Gene Scene. A pack of 5 topics exploring the world of Genetics, aimed at S1-S3 pupils

Transcription

1 pack of 5 topics exploring the world of enetics, aimed at S1-S3 pupils

2 ontents ontents Overview of Information Pack... 3 opic 1: Inheritance... 4 ctivity 1: Nature or Nurture?... 4 ctivity 2: raits... 6 opic 2: What are genes made of?... 9 ctivity 1: DN odes... 9 DN ode rids DN Information Sheet ctivity 2: DN Model ctivity 3: DN Isolation from Fruit and Vegetables opic 3: Breaking the ode : ctivity 1: RN ranscription Jigsaw ctivity 2: Breaking the ode ranslating the ode opic 4: Proteins : ctivity 1: Protein Match opic 4: Proteins Protein Match : Pupil Worksheet ctivity 2: What s in a Name? opic 5: enetic Predictions 29 2

3 Overview Overview of Information Pack his information pack contains an overview of each of the 5 topics along with teacher s notes, background information, details of how to set up the activities and Pupil worksheets where appropriate. enetics is the study of the genome, which is a complete set of an organism s genes. his is important as human genetics give information about people s traits. he information pack introduces the topic of inherited traits before looking at some of the science behind this. enes themselves are small pieces of DN. herefore, the resource also has activities looking at DN and how it can code for mrn, which in turn codes for functional proteins. It is proposed that this information pack contains enough material for at least 6 weeks work. It is aimed at S1-S3 pupils. For some of the topics, there are a number of activities that, depending on the duration of the club, may all be able to be carried out in the same week, but could be split over different sessions. 3

4 opic 1: Inheritance opic 1: Inheritance Overview: his topic is used to introduce the pupils to inherited traits. Every attempt has been made to generalise the information in as far as possible, to avoid any issues due to family circumstances, but this topic requires some sensitivity to pupils circumstances. here are two activities in this topic: 1. Nature or nurture? 2. raits ctivity 1: Nature or Nurture? ims: o introduce different traits Materials: ape measures may be helpful Enough clear space for the pupils to get into groups or a line Paper and pens for recording results Sort each person in the class into groups or a line by the following characteristics: 1. Male/female 2. Eye colour 3. Dimples 4. Hair colour 5. Height 6. Shoe size 4

5 opic 1: Inheritance Suggested questions to ask the pupils [and expected results]: What characteristics were easy to determine your grouping? [hose with clear cut categories and those that were easily observable.] What groups were you in? Which characteristics have definite options? [Male/female, eye colour, hair colour, dimples hese are called discrete variables as there are definite categories.] What characteristics have a ranked line order? [Height, shoe size hese are continuous categories that have a large range.] Where did you come in the line? What characteristics can be affected by environmental conditions? [Height and shoe size quality and quantity of food affect growth too. Eye colour could have coloured lenses. Hair colour could be dyed.] hese observable characteristics are called traits. Some traits are passed down from parent to child or affected by the environmental conditions. 5

6 opic 1: Inheritance ctivity 2: raits raits are the observable characteristics that people exhibit. hey can be inherited, learnt or affected by the environment. ims: o investigate how common different traits are within a population group. Safety: In the past, the P taste test has also been used to test for genetic traits. However, there is concern about the safety and so it is advised that the P test should not be carried out. Materials: Pen Small sticky notes two colours Large sheets of paper with one of the following headings: tongue rolling and ear lobe attachment. Below each heading, draw a line halving the paper and put yes in one half and no in the other. Mirrors (optional) Large piece of paper with the diagram shown in Figure 1 Part 1: 1. ive each boy one colour of post-it notes and the girls the other colour. Each pupil will need two post-it notes. 2. sk the pupils if they can roll their tongue lengthways. hey may wish to have access to a mirror to check. he pupils should put one post-it note in the yes or no column depending on their answer. 3. sk the pupils if the bottom of their ear lobes attached right to the very bottom of the ear lobe, or are they detached at the bottom. gain the pupils should put one post-it note in the yes or no column depending on their answer. 6

