Revision10

Revision10 Bio3B

Structure of the exam paper Section One -Multiple-choice – 20 questions – 40 marks Answer all questions, using a blue or black pen, on the separate Multiple Choice Answer Sheet. Suggested working time 30 minutes Section Two -Short answers – 5 questions – 100 marks Answer in the spaces provided in this Question/Answer Booklet. Do not answer this section in the Standard Answer Book. A blue or black ball point or ink pen should be used for written answers and pencil for diagrams. Suggested working time 90 minutes Section Three - Extended answers Part A – select 2 questions from a choice of 4 – 30 marks (15 marks each) Part B – select 2 questions from a choice of 4 – 30 marks (15 marks each) Write your answers in the Standard Answers Book. Your writing or printing must be LEGIBLE. Use a blue or black ball point or ink pen for this section. Answers may be presented in a combination of different ways provided they communicate your ideas effectively. You may choose to: • present a clearly labelled diagram or flow chart; • write notes besides a clear diagram; • write lists of points, with sentences which link them; • write concisely worded sentences; • use some other appropriate way to present ideas. Suggested working time 60 minutes (30 minutes for Part A and 30 minutes for Part B) Total marks 200 The mock exam and the WACE are on the whole year’s work (A and B)

Notes about exam format The WACE Biology examination will be marked online. Students will write all of their responses for sections B and C in the question/answer booklet. The following points will facilitate the on-line marking: • Please write in blue or black ink, not pencil. • If drawing diagrams in pencil, please press firmly to ensure a strong line. • Avoid highlighters. The examiners’ reports discourage their use and they will not show up in online marking. • The only answer that the examiners will see in colour is the compulsory graphing question in Section B, where some candidates use colour in the legend. It is unnecessary to use colour elsewhere. • Wherever possible, confine answers to the lined spaces provided in the answer book. The mock exams are set up in exactly the same format as the WACE exams.

Non-programmable calculators There is no limit on the number of non-programmable calculators permitted in these examinations. An approved non-programmable calculator is any commercially produced calculator which is battery or solar operated, silent, hand held, non-programmable and does not have either a full alphabetic display or a graphical display. As a guide only, the following typically appear on programmable calculators - data bank - load - execute - memo - formulae - programme - forward - reverse - go to - run - learn - LRN - letters of the alphabet Watches, rulers, pens or any other equipment with built-in calculators or memory functions must also conform to the criteria for an approved calculator.

Extended answer format Part A Answer any two questions from questions 26 to 29. (30 marks) Indicate the first question you will answer by ticking the box next to the question.Write your answer on the pages provided. Q26. You could answer this one OR Q27. You could do this one OR Q28. You could answer this one OR Q29. You could do this one Indicate the second question you will answer on page 34. Five ruled pages for the answer will be provided (pages 29-33). Then on page 34: Indicate the second question you will answer by ticking the box next to the question. Write your answer on the pages provided. Then you do the same for part B – ticking the box & answering each question on the pages indicated

Conservation Over the last century, thousands of species have decreased in numbers, around the world. In WA alone over 20 species of small marsupials are threatened with extinction within the next decade. • Discuss reasons for the decrease in numbers of species. • Discuss the consequences of the permanent extinction of these and other native species. • Describe strategies that could be used to prevent the extinction of these and other species

Conservation Over the last century, thousands of species have decreased in numbers, around the world. In WA alone over 20 species of small marsupials are threatened with extinction within the next decade. • Discuss reasons for the decrease in numbers of species. Habitat loss (agriculture, mining, logging, urbanisation) Pollution (eutrophication, pesticides/biomagnification, heavy metals) Environmental degradation (salinity, erosion, desertification)  loss of habitat Introduced species (competitors, predators, diseases, non-edible vegetation) Poaching/hunting b) Discuss the consequences of the permanent extinction of these and other native species. Loss of species raises the following questions: Aesthetic value of biodiversity Ethics – is it right to destroy biodiversity? Custodial – we should preserve biodiversity for future generations Utility – biodiversity may provide useful products (e.g. medicines) Ecosystem stability – biodiversity contributes to ecosystem services Recreation/ecotourism Scientific research Education Affects ability to cope with environmental change/greater genetic diversity

Conservation Over the last century, thousands of species have decreased in numbers, around the world. In WA alone over 20 species of small marsupials are threatened with extinction within the next decade. • Describe strategies that could be used to prevent the extinction of these and other species Management strategies involve controlling access to and use of areas eg parks, reserves, limits on size or numbers of organisms to be taken Environmental strategies involve maintaining habitats and controlling changes eg reafforestation, biological control, removal of introduced species Genetic strategies involve manipulation of DNA or gene pools eg breeding programs, genetic engineering, DNA profiling, seed banks Remember marks are often given for examples eg breeding programs and release of numbats, cloning of Tasmanian tigers etc

Protein synthesis Name structures: 1 2 4 Indicate on the diagram the location of • transcription • translation • the template strand • DNA • a codon • an anticodon • a protein

Protein synthesis protein DNA anticodon codon translation Name structures: 1 mRNA 2 tRNA 4 Ribosome Indicate on the diagram the location of • transcription • translation • the template strand • DNA • a codon • an anticodon • a protein transcription

DNA replication and protein synthesis Compare and contrast the processes of transcription, translation and DNA replication. Include in your answer the: Inputs Outputs Enzymes involved Roles of RNA and DNA Importance to the functioning of organisms

