Life Sciences Grade 12 KZN March Test 2024 Paper & Memo

Downloaded from Stanmorephysics.com KWAZULU-NATAL PROVINCE EDUCATION REPUBLIC OF SOUTH AFRICA NATIONAL SENIOR CERTIFICATE MARKS: 50 TIME: 1 hour This question paper consists of 9 pages.

Lite Rewealoaded from Stanmorepiaysics.com March Common Test 2024 2 INSTRUCTIONS AND INFORMATION Read the following instructions carefully before answering the questions. 1. 2. 10. 11. Answer ALL the questions. Write ALL the answers in the ANSWER BOOK. Start the answers to each question at the top of a NEW page. Number the answers correctly according to the numbering system used in this question paper. Present your answers according to the instructions of each question. Do ALL drawings in pencil and label them in blue or black ink. Draw diagrams, tables or flow charts only when asked to do so. The diagrams in this question paper are NOT necessarily drawn to scale. Do NOT use graph paper. You may use a non-programmable calculator, protractor and a compass. Write neatly and legibly. Copyright reserved Please Turn Over

Lite Reweoaded from Stanmorepiysics.com March Common Test 2024 3 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 to D) next to the question number (1.1.1 to 1.1.4) in the ANSWER BOOK, for example 1.1.5 D. 1.1.1. Which ONE of the following chromosomes would be found in a normal human cell during metaphase I? Single thread chromosomes showing variation Double thread chromosomes showing no variation Double thread chromosomes showing variation Single thread chromosomes showing no variation VONDD 1.1.2 The following is a list of some functions that occur during gestation: <ygen from the mother to the foetus progesterone retory wastes from the mother to the Foetus ients from the mother to the foetus llowing is a correct combination of the functions of (ii) only (i), (ii) and (iv) only (i), (iii) and (iv) only (i), (ii), (iii) and (iv) G0QNWD> 1.1.3. The Red kangaroo (Osphranter rufus) reproduces sexually and has a gestation period of 33 days. It then gives birth to an offspring. Which ONE of the following is correct with regard to the Red kangaroo species? A ___ Internal fertilisation and viviparous B Internal fertilisation and ovoviviparous C_ External fertilisation and oviparous D External fertilisation and viviparous Copyright reserved Please Turn Over

Lite Beweloaded from Stanmorepiaysics.com 4 March Common Test 2024 1.1.4 The diagrams below show an animal cell in the various stages of meiosis in the incorrect order. Which ONE of the following represents CORRECT diagram and phase? DIAGRAM PHASE A Ww Anaphase | B Xx Metaphase II c Y Prophase II D Zz Telophase | (4 x 2) (8) 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 1.2.3) in the ANSWER BOOK. 1.2.1 The type of bond found between nitrogenous bases of a DNA molecule 1.2.2 | The organelle in the cell that forms spindle fibres during meiosis 1.2.3 Anextra embryonic membrane of the amniotic egg that is responsible for gaseous exchange and waste storage Copyright reserved (3x1) = (3) Please Turn Over

Lite Beweloaded from Stanmorepiaysics.com March Common Test 2024 5 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 1.3.2) in the ANSWER BOOK. COLUMN | COLUMN II 1.3.1 | A reproductive strategy where the} A: Altricial young is independent of their |B: Precocial parents 1.3.2 | The importance of DNA replication | A: Doubles genetic material B:_ Formation of mRNA (2 x 2) (4) 1.4 A short piece of the complimentary mRNA and DNA molecule that are 18 nitrogenous bases long each were analysed to determine the number of nitrogenous bases. The results are shown in the table below. BASES DNA STRAND | mRNA STRAND Adenine : : | _Cytosine. - : = it 2 . oe ne 4 1.4.1 Name the: (a) Monomers of the DNA strand (1) (b) Type of sugar in the mRNA strand (1) 1.4.2 How many: (a) Adenine bases are present in the DNA strand (1) (b) Cytosine bases are present in the mRNA strand (1) 1.4.3. Give the percentage of uracil in the DNA strand from the table above. (1) (5) TOTAL SECTION A: 20 Copyright reserved Please Turn Over