7 opic 1: Inheritance Suggested questions to ask the pupils [and expected results]: How many are in the class? How many people can roll their tongue? What percentage is this? How many people cannot roll their tongue? What percentage is this? What percentage of the people who can roll their tongue are male? What percentage of the people who can roll their tongue are female? How many people have attached earlobes? What percentage of males have attached earlobes? What percentage of females have detached earlobes?? here are lots of different traits. In a population, some traits are more common than others. Part 2: 1. ive each boy one colour of post-it notes and the girls the other colour. Each pupil will need four post-it notes. 2. Everyone should put one post it note next to class. 3. hey should then add a post it note to each trait that applies to them, following the lines. (e.g. going along the top, the first is class, then males, then males who have their earlobe attached, then males who have their earlobe attached and who can roll their tongue). Suggested questions to ask the pupils [and expected results]: an you see how there are common traits in the group? Do you notice anything about the groups as you move from left to right? [Less people as the groups get more specific.] Which group has the most people and therefore is the most common grouping of traits? Which group has the least people and therefore is the least common grouping of traits? Every person will have a slightly different combination of all the possible traits. 7

8 opic 1: Inheritance lass Figure 1: Diagram for raits ctivity (part 2) Male Female Ear lobe attached Ear lobe detached Ear lobe attached Ear lobe detached an roll tongue annot roll tongue an roll tongue annot roll tongue an roll tongue annot roll tongue an roll tongue annot roll tongue 8

9 opic 2: What are genes made of? opic 2: What are genes made of? Overview: enetics is the science of how traits are passed from one generation to another via genes. enes are parts of DN molecules. he DN is contained in chromosomes in the nucleus of cells. Each person has 46 chromosomes 23 from your mother and 23 from your father. here are lots of different combinations. Every person has a different genetic makeup. his topic uses two activities to illustrate the DN structure: 1. DN codes this introduces the building blocks of DN and how they join together 2. DN model this uses sweets and cocktail stick to model the DN helix structure. here is then a third activity to isolate plant DN. Extension: Make a DN origami model from ctivity 1: DN odes ims: o introduce the students to the DN code Materials: DN Information Sheets (see page 13) DN ode Sheets (see below and page 11) Pens Figure 2: DN ode rid 9

10 opic 2: What are genes made of? 1. On the top line of the grid in the code sheet, write a random list in the blank boxes of the following four letters:,, and. hese letters,,, and represent the DN building blocks, called bases. he bases are bonded to each other. his is represented by the between the boxes. 2. DN is made up of two chains. Fill in the bottom line according to the DN rules : o If there is an in the top row, put a in the bottom square. o If there is a in the top row, put a in the bottom square. o If there is a in the top row, put a in the bottom square. o If there is a in the top row, put an in the bottom square. 3. s well as being bonded to each other in the chain, the bases are also bonded to the other chain. Join the each of the letters in the top row with the bottom row by bond lines. Keep the code you have written as it will be used in later activities. he order of this code gives the genetic detail. he chains are then twisted into a shape called a double helix. his will be demonstrated in the next activity. Suggested questions to ask the pupils [and expected results]: Does anyone have a matching code? [nlikely as there are so many combinations possible.] 10

11 opic 2: What are genes made of? DN ode rids DN ode rids 11

12 opic 2: What are genes made of? DN Information Sheet DN stands for deoxyribonucleic acid. DN is contained in chromosomes in the nucleus of cells. It is a long molecule made up of combinations of 4 different subunits called bases. hese are known by the letters,, and and are shown in Figure 3:, denine, hymine, uanine, ytosine Figure 3: Structures of the DN bases hese bases are joined together in long chains via deoxyribose and phosphate. wo chains are joined together via base pairing, where bonds with and bonds with. hese chains are twisted as shown in Figure 4. his shape is called a double helix. Figure 4: DN double helix structure. 12

13 opic 2: What are genes made of? ctivity 2: DN Model ims: o model the 3D shape of DN Safety: DO NO eat the sweets heck for allergies ake care when using the cocktail sticks Materials: DN information sheet ocktail sticks Jelly sweets in 4 different colours he code from the previous activity 1. Read the DN information sheet 2. s a class decide on a colour code for the bases. 3. sing the jelly sweets and the colour code, going along the top row of your code, join the jelly sweets together using the cocktail sticks. 4. Repeat with the bottom row of the code. 5. Join the rows together so each complementary base pair is bonded using the cocktail sticks. 6. Once you have completed this, it will look like a ladder. o make this into a double helix, lift the model at both ends and twist. his twisted model (as shown in Figure 5) illustrates the double helix structure of DN. Figure 5: DN model 13

