remo’ m the - Y don p and j allo multiply. { a - 2 The nuclei are taken from the donor cells and imported into “foster eggs” (nuclei-less ova from another sheep). They are allowed to develop. The eggs are implanted into the wombs of foster sheep where they 2.5.1 Explain why the lambs produced by this technique are identical to each other. 2 2.5.2 | Explain why the lambs are not genetically identical to the sheep which produced the “foster” eggs. 2 2.5.2 | Describe how cloning in animals or plants can be beneficial to humans 2 (6) [50] Page 12 of 17

Roweleaded frompSitaminerahys kessse@ntycr 12 NSC Mogalakwena: May 2023 | QUESTION 3 3.1 human. The diagram ae represents a portion of the central nervous system of a Portion of the central nervous system of a human Give the LETTER and the NAME of the part responsible for each of the following: 3.1.1 | Regulation of breathing 2 3.1.2 | Origin of voluntary actions 2 3.1.3 | Maintenance of balance and equilibrium 2 (6) Page 13 of 17

Bosuelaaded fromp:Skcupinesapahyss tesssG@KtycR 12 — Mogalakwena: May 2023 NSC 3.2 Study the diagram that represents the human eye and answer the questions that follow. The Human eye Write down the letter and name of each of the following. 3.2.1__| Liquid that helps to keep the shape of the cornea. 2 3.2.2 | Area where the clearest image is formed. 2 3.2.3. | Part of the eye responsible for the colour of the eye. 2 (6) Page 14 of 17

Roweleaded frompSitaminerahys kessse@ntycr 12 Mogalakwena: May 2023 NSC 3.3 | Study the diagram below showing a portion of the human ear and answer the questions that follow. Portion of the ear 3.3.1 | Provide labels for parts A, C and D, respectively. 3 3.3.2 | State ONE function for parts B and D, respectively. 2 3.3.3. | How are parts A and C together suited for the amplification of sound? 2 3.3.4 | Explain what would happen if part E is blocked with mucus. 2 (9) 3.4 | The diagram below shows a certain species of fish mating. Male fish Female fish Page 15 of 17

Bosuelaaded fromp:Skcupinesapahyss tesssG@KtycR 12 — Mogalakwena: May 2023 NSC 3.4.1 | Identify the type of fertilization displayed by the fish species. 3.4.2 State TWO visible ways in which the chances of fertilisation in these fisharesncreased. 2 3.4.3 | Give reasons why there is no need for then eggs of these fish to be cover a hard or leathery shell 2 (5) 3.5 | An investigation’ was conducted to determine the relationship between the ages of women, the number of pregnancies per month and the chances of miscarriages. The results of the investigation are shown in the table below. AGES OF | PREGNANCIES| MISCARRIAGES WOMEN PER MONTH (%) (%) 22 25 10 28 24 11 34 18 15 40 6 24 46 2 50 [Adapted from http://www.children.gov.on.ca] 3.5.1 | Draw a line graph to show the relationship between the ages of the women and the percentage of pregnancies per month. 6 3.5.2 | Describe the relationship that exists between the ages of women and the chances of them miscarrying. 2 (8) 3.6 | The diagram below represents a sperm. 3.6.1 | Label part A and B Cc 2 3.6.2 | Explain TWO ways in which the sperm is adapted to ensure effective 4 movement towards the Fallopian tubes. (6) Page 16 of 17

Bosuelaaded fromp:Skcupinesapahyss tesssG@KtycR 12 — Mogalakwena: May 2023 NSC 3.7 An investigation was done to determine the effect of different amounts of thyroxin on body weight in rats. Group A was injected daily with methimozole which inhibits the production of thyroxin in rats. e Group B was injected daily with DL-thyroxin which stimulates the production of more thyroxin than under normal conditions in rats. e Group C was given no treatment. All three groups were exposed to the conditions above for 2 months. The average body weights of all the groups were determined weekly. 37.1 In the investigation identify the: (a) Independent variable (b) Dependent variable 3.7.2 | State THREE factors that were kept constant during the investigation. 3 3.7.3 | Which group of rats (A, B or C) would be expected to gain the most weight? 1 3.7.4 | Explain your answer to QUESTION 3.7.3 3 3.7.5 | In which group of rats (A, B or C) would the levels of TSH in the blood be low? 1 (10) [50] GRAND TOTAL | 150 Page 17 of 17

Downloaded from Stanmorephysics.com PROVINCIAL GOVERNMENT REPUSLUC OF SOUTH AFRICA DEPARTMENT OF EDUCATION NATIONAL SENIOR CERTIFICATE GRADE 12 Total Marks: 150 Duration: 2,5 HOURS These marking guidelines consist of 9 pages including the “~@

