Year 10 Genetics Name: ______
Priority Suggested Activities Extension & Variation 4.1 Inheritance Possible activities:; Introduction to DNA & Chromosomes sheet, Rikki Lake genetics, Intro to Genetics problems – dihybrid crosses Dominant/recessive, genes, locus, Mendel, Punnett squares worksheet, Genetics problems – monohybrid crosses Genetics problems – advanced probability chromosomes, haploid/diploid, Websites: Genetics tour of the basics (http://learn.genetics.utah.edu/content/begin/tour/) & mitosis/meiosis, gametes/somatic cells, worksheet; http://www.dnaftb.org/ (many animations, including how Punnett squares work) Science at work activities p. 138 genotype/phenotype, Punnett squares & Video: Mendel’s experiments with pea plants; mitosis video; meiosis video; meiosis animation Modelling meiosis p. 139 expected ratios, codominance, incomplete http://highered.mcgraw- dominance, heterozygous/homozygous hill.com/sites/0072495855/student_view0/chapter28/animation__how_meiosis_works.html Homework book: Heterozygous and homozygous (p.61) Questions: 1-23 (p137-138) 4.2 Human Inheritance Possible activities: People and Pedigrees investigation; Genetics problems – pedigrees, Science at work activities p. 147 Boy vs. girl, pedigrees, sex-linked inheritance Genetics problems – sex-linked inheritance, Comparing traits worksheet (or p. 148) Blood groups Website: http://www.dnaftb.org/ (Pedigree animation) Continuous & discontinuous variation Prac: vegetable people (p. 149) Video: Hand-Me-Down Genes (and worksheet); Reproduction and Genetics video 530 SPE (and worksheet) Homework book: Pedigree analysis (p.62) Questions: 1-24 (p146-147)
Revision Possible activities: Genetics revision board game; genetics revision worksheets Homework book: Genetics crossword (p. 69); Sci-words (p. 70-71) Questions: 1-18 (p170-171) Quiz Students who do not achieve 15/20 for their quiz will be required to sit a make-up quiz Genetics Counseling Project (4-5 lessons needed) Further Extension Work 4.3 Chemical Code for Life Prac: DNA extraction Science at work activities p. 155 DNA, nitrogenous bases (adenine, thymine, Video: DNA structure guanine, cytosine), sugar, phosphate Homework book: Model DNA (p. 63-65) DNA replication video Questions: 2-12, 14-21, 23 (p 154-155) 4.4 Controlling Inheritance Possible activities: Controlling inheritance persuasive piece; Biotechnology debate; Controlling Science at work activities p. 163 Selective breeding, genetic engineering, Inheritance PMI genetically modified, transgenic, gene probe, Homework book: Human cloning (p. 67-8) Biotechnology DNA fingerprinting, cloning, gene therapy, Questions: 1-20 (p163) PCR investigation, PCR simulation, PCR human genome Simulation: http://learn.genetics.utah.edu/content/la bs/pcr/ Qs 1-2 (p169) Year 10 Genetics
Gel Electrophoresis Simulation: http://learn.genetics.utah.edu/content/la bs/gel/ Assessment Range of worksheets Quiz Genetics Counselling Project Year 10 Genetics
Lesson Outline Resources needed 1 Introduction to Genetics/Heredity/Inheritance (5 mins) Discussion: - What does it mean? - Other than heredity, what other important factor influences how we look/act? (Environment – sometimes hard to say which traits are environmental and which are because of genetics) - What is an example of how one’s environment might influence their Intro to DNA & characteristics? (Diet, amount of exercise, sun can tan skin/bleach hair etc) Chromosomes info - Why is genetics important in the real world or where can it be used? sheet (Cloning, genetically modified foods, test-tube babies etc)
Intro to DNA/Chromosomes (20 mins) Discussion/notes: - Follow info sheet (intro to DNA & Chromosomes)
Activity: in one sentence, describe the relationship between genes, DNA and chromosomes.
Karyotypes (5 mins) - Use diagrams called karyotypes to show all the chromosomes in an individual - What might karyotypes be useful for? - Determining sex of a child – look at sex c’somes (XX = female, XY = male) - Picking up abnormalities or defects
Looking at picture on worksheet: (5 mins) - Every person has 23 pairs of c’somes – 22 pairs of autosomes & 2 sex chromosomes - Chromosomes are arranged in homologous pairs (matching pairs) – for each pair, one has come from the mother and one from the father
Mitosis & Meiosis (10 mins) Discussion/Notes - Can’t just give away our chromosomes or cells to make offspring, so how does this happen? - In order to produce new people, humans must go through cell division - Two different types of cell division
Mitosis is cell division in which a cell with 46 chromosomes splits into 2 daughter cells, each with 46 chromosomes. The daughter cells are identical to the original cell Mitosis & meiosis (draw diagram). videos, computer, data projector Meiosis is cell division in which a cell starts with 46 chromosomes and splits into 4 daughter cells, each with 23 chromosomes. Daughter cells therefore have half the number of chromosomes as the original cell (draw diagram).