14 opic 2: What are genes made of? ctivity 3: DN Isolation from Fruit and Vegetables ims: o isolate a DN sample from fruit and vegetables Safety: Do not eat the fruit and vegetables ake care the water temperature is not too hot are should be taken when using the blender it is best that the teacher blends the fruit and then portions this. risk assessment and OSHH form should be completed for using ethanol and all necessary precautions taken. Materials: old water Ice Salt Washing up detergent Warm water Plastic bowl 100 ml and 250 ml beakers Ethanol Salt Balance or teaspoon Measuring cylinder Blender Fruit, e.g. banana, strawberries, onions Sieve Filter paper Stirring rod Boiling tube 14

15 opic 2: What are genes made of? Method: 1. Place ice and some cold water in the plastic bowl. 2. Pour approximately 50 ml of ethanol into a beaker and place the beaker in the ice bath to cool the ethanol. 3. Dissolve approximately 5 g (or add a small teaspoonful) of salt and 10 ml (or two teaspoonfuls) of detergent in 150 ml warm water. 4. Blend the fruit (approximately 50 g per experiment) 5. dd the warm water, salt and detergent mix to the blended fruit, then mix. 6. Put the filter paper in the sieve and sieve the mixture into the beaker. he pupils will need to mix with care, taking care not to rip the filter paper. 7. ransfer about 5 ml of filtrate to the boiling tube. 8. arefully add 5-10 ml of the cold ethanol down the side of the boiling tube on top of the filtrate. 9. Let the solution sit for about 2 minutes without disturbing the layers. 10. Look at where the ethanol meets the water mixture and you will see some white strands. his is the DN from the fruit. Point out that it doesn t look like the twisted structure from the earlier activity as it is very small and you cannot see one individual strand. 15

16 opic 3: Breaking the ode opic 3: Breaking the ode : Overview: he DN letters are the DN code. he order of the DN bases,, and gives the DN code. It is used for making proteins, but it doesn t do this directly. he DN code can determine the structure of proteins. o do this, there is a two-step process. First the DN code is transcribed to a RN code. his RN code is then translated into a sequence of amino acids which are joined together to form the protein. his topic uses two activities to illustrate how DN codes for proteins via mrn: 1. RN ranscription Jigsaw 2. ranslating the ode ctivity 1: RN ranscription Jigsaw ims: o transcribe the DN code to an RN code. Materials: Jigsaw pieces - each sheet of jigsaw pieces should be copied on different colours of paper so each base has a different colour see p Scissors ask the pupils to cut out the jigsaw pieces he code from the previous activities 1. fter cutting out the jigsaw pieces, put them in a pile to mix them up. he pupils should use the,, and jigsaw pieces to make the DN code written earlier. You should have two linked chains. he DN code is then transcribed into another code called a RN code. RN stands for ribonucleic acid. he RN is only a single strand and is made up of,, and (racil). his time bonds with. 16

17 opic 3: Breaking the ode 2. Separate the two DN chains from each other and then use the RN jigsaw pieces to form the RN code. 3. Write down the RN sequence and keep a copy of this for the next activity he RN code is then translated into a protein. 17

18 opic 3: Breaking the ode 18

19 opic 3: Breaking the ode 19

20 opic 3: Breaking the ode 20

21 opic 3: Breaking the ode 21

22 opic 3: Breaking the ode 22

23 opic 3: Breaking the ode ctivity 2: Breaking the ode ranslating the ode ims: o translate the RN code into a protein Materials: he RN code from the previous activity he amino acid code sheet see p26 From your DN code, you transcribed a RN code. o get a protein, you need to translate the RN code. In this activity you will translate your RN code into amino acids. he amino acids join together to form a protein. 1. When translating the RN code into a protein, starting from the end, group the RN code into three letter groups. 2. sing the amino acid code sheet, find the amino acid that corresponds to each of the three letter codes. e.g. is Ser or S 3. ontinue until you have a list of five amino acids. he amino acids are bonded together to form a protein. he sequence determines the type of protein and its function. Suggested questions to ask the pupils [and expected results]: Has anyone got the same protein sequence? [his is very unlikely as although there are only 4 different options for the bases, these bases can create lots of different sequences.] 23

24 mino cid ode Sheet opic 3: Breaking the ode Second Letter First Letter Lys (K) rg (R) Ile (I) sn (N) Ser (S) hr () Lys (K) rg (R) Met (M) sn (N) Ser (S) Ile (I) ln (Q) His (H) Pro (P) rg (R) ln (Q) 24 His (H) lu (E) sp (D) rg (R) ly () lu (E) sp (D) SOP Leu (L) Val (V) SOP Leu (L) yr (Y) ys () Phe (F) Ser (S) SOP rp (W) Leu (L) yr (Y) ys () Phe (F) hird Letter

