Year 10 Genetics
Priority
4.1 Inheritance
Dominant/recessive, genes, locus, Mendel,
chromosomes, haploid/diploid,
mitosis/meiosis, gametes/somatic cells,
genotype/phenotype, Punnett squares &
expected ratios, codominance, incomplete
dominance, heterozygous/homozygous
4.2 Human Inheritance
Boy vs. girl, pedigrees, sex-linked inheritance
Revision
Quiz
Genetics Counseling Project (4-5 lessons
needed)
Further Extension Work
4.3 Chemical Code for Life
DNA, nitrogenous bases (adenine, thymine,
guanine, cytosine), sugar, phosphate
4.4 Controlling Inheritance
Selective breeding, genetic engineering,
genetically modified, transgenic, gene probe,
DNA fingerprinting, cloning, gene therapy,
human genome
Name: _________________________________________
Suggested Activities
Possible activities:; Introduction to DNA & Chromosomes sheet, Rikki Lake genetics, Intro to
Punnett squares worksheet, Genetics problems – monohybrid crosses
Websites: Genetics tour of the basics (http://learn.genetics.utah.edu/content/begin/tour/) &
worksheet; http://www.dnaftb.org/ (many animations, including how Punnett squares work)
Video: Mendel’s experiments with pea plants; mitosis video; meiosis video; meiosis animation
http://highered.mcgrawhill.com/sites/0072495855/student_view0/chapter28/animation__how_meiosis_works.html
Homework book: Heterozygous and homozygous (p.61)
Questions: 1-23 (p137-138)
Possible activities: People and Pedigrees investigation; Genetics problems – pedigrees,
Genetics problems – sex-linked inheritance, Comparing traits worksheet (or p. 148)
Website: http://www.dnaftb.org/ (Pedigree animation)
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)
Extension & Variation
Genetics problems – dihybrid crosses
Genetics problems – advanced probability
Science at work activities p. 138
Modelling meiosis p. 139
Science at work activities p. 147
Blood groups
Continuous & discontinuous variation
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)
Students who do not achieve 15/20 for their quiz will be required to sit a make-up quiz
Prac: DNA extraction
Video: DNA structure
Homework book: Model DNA (p. 63-65)
Questions: 2-12, 14-21, 23 (p 154-155)
Possible activities: Controlling inheritance persuasive piece; Biotechnology debate; Controlling
Inheritance PMI
Homework book: Human cloning (p. 67-8)
Questions: 1-20 (p163)
Science at work activities p. 155
DNA replication video
Science at work activities p. 163
Biotechnology
PCR investigation, PCR simulation, PCR
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
1
Outline
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
characteristics? (Diet, amount of exercise, sun can tan skin/bleach hair etc)
- Why is genetics important in the real world or where can it be used?
(Cloning, genetically modified foods, test-tube babies etc)
Resources needed
Intro to DNA &
Chromosomes info
sheet
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
(draw diagram).
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
Mitosis & meiosis
videos, computer,
data projector
Year 10 Genetics
Brainstorm (15 mins)
- Why is each of these types of cell division necessary?
2
-
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
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
Punnett squares.
Punnett Squares
Worksheet: explains the above example using Punnett squares (20 mins)
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
4
Homework: Text Qs p. 137 –16, 20, 22
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
Intro to Punnett
squares worksheet
Rikki Lake genetics
worksheet
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
5
Homework: complete comparing traits worksheet
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.
6
Homework: Text questions p. 146 – 5, 7, 12, 14, 15, 23, 24 (to hand in next lesson)
Go over homework (10 mins)
Revision
Summary Qs p. 170 of text
Quiz
20 mins
Year 10 Genetics
7
8
9
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11
Other
Genetics Counseling Task – intro & research
Genetics Counseling Task – research
Genetics Counseling Task – research
Genetics Counseling Task – research
Genetics Counseling Task - presentations
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
Year 10 Genetics
Worksheet: controlling inheritance PMI
Persuasive piece