This document is the cover page for a Life Sciences exam consisting of 16 pages. It provides instructions for candidates taking the exam, including answering all questions, writing answers in the answer book, numbering answers correctly, presenting answers as instructed, using pencil for drawings, only drawing diagrams when asked, and writing neatly. It also allows for the use of a calculator, protractor, and compass where necessary.
El documento describe diferentes mecanismos de transporte celular como la difusión simple, difusión facilitada y el transporte activo mediado por bombas iónicas. También describe procesos de endocitosis como la pinocitosis, fagocitosis y endocitosis mediada por receptor, así como la exocitosis. Explica las fases del ciclo celular y la división celular en mitosis y meiosis. Finalmente, detalla los tipos de uniones intercelulares como las uniones estrechas, adherentes y desmosomas.
Genes are segments of DNA that influence specific characteristics and occupy positions on chromosomes. The Human Genome Project sequenced the entire base sequence of human genes, finding around 20,500 genes. New alleles are formed through mutations that change one or a few DNA bases, such as the single base substitution causing sickle cell anemia by replacing glutamic acid with valine in the hemoglobin protein.
El documento describe las fases del ciclo celular eucariótico, incluyendo la interfase y la división celular. La interfase consta de las fases G1, S y G2, donde la célula crece y duplica su ADN. Luego, la mitosis y citocinesis dividen el material genético y el citoplasma entre las dos células hijas nuevamente. El ciclo celular asegura que toda célula se origine de otra preexistente a través de la replicación y división controlada.
El azufre se encuentra en la naturaleza y pasa por un ciclo biogeoquímico. Los compuestos de azufre se absorben del suelo por las plantas y son incorporados en las cadenas alimenticias, mientras que la descomposición de materia orgánica libera azufre de nuevo al suelo.
This document discusses cell division and mitosis. It defines cell division as the process where a parent cell divides into two or more genetically identical daughter cells. Mitosis is described as the process where a cell duplicates its contents and splits to form two daughter cells, ensuring the daughter cells have the same genetic material as the original cell. The stages of mitosis - interphase, prophase, metaphase, anaphase, telophase and cytokinesis - are outlined in detail. The importance of mitosis in growth, repair and asexual reproduction is also noted.
The document discusses cell reproduction through mitosis and meiosis. It provides details on:
1) The stages of the cell cycle including interphase and the phases of mitosis (prophase, metaphase, anaphase, telophase).
2) The key differences between mitosis, which produces identical daughter cells, and meiosis, which produces gametes with half the number of chromosomes.
3) The stages and outcomes of meiosis I and meiosis II, which reduce the chromosome number and lead to genetic diversity through independent assortment and crossing over.
The document summarizes photosynthesis, including both the light-dependent and light-independent reactions. It explains that the light-dependent reactions take place in the thylakoid membranes and produce ATP and NADPH through the absorption of light by photosystems. The light-independent reactions take place in the chloroplast stroma and use ATP and NADPH to produce glucose through the Calvin cycle. The structure of the chloroplast is adapted to efficiently carry out these two stages of photosynthesis through the stacking of thylakoids and positioning of the stroma.
El documento describe la célula como la unidad estructural y funcional de los seres vivos. Explica que existen dos tipos de células, las procariotas y las eucariotas, y describe las características y componentes clave de cada una. Las células eucariotas contienen un núcleo y varias organelas especializadas, mientras que las procariotas carecen de núcleo y sus funciones están menos compartimentalizadas.
El documento describe diferentes mecanismos de transporte celular como la difusión simple, difusión facilitada y el transporte activo mediado por bombas iónicas. También describe procesos de endocitosis como la pinocitosis, fagocitosis y endocitosis mediada por receptor, así como la exocitosis. Explica las fases del ciclo celular y la división celular en mitosis y meiosis. Finalmente, detalla los tipos de uniones intercelulares como las uniones estrechas, adherentes y desmosomas.
Genes are segments of DNA that influence specific characteristics and occupy positions on chromosomes. The Human Genome Project sequenced the entire base sequence of human genes, finding around 20,500 genes. New alleles are formed through mutations that change one or a few DNA bases, such as the single base substitution causing sickle cell anemia by replacing glutamic acid with valine in the hemoglobin protein.
El documento describe las fases del ciclo celular eucariótico, incluyendo la interfase y la división celular. La interfase consta de las fases G1, S y G2, donde la célula crece y duplica su ADN. Luego, la mitosis y citocinesis dividen el material genético y el citoplasma entre las dos células hijas nuevamente. El ciclo celular asegura que toda célula se origine de otra preexistente a través de la replicación y división controlada.
El azufre se encuentra en la naturaleza y pasa por un ciclo biogeoquímico. Los compuestos de azufre se absorben del suelo por las plantas y son incorporados en las cadenas alimenticias, mientras que la descomposición de materia orgánica libera azufre de nuevo al suelo.
This document discusses cell division and mitosis. It defines cell division as the process where a parent cell divides into two or more genetically identical daughter cells. Mitosis is described as the process where a cell duplicates its contents and splits to form two daughter cells, ensuring the daughter cells have the same genetic material as the original cell. The stages of mitosis - interphase, prophase, metaphase, anaphase, telophase and cytokinesis - are outlined in detail. The importance of mitosis in growth, repair and asexual reproduction is also noted.
The document discusses cell reproduction through mitosis and meiosis. It provides details on:
1) The stages of the cell cycle including interphase and the phases of mitosis (prophase, metaphase, anaphase, telophase).
2) The key differences between mitosis, which produces identical daughter cells, and meiosis, which produces gametes with half the number of chromosomes.
3) The stages and outcomes of meiosis I and meiosis II, which reduce the chromosome number and lead to genetic diversity through independent assortment and crossing over.