25 opic 4: Proteins opic 4: Proteins : Overview: he previous two topics have looked at DN and how it codes for proteins. Often pupils think of proteins as components of food. his topic introduces the wide range of proteins. his topic uses two activities to discuss proteins: 1. Protein Match 2. What s in a Name? ctivity 1: Protein Match ims: Materials: o show some the wide variety of functions of proteins within the body Protein grid Pens Internet access will be needed for some of the examples able 1 shows some functions for proteins within the body. Match the names to the descriptions complete the table on p28. able 1: nswers for the protein match activity Name Haemoglobin in blood Insulin Myosin and actin in muscles Fibrin ntibodies Pepsin ollagen ubulin Keratin Description ransports oxygen round the body Involved in regulating blood sugar uptake Involved in movement Involved in wound healing Defend your body against infection Example of digestive enzyme Structural protein that supports connective tissues, e.g. skin, ligaments and tendons. Forms hollow tubes supporting cell structure In strands of hair and in nails 25

26 Proteins Match Pupils Worksheet opic 4: Proteins Protein Match : Pupil Worksheet In the previous activities, you have shown how the DN code can be translated to a protein (via RN). In this activity, you will try to identify some of the proteins that are found in your body. he following table shows some functions for proteins within the body. Match the names to the descriptions. You may need to do some research for this activity. Name Description ransports oxygen round the body Involved in regulating blood sugar uptake Involved in movement Involved in wound healing Defend your body against infection Example of digestive enzyme Structural protein that supports connective tissues, e.g. skin, ligaments and tendons. Forms hollow tubes supporting cell structure In strands of hair and in nails ntibodies; ollagen; Fibrin; Haemoglobin in blood; Insulin; Keratin; Myosin and actin in muscles; Pepsin; ubulin 26

27 opic 4: Proteins ctivity 2: What s in a Name? ims: o use the concept of coding to find a DN sequence and a protein, using the pupils name as the amino acid code Materials: ccess to internet Paper and pens mino acid code table In the previous activities you have used the DN code to find the RN code and then find the protein amino acid code. he sequence of the letters can be in any order so there are lots of possible combinations. In this activity, you will use your name as an amino acid code and see if you can find the DN code and then identify your name as a protein! Part 1: 1. Write your name down. 2. se the amino acid code table to convert your name into an RN sequence. E.g. if the first letter is L, then this would correspond to the amino acid leucine (Leu). From the table, the RN code for Leu is either or, choose one and write this down. If your name has a letter that is not an amino acid then the RN triplet should be written as NNN. he N means that it could stand for any combination of bases. 3. onvert the RN sequence to a DN sequence ( becomes, becomes, becomes and becomes ). If you have used NNN in the RN sequence then keep this as NNN for the DN sequence. his is the DN code for your name. 27

28 opic 4: Proteins Part 2: 1. Find the website page 2. ype your name in the box and press decode. his will give you a similar DN code and also search the database to see if this DN code corresponds to any known proteins that are found in any genomes that have been sequenced to date. Which genome contains YOR protein? 28

29 opic 5: enetic Predictions opic 5: enetic Predictions Overview: Since people s traits can be inherited, knowing the full genotypes of the parents allows you to make predictions for the probability of the offspring exhibiting certain traits and characteristics. his topic uses three different examples to illustrate how this can be achieved using the Punnett Square method: 1. Boy or irl? 2. Dominant vs Recessive 3. Eye olour 4. Blood ypes ims: o predict the probability of a number of characteristics using a tool called a Punnett Square. Materials: Pen opies of the Punnett square sheets (pupils worksheet) Example 1: Boy or irl? In their genetic material, females have XX chromosomes, while males have XY chromosomes. If each parent were to give one of these chromosomes to their offspring, what percentage chance would there be of them having a boy and what percentage chance would there be of them having a girl? o find this out, we use something called a Punnett square. 29

30 opic 5: enetic Predictions In the grid shown in able 2, you will see four empty boxes which you will fill in with the children s inherited chromosomes. able 2: Male or female Punnett square grid Father: XY X Y Mother: XX X X he father s XY chromosomes are at the top. he offspring can inherit either an X or a Y. o show this on the grid, they should write an X in each of the boxes in the column below the X. hen do the same for the Y column. Next, the mother s chromosomes are XX and are on the side of the grid. he offspring can either inherit one X or the other. o show this on the grid, they should then write an X in each of the boxes in the row next to the top X, before doing the same for the other row. hey should now have written two letters in each of the blank boxes and be able to identify the % chance of having a boy or girl. 30