Mitosis occurs in most body cells. These are called somatic cells (e.g. nerve cells, brain cells, skin cells). The cells are referred to as being diploid because they have 2 sets of chromosomes. Meiosis occurs in the cells that produce eggs and sperm. Eggs and sperm are called gametes or sex cells. These cells are referred to as being haploid because they have one set of chromosomes.
Videos (5 mins) - Mitosis Video - Meiosis video Year 10 Genetics
Brainstorm (15 mins) - Why is each of these types of cell division necessary?
- Mitosis needed for growth (is how we get bigger, develop from a single cell) and repair (cells die all the time & we need to create new ones).
- Meiosis is needed to create ova and sperm. Ova & sperm need to be haploid so they can come together to produce once cell (called a zygote) with the normal number of c’somes. This cell will then go through mitosis to grow & develop.
Homework: draw a mind map linking the following terms – c’some, gene, DNA, karyotype, homologous pair, mitosis, meiosis, haploid, diploid, somatic cells, gametes 2 Have now answered WHY we look like our parents but not why we may look more like one parent than the other or how some children end up looking more like their grandparents than their parents.
Mendalian Genetics Gregor Mendel (10 mins) - Gregor Mendel was an Austrian monk who conducted many experiments on pea plants that are responsible for much of the knowledge we have today about genetics - For example, he is the reason we know why you might have blue eyes but both your parents have brown eyes, or why you inherit curly hair from your father rather than straight hair from your mother - He bred different pea plants together and analysed the traits of the offspring
Draw diagrams on board to illustrate the following: - Mendel bred pea plants that were tall with pea plants that were short and noted that most offspring were tall and some were short - Bred pea plants that were short together and found that all the offspring were short - Bred pea plants that were tall together and found that some offspring were tall and some were short - didn’t understand how this could happen!
Using Mendalian genetics definitions sheet (30 mins) - Have talked about how we inherit genes/chromosomes from our parents. Each parent will pass on to us one of each gene. For example, we inherit the gene for eye colour from our mother and the gene for eye colour from our father. However, these genes may not be identical – they have different forms (e.g. one will make an individual have blue eyes, one brown eyes, one green eyes etc). These different forms of genes are called alleles.
- An individual is said to be homozygous if they inherit two identical alleles. (e.g. You may inherit an allele for brown hair from your mother and an allele for brown hair from your father).
- An individual is said to be heterozygous if they inherit two alleles that are different. (e.g. you may inherit an allele for brown hair from your mother but an allele for black hair from your father).
- Genotype: is how we describe what genes an individual has. We use letters to represent each allele that an individual inherits. For example, if using the letter B to represent eye colour, B could represent brown eyes and b blue eyes. This way we can show what they have inherited from each parent and Year 10 Genetics it allows us to determine what traits they have.
- Phenotype: are the physical characteristics that an individual has (e.g. having blue eyes or brown hair or being tall/short). The phenotype of an individual is determined by their genes/genotype.