Lite Reweloaded from Stanmorephysics.com SECTION B QUESTION 2 March Common Test 2024 2.1 The diagram below shows part of the process of protein synthesis. once n--- Show base pairing: 2.1.1 2.1.2 2.1.3 2.1.4 2.1.5 Identify molecule: (a) R (b) P Write down the sequence of the DNA base triplet complimentary to the codon Q. State ONE significance of the nitrogenous base sequence on the MRNA molecule. Explain the effect if there was a change in the sequence of the DNA base triplet in QUESTION 2.1.2. Name the organelle where proteins are synthesised in a plant cell. Copyright reserved Please Turn Over (1) (1) (1) (1) (3) (1) (8)

Lite Rewealoaded from Stanmorepiaysics.com March Common Test 2024 7 2.2 Read the information below. Down syndrome occurs in people of all races and economic levels. It occurs as a result of mutation during meiosis. Individuals with Down syndrome suffer from learning delays, distinct physical features and poor muscle development. The maternal age has an impact on the risk of Down syndrome. The table below shows the relationship between the maternal age and risk of Down syndrome. 2.2.1 2.2.2 2.2.3 2.2.4 MATERNAL AGE | DOWN SYNDROME RISK 25 1 in 1250 31 1 in 1000 35 1 in 400 40 1 in 100 State TWO symptoms of Down syndrome from the information above. Identify the maternal age (25, 31, 35 or 40), which is expected to have the greatest risk of having a child with Down syndrome? Calculate, how many times did the risk of Down syndrome in females increase between the age 35 and 40? Show ALL working. Describe the events of the phase of meiosis II that results in an abnormal gamete that leads to Down syndrome. Copyright reserved Please Turn Over (2) (1) (2) (2) (7) [15]

Lite Reweoaded from Stanmorepiysics.com March Common Test 2024 8 QUESTION 3 3.1 The diagram below shows the gland X and its influence within the ovary. 3.1.1 3:12 3.1.3 3.1.4 Gland X Identify: (a) Gland X (b) PartA Apart from process B, state ONE function of Luteinizing hormone. Explain the effect that the corpus luteum defect (unable to produce enough progesterone) will have on the developing embryo. Central hypogonadism is a condition that happens when a pituitary gland does not release enough LH and FSH. Explain the effect that the central hypogonadism may have on the uterus. Copyright reserved Please Turn Over (1) (1) (1) (3) (3) (9)

Lite Reweloaded from Stanmorephysics.com 3.2 Anastrozole medicine is used to treat subfertility in men with low testosterone level.in the blood. Subfertility refers to the low number of sperm cells present in the semen. An investigation was done to determine the effect of anastrozole medicine on the level of testosterone in men with subfertility. Methods: Thirty men between 25 and 30 years affected by subfertility participated in the investigation. Thirty men were divided into two equal groups (A and B). Group A was not given any medicine. Group B was given 1 mg anastrozole medicine daily for five months. Testosterone level of each group was measured at the beginning and after the investigation. The average testosterone level was calculated in each group. The results are shown in the table below. AVERAGE TESTOSTERONE LEVEL GROUP ng/dL) At the beginning After five months A 271.3 271.1 B 270.6 412 3.2.1 Identify the independent variable in the investigation. 3.2.2 | State ONE way in which the reliability of the results was ensured for this investigation. 3.2.3. Group A was the control. Explain the importance of group A in this investigation. 3.2.4 State a conclusion for this investigation. TOTAL SECTION B: GRAND TOTAL: Copyright reserved March Common Test 2024 (1) (1) (2) (2) (6) [15] 30 50

Downloaded from Stanmornapiaysics.com KWAZULU-NATAL PROVINCE EDUCATION REPUBLIC OF SOUTH AFRICA NATIONAL SENIOR CERTIFICATE MARKS: 50 This memorandum consists of 6 pages PRINCIPLES RELATED TO MARKING LIFE SCIENCES MARCH 2024