DNA replication and protein synthesis Transcription - copying of DNA to make RNA – 1st step in the process of protein synthesis Uses the base pair rule Cytosine in DNA  Guanine in RNA Guanine in DNA  Cytosine in RNA Adenine in DNA  Uracil in RNA Thymine in DNA  Adenine in RNA (RNA contains Uracil not Thymine) DNA acts as template, mRNA is made Inputs – ribose nucleotides (A, C, U and G) Outputs – mRNA Enzymes – Helicase unwinds DNA, RNA polymerase glues nucleotides together Translation - reading of mRNA to make proteins – occurs at ribosomes – 2nd step in protein synthesis Inputs – amino acids, tRNA (carries amino acids into ribosome), mRNA (codes for sequence), ribosome Outputs – protein (ribosomes, mRNA & tRNA undamaged) Ribosomal enzymes attach amino acids together Anticodons on tRNA attach to codons on mRNA using base pair rule DNA replication – duplication of DNA – necessary for cell division (reproduction or replacement of cells) Uses base pair rule A -T, C – G Inputs – deoxyribose nucleotides (A, T, C and G) Outputs - new DNA strands Enzymes - Helicase unwinds DNA, DNA polymerase glues nucleotides together, RNA primase makes primer RNA fragments act as primers to start the replication process

Using DNA technology The diagram opposite shows the results of gel electrophoresis on members of a family. One of the children is adopted. • Which child is it? • How can you tell? One of the children is the result of a previous marriage of one of the parents. • Which child is it? • Who is the genetic parent & who is the step-parent? • How can you tell?

Using DNA technology The diagram opposite shows the results of gel electrophoresis on members of a family. One of the children is adopted. • Which child is it? S2 • How can you tell? No genes in common One of the children is the result of a previous marriage of one of the parents. • Which child is it? D2 • Who is the genetic parent & who is the step-parent? Mother is gene dor, father is stepfather • How can you tell? Daughter shares genes with mother but not father

Biotechnology Describe how the following can be used in agriculture or conservation. Include a description of each technique • DNA sequencing • Gel electrophoresis • PCR (polymerase chain reaction) • Genetic probes • Recombinant DNA techniques • Cloning • Tissue culture • Transgenic organisms

DNA sequencing DNA sequencing involves identifying the precise order of nucleotide in DNA. In DNA profiling sequences are compared between individuals (DNA fingerprint or profile) Special enzymes called restriction enzymes are use to split the DNA into segments so the sequence of nucleotides can be identified. It is used to • identify the genetic relationships between individuals (eg to confirm paternity) • forensic science (eg identifying criminals) • look for genetic disease

Gel electrophoresis Gel electrophoresis refers to a process that allows identification or observation of DNA patterns Uses include identification of • individuals from samples (eg forensic science) • genome sequences • presence of inherited disease

Polymerase chain reaction Polymerase chain reaction (PCR) refers to the process used to replicate DNA. This increases the amount of DNA present in a sample. It is needed so that there is enough DNA present to test.

Genetic probes Probes are nucleic acid bases arranged in a sequence which is complementary to a sequence in the genome They usually have radioactive or chemical markers that are used to make them easily visible They can be used to detect if a genomic sequence is present, deleted or altered. They are often used to identify the presence of a gene for a disease

Recombinant DNA technology This is also known as genetic engineering This refers to the processes that allow introduction of new DNA into a cell. This allows the taking of genes from one organism and placing them in the chromosomes of another producing a transgenic organism. The genes can come from individuals of the same species (eg transferring a healthy gene from one person into a person with a genetic disease = gene therapy) or from a different species (eg placing insulin producing gene into a bacteria) Uses include gene therapy, producing transgenic bacteria that can produce useful products (eg insulin). Products now being produced by this technology include hormones (eg insulin, hGH, FSH), factor VIII or vaccines

Recombinant DNA techniques Restriction enzymes are used to cut sections of DNA at specific locations and are necessary because they allow the selection of 1 gene or DNA fragment Ligation refers to joining of the two segments and is necessary because it produces 1 strand of DNA or a plasmid now containing the gene A gene for antibiotic resistance is usually added so that the bacteria with the new DNA can be identified and collected

Gene cloning In gene cloning the host cell's biochemical processes are used to make many copies of the inserted gene and the protein it codes for.

Cloning animals The cloning of animals has many important commercial implications. It allows an individual animal with desirable features, such as a cow that produces a lot of milk, to be duplicated several times. Mice have successfully been cloned from frozen tissue Cloned mice provide identical test subjects for research

Tissue culture Tissue culture is the growth of tissues and/or cells separate from the organism in a growth medium – this can be liquid or solid (eg on agar). In plants this has been used for centuries for propagation. In animals it is being used to grow tissues for research and medical treatments (eg skin grafts) Another recent area of research is tissue culture to produce meat products, instead of raising animals to be killed for food – animal tissue will be grown in vats and harvested.

Transgenic organisms These are organisms with inserted genes. They are also known as genetically modified organisms or GMO’s. Uses include inserting genes for: • pest or disease resistance eg cotton • turning off the gene for ripening to give a longer shelf life eg tomatoes • ability to cope with salt or drought eg wheat • add nutrients to food eg omega 3 fatty acids into vegetable • create cyanobacteria capable of making ‘diesel’ fuel

Revision10

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