Genetics Buzzwords
physical appearance of an
organism.
the set of genes (alleles) that an
organism possesses
different forms of the
same gene
when two alleles (gene types)
are identical
when the two alleles are
different
allele which controls the
characteristic whenever it is
present.
BB or Bb
allele whose characteristics only show up when it is present on both
chromosomes
bb
Determining characteristics
In pea plants, tallness (T) is
dominant to dwarfness (t)
A tall pea plant could have a
genotype of:
TT homozygous dominant
Tt heterozygous
Both combinations have the
same phenotype- tall.
A dwarf pea plant could only have the genotype tt
homozygous recessive
Phenotype- dwarf.
Gene combinations
The simplest genetic cross involves one characteristic
and is called a monohybrid cross.
In this the parents (P) are crossed (bred) with each other, and
the offspring (F1 generation) observed and counted.
Follow the procedure on the board!!
Mother
Father
XX
XY
gametes
X
Offspring:
Male or
female?
X
X
Y
XX
XY
XX
XY
F
M
F
M
1:1 ratio
male to
female
offspring
This explains how the sex of a child is
determined by X and Y chromosomes.
This can also be shown and
combinations worked out using
a Punnett square:
X
X
X
XX
XX
Y
XY
XY
Task
1. Complete the problems in the Monohybrid
Crosses booklet
• DO NOT SKIP STEPS!!
• Always define the alleles
• Always draw the Punnet square
2. Let´s play Traits Bingo! (15 min)
Keywords review
• Can you match up the key words to the
definitions?
• You only have 4 min before the bomb goes
off!
STARTER: Get your brains in gear!
NO NOTES!!!
A – normal skin
pigmentation
a – albino
What percentage chance is there of
producing a child with albinism?
Tasks this lesson
1: Finish the Monohybrid Crosses revision
booklet (15 min)
2: Try the problems in the More Monohybrid
crosses booklet! (20 min)
3: Let’s play Traits bingo! (15 min)
1. Who is known as “the man of 1000 peas?”
2. How long has he been running his experiments for?
STARTER
3. How many plants did he grow?
4. What did he notice when he first grew pea plants?
5. What field of biology has come about because of his experimenting on peas?
Tasks this lesson
1.
2.
3.
Finish the More Monohybrid Crosses booklet
Attempt the past paper questions (put the theory into practice!)
Finish the lyrics!
Tasks this lesson
1.
2.
3.
Have a go at the past paper question booklet
Read the Mendel´s Laws booklet and answer the questions
The genetics of skin colour TED talk