Life Scie OW MOAT EM ERO Data mLaneialny Rliaaineger 12. Mogalakwena: May 2023 NSC PRINCIPLES RELATED TO MARKING LIFE SCIENCES 10. 11. 12. 13. Page 2 of 9 If moreinformation than marks allocated is given Stop marking when maximum marks is reached and put a wavy line and 'max' in thestight hand margin. If, for'example, three reasons are required and five are given Mark the first three irrespective of whether all or some are correct/incorrect. If whole process is given when only part of it is required Read all and credit relevant part. If comparisons are asked for but descriptions are given Accept if differences/similarities are clear. If tabulation is required but paragraphs are given Candidates will lose marks for not tabulating. If diagrams are given with annotations when descriptions are required Candidates will lose marks. If flow charts are given instead of descriptions Candidates will lose marks. If sequence is muddled and links do not make sense Where sequence and links are correct, credit. Where sequence and links is incorrect, do not credit. If sequence and links becomes correct again, resume credit. Non-recognized abbreviations Accept if first defined in answer. If not defined, do not credit the unrecognised abbreviation but credit the rest of answer if correct. Wrong numbering If answer fits into the correct sequence of questions but the wrong number is given, it is acceptable. Indicate that the candidate's numbering is wrong. If language used changes the intended meaning Do not accept. Spelling errors If recognizable accept provided it does not mean something else in Life Sciences or if it is out of context. If common names are given in terminology Accept, provided it was accepted at the National memo discussion meeting.

Rossered dechifenteraDit@ HBGRA PAY KGEg KLUEInes /GR 12 Mogalakwena: May 2023 NSC 14. 15. 16. 17. Page 3 of 9 If only the letter is asked for but only name is given (and vice versa) No credit. If units are not given in measurements Memorandum will allocate marks for units separately, except where it isalready given-in the question. Be sensitive to the sense of an answer, which may be stated in a different way. Caption Credit will be given for captions to all illustrations (diagrams, graphs, tables, etc.) except where it is already given in the question.

Rosuead dachifentera Rita tBacephymiGig G£NKlines /GR 12 Mogalakwena: May 2023 NSC SECTION B QUESTION 2 21 12.1.4 | (a) DNAY 1 (b) Ribosome v 1 2.1.2 | (a) 1 (b) 1 2.1.3 = codes for a particular protein v but cannot leave nucleus - strand of DNA is used as a template “ — toformmRNA ¥ 3 21.4 — According to the codons on mRNA ~ — {tRNA molecules with matching anticodons ~ — bring the required amino acids to the ribosome ~ — This is called translation ~ — The amino acids become attached by peptide bonds “ — to form the required protein ~ (any 4) 4 2.1.5 | - Agene mutation affects arrangementitype of the nitrogen bases/nucleotidesY” - This changes the code on the DNA ¥ - which changes the code on the RNAY - Adifferent amino acidY may be coded for - which causes a change in the amino acid sequence inv the protein - leading to the formation of a different/alternate/no protein’ ANY 5 5 (16) 2.2 | 2.2.1 23v 4 2.2.2 | (a) Centromerew 1 (b) Chiasma-/chiasmata 1 2.2.3 | OvaryY 1 2.2.4 | (a) Crossing over” 1 (b) Prophase |~ 1 (c) ovav’/gametes/sex cells 1 2.2.5 | C>B> Av (correct sequence) 1 (8) 2.3 | 2.3.1 (a) White-fur (b) Black~ fur me 939 (a) 1¥ and 3v 2 (Mark first TWO only) jaa (b) 1” (Mark first ONE only) Page 5 of 9

Rosuead dachifenttaditah nave phy mass £Klnes /GR 12 Mogalakwena: May 2023 NSC 2.3.3 | Py Phenotype Black X Whiter Genotype BB x bb~ Meiosis G/gametes 6.B x b, bv. revs ~<a F, Genotype Bb: Bb. Bb: Bb v Phenotype All black *0v %white P,; and Fi~ Meiosis and fertilisation~ ("compulsory mark + 5) OR P, Phenotype Black x Whiter Genotype BB xX _ bby Meiosis Gametes 6 i=} Fertilisation b Bb Bb b Bb Bb 1 mark for correct gametes 1 mark for correct genotypes Fy Phenotype All black *0-% white P,; and Fix Meiosis and fertilisation~ (" compulsory mark + 5) 6 (11) 24 |2.4.1 (a) X4Y¥v¥ 2 (b) X8xXav v 2 2.4.2 3 _X100 Y =42,86/42,9/43% 2 7 243 - An affected female carries two/only recessive allelesv X°X" - Sons/matles inherit one X chromosome-’ from their mothers - Sons/males need only one recessive allele to be affected~ - And therefore must inherit X* from their mother~ 3 ear Any 3 (9) 2.5 | 2.5.1 | Contain the same chromosomes v because the embryonic as divided by mitosis ~// they are all produced from nuclei of the donor ¥ which multiply / divide by mitosisv therefore have the same DNA v 2 Page 6 of 9

