Life Sciences Grade 12 KZN March 2023 Paper & Memo

WR) KWAZULU-NATAL PROVINCE EDUCATION REPUBLIC OF SOUTH AFRICA MARKS: 50 TIME: 1 hour This question paper consists of 10 pages. Reserved

Lite sRQWoloaded from Stanmorephysics.com March Common Test 2023 NSC-Grade12 . INSTRUCTIONS AND INFORMATION Read the following instructions carefully before answering the questions. 1. Answer Aliijthe questions. 2. Write AUithe 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, 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. 40. You may use a non-programmable calculator, protractor and a compass. 11. Write neatly and legibly. Copyright reserved Please Turn Over

lite seeaynloaded from Stanmorephysics.com March Common Test 2023 ’ NSC-Grade12 SECTION A QUESTION 1 1.1. Various options are provided as possible answers to the following questions. Choose the‘aiswer and write only the letter (A to D) next to the question number (1.1.1 fo“ 1.1.3) in the ANSWER BOOK, © for example 1.1.4 D. 1.1.1 Which ONE of the following in a male reproductive system stores sperms temporarily? A _ Vas deferens B Seminal vesicle C Urethra D_ Epididymis 1.1.2 The diagram below shows the nucleotide of a tRNA molecule. | > The correct label for part 4 is ... A deoxyribose sugar. B_ ribose sugar. C phosphate. D adenine. 1.1.3. Which ONE of the following is correct with regard to the biological importance of meiosis? A Reduces chromosome number by half and ensures genetic variation in gametes Produces diploid gametes and ensures genetic variation Produces haploid gametes that are genetically identical Produces haploid gametes and is responsible for théldevelopment of the zygote into foetus. 00owW (3x2) (6) Copyright reserved Please Turn Over

Downloaded from Stanmorepfysics.com NSC-Grade12 Life Sciences March Common Test 2023 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 THeltype of bond found between amino acids 1.2.2 THe@lorganelle in the cytoplasm on which protein synthesis occurs 4.2.3. Ahormone that stimulates the maturation of sperms and puberty in males (3x1) (3) 4.3 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 Il. 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. COLUMN | COLUMN II 1.3.1. ] Production of female gametes A: Spermatogenesis B: Oogenesis 1.3.2 | Location of DNA ina human cell | A: Nucleus B: Mitochondrion 1.3.3 | The pair of chromosomes A: Gonosomes responsible for sex determination | B:_Autosomes Copyright reserved (3x2) (6) Please Turn Over

Life SPoanloaded from Stanmorephysics.com . NSC-Grade12 March Common Test 2023 1.4 The diagrams below show reproductive strategies in different organisms. Fish & Male Female vA me A Bird with hatchling 1.4.1 Which of the diagrams (A, B or C) belong/s to: (a) Viviparous (b) Altricial development (c) Precocial development 1.4.2 State the type of fertilisation shown by fish in diagram A. Copyright reserved TOTAL SECTION A: Please Turn Over

Lite se QWNloaded from Stanmorephysics.com March Common Test 2023 NSC-Grade12 SECTION B QUESTION 2 2.1 The table Arbelow shows part of the DNA sequence. Table A DNA BASE TRIPLET NUMBER | _ 1 2 3 4 5 6 DNA SEQUENCE ACG | TGC | ACA | ATG | TGC| CAT 2.1.1 Write down the tRNA base triplet that codes for DNA base triplet number 6. 2.1.2 Explain the role of a DNA sequence during protein synthesis. 2.1.3 The table B below shows the mRNA base triplets that code for different amino acids. Table B mRNA BASE AMINO ACID TRIPLETS AAA Lysine GUG Valine CCU Proline UAC Tyrosine ACG Threonine UGC Cysteine With reference to table A of DNA sequence and table B of mRNA base triplets that code for different amino acids above: Write down the: (a) Amino acid coded for by DNA base triplet number 5 (b) DNA base triplet that codes for tyrosine 2.2 Describe the process of DNA replication. Copyright reserved Please Turn Over (1) (2) (1) (1) (5) (6)

Life Sa9eRnloaded from Stanmorephysics. com March Common Test 2023 : NSC-Grade12 2.3 The diagrams below in no particular order show part of the phases in meiosis. Ww x Y z DOU \ J i Diagram i Diagram I a 2.3.1 Identify structure: {a) A (1) (o) B (1) 2.3.2 Explain why ceil Y in diagram I does not have any chromosome. (2) a Copyright reserved Please Turn Over

Lite sQeyynloaded from Stanmorephysics.com March Common Test 2023 NSC-Grade12 QUESTION 3 3.1. The diagrams:below show part of mitosis and meiosis in human cells. Diagram | Diagram li ‘YQ @& B Numbers inside the cells represent the chromosome number. 3.1.1. Name the type of cell division shown in diagram I. (1) 3.1.2 From the diagrams f and Il, state ONE way in which mitosis is similar to meiosis Il. (1) 3.1.3 Write down the LETTER only of the cell that represents the gamete. (1) (3) Copyright reserved Please Turn Over