The document summarizes photosynthesis, including both the light-dependent and light-independent reactions. It explains that the light-dependent reactions take place in the thylakoid membranes and produce ATP and NADPH through the absorption of light by photosystems. The light-independent reactions take place in the chloroplast stroma and use ATP and NADPH to produce glucose through the Calvin cycle. The structure of the chloroplast is adapted to efficiently carry out these two stages of photosynthesis through the stacking of thylakoids and positioning of the stroma.
El documento describe la célula como la unidad estructural y funcional de los seres vivos. Explica que existen dos tipos de células, las procariotas y las eucariotas, y describe las características y componentes clave de cada una. Las células eucariotas contienen un núcleo y varias organelas especializadas, mientras que las procariotas carecen de núcleo y sus funciones están menos compartimentalizadas.
This document provides the memorandum for marking Life Sciences Paper 1 from November 2010 for the National Senior Certificate in South Africa. It outlines 20 principles for marking, including how to allocate marks for partial or incorrect answers. The memorandum then provides the answers and marking schemes for questions in Sections A, B and C of the paper. It gives the correct responses and number of marks awarded for each answer line or part. In total 150 marks were available for the paper.
This document provides instructions for a Life Sciences exam consisting of 13 pages and 150 marks over 2.5 hours. It is divided into 3 sections. Section A contains multiple choice and matching questions about topics in evolution, genetics, human origins, and inheritance patterns. Section B asks students to represent genetic crosses, discuss advantages and disadvantages of genetic engineering, and interpret data on human height. Section C contains diagrams of skulls and asks students to identify species, compare evolutionary trends, and describe evidence for the African origin of humans.
The memorandum provides principles for marking Life Sciences papers in 2012. It details 20 marking principles, including crediting relevant parts of answers even if extra information is provided, marking the first few reasons or examples given, and being sensitive to answers stated differently but conveying the same meaning. The memorandum also addresses aspects like spelling, abbreviations, diagrams, flow charts, and language.
This 10-page memorandum provides marking guidelines for a Life Sciences P2 examination consisting of 150 marks. It details 20 marking principles, including how to mark answers that provide more information than required or have sequencing and language issues. The memorandum then provides answer keys for 50 marks of section A multiple choice and structured questions, 60 marks of section B short answer and diagram labeling questions, and 40 marks of section C essay questions on topics like population growth and endocrine system function.
This 10-page memorandum provides marking guidelines for a Life Sciences P1 exam consisting of 150 marks and taken by full-time candidates in February/March 2013. It outlines 20 principles related to marking, including how to mark answers that provide more or less information than required or have incorrect sequencing. The memorandum also provides answer keys and mark allocations for 4 sections worth a total of 150 marks. Section A covers multiple choice, terminology, and genetics inheritance questions. Section B addresses DNA structure, sex-linked inheritance, protein synthesis, and meiosis. Section C involves human evolution topics and a graphing activity. Section D covers genetics principles like phenotypes and genotypes.
This document provides instructions for a Life Sciences exam consisting of 15 pages with 150 marks over 2.5 hours. It instructs students to answer all questions, write answers in the answer book, number answers correctly, and do all drawings in pencil with labels in ink. Diagrams are not necessarily to scale. Students must use a non-programmable calculator, protractor, and compass where needed. The exam consists of two sections. Section A contains multiple choice, matching, and short answer questions. Section B involves labeling diagrams and short answer questions related to DNA, RNA, protein synthesis, and meiosis.
This document is a 10 page memorandum for a Life Sciences exam consisting of 4 sections and 15 questions. It provides the answers and explanations for each question, along with the number of marks allocated to each part. The memorandum also includes rubrics for marking diagrams and explanations. In total, there are 150 marks available for the exam.
This memorandum consists of 11 pages and provides grading guidelines for answering questions about Life Sciences. It includes 20 principles for marking answers, such as crediting parts of responses even if the whole process isn't described. The memorandum also provides the answers to sample questions on topics like human reproduction, genetics, ecology and the human nervous and endocrine systems.
This memorandum provides marking guidelines for Life Sciences Paper 2 for the February/March 2013 examination in South Africa. It consists of 9 pages outlining the principles for marking, answers to questions in Sections A, B and C, and allocation of marks. The memorandum addresses topics related to human reproduction, genetics, ecosystems, population ecology, and endocrine system regulation.
This document contains assessment exemplars for Life Sciences for Grade 10, including control tests, a research project, and practical tasks. It provides teacher guidelines, assessment rubrics, and worksheets for learners for each assessment. The introductions explain that the exemplars are meant to be used for continuous assessment throughout the year. They assess the three learning outcomes, with the tests and project assessing mastery of content and skills, and the practical tasks assessing skills. Guidelines are provided for implementing the research project and practical activities, including classroom management, technology use, and thinking strategies.
This document shows demonstration of a heart dissection, if the teacher wishes to this practical he/she should moderate the learners so that they don't hurt themselves
This document provides instructions for a Grade 12 Life Sciences exam. It consists of 14 pages and students have 2.5 hours to complete it. The exam contains 3 sections. Section A has 10 multiple choice questions worth 1 or 2 marks each, and short answer questions worth 1-8 marks. Section B contains diagram and graph interpretation questions worth 1-14 marks. Section C involves investigating the resistance of mosquitoes to DDT over time, with associated graphing and analysis questions worth 1-6 marks. Students are instructed to show all working, use scientific terms correctly, and answer all questions in full sentences in the answer book provided.
This document is a 16-page Life Sciences question paper for Grade 12 from the February/March 2013 National Senior Certificate exams in South Africa. It consists of 4 sections with multiple choice, short answer, and longer answer questions testing knowledge of topics like genetics, evolution, and human origins. The instructions state that students have 2.5 hours to complete the paper and must answer all questions, showing their work in the provided answer book.
This document provides instructions for students taking the Grade 12 Life Sciences exam. It consists of three sections with a total of 150 marks over 21⁄2 hours. Students must answer all questions, writing their answers in the answer book and numbering them correctly. Diagrams should be drawn in pencil and labeled in ink. Calculators, protractors, and compasses may be used.
