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WorksheetsBiol Revision
Total questions: 10
Worksheet time: 7mins
A female human will have ______ chromosomes in an ovum
46
45
23
22
24
A person with Down's syndrome has ...
1 extra chromosome 21
a missing 1 copy of chromosome 21
2 missing copies of chromosome 21
1 extra X chromosome
An onion cell has 16 chromosomes. After mitotically dividing the resulting cells are called...
brother cells
sister cells
mother cells
daughter cells
The cells resulting from mitotic division of an onion cell will be genetically (a) to the parent cells.
How many chromosomes does an onion seed have?
16
32
8
4
Our onion friend carries a gene for leaf disease resistance and one normal gene in a pair. This pair of genes on homologous chromosomes are called...
alleles.
gene pairs.
mutations.
bases.
The onion above is said to be __________ for the leaf disease resistance gene?
homozygous
heterozygous
mutated
recessive
A commercial onion strain with the phenotype Dd for leaf disease (a recessive disorder) was crossed with a wild variety homozygous for disease resistance. Predict the ratio of diseased to healthy offspring.
(a)
Colour blindness is a X linked recessive disorder. A couple have 6 male children all with colour blindness. What is the most likely phenotype of the parents?
Mother Homozygous, Father Heterozygous.
Mother Heterozygous, Father Heterozygous.
Mother Heterozygous, Father no gene.
A fragment of DNA recovered from a fossil contained the base sequence GCGTAAT. A complimentary strand that could be used to detect the fragment would have what base sequence?
(a)
