The document discusses basic genetics concepts including Punnett squares, dominance and recessiveness of alleles, and the significance of homozygous and heterozygous traits. It illustrates how traits like ear lobe shape and plant flower colors are inherited, as well as the influence of multiple alleles on traits such as blood type. Additionally, it emphasizes the interaction between genes and environmental factors in determining characteristics.

1.  Punnett squares and uses.
 Genes (Alleles).
 Why are some genes dominant and others
recessive? How do we write symbols for
these genes?
 What is homozygous and heterozygous?
 Predict phenotypes from genotypes.
 Test crosses.
 Blood Types.

2.  Diagram used to determine genetic
crosses
 A a
A
a

3.  Diagram used to determine genetic
crosses
 A a
A
a
AA

4.  Diagram used to determine genetic
crosses
 A a
A
a
AA Aa

5.  Diagram used to determine genetic
crosses
 A a
A
a
AA
Aa aa
Aa

6.  Use different Letters or Symbols
 G @
B
@

7.  Use different Letters or Symbols
 G @
B
@
BG

8.  Use different Letters or Symbols
 G @
B
@
BG B@

9.  Use different Letters or Symbols
 G @
B
@
BG
G@ @@
B@

10.  Worksheet Q 1-6
 Planners - Tuesday 13/3/12

11.  Genes are how living organisms inherit
features from their ancestors
 What did you inherited from your parents'
genes
 Genetics tries to identify which features
are inherited, and explain how these
features are passed from generation to
generation.

12.  Different forms of a gene
 Your ear lobes are
inherited
 From your DNA
 Genes (Alleles) are inherited as units,
with two parents dividing out copies of
their genes to their offspring.

13.  The ear lobe is controlled by 2 alleles.
 Mum and Dad
 YOU

14.  A DOMINANT allele covers up the recessive form.
 A recessive allele gets covered up in the
presence of a dominant allele
 A DOMINANT allele is represented in CAPITALS
 i.e. L – for an attached lobe as this is dominant
 a recessive allele is represented in lower case
 i.e. l – for an unattached lobe as this is a
recessive allele
 The dominate allele will be seen.

15.  Phenotype – is the physical
characteristic of the gene
ie attached lobe
 Genotype is the combination of alleles
(genes) that make up the gene –
represented in letters. LL,
Ll (lL), ll

16.  L – for an attached lobe
 l – for an unattached lobe
 2 alleles.
LL ll
Ll

17.  L – for an attached lobe
 l – for an unattached lobe
LL ll
Ll

18.  L – for an attached lobe
 l – for an unattached lobe
 Phenotypes
LL ll
Ll

19.  L – for an attached lobe
 l – for an unattached lobe
 Phenotypes
Genotypes LL ll
Ll

20.  Homozygous –
 the same allele – LL or ll
 Heterozygous –
 different allele - Ll

21.  Mum has a heterozygous ear lobe, Ll and Dad
has a recessive ear lobe, ll (thus Homozygous).
What ear lobe will their children have?
Mum = Ll Dad = ll
I I
L Ll Ll
I ll ll
Punnett Square

22.  Mum has a homozygous ear lobe
that is attached and Dad has a recessive allele ear
lobe. What ear lobe will their children have?
Mum = LL Dad = ll
I I
L Ll Ll
L Ll Ll
All the childen will have Ll Genotypes their
ear lobe genes are hetrozygous.

23.  LL
 Ll
 ll

24.  Two black fish look the same but have
different genotypes. The fish with genotype
BB is said to be homozygous, or pure
breeder because both the alleles for the skin
colour gene are the same. The other fish is
said to be heterozygous or Hybrid, because
its two alleles for skin colour gene are
different.
 What offspring can occur when the fish
cross breed, that is BB & Bb.
 What offspring can occur when 2
heterozygous breed?

25.  Incomplete dominance is a condition when neither
allele inherited is dominant or recessive over the
other
 This will result in a blend/fusion of characteristics
 An example of this is in snapdragons, a flower
where its colour can be red, pink, or white.
 A white (WW) snapdragon crossed with a red (RR)
snapdragon produces all pink offspring
 The heterozygous (RW) condition results in pink flowers.

26. RED = RR White = WW
RW RW
RW RW
All the off spring will be RW – Pink
R R
W
W

28.  When both alleles contribute to the
phenotype of an organism
Ex.) Speckled Chickens

29. Black = BB White = WW
BW BW
BW BW
All the off spring will be BW – Black
with White
B B
W
W

30. BW offspring = BW White = WW
BW WW
BW WW
The off spring ratio would be
1:1 BW:WW
B W
W
W

31.  When more than two possible alleles
exist in a population
Ex.) blood type
 IA
 IB
 i
Dominant
Recessive

32. Video on blood types

33. Human Blood Types
Phenotype Genotype
A
B
AB
O
IA
IA
or IA
i
IB
IB
or IB
i
IA
IB
ii

34.  Traits controlled by two or more genes
Ex.) eye color, skin color

35.  The characteristics of any organism, is
not only determined by the genes it
inherits
 Characteristics are determined by
interactions between genes and the
environment
 Ex.) genes may affect a plants height
but the same characteristic is
influenced by climate, soil conditions
and availability of water

36.  Human hair is inherited by incomplete
dominance. Human hair may be curly
(CC) or straight (cc). The heterozygous
genotype (Cc) produces wavy hair.
Show a cross between two parents
with wavy hair

37.  A man is suing his wife on grounds of
infidelity. The man claims that the child is
blood type O and therefore must be
fathered by someone else. Can he use
this evidence in court if he and his wife
both have heterozygous B genotypes?
 Show the cross of the two parents