Topic 12

Question 1

Outline the role of genes in
the inheritance of human
characteristics.

Answer 1

Limit to the following.
* Chromosomes are mainly made of
deoxyribonucleic acid (DNA), sections of
which are referred to as genes.
* DNA undergoes replication as part of cell
division to pass on the genes to new cells.
* Children inherit genes from their parents
via the sex cells (gametes), with 50% from
the mother and 50% from the father. Many
millions of different combinations of these
genes from the same parents are possible.
* Human characteristics (or phenotype) are
determined by their genes (the genotype).
* Some characteristics are expressed
developmentally by genes (for example,
eye colour, gender), others also require an
environmental switch (for example, height,
VO2max).
Note: Students are not expected to know the
structure of DNA, the mechanism of replication, or
the details of meiosis

Question 2

Outline how genes
can influence human
characteristics

Answer 2

Limit to the following.
* Genes code for the production of proteins, which are responsible for the development of an individual.
* Genes can be switched on or switched off depending on internal or external factors, so that characteristics influencing athletic performance can change during a person’s lifetime.
* Multiple genes determine the measurable heritable characteristics for each individual so it is highly unlikely that a single or even a few genetic elements are associated with superior athletic performance.
Note: Students are not expected to know the
mechanisms of transcription or regulation of gene
expression.

Question 3

Discuss the relative
contribution of genetic and
environmental factors on
performance in different
sports

Answer 3

Characteristics that are influenced by genetics include height, muscle fibre type, anaerobic threshold, lung capacity and flexibility. Environmental factors that also influence performance include physical training, nutrition, technological aids and climate. Training maximizes the likelihood of obtaining a performance level with a genetically controlled ceiling.
Elite athletes can be distinguished from less wellperforming athletes with respect to both inherited (genetic) characteristics and training histories. It is presently not possible to ascertain the relative contribution of genetics or training to elite sporting performance, and this contribution is likely to differ for different sports.

TOK: Both environmental and genetic factors
influence sporting performance. When two areas
of knowledge are linked, how can we decide
which has more relevance?
Aim 8: Studies on twins have provided much
scientific knowledge about the “nature versus
nurture” debate, but are such studies morally
acceptable?

Question 4

Discuss the implications of
genetic screening for sports,
exercise and health

Answer 4

Consider:
* the identification of life-threatening
conditions such as risk of sudden cardiac
death, connective tissue disorder
* the potential to predict susceptibility to
injury and so reduce risk/improve safety for
an individual athlete
* ethical implications of involuntary exclusion
from, or discrimination in, one or more
sports
* ethical implications of discrimination
beyond sport, for example, in employment
* the possibility of gene doping in the future
to improve athletic performance.
Link to option B: Psychology of sports: Talent
identification and development