31 opic 5: enetic Predictions he same technique can be used for other characteristics inherited from through genes. Suggested questions to ask the pupils [and expected results]: How many XX have they written? [2] How many XY have they written? [2] What does this mean? [Remember back to the start, where we said females were XX and males were XY.] How many of the 4 offspring would be girls? [2] How many of the 4 offspring would be boys? [2] What % chance would the parents have of having a girl? [2 of the 4, therefore 50% chance] What % chance would the parents have of having a boy? [2 of the 4, therefore 50% chance] Example 2: Dominant vs recessive similar process can be used for other genetic characteristics. Next, the pupils should repeat the previous process with the Punnett square in able 3,. In this example, both parents have the same genetic information for this characteristic, Ee. his is going to represent earlobe attachment with both parents having unattached earlobes. It is written in this way because the capital E is dominant over the small e, which is the recessive characteristic of attached earlobes. his means that if the capital E is present then the earlobe will be unattached. he earlobe would only be attached if the person has the genotype ee. able 3: Dominant or recessive Punnett square grid Father: a E e Mother: a E e 31

32 opic 5: enetic Predictions Punnet Square rids Suggested questions to ask the pupils [and expected results]: How many different combinations are there? [3, EE, Ee, ee] How many of each type? [I EE, 2 Ee and 1 ee] What % chance would the child have of having unattached earlobes? [75%, 3 out of the 4 have E present at least once] What % chance would the child have of having attached earlobes? [25%, only the ee genotype doesn t have E present at all] Example 3: Eye olour he previous example used one gene type. here are other characteristics that have two or more genes and this makes the Punnett square bigger and the predictions more difficult to predict. Eye colour can be simplified to two genes with them being represented by the letter and B. he rules: 1. is for brown eyes 5. b is for lighter eyes 2. a is for blue eyes 6. B is dominant and b is recessive 3. is dominant and a is recessive 7. is more dominant than B. 4. B is for green eyes sing a similar strategy to the previous examples, complete able 4 able 4: Eye colour Punnett square grid Father: abb B b ab ab B Mother: abb b ab ab 32

33 opic 5: enetic Predictions Punnet Square rids Male or female Punnett square grid Dominant or recessive Punnett square grid Father: XY Father: a X Y E e Mother: XX X X Mother: a E e Eye colour Punnett square grid Father: abb B b ab ab B Mother: abb b ab ab 33

34 opic 5: enetic Predictions Suggested questions to ask the pupils [and expected results]: able 5: nswers ype How many of each? What colour would these give? BB 1 Brown Bb 2 Brown bb 1 Brown abb 2 Brown abb 4 Brown abb 2 Brown aabb 1 reen aabb 2 reen aabb 1 Blue How many different types are there? How many of each? What colours would each type give? Do you think all the brown eyes would be the same colour? Why? [No, some will be darker than others due to the effect of the b gene.] Which brown genotype do you think would be darkest? [BB would be darkest because of the presence of only dominant brown on one gene and no presence of the lighter b on the other gene.] 34

35 opic 5: enetic Predictions In practice, while this is a very good approximation for eye colour genetics, the genetics can be more complex than this. Example 4: Blood ypes: Everyone has one of four blood types,, B, B or O. he genetic information for the blood types is shown in able 6. Both and B are dominant over O which is recessive. able 6: Blood type genotypes Blood ype B B O enotype or O BB or BO B OO omplete the family tree information (Figure 6) with blood type and genotype. HIN: Look for the blood types with only one genotype and fill these in first as this should help for the others. nswers are shown in Figure 7 35

36 opic 5: enetic Predictions Pupil Worksheet Blood roup Blood roup B enotype O enotype Blood roup Blood roup Blood roup B Blood roup B Blood roup O Blood roup enotype O enotype enotype enotype enotype enotype Blood roup Blood roup Blood roup Blood roup B enotype enotype enotype enotype Figure 6: Blood type family tree 36

37 opic 5: enetic Predictions Blood roup Blood roup B enotype O enotype BO Blood roup Blood roup Blood roup B Blood roup B Blood roup O Blood roup B enotype O enotype O enotype BO enotype B enotype OO enotype B Blood roup Blood roup Blood roup Blood roup B enotype O enotype O enotype O enotype BO or or Figure 7: Blood type family tree answers 37