Download Excellence

Low Excellence
Introductory paragraph defines gene and states the relationship between a
gene and an allele.
Allele examples relating to the question on flower colour are clearly stated.
Diagram does not link allele and base sequence.
Needs to link base sequences with genes.
Achievement criteria met. One of three Merit criteria achieved
therefore an overall Achievement grade for Question One.
Definition of gametes
and role in number of
chromosomes
explained.
Chromosome separation at
meiosis covered.
Reference to benefit for
population if genetic
variation.
Clear Merit overall. Excellence would be gained if candidate
noted the importance of constant reshuffling by meiosis to a
species.
Dominant allele defined.
Evidence of cleft chin being dominant.
Clear explanation of requirement for A to be heterozygous.
Punnett square, probability, and sample size well covered.
Merits in (a) and (b), plus Excellence in (c) give an overall
Excellence grade for Question Three.
Confusion in mutation definition - a mutation is a
“change”, not necessarily wrong.
Clear understanding that inheritable mutations require
gametes to pass them on to the next generation.
Link with genetic change (mutation) and variation.
Clear understanding that large leaved individuals
of species A are better adapted to survive and
reproduce. This enables species A to survive.
Excellence opportunities obtained by giving
Excellence answers overall in Question Four.
High Excellence
Gene and allele defined and related to flower colours.
Response covers base sequences
on genes determining phenotype.
Diagram showing relationship
between DNA, genes, and alleles.
All criteria for Excellence met (Three
Merit plus one Excellence).
Gamete definition and role in chromosome
numbers of cell stated.
Meiosis linked to chromosome separation.
Demonstrates understanding that variation aids
species survival in environmental change.
All Merit criteria met along with Excellence
criteria resulting in Excellence overall.
Good explanation.
Clear reasoning to
support cleft chin
dominance.
Clear explanation linking A with Generation 3.
Punnett square, probability,
and sample size covered.
Two Merit opportunities plus one Excellence
opportunity reached, giving Excellence grade
overall for Question Three.
Definition acceptable.
No link with mutation being
passed on by gametes.
Recognises large leaf sizes will be adapted to
survive and ensure survival of individuals and
the species.
Achievement overall, only one opportunity
reached beyond Achievement level.