This document contains instructions for a 150 mark, 2.5 hour Life Sciences exam for Grade 12. It outlines:
- The number of questions and pages in the paper
- Instructions that students must answer all questions, write answers in the answer book, and number them correctly
- Information on drawings, diagrams, and materials allowed
- The exam contains 3 sections: Section A with 7 multiple choice and descriptive questions worth 50 marks, Section B with 4 extended response questions worth 30 marks, and Section C with 1 extended response question worth 30 marks.
This document provides instructions for a Life Sciences exam consisting of 17 pages. It outlines that students must answer all questions, writing answers in the answer book and numbering them correctly. Diagrams should be drawn in pencil with labels in ink. Calculators and other equipment may be used. Students should write neatly and legibly. The exam is worth 150 marks and must be completed in 2.5 hours.
This document provides instructions for a Life Sciences exam consisting of 3 sections worth 150 marks over 21⁄2 hours. Section A is worth 50 marks and contains multiple choice, matching, and short answer questions testing various concepts in Life Sciences. Section B is worth 30 marks and contains diagram labeling, sequencing, and longer answer questions on topics like meiosis and protein synthesis. Section C is worth 9 marks and contains labeling and short answer questions testing knowledge of the female reproductive system. The exam paper consists of 14 pages and students are instructed to answer all questions, show their work, and draw diagrams as required. Calculators and drawing tools are permitted.
This document is a 14-page question paper for the Life Sciences P1 exam with the following details:
- Marks: 150
- Time: 2.5 hours
- Consists of 7 sections with multiple choice, matching, short answer and long answer questions testing knowledge of topics like meiosis, genetics, the menstrual cycle, protein synthesis and DNA profiling. Instructions are provided on how to answer the questions and various diagrams accompany some questions.
This document provides instructions for a Life Sciences exam consisting of three sections worth a total of 150 marks over 21⁄2 hours. Section A is worth 50 marks and includes multiple choice, matching, and short answer questions testing concepts in evolution, ecology and microbiology. Section B is worth 30 marks for each of two structured questions on topics like pollution indicators, deforestation, and comparative anatomy. Section C consists of an essay worth 40 marks. Students are instructed to answer all questions, show workings, use diagrams where required, and write neatly.
This document provides instructions for a Life Sciences exam consisting of 150 marks over 2.5 hours. It is divided into three sections: Section A with 50 marks, Section B with 60 marks, and Section C with 40 marks. The paper contains various types of questions including multiple choice, matching columns, labeling diagrams, short answers and longer explanations. Students are instructed to answer all questions in their answer book and show all working where necessary. They are permitted to use a calculator, protractor and compass during the exam.
This document is a 16-page Life Sciences question paper for Grade 12 students taking a test. It consists of various multiple choice and short answer questions testing knowledge of topics like sexual reproduction, population ecology, human physiology, and more. The questions are formatted in numbered sections and subsections, with space provided to write answers directly in the test booklet.
This document provides instructions for a Life Sciences exam that will take place over 150 minutes. It consists of 15 pages and covers topics related to human anatomy and genetics. The exam is divided into 3 sections. Section A contains multiple choice and short answer questions. Section B focuses on human reproduction and inheritance. Section C addresses genetics concepts like inheritance patterns, genetic crosses and co-dominance. Students are instructed to answer all questions, show their work, and label diagrams clearly. Calculators and drawing tools are permitted.
This document provides the memorandum for marking Life Sciences Paper 1 from November 2010 for the National Senior Certificate in South Africa. It outlines 20 principles for marking, including how to allocate marks for partial or incorrect answers. The memorandum then provides the answers and marking schemes for questions in Sections A, B and C of the paper. It gives the correct responses and number of marks awarded for each answer line or part. In total 150 marks were available for the paper.
This document provides instructions for a Life Sciences exam consisting of 13 pages and 150 marks over 2.5 hours. It is divided into 3 sections. Section A contains multiple choice and matching questions about topics in evolution, genetics, human origins, and inheritance patterns. Section B asks students to represent genetic crosses, discuss advantages and disadvantages of genetic engineering, and interpret data on human height. Section C contains diagrams of skulls and asks students to identify species, compare evolutionary trends, and describe evidence for the African origin of humans.
The memorandum provides principles for marking Life Sciences papers in 2012. It details 20 marking principles, including crediting relevant parts of answers even if extra information is provided, marking the first few reasons or examples given, and being sensitive to answers stated differently but conveying the same meaning. The memorandum also addresses aspects like spelling, abbreviations, diagrams, flow charts, and language.
This 10-page memorandum provides marking guidelines for a Life Sciences P2 examination consisting of 150 marks. It details 20 marking principles, including how to mark answers that provide more information than required or have sequencing and language issues. The memorandum then provides answer keys for 50 marks of section A multiple choice and structured questions, 60 marks of section B short answer and diagram labeling questions, and 40 marks of section C essay questions on topics like population growth and endocrine system function.
This 10-page memorandum provides marking guidelines for a Life Sciences P1 exam consisting of 150 marks and taken by full-time candidates in February/March 2013. It outlines 20 principles related to marking, including how to mark answers that provide more or less information than required or have incorrect sequencing. The memorandum also provides answer keys and mark allocations for 4 sections worth a total of 150 marks. Section A covers multiple choice, terminology, and genetics inheritance questions. Section B addresses DNA structure, sex-linked inheritance, protein synthesis, and meiosis. Section C involves human evolution topics and a graphing activity. Section D covers genetics principles like phenotypes and genotypes.
This document provides instructions for a Life Sciences exam consisting of 15 pages with 150 marks over 2.5 hours. It instructs students to answer all questions, write answers in the answer book, number answers correctly, and do all drawings in pencil with labels in ink. Diagrams are not necessarily to scale. Students must use a non-programmable calculator, protractor, and compass where needed. The exam consists of two sections. Section A contains multiple choice, matching, and short answer questions. Section B involves labeling diagrams and short answer questions related to DNA, RNA, protein synthesis, and meiosis.
