Unit 1 Revision: Cloze Exercise 5.
Cell Function & Inheritance
What you should know (Chapters 11-14)
Inheritance, Mutations & Genetic Screening.
WORDBANK: ABNORMALIES, AMNIOCENTESIS, BASE, CO-DOMINANCE,
COMPLETE, CONTINUAL, COUNSELLOR, DELETION, EMPITICAL, FAMILY
TREE,
FOETAL,
INTERMEDIATE,
MULTIBLE,
FULLY,
GENOTYPE,
INVERSION,
MUTAGENIC,
HOMOLOGOUSE,
KARYOTYPE,
MASKS,
NON-DISJUNCTION,
INCOMPLETE,
MONOHYBRID,
NUMBER,
POLYGENIC,
RANDOM, RISK, SCREENING, SEX-LINK, SMALLER.
1. A
cross is one that involves two parents who differ in
one way with respect to a particular characteristic.
2. One member of a pair of alleles of a gene exhibits
dominance if it completely
the expression of the
other allele in the phenotype resulting from the heterozygote.
3. The members of a pair of alleles show
dominance if
the heterozygote results in a phenotype
between
those of the two homozygotes.
4. The members of a pair of alleles show
if the
heterozygote produces a phenotype where both alleles
are
expressed.
5. It three or more alleles of a gene exist, it is said to
have
alleles.
6. Human females posses a pair of homologous sex chromosomes called X
chromosomes; human males have one X and a
chromosome which is
Y
to part of the X chromosome.
7. Genes present on an X chromosome but not on a Y chromosome are said
to be
.
8. A characteristic which shows
variation is controlled
by alleles of more than one gene and is said to show
inheritance.
9. Mutations are changes in the
alteration of
in
which involve an
type or sequence in DNA or a change
of chromosomes.
10. Substitution and
bring about minor changes and are
called point mutations; insertion and
lead to major
changes and are called frameshift mutations.
11. Mutations occur rarely and at
be increased by
. Their frequency can
agents.
12.
occurs when a spindle fibre fails during meiosis and
the members of a pair of homologous chromosomes fail to separate. This
results in some gametes receiving one chromosome too many or one
chromosome too few and leads to the formation of individuals suffering
chromosome
.
13. A pattern of inheritance amongst the members of a family can be
established constructing a
. Analysis of a family tree
relating to a genetic disorder enables a genetic
to help
people make decisions about parenthood based on assessment
of
14. A
.
is a display of a complement of chromosomes
showing their form, size and number.
15.
enable
and chorionic villus sampling
material to be karyotyped and inspected for
chromosomal abnormalities.
16. Risk evaluation in cases of polygenic inheritance is
usually
17. Post natal
phenylketonuria.
.
is done to identify babies suffering
ANSWERS: Unit 1 Revision: Cloze Exercise 5.
Cell Function & Inheritance
What you should know (Chapters 11-14)
Inheritance, Mutations & Genetic Screening.
1. A monohybrid cross is one that involves two parents who differ in one way with respect to a
particular characteristic.
2. One member of a pair of alleles of a gene exhibits complete dominance if it
completely masks the expression of the other allele in the phenotype resulting from the
heterozygote.
3. The members of a pair of alleles show incomplete dominance if the heterozygote results in a
phenotype intermediate between those of the two homozygotes.
4. The members of a pair of alleles show co-dominance if the heterozygote produces a
phenotype
where
both
alleles
are fully expressed.
5. It three or more alleles of a gene exist, it is said to have multiple alleles.
6. Human females posses a pair of homologous sex chromosomes called X chromosomes;
human males have one X and a smaller Y chromosome which is homologous to part of the X
chromosome.
7. Genes present on an X chromosome but not on a Y chromosome are said to be sex-linked.
8. A characteristic which shows continuous variation is controlled by alleles of more than one
gene and is said to show polygenic inheritance.
9. Mutations are changes in the genotype which involve an alteration of base type or sequence
in DNA or a change in number of chromosomes.
10. Substitution and inversion bring about minor changes and are called point mutations;
insertion and deletion lead to major changes and are called frameshift mutations.
11. Mutations occur
by mutagenic agents.
rarely
and
at random.
Their
frequency
can
be
increased
12. Non-disjunction occurs when a spindle fibre fails during meiosis and the members of a pair
of homologous chromosomes fail to separate. This results in some gametes receiving one
chromosome too many or one chromosome too few and leads to the formation of individuals
suffering chromosome abnormalities.
13. A pattern of inheritance amongst the members of a family can be established constructing
a family tree. Analysis of a family tree relating to a genetic disorder enables a
genetic counsellorto help people make decisions about parenthood based on assessment
of risk.
14. A karyotype is a display of a complement of chromosomes showing their form, size and
number.
15. Amniocentesis and chorionic villus sampling enable foetal material to be karyotyped and
inspected for chromosomal abnormalities.
16.
Risk
evaluation
in
cases
of
polygenic
inheritance
is
17. Post natal screening is done to identify babies suffering phenylketonuria.
usually empirical.