B2 Topic 1 Revision

Slides 2-12 GM - these activities are designed to take a whole lesson. Make sure you stick to the

timings given in the notes that go with each slide.Slides 13- 19 Graphs, data and enzymes - these

activities should take 30mins.Slides 20-29 Mitosis & Meiosis, protein synthesis

and DNA replication - this content recap and exam questions should take 30-40mins

Slide 30 - Revision Quiz, covers lots of bits and pieces, 15 questions, will probably take 20-25mins

1. This question is about genetic modificationExplain how bacteria can be genetically modified to produce human insulin.Suggest benefits of using human insulin rather than insulin extracted from animals. (6 marks)

(The quality of written communication will be assessed in your answer to this question)

Logical order, uses key words, good spelling, good punctuation

At least 6 statements about science in your answer

Science-y bit - step by step guide to GM (worth 4 marks)

2 reasons why it is used (think science - proteins and their shape)

Unpicking the QuestionUnpicking the Question

The Science - Genetic Engineering1. Isolate the desired gene using enzymes 2. Replicate the gene

5. Bacteria will now produce the protein from the desired gene

4. Transfer vector containing gene into bacteria

3. Put gene into vector (eg a plasmid)

Decide: which two of the following are relevant to the question being asked?

Suggest benefits of using human insulin rather than insulin extracted from animals.Using human insulin is better because vegetarians will be able to use it tooHuman insulin will be an exact match for the insulin needed by the diabetic person, animal insulin is a slightly different shaped proteinIt isn’t right to kill pigs to collect insulin from themThe immune system might reject or attack the pig insulin as the protein is a different shape to human insulin

Explain how bacteria can be modified to produce human insulin. Suggest benefits of using human insulin rather than insulin extracted

from animals (6 marks QWC).

Vocab Diagrams

ParagraphBullet points

2 mins 3 mins

4 mins 5 mins

Swap books and mark someone else’s answer.Give them a WWW and EBI.

How many marks did they get for the Science (max 6)?

Now mark the quality of their writing using the criteria on the left.

Did they use the key words?Is it logical?Are all the spellings correct?Good use of punctuation?

Give them a WWW and EBI for the quality of their answer

Now improve your answer!3 minutes

Mark your own work this time.

How did you do compared to your first attempt?

Organisms can be genetically engineered to make them more useful to humans.Suggest how wheat could be genetically engineered to allow it to grow in wet, marshy land (6 marks QWC)

Now take what you know and apply it!

Mark scheme - mark your own this time

Identify a gene that allows a plant to grow in wet/marshy areas.Isolate/extract/cut out the gene with a restriction (endonuclease)/enzymeReplicate the geneInsert desired gene into a vector (eg plasmid/virus)Transfer vector/plasmid containing desired gene into wheat/cropCrop plant will now produce/synthesis protein that allows it to grow in wet/marshy conditions

Give yourself a WWW and EBI

The Science - Genetic Engineering1. Isolate the desired gene using enzymes 2. Replicate the gene

5. Bacteria will now produce the protein from the desired gene

4. Transfer vector containing gene into bacteria

3. Put gene into vector (eg a plasmid)

2 - Daunting Data and Grim Graphs

(ii) Describe the effect of temperature on the volume of juice produced between 10°C and 40°C (2)(iv) Use the lock and key hypothesis to help you explain the activity of pectinase in juice production between 10°C and 70°C (6)

Tell me what you see, using numbers from the graph

Use Science to tell me why you see this pattern

What is happening to the enzymes here?

Why is the volume at it’s highest here?

What is happening to the enzymes here?

Student Model AnswersStudent Aa)As the temperature increases, the volume of juice produced increases.b)Between 10oC and 40oC the enzymes are gaining kinetic energy meaning they are moving around faster and will form more enzyme-substrate complexes. At 70oC the enzymes have been denatured and don’t work anymore.Student Ba)The volume of juice produced increases as the temperature increases. At 10oC 0.6cm3 is produced and at 40oC 2.7cm3 of juice is produced.b)The enzyme has a specific active site and the substrates will only fit into the active site if it hasn’t been denatured by getting too hot. On the graph it denatures when it goes down. Before that, the enzyme works faster as it gets hotter.Student Ca)The graph goes up and then goes down again. It goes up between 10oC and 40oC from 0.6 to 2.7.b)The enzyme works faster as the temperature gets hotter. From 10oC to 40oC the enzymes gain kinetic energy so collide with each other more often, forming more enzyme-substrate complexes. The substrate fits into the active site, but when it gets too hot the enzyme denatures and the active site changes shape meaning that no more enzymes-substrate complexes will be formed. The graphs dips down after 50oC when the enzyme denatures.

Mark the student answers and give each a WWW and EBI

Use what you have learnt!