This document is a 10 page memorandum for a Life Sciences exam consisting of 4 sections and 15 questions. It provides the answers and explanations for each question, along with the number of marks allocated to each part. The memorandum also includes rubrics for marking diagrams and explanations. In total, there are 150 marks available for the exam.
This memorandum consists of 11 pages and provides grading guidelines for answering questions about Life Sciences. It includes 20 principles for marking answers, such as crediting parts of responses even if the whole process isn't described. The memorandum also provides the answers to sample questions on topics like human reproduction, genetics, ecology and the human nervous and endocrine systems.
This memorandum provides marking guidelines for Life Sciences Paper 2 for the February/March 2013 examination in South Africa. It consists of 9 pages outlining the principles for marking, answers to questions in Sections A, B and C, and allocation of marks. The memorandum addresses topics related to human reproduction, genetics, ecosystems, population ecology, and endocrine system regulation.
This document contains assessment exemplars for Life Sciences for Grade 10, including control tests, a research project, and practical tasks. It provides teacher guidelines, assessment rubrics, and worksheets for learners for each assessment. The introductions explain that the exemplars are meant to be used for continuous assessment throughout the year. They assess the three learning outcomes, with the tests and project assessing mastery of content and skills, and the practical tasks assessing skills. Guidelines are provided for implementing the research project and practical activities, including classroom management, technology use, and thinking strategies.
This document shows demonstration of a heart dissection, if the teacher wishes to this practical he/she should moderate the learners so that they don't hurt themselves
This document provides instructions for a Grade 12 Life Sciences exam. It consists of 14 pages and students have 2.5 hours to complete it. The exam contains 3 sections. Section A has 10 multiple choice questions worth 1 or 2 marks each, and short answer questions worth 1-8 marks. Section B contains diagram and graph interpretation questions worth 1-14 marks. Section C involves investigating the resistance of mosquitoes to DDT over time, with associated graphing and analysis questions worth 1-6 marks. Students are instructed to show all working, use scientific terms correctly, and answer all questions in full sentences in the answer book provided.
This document is a 16-page Life Sciences question paper for Grade 12 from the February/March 2013 National Senior Certificate exams in South Africa. It consists of 4 sections with multiple choice, short answer, and longer answer questions testing knowledge of topics like genetics, evolution, and human origins. The instructions state that students have 2.5 hours to complete the paper and must answer all questions, showing their work in the provided answer book.
This document provides instructions for students taking the Grade 12 Life Sciences exam. It consists of three sections with a total of 150 marks over 21⁄2 hours. Students must answer all questions, writing their answers in the answer book and numbering them correctly. Diagrams should be drawn in pencil and labeled in ink. Calculators, protractors, and compasses may be used.
This document contains instructions for a 150 mark, 2.5 hour Life Sciences exam for Grade 12. It outlines:
- The number of questions and pages in the paper
- Instructions that students must answer all questions, write answers in the answer book, and number them correctly
- Information on drawings, diagrams, and materials allowed
- The exam contains 3 sections: Section A with 7 multiple choice and descriptive questions worth 50 marks, Section B with 4 extended response questions worth 30 marks, and Section C with 1 extended response question worth 30 marks.
This document provides instructions for a Life Sciences exam consisting of 17 pages. It outlines that students must answer all questions, writing answers in the answer book and numbering them correctly. Diagrams should be drawn in pencil with labels in ink. Calculators and other equipment may be used. Students should write neatly and legibly. The exam is worth 150 marks and must be completed in 2.5 hours.
This document provides instructions for a Life Sciences exam consisting of 3 sections worth 150 marks over 21⁄2 hours. Section A is worth 50 marks and contains multiple choice, matching, and short answer questions testing various concepts in Life Sciences. Section B is worth 30 marks and contains diagram labeling, sequencing, and longer answer questions on topics like meiosis and protein synthesis. Section C is worth 9 marks and contains labeling and short answer questions testing knowledge of the female reproductive system. The exam paper consists of 14 pages and students are instructed to answer all questions, show their work, and draw diagrams as required. Calculators and drawing tools are permitted.
This document is a 14-page question paper for the Life Sciences P1 exam with the following details:
- Marks: 150
- Time: 2.5 hours
- Consists of 7 sections with multiple choice, matching, short answer and long answer questions testing knowledge of topics like meiosis, genetics, the menstrual cycle, protein synthesis and DNA profiling. Instructions are provided on how to answer the questions and various diagrams accompany some questions.
This document provides instructions for a Life Sciences exam consisting of three sections worth a total of 150 marks over 21⁄2 hours. Section A is worth 50 marks and includes multiple choice, matching, and short answer questions testing concepts in evolution, ecology and microbiology. Section B is worth 30 marks for each of two structured questions on topics like pollution indicators, deforestation, and comparative anatomy. Section C consists of an essay worth 40 marks. Students are instructed to answer all questions, show workings, use diagrams where required, and write neatly.
This document provides instructions for a Life Sciences exam consisting of 150 marks over 2.5 hours. It is divided into three sections: Section A with 50 marks, Section B with 60 marks, and Section C with 40 marks. The paper contains various types of questions including multiple choice, matching columns, labeling diagrams, short answers and longer explanations. Students are instructed to answer all questions in their answer book and show all working where necessary. They are permitted to use a calculator, protractor and compass during the exam.
This document is a 16-page Life Sciences question paper for Grade 12 students taking a test. It consists of various multiple choice and short answer questions testing knowledge of topics like sexual reproduction, population ecology, human physiology, and more. The questions are formatted in numbered sections and subsections, with space provided to write answers directly in the test booklet.