If an individual inherits two different alleles for a trait, how do we know which will show in their phenotype? - Some traits are dominant and some are recessive - If an individual inherits an allele for the dominant trait, that trait will show (e.g. BB or Bb) - If an individual inherits two alleles for the recessive trait, that trait will show (e.g. bb)
Worksheet (20 mins) - On back of definitions sheet to test understanding - Go over answers
Homework: Text Qs p. 137 – 1, 6, 7, 8, 12, 13, 14
3 Go over homework (10 mins)
Mendel’s Experiments (15 mins) Revision of terms - Look at figure 4.1.10 p. 135 & talk through: 1. Green pea plant is being bred with yellow pea plant 2. Green is homozygous for the dominant trait, yellow is homozygous for the recessive trait 3. Meiosis makes sure we only have ½ the number of chromosomes, so each offspring receives one allele from each parent 4. Egg and sperm come together – offspring gets G from green parent and g from other 5. Means all offspring are Gg – Heterozygous green
Diagram is a very complex way of determining possible offspring – easier to use Intro to Punnett Punnett squares. squares worksheet Punnett Squares - Worksheet: explains the above example using Punnett squares (20 mins) Rikki Lake genetics worksheet Rikki Lake Genetics Sheet (30 mins) - Match sets of parents with their children using their physical characteristics - Part 1 – answer the Qs (look at your definitions) - Part 2 – fill in parent genotypes using table of characteristics; use the punnett squares on the last page to show what possible combinations of offspring the parents could have - Part 3 – Match the children to the parents using the results of your punnett squares - Part 4 – the scandal
Homework: Text Qs p. 137 –16, 20, 22 4 Go over homework (10 mins)
Codominance and Incomplete Dominance (15 mins) Notes/Discussion: - So far, the inheritance we’ve been talking about is complete dominance – one trait completely masks the other - However, can have situations where both traits show
- Codominance: the phenotype of the heterozygous organism is a Year 10 Genetics combination of the phenotypes of the homozygous organisms – for example – pure red cows (RR), pure white cows (WW) and ‘roan’ (white and red) cows (RW). In this case we use two different capital letters to show that one allele is not dominant over the other; rather, they are CODOMINANT
- Incomplete dominance: the heterozygous organism has a phenotype between the two phenotypes of the heterozygous organisms – for example – red snapdragons and white snapdragons produce a heterozygous offspring that is pink.
Boy vs. Girl (5 mins) Read p. 143 - 46 pairs of chromosomes - One pair are the sex chromosomes - Males have X and Y - Females have X and X Draw a Punnett square to illustrate the probability of having a boy or a girl
Comparing Traits - maybe cut out for 10D - worksheet
Homework: complete comparing traits worksheet 5 Collect homework
Sex-linked Inheritance Discussion/Notes: - So far, the traits we have considered are carried on our normal body cells (somatic cells). However, traits may also be carried on our sex chromosomes. - Read through p. 145 - Emphasise: notation for sex-linked disorders & meaning of carrier
Possible notes: Sex-linked inheritance: Some conditions or traits can be carried on our sex chromosomes. These are mostly found on the X chromosome as the Y chromosome if small and has very few genes. To show that a condition is found on the X chromosome, we write the alleles like this (if we decide to use the letter H) : XH for the dominant allele and Xh for the recessive allele. Traits that are recessive and carried on the X chromosome are much more common in males than females.
Pedigrees Discussion: - Read through p. 144-145 - Use figure 4.2.10 to show how to determine if a trait is dominant or recessive Worksheet: People & pedigrees investigation – if you think you have a good understanding of pedigrees, may work individually. If you don’t get it, come to back of room & we’ll go through the sheet together.
Homework: Text questions p. 146 – 5, 7, 12, 14, 15, 23, 24 (to hand in next lesson) 6 Go over homework (10 mins)
Revision Summary Qs p. 170 of text
Quiz 20 mins 7 Genetics Counseling Task – intro & research 8 Genetics Counseling Task – research Year 10 Genetics 9 Genetics Counseling Task – research 10 Genetics Counseling Task – research 11 Genetics Counseling Task - presentations Other Hand-Me-Down Genetics video Reproduction & Genetics video
Blood groups (30 mins) Read through p. 142 together - Important points: 6 genotypes 4 phenotypes A and B are dominant to O AB are co-dominant with each other Worksheet: blood groups
Simple & Complex inheritance (20 mins) Read p. 142-3 - Some traits are only affected by one gene, others by lots of genes - Not always as simple as we show in Punnett squares
Continuous and Discontinuous variation Read p. 143 - Clearly defined characteristics show discontinuous variation: e.g. right handed or left-handed can’t be 40% left and 60% right etc - Where a range of characteristics may occur, called continuous variation e.g. can be lots of heights , not just tall or short
Genetic diseases report
DNA Structure Notes/Discussion: - Go through structure on board - Think of DNA as being a ladder - Sugar/phosphate backbone - Nitrogenous bases - Complementary base pairs - DNA usually coiled up very tight into a structure called a double helix, but unwinds to replicate
Worksheet: DNA modeling (from homework book) OR lolly DNA
DNA Extraction Demonstrate method - Step 3 – don’t plonk metho in middle of solution or it won’t work
Clean up: - DO NOT POUR ANYTHING DOWN SINK - Wash and return stirring rods to container - All waste into big beaker - Rinse beakers and test tubes – test tubes to waste tray, beakers back - Return metho & detergent to front - Wipe down benches
Controlling inheritance - Read pp. 157-162 Worksheet: controlling inheritance PMI Persuasive piece Year 10 Genetics