Now write your own response to the questions

(ii) Describe the effect of temperature on the volume of juice produced between 10°C and 40°C (2)

(iv) Use the lock and key hypothesis to help you explain the activity of pectinase in juice production between 10°C and 70°C (6)

Now mark your own answers

3 - Genes, Protein Synthesis, DNA Replication, Mitosis and Meiosis,

Cloning

Ribosome

Protein Synthesis

TranscriptionTranscription

TranslationTranslation

DNA Replication

Before mitosis and meiosisSemi-conservative

1. Enzyme unzips DNA2. Free complementary bases line up with exposed bases on DNA3. A different enzyme zips them together4. Two identical strands of DNA formed

Mitosis or Meiosis? Daughter cells are genetically identical to parent cells Produces cells with only half the number of chromosomes Produces gametes The cell goes through one division Produces 4 daughter cells that are genetically different Produces diploid cells Is a process within the cell cycle Occurs in the ovaries and testes The cell goes through two divisions Is used in Asexual reproduction

Describe and explain the differences in chromosome number between the daughter cells produced by

Mitosis and Meiosis (6 marks)Mitosis1 division/2 daughter cellsChromosome number maintainedDaughter cells contain 2n/23 pairs/46 chromosomesFor growth and repair/ asexual reproduction

Meiosis2 divisions/ 4 daughter cellsChromosome number halvedDaughter cells contain n/23 individual chromosomesFor making gametes/egg cells/sperm cellsChromosome number restored at fertilisation

Cloning - put these statements into the correct order

A Enucleate the egg cell

B The diploid nucleus inside the egg cell starts dividing by mitosis

C Insert the diploid donor nucleus into the enucleated egg cell

D Implant the growing embryo into womb of surrogate

E Collect an egg cell from the egg cell donor

F Diploid nucleus is removed from body cell of organism you want to clone

G Stimulate the diploid nucleus using an electric shock or chemicals

A clone is born!Answer: F, E, A, C, G, B, D

Q1.

(a) The diagram shows the mass of DNA (m), before, during and after cell division in one cell.(i) Name the type of cell division taking place in this cell. (1)(ii) Complete the sentence: A gene is a section of DNA that codes for ……………………(1)(b) Mutations can cause genetic disorders in humans. Phenylketonuria (PKU) is a genetic disorder caused by a gene mutation. People with PKU produce an inactive enzyme.The normal base sequence and the mutated base sequence which can cause PKU are shown below.

normal base sequence ....... C T C G G C C C T ....... mutated base sequence ....... C T T G G C C C T .......

(i) Describe how the changes that have occurred in the mutated base sequence produce an inactive enzyme (2)(ii) Explain how the mutated base sequence will result in an inactive enzyme being produced during protein synthesis. (6)(c) Explain how the shape of an enzyme can make it inactive. (2)

Mark schemea) i) Meiosisii) Cb) i) A description including any two from the following points • change in a base from C to T (1) • (causes) change in one {codon/triplet} of bases (1) • results in a different amino acid (1)

b) ii) next page

c) An explanation linking the following points• active site {different / blocked / changed} (1)• substrate cannot bind /eq (1)

An explanation linking some of the following points • enzymes are proteins • mutation in DNA will result in different mRNA strand• during transcription • mRNA leaves the nucleus through the nuclear pore • the attachment of mRNA at the ribosomes • involvement of tRNA and amino acids • at the ribosome • which is translation • amino acid chain/peptide sequence altered • different protein formed/protein not folded correctly (6) QWC 5 - 6 marksthe response is likely to indicate the type of mutation and link this to a change of codon/proteinthe response will show good evidence of understanding that an incorrect mRNA molecule is formed and translation by tRNA will result in an incorrect amino acid being incorporated into the protein chainthe answer communicates ideas clearly and coherently uses a range of scientific terminology accuratelyspelling, punctuation and grammar are used with few errors

Revision Quiz

1. Name two of the scientists involved in the discovery of DNA2. How many cells are produced as a result of meiosis3. By how much can an electron microscope magnify a specimen?4. What bonds hold the two complementary strands of DNA together?5. What does the word ‘diploid’ mean?6. In cloning, what is used to stimulate the egg cell to start dividing?7. Give one feature of a bacterial cell that isn’t present in animal or plant cells.8. What is the function of the mitochondria?9. By how much can a light microscopes magnify a specimen?10. What do the letters A, T, C and G stand for in DNA?11. A specimen appears 15mm under a light microscope at a magnification of

1000, what is its real length?12. What is a gene?13. Name two organisms that have been genetically engineered to benefit

humans14. Where do the majority of stem cells come from that are used in stem cell

research?15. What happens when an enzyme becomes denatured?

1. Watson, Crick, Rosalind, Franklin2. Four3. 2 000 000x4. Hydrogen bonds5. Two of each chromosome/chromosomes in pairs6. Body cell nuclus donor7. Plasmid/chromosomal DNA, cell wall not made of cellulose, mesosome,

Pilli (not flagella; sperm cells have flagella so be careful with this one)8. Release energy OR produce/make ATP (NOT make energy!)9. 1500x10. Adenine, thymine, cytosine, guanine11. 0.015mm (remember the units!)12. Section of DNA that codes fro a protein13. Bacteria to produce insulin, golden rice, herbicide resistant crop plants14. Embryos left over from IVF15. The active site changes SHAPE