This document provides instructions for a Life Sciences exam that will take place over 150 minutes. It consists of 15 pages and covers topics related to human anatomy and genetics. The exam is divided into 3 sections. Section A contains multiple choice and short answer questions. Section B focuses on human reproduction and inheritance. Section C addresses genetics concepts like inheritance patterns, genetic crosses and co-dominance. Students are instructed to answer all questions, show their work, and label diagrams clearly. Calculators and drawing tools are permitted.
This document contains instructions for a Grade 12 Life Sciences exam. It consists of 17 pages and students have 2.5 hours to complete it. The exam contains multiple choice questions, terminology questions, matching questions and short answer questions testing knowledge of human anatomy and physiology, genetics, ecology and other topics. Students must answer all questions in the answer book provided and show all working where required. Diagrams should be drawn in pencil. Calculators and other aids are permitted.
This document provides instructions for a Life Sciences exam. It consists of 15 pages and students have 2.5 hours to complete it. The instructions state that students must answer all questions, write answers in the answer book provided, number answers according to the question paper, present drawings according to instructions, and write neatly. It also provides information about the number of marks allocated, use of calculators and drawing tools, and copyright notice.
This memorandum provides answers and guidance for grading a Life Sciences exam consisting of 12 pages. It includes answers to multiple choice questions, short answer questions, and longer essay questions on topics relating to human reproduction, genetics, and biotechnology. Scoring rubrics are provided for questions involving diagrams, graphs, and experimental designs. The memorandum also notes common student errors to avoid for certain questions.
(1) This document provides instructions for a Life Sciences exam consisting of 3 sections with multiple choice, matching, and short answer questions. It gives the time allotted, 150 marks, and details that all answers must be written in the answer book and drawings done in pencil.
(2) Section A includes 7 multiple choice questions testing content knowledge, 7 short answer questions requiring biological terms, and 6 matching questions. Section B has short answer questions on evolution, adaptations, natural selection, and speciation. Section C addresses disease transmission, resource use, and human evolution.
This document provides principles for marking the Life Sciences memorandum for the 2011 National Senior Certificate Grade 12 examination. It outlines 20 principles related to marking, including how to mark answers that provide extra information, partial processes, diagrams instead of descriptions, non-recognized abbreviations, and spelling errors. It also provides guidance on marking different language responses and adhering only to approved marking memoranda.
This document contains instructions for homework assignment #2 in a genetics course. It includes questions about gene expression, mutation, protein function, recombination, and cancer genetics. Students are asked to answer questions about promoter sequences, start/stop codons, amino acid changes, Holliday junction formation, cancer hotspots, and pedigrees. Diagrams illustrate chromosome structure, gene fusions, and potential recombination outcomes.
This document contains instructions for homework assignment #2 in a genetics course. It includes questions about gene expression, mutation, protein function, recombination, and cancer genetics. Students are asked to answer questions about DNA sequences, genetic code, chromosome structure, and mechanisms like transcription, translation, and recombination through diagrams and short explanations.
Heredity is the fascinating study of how traits are passed down from one generation to the next. It forms the foundation for understanding the similarities and differences among living organisms, providing insights into the mechanisms of inheritance. From the color of our eyes to the texture of our hair, heredity influences a wide array of physical and physiological characteristics in all living beings.
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Similar to Life sciences p1 nov 2012 version 1 eng (20)
The document summarizes human reproduction. It describes sexual reproduction involving the fusion of egg and sperm cells. The male reproductive system produces sperm in the testes and transfers them through the penis during intercourse. The female reproductive system involves ovaries releasing eggs, fallopian tubes and uterus where fertilization and fetal development occur. The menstrual cycle and process of fertilization are also outlined.
This document provides examination guidelines for the Grade 12 Life Sciences exam in South Africa. It consists of 19 pages covering: the format and weighting of the exam papers; the formal assessment program and sequence of topics; and an elaboration of the content to be assessed for each topic, including DNA, meiosis, reproduction, genetics and inheritance. The topics will be assessed across two question papers that contain short answers, structured questions and an essay. The guidelines are intended to clarify the scope of the exam and assist teachers in preparing learners.
1. The document defines evolution as gradual changes in organisms over generations due to natural selection. It discusses key figures in the development of evolutionary theory like Lamarck, Darwin, and Wallace.
2. Mechanisms of evolution include genetic variation, inheritance of traits, natural selection of advantageous variations, and accumulation of small changes over long periods of time leading to new species.
3. Evidence for evolution comes from fossils that show gradual changes in ancient species over millions of years, as well as anatomical, genetic, and biochemical similarities between living and extinct species, indicating common ancestry.
1) Fossil evidence from sites in South Africa like Sterkfontein provide insight into early hominids that lived over 3 million years ago, including Australopithecus africanus.
2) As hominids evolved, they exhibited skeletal changes associated with bipedalism as well as increases in brain size and cultural adaptations like tool use.
3) Genetic and fossil evidence supports the 'Out of Africa' theory where modern humans evolved in Africa around 200,000 years ago and migrated elsewhere, replacing earlier hominid species like Neanderthals.
Meiosis is a cell division process that produces gametes, or sex cells, with half the normal number of chromosomes. It occurs in two stages: Meiosis I splits homologous chromosome pairs, resulting in haploid cells, and Meiosis II splits the remaining sister chromatids into individual chromosomes, resulting in four haploid cells. This ensures that offspring receive a mixture of maternal and paternal chromosomes and introduces genetic variation through processes like crossing over during prophase I. Meiosis is essential for sexual reproduction, as it maintains the chromosome number between generations and produces genetic diversity in offspring.
This document discusses genetics and inheritance of genetic diseases. It covers Gregor Mendel's experiments with pea plants which laid the foundations of genetics, including genes, alleles, dominant and recessive traits. It also discusses chromosomes, genetic crosses, sex-linked inheritance and examples of genetic disorders like cystic fibrosis and muscular dystrophy. The role of mutations in causing genetic diseases as well as the process of genetic counseling is summarized.