Lite Reweoaded From Staraereypdayrgnmeman March 2024 2 Be 10. 11. 42) 13. 14. 15. 16. If more information than marks allocated is given Stop marking when maximum marks are reached and put a wavy line and ‘max’ in the right-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 and 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-recognised abbreviations Accept if first defined in answer. If not defined, do not credit the unrecognized 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. 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 given in terminology Accept provided it was accepted at the National memo discussion meeting. If only letter is asked for and only name is given (and vice versa) No credit If units are not given in measurements Candidates will lose marks. Memorandum will allocate marks for units separately Be sensitive to the sense of an answer, which may be stated in a different way. Copyright reserved Please turn over

Lite Reweoaded From Staraereydayrgnmeman March 2024 3 17. Caption Altillustrations (diagrams, graphs, tables, etc.) must have a caption 18. Code-switching of official languages (terms and concepts) A single word or two that appears in any official language other than the learners’ 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. Copyright reserved Please turn over

Desvatoaded from Stanmonephysiosoeonrs SECTION.A QUESTION 1 1.1 111 Cv¥v 1.1.2 BvYv 1.1.3 AVvv 1.1.4 Dvv 1.2 1.2.1 Hydrogen’ bond 1.2.2 Centrosomev/centriole 1.2.3 AllantoisY 1.3 1.3.1 BonlyYv 1.3.2 Aonlyvv 1.4 141 (a) 14.2 (a) 1.4.3 Ov Copyright reserved NucleotidesY Ribose” sugar 3v 5vY March 2024 (4 x 2) (3 x 1) (2 x 2) TOTAL SECTION A: Please turn over (8) (3) (4) (1) (1) (1) (1) (1) (5) 20

Deosvaleaded from Stanmonrephysiosveonrs March 2024 SECTION. B QUESTION 2 2.1 2.1.1 (a) Amino acidY (b) mRNAY 2.1.2 TCAY 2.1.3 Determines the sequence of amino acids that form a protein’ (Mark the first ONE only) 2.1.4 There will be a change in the sequence of bases on the MRNAY which may lead to the different tRNAY bringing different amino acid resulting to the formation of different protein’ OR - There will be a change in the sequence of bases on the mMRNAY - which may lead to the different t(RNAY - bringing same amino acidY - resulting to the formation of same proteinY Any 2.1.5 RibosomeY 2.2 2.2.1 - Learning delaysY - Distinct physical featuresY - Poor muscle developmentY Any (Mark the first TWO only) at position 21V - fail to separate /non-disjunction of chromatids - leading to an extra chromosome 21v in the gametes Any Copyright reserved Please turn over (1) (1) (1) (1) (3) (1) (8) (2) (1) (2) (2) (7) [15]

Dosvaeloaded from Stanmonrephysiosveonrs March 2024 QUESTION 3 3.1 641 3.1.2 3:1:3 3.1.4 3.2 3.2.1 3.2.2 3.2.3 3.2.4 (a) PituitaryY gland (b) Corpus luteumv It converts the ruptured follicle into corpus luteumv (Mark the first ONE only) - Endometrium will not be further thickenedyY - no implantation may occurY - Miscarriage will occurY /no pregnancy OR - Endometrium will not be maintainedv - and no maintenance of pregnancyY - Miscarriage may occurY - It decreases the FSH level in the bloodv - and no follicle developmentY - leading decreased oestrogenv in the blood - Therefore, no thickening of the endometriumY Any Anastrozole medicinev - Thirty men participatedv in the investigation - Average testosterone level was calculatedY Any (Mark the first ONE only) - To show that testosterone level increases in group BY - is due to the anastrozole medicinev Anastrozole medicine increases the average testosterone levelv v in sub fertile men TOTAL SECTION B: GRAND TOTAL: Copyright reserved (1) (1) (1) (3) (3) (9) (1) (1) (2) (2) (6) [15] 30 50