Rosuead dachifenttaditah nave phy mass £Klnes /GR 12 Mogalakwena: May 2023 NSC 2.5.2 | The nucleus and genetic material v originated from another sheep v / the nuclei of the foster sheep were not used ~ and therefore did not contain the same genetic material / the ova used did not contain nucleiv / it is the nucleus which contains-the genetic material v 2 2.5.3. | Anim plants with superior / favourable characteristics v can be produced toen food production ~ / biotechnology. 2 ae (6) [50] QUESTION 3 3.1 ]3.1.1 | Cv —Medulla Oblongatav 2 3.1.2 | Av- Cerebrumy” 2 3.1.3 | Dv - Cerebellum” 2 (6) 3.2 /3.2.1 | Av - aqueous humour / fluid ” . 3.2.2 | Fv - yellow spot / fovea centralis ¥ 2 3.2.3 | BY - irisv 2 2 3.3 | 3.3.1 A— Tympanic membranev/ Tympanum/Eardrum C -— Oval window~ /fenestra ovalis D — Round window~ /fenestra rotunda I 3.3.2 | B— transmit vibrations~ from the tympanic membrane to inner ear/ amplifies sound waves D — prevents pressure build up of waves~ /absorbs pressure wave set up by tympanic canal of the inner ear/eases sound waves out of inner ear/ prevents sound waves from moving backwards in perilymph 2 3.3.3 | Tympanic membrane/A has a larger surface areav than the oval windowy/C . 3.3.4 | Ossicles will not vibrate freely v to transmit vibrations to the inner ear~’/ causing partial deafness OR Cannot equalise pressure von either side of tympanic membrane leading to painy’/ middle ear infection/ a burst eardrum rations not being transmitted/ partial deafness (1x 2) [aYaYay r= (9) Page 7 of 9

Rosuead dachifentera Rita tBacephymiGig G£NKlines /GR 12 Mogalakwena: May 2023 NSC 3.4 3.4.1 External ~ fertilization 3.4.2 - A large amount of sperm is released “” - A large amount of eggs is released ~ - Th le and female swim close to each other ~/the sperm is rel d close to the eggs (Any 2) (Mark first TWO only) 3.4.3 - No danger of drying out “ 3.5 3.5.1 Graph to show the relationship between ages of women and the percentage of pregnancies per month w o 24 + -===@__ 20 ~~_ 18 Pregnancies per month (%) a ’ 22 28 34 40 Ages of women (years) Mark allocation of the graph Criteria Mark Allocation Correct type of graph drawn for the A 1 pregnancies per month only Title of graph including the two variables (Age of women and 1 pregnancies per month) Correct label and unit for X-axis 1 and Y-axis Correct scale for X-axis and Y-axis 1 Drawing of the graph 0: No points plotted correctly 1: 1 to 4 points plotte’ ectly 2: _All5 points plott ectly Page 8 of 9

Rosuead dachifentera Rita tBacephymiGig G£NKlines /GR 12 Mogalakwena: May 2023 NSC 3.5.2 The older the women, the higher the chances of having miscarriagesv ~ OR The y! jer the women, the lower the chances of having mis esv ~ eoay (8) 3.6 3.6.1 A— Middle piece v B—acrosome V 3.6.2 Mitochondria: “supplies energy Y for locomotion of the sperm cell Tail : “can propel forward ~ for swimming/locomotion of the sperm cellTorpedo shape : “reducing friction “ (MARK FIRST TWO ONLY) 3.7 3.7.1 (a) Amount of thyroxin’” (b) Body weight” = 3.7.2 - Same number of rats in each group” - Allrats were of the same species” - All groups were investigated for the same period of timev - Allrats were the same gender” All groups were weighed after the same intervalv (Any 3) (Mark first THREE only) 3.7.3 sion AY 3.7.4 Low thyroxin levels” - will lead to low metabolic ratew - Therefore the energy from the diet is used very slowly” - and more organic compounds are stored~ (Any 3) 3.7.5 Group BY (10) [50] GRAND TOTAL 150 Page 9 of 9