DNA controls cellular activities and protein synthesis. It is found in the cell nucleus as a double-stranded helix made up of nucleotides. DNA replicates itself using DNA polymerase and stores the genetic code in genes that determine protein sequences. During transcription, a complementary mRNA strand is produced from DNA in the nucleus. Translation then occurs on ribosomes in the cytoplasm, where tRNA brings amino acids to the ribosome according to mRNA codons, assembling proteins from the genetic code carried by DNA.
This document discusses speciation and the factors that can lead to the formation of new species. It outlines two main types of speciation: allopatric speciation which is caused by geographic isolation, and sympatric speciation which does not require a large geographic barrier. Factors that can influence speciation include genetic variation due to isolation, inbreeding within small isolated populations, outbreeding between unrelated individuals, founder effects in small groups colonizing new areas, population bottlenecks from catastrophic events, and reproductive isolation through mechanisms like breeding at different times or adapting to different pollinators.
This document provides marking guidelines for grading Life Sciences papers in South Africa. It details 20 principles for markers to follow, such as marking the first three reasons given if more than three are provided. It also notes that abbreviations must be defined and that changes to memoranda require moderator approval. The document is signed, showing moderator consensus on the policies.
The document is an 11-page memorandum for a Life Sciences exam consisting of principles for marking, answers to exam questions, and a section on marking criteria. It provides concise summaries and the essential information needed to mark exam responses in 3 sentences or less.
This memorandum provides marking guidelines for Life Sciences Paper 2. It consists of 20 pages detailing the answers and marks allocated for each question. Principles for marking include stopping when maximum marks are reached, marking the first answer if more than required are given, and crediting relevant parts of longer answers. Abbreviations must be defined to receive marks. Diagrams or flow charts lose marks if descriptions are required.
This memorandum provides guidelines for marking the 2011 Life Sciences Paper 2 for the National Senior Certificate in South Africa. It consists of 20 principles to ensure consistent and fair marking. Some key principles include: awarding marks for the first few reasons/examples provided, even if incorrect; accepting answers that demonstrate understanding despite differences in format; and not penalizing for spelling errors if the word is recognizable. The memorandum also provides mark allocations for each question and sub-question.
This document is a 16-page exam paper for Life Sciences P2 from February/March 2010. It contains instructions for the exam, which is divided into two sections worth a total of 150 marks and takes 2.5 hours. Section A contains multiple choice and short answer questions testing concepts related to evolution, ecology, genetics and the timeline of life on Earth. Section B includes several longer answer questions requiring explanations and descriptions related to topics like natural selection, Lamarckism, water pollution and plant uses.
This memorandum consists of 11 pages and provides answers and marking schemes for questions in Life Sciences P2 from February/March 2010. Section A contains multiple choice and short answer questions on topics such as evolution, classification of organisms, geological time periods, and human evolution. Section B involves longer answer questions on natural selection, inheritance of acquired characteristics, environmental issues, and river pollution. Section C contains questions on plant germination, data analysis, human evolution, and fisheries management. The memorandum provides detailed answers and point allocations for each question.
This 10-page memorandum provides guidance for grading South African Grade 12 Life Sciences students' answers. It covers Sections A, B, and C, with Section A including multiple-choice and matching questions on topics like meiosis, genetics, and reproduction. Section B involves labelling diagrams and short questions on subjects like the male reproductive system and the menstrual cycle. Section C consists of longer essay questions on genetics, forensics, and genetically modified organisms.
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MARKS: 150
TIME: 2½ hours
This question paper consists of 16 pages.
LIFE SCIENCES P1
VERSION 1 (NEW CONTENT) FOR FULL-TIME CANDIDATES
NOVEMBER 2012
NATIONAL
SENIOR CERTIFICATE
GRADE 12
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INSTRUCTIONS AND INFORMATION
Read the following instructions carefully before answering the questions.
1.
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11.
Answer ALL the questions.
Write ALL the answers in your ANSWER BOOK.
Start the answer 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.
ALL drawings should be done in pencil and labelled in blue or black ink.
Draw diagrams or flow charts only when asked to do so.
The diagrams in this question paper are NOT necessarily all drawn to scale.
Do NOT use graph paper.
You may use a non-programmable calculator, protractor and compass where necessary.
Write neatly and legibly.
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SECTION A
QUESTION 1
1.1
Various options are provided as possible answers to the following questions. Choose the correct answer and write only the letter (A to D) next to the question number (1.1.1 to 1.1.10) in your ANSWER BOOK, for example 1.1.11 D.
1.1.1
The present-day distribution of organisms is referred to as ...
A
B
C
D
mutations.
biodiversity.
biochemistry.
biogeography.
1.1.2
Changes to genetic material in organisms can ONLY be inherited by the next generation if they ...
A
B
C
D
occur in somatic cells.
increase the survival chances of the species.
occur in reproductive cells.
increase the survival chances of an individual.
1.1.3
Study the diagrams of hominid skulls below.
The correct sequence of evolution, from oldest to youngest, of the hominid species shown is ...
A
B
C
D
2, 3, 1.
3, 1, 2.
1, 3, 2.
2, 1, 3.
1
2
3
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1.1.4
DNA sequences are now routinely used to determine how closely related different species are to each other. The table below shows DNA sequences from the amylase gene of four different organisms.
Based on this information alone, which TWO organisms are most closely related?
A
B
C
D
Organism 1 and Organism 2
Organism 2 and Organism 3
Organism 2 and Organism 4
Organism 3 and Organism 4
1.1.5
The photograph below represents a human karyotype prepared from a sample of foetus cells collected during amniocentesis.
It is reasonable to conclude that …
A
B
C
D
the foetus is a female.
the child will develop Down syndrome.
the foetus is a male.
there are 46 autosomes.