Lie S#9q@xanloaded from Stanmorephysics.com March Common Test 2023 NSC-Gradei2 3.2 The diagram below shows the sequence of events that takes place in a part of the female reproductive system. 3.2.1 Identify process A. (1) 3.2.2 State ONE reason why the foetus would die if the vein in structure C was biocked. (1) 3.2.3 Explain the role of hormones produced by structure B during the menstrual cycle. (4) (8) Copyright reserved Please Turn Over

Lite sf@Qunloaded from Stanmorephysics.com March Common Test 2023 NSC-Grade12 3.3. An investigation was conducted to determine the effect of different amounts of progesterone on FSH level in the blood. The procedure was as follows: 30 healthy, non-pregnant females of the same age were used. TheyWére divided into three groups of 10 each (Group A, B and C). Their average FSH level was determined and recorded. Group A was given daily pills with progesterone which inhibits the production of FSH. Group B was injected monthly with trilostane (chemical substance) which decreases the production of progesterone more than under normal conditions. Group C was given no treatment. Ali three groups were exposed to the conditions above for 6 months. The average FSH level of all the groups were determined monthly. 3.3.1 Identify the dependent variable in the investigation. (1) 3.3.2 State ONE reason why the investigation was done for 6 months instead of 2 months. (1) 3.3.3. Give ONE factor that was kept constant during the investigation. (1) 3.3.4 Which group of females (A, B or C) would be expected to have the highest level of FSH for the duration of the investigation? (1) 3.3.5 Explain your answer in QUESTION 3.3.4. (2) (6) [15] TOTAL SECTION B: [30] GRAND TOTAL: [50] Copyright reserved

Downloaded from Stanmqeppiwegics.com NATIONAL SENIOR CERTIFICATE GRADE 12 | MARKS: 60 This memorandum consists of 6 pages

Lite Brenetoaded from Stage reydayremseinesn March 2023 2 PRINCIPLES RELATED TO MARKING LIFE SCIENCES SEPTEMBER 2022 1. 10. 11. 12. 13. 14. 15. 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 discussioh 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 Copyright reserved Please turn over

Lite Benetoaded from Stage reydayremseinesn March 2023 3 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 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

Desvalaaded from Stanmoxephysiosvcenes SECTION A QUESTION 1 11.00 444 1.1.2 1.1.3 1.2 1.2.4 1.2.2 1.2.3 13° 13.4 1.3.2 1.3.3 14° 141 1.4.2 SECTION B QUESTION 2 21 24.1 2.1.2 2.1.3 ony BY Wana Peptidew bond RibosomevY TestosteroneY B only¥v Both A and BVY A onlyYv (a) BY (b) Cv (c) -Av - BY Externalv fertilisation CAUY - Determines the sequence of mRNA bases¥ March 2023 (3 x 2) (3 x 1) (3 x 2) TOTAL SECTION A: - to provide coded messagew/sequence of amino acids - for the formation of a particular protein’ (a) ThreonineY (b) ATGY Copyright reserved Any Please turn over (6) (3) (6) (1) (1) (1) (1) (1) (5) 20 (1) (2) (1) (1) (5)

Dewaleaded from Stanmoxephysiosvcones March 2023 2.2 - The double helix DNA unwinds” - The double-stranded DNA unzips”/weak hydrogen bonds break to form two separate strands - Both strands are used as templatesY - to formicomplimentary DNA strands¥ - using frée’ DNA nucleotides from the nucleoplasm”/Adenine pairing with thymineand cytosine pairing with guanine - Two identical DNA molecules are formedY - Eachmolecule consists of one new strand and one original strandY Any 2.3. 2.3.1 (a) Homologous chromosome’ pair (b) Spindle fibrew 2.3.2 - Due to non-disjunction during Anaphase II“ - Two chromatids moved to one pole in one cellv - and none moved to the other pole of the cellv Any QUESTION 3 3.1 3.1.1 Mitosis 3.1.2 No halving of chromosome number” (Mark the first ONE only) 3.1.3 BY 3.2 3.2.1 Fertilisation’ 3.2.2 Foetus will not receive nutrients and oxygenv from the placenta (Mark the first ONE only) 3.2.3 - Oestrogeny - thickens the endometrium” - in preparation for the implantation’ - ProgesteroneY - Further thickens endometrium” - to maintain pregnancyY Any (2 x 2) Copyright reserved Please turn over (6) (1) (1) (2) (4) [15] (1) (1) a (1) (1) (4) (6)

Desvalaaded from Stanmoxephysiosucones 3.3 3.3.1 3.3.2 3.3.3 3.3.4 3.3.5 FSH levelv To increase reliability” (Mark the first ONE only) “Only non-pregnant females were usedv =Females of the same agev -Groups of equal numberv’/10 - Duration of the treatments was 6 months (Mark the first ONE only) BY March 2023 Any - Trilostane decreases the production of progesteronev - and no inhibition of pituitary glandv - from producing FSHY Copyright reserved Any TOTAL SECTION B: GRAND TOTAL: (1) (1) (1) (1) (2) (6) [15] 30 50