Amylase DNA sequence
Organism 1
C
A
G
G
T
C
A
G
T
T
Organism 2
C
C
G
G
T
C
A
G
G
T
Organism 3
C
A
G
G
A
C
A
T
T
T
Organism 4
C
C
G
G
T
C
A
C
G
T
Human karyotype
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1.1.6
The diagrams below represent six different phases of meiosis taking place in a cell with four chromosomes.
The correct sequence of the different phases in which the above- mentioned division takes place is …
A
B
C
D
1, 2, 3, 4, 5, 6.
6, 2, 5, 4, 1, 3.
3, 5, 4, 2, 6, 1.
3, 4, 5, 6, 1, 2.
1.1.7
Two types of birds belong to the same species if they ...
A
B
C
D
look similar.
are separated by a geographical barrier.
successfully interbreed.
live in the same habitat.
1
2
5
3
6
4
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1.1.8
Which of the following is CORRECT regarding scientific investigations?
A
B
C
D
Increasing the sample size decreases the validity.
Allowing many variables increases the reliability.
Controlling the variables decreases the validity.
Repeating the investigation increases the reliability.
CHILD
BLOOD GROUP
1
A
2
O
3
AB
4
B
A
B
C
D
Blood group A
Blood group B
Blood group O
Blood group AB
1.1.10
In a monohybrid cross the two parental genotypes are AA and aa. The genotype of all the F1 plants is Aa. If the F1 plants are crossed, what percentage of the F2 generation will have the dominant phenotype?
A
B
C
D
25
50
75
100 (10 x 2)
(20)
1.1.9
Two parents have children with the following blood groups:
If the father has blood group A, what blood group must the mother have?
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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 your ANSWER BOOK.
1.2.1
1.2.2
1.2.3
1.2.4
1.2.5
1.2.6
1.2.7
1.2.8
The formation of new species in the absence of a physical barrier
Failure of one or more chromosomes to separate during meiosis
Organisms having two identical alleles at a given locus
The condition in which an organism has more than two complete sets of chromosomes in a cell
Similar structures that descend from a common ancestor
Monomers/Building blocks of a nucleic acid
The division of the cytoplasm during cell division in plant and animal cells
The process of making new DNA from existing DNA
(8)
1.3
Indicate whether each of the statements in COLUMN I 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 1.3.8) in your ANSWER BOOK.
COLUMN I
COLUMN II
1.3.1
Examples of reproductive isolation mechanisms
A: Adaptation to different pollinators
B: Breeding at different times
1.3.2
Fossils found in the Great Rift Valley
A: Nutcracker man
B: Taung child
1.3.3
Supports the 'Out of Africa' hypothesis
A: Y-chromosome mutations
B: Migration of Homo erectus
1.3.4
Characteristics that may be used by scientists to build a phylogenetic tree
A: Similarity of DNA sequencing
B: Fossil evidence
1.3.5
Foramen magnum is towards the back of the skull
A: Human
B: Chimpanzee
1.3.6
Characterises blood grouping
A: Multiple alleles
B: Co-dominance
1.3.7
An organism's complete set of DNA
A: Genotype
B: Genome
1.3.8
A sudden change in the sequence of nitrogen bases in DNA
A: Translation
B: Transcription
(8 x 2)
(16)
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1.4
The diagram below shows a short section of a DNA molecule.
1.4.1
Identify part C and part D respectively.
(2)
1.4.2
1.4.3
1.4.4
Name the type of bond that joins A and B.
Give ONE visible reason for identifying the above molecule as DNA.
Name TWO structures in a non-dividing human cell where DNA is found.
(1)
(1)
(2)
(6)
TOTAL SECTION A:
50
A
B
C
D
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SECTION B
QUESTION 2
2.1
The diagram below shows crossing over in a pair of homologous chromosomes.
2.1.1
Identify the point X and part Z respectively.
(2)
2.1.2
2.1.3
2.1.4
2.1.5
Give ONE observable reason why the chromosomes above are regarded as homologous.
Give ONE reason why crossing over is important.
Name ONE other process occurring during meiosis that has the same importance as crossing over.
If a mouse egg cell contains 20 chromosomes, how many chromosomes will there be in its skin cell?
(1)
(1)
(1)
(1)
(6)
X
Z
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2.2
The first 7 triplets of nitrogenous bases that form part of the gene coding for one chain of the haemoglobin protein that makes up red blood corpuscles in humans is shown below.
DNA TEMPLATE
CAC
GTG
GAC
TGA
GGA
CTC
CTC
BASE TRIPLET NUMBER
1
2
3
4
5
6
7
2.2.1
How many of the following are coded for in the DNA template sequence above:
(a)
(b)
(c)
Nitrogenous bases
Different types of t-RNA molecules that are required to form the polypeptide from this piece of DNA
Amino acids
(1)
(1)
(1)
2.2.2
2.2.3
2.2.4
Write down the mRNA sequence from triplet number 4 to triplet number 6 for the DNA template above.
Using the table below, determine the amino acid sequence coded by triplet number 4 to triplet number 6.
Anticodons on tRNA coding for the amino acid
Amino acid coded for
CUC
Glutamate
GUG
Histidine
GGA
Proline
GAC
Leucine
UGA
Threonine
CAC
Valine
If the T in the 6th triplet of bases changed to A in the DNA template above:
(3)
(3)
(a)
(b)
Write down the new amino acid (using the table above) that this 6th triplet now codes for
State the type of gene mutation that has occurred
(1)
(1)
2.2.5
The change of T to A, referred to in QUESTION 2.2.4, is the mutation that causes sickle cell anaemia. It is characterised by the red blood corpuscles changing shape from biconcave to sickle-shaped with a much smaller surface area than normal red blood corpuscles.
Explain how this may possibly affect the person suffering from sickle cell anaemia.
(3)
(14)
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2.3
A geneticist wanted to find out which corn colour is dominant in a species of maize. The species has two phenotypes for colour, yellow and white. She performed four genetic crosses and recorded the colour of the offspring as shown in the table below.
Genetic crosses
Parent phenotypes
Offspring phenotypes
1
yellow x yellow
all yellow
2
white x white
51 white and 17 yellow
3
white x yellow
32 white and 34 yellow
4
white x white
all white
2.3.1
2.3.2
2.3.3
2.3.4
According to the results, which colour is dominant?
Which ONE of the genetic crosses (1, 2, 3 or 4) from the table allows the conclusion suggested in QUESTION 2.3.1?
Give a reason for your answer to QUESTION 2.3.2.
Use the symbols G and g to represent genetic cross 2. Also indicate the proportions of the F1 phenotypes.
(1)
(1)
(2)
(6)
(10)
[30]
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QUESTION 3
3.1
The pedigree diagram below traces the inheritance of haemophilia in a family.
Key:
3.1.1
3.1.2
3.1.3
How many family members not affected by haemophilia are carriers?
Explain why this disorder affects mostly males in this family.
Use the possible alleles XH, Xh and Y to determine the genotype of the following:
(1)
(3)
(a)
(b)
Individual 1
Individual 4
(2)
(2)
3.1.4
3.1.5
What are the chances of individual 10 and his wife, who is a carrier (not shown in the pedigree), having a son who is affected?
Give TWO reasons why individual 9 and his partner should undergo genetic counselling before starting a family.
(2)
(2)
(12)
7
8
9
10
11
2
5
4
6
1
3
Unaffected female
Affected male
Unaffected male
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3.2
During their work to establish the structure of DNA, Watson and Crick were interested in the proportion of nucleotides in the DNA of skin cells from a particular organism. They considered the results from three different samples done in the same laboratory, as shown in the table below.
3.2.1
3.2.2
3.2.3
3.2.4
Why did Watson and Crick consider results from three samples?
What is the ratio of adenine to thymine in the overall experiment?
Give a reason for your answer to QUESTION 3.2.2.
Draw a pie chart illustrating the percentages of the different nucleotides in sample 1. Show ALL working.
(1)
(1)
(1)
(8)
(11)
3.3
Genetically modified organisms (GMO) bring new hope for medical cures, promise to increase yields in agriculture and have the potential to help solve the world's pollution and resource crisis.
There are also many objections to GMO, some stating that they are expensive and a threat to our biodiversity.
3.3.1
Give TWO reasons why:
(a)
(b)
The initial cost of production of GMO is high
GMO are considered a threat to biodiversity
(2)
(2)
3.3.2
Apart from those in the text, state THREE objections that some people have against the production of GMO.
(3)
(7)
[30]
TOTAL SECTION B:
60
Percentage of each nucleotide
Nucleotides in DNA
Sample 1
Sample 2
Sample 3
A
29
31
30
T
31
29
30
C
21
20
19
G
19
21
20
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SECTION C
QUESTION 4
4.1
Study the information about the discovery of a new species of australopithecine in South Africa.
DISCOVERY OF A NEW SPECIES IN SOUTH AFRICA
Professor Lee Berger a paleoanthropologist at the University of the Witwatersrand, with the help of his 9-year-old son, found two fossils in South Africa on 15 August 2008.
Berger and about 60 of his colleagues from all over the world, studied the fossilized bone fragments before they announced their findings to the public on 8 April 2010. Their findings were published in a scientific journal.
They presented it as a new species called Australopithecus sediba, dated to approximately 1,78 to 1,95 million years ago. It consists of many primitive features characteristic of other australopithecine species and more advanced features typical of later Homo species.
The almost 2-million-year-old partial skeletons are thought to possibly be that of the transitional species between Australopithecus africanus (such as the famous Mrs Ples) and either Homo habilis or Homo erectus, the early ancestors of humans.
Berger said that the brain, hand and foot have characteristics of both modern and early pre-human forms. It represents a model that could have led to the human genus Homo.
It was noted that the brain of A. sediba is small, like that of a chimpanzee, but with a re-organisation more human-like, particularly with an expansion behind and above the eyes.
[Adapted from http://www.sciencemag.org]
4.1.1
Explain why scientists took a long time to present their findings to the public.
(2)
4.1.2
Explain why it was important to publish their findings in a scientific journal.
(2)
4.1.3
4.1.4
4.1.5
Define the term transitional form.
Use ONE characteristic from the passage to explain your answer to QUESTION 4.1.3.
State SIX similarities not mentioned in the passage above, between Homo sapiens and other primates such as Australopithecus sediba.
(2)
(2)
(6)
(14)
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4.2
Study the phylogenetic tree of nine elephant species over six geologic time periods from 55 million years ago (mya) to the present and answer the questions below.
Eocene
Oligocene
Miocene
Pliocene
Pleistocene
Present
55 mya
38 mya
24 mya
5 mya
2 mya
10 000 years
Time line (years)
A phylogenetic tree of nine elephant species
Key:
A: Palaeomastodon species B: Gomphotherium species
C: Primelaphus species D: Anancus species
E: Mammuthus species F: Elephas species
G: Loxodonta species H: Mammut species
I: Stegodon species
4.2.1
According to the phylogenetic tree above, which is the ancestral species of ALL the named species?
(1)
4.2.2
Name the TWO species of elephants that exist today.
(2)
4.2.3
Name the immediate ancestor of the two species mentioned in QUESTION 4.2.2.
(1)
4.2.4
In which period did:
(a) The Anancus species first appear
(b) The Stegodon species become extinct
(1)
(1)
(6)
A
H
C
D
F
B
E
G
I
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4.3
One of the observations Darwin made during his study of pigeons was about artificial selection. In 1859 Darwin and Wallace jointly proposed that new species could develop by a process of natural selection.
Using examples, describe natural and artificial selection and also highlight the differences between these two processes.
Content:
Synthesis:
(17)
(3)
(20)
NOTE:
NO marks will be awarded for answers in the form of flow charts or diagrams.
TOTAL SECTION C:
GRAND TOTAL:
40
150