IB Biology Topic 3 Review

The image shows a karyogram. What information can be determined from this karyogram?

• The sex is female.

• The haploid number is 54.

• Disjunction occurred during meiosis.

• The species is not human.

Tags

NGSS.HS-LS3-1

What distinguishes an allele from a gene?

• An allele is made of RNA.

• An allele is shorter.

• An allele is a variety of a gene.

• An allele cannot be transferred during genetic modification.

Which is a characteristic of the pairs of sister chromatids that are visible during meiosis?

• They result from the replication of DNA before meiosis.

• They are only present in meiosis I.

• They split apart during metaphase I in meiosis.

• They are only present in meiosis II.

What is characteristic of homologous chromosomes?

• They have an identical DNA sequence.

• They are of the same length in karyograms.

• They form pairs in prokaryotes.

• They carry the same alleles.

What is the effect of dominant alleles?

I. They mask the effect of recessive alleles.

II. They become more frequent than recessive alleles in a population.

III. They have a joint effect with recessive alleles when characteristics are co-dominant.

• I only

• I and II only

• I and III only

• I, II and III

Tags

NGSS.HS-LS4-3

What is a possible source of the chromosomes used for pre-natal karyotype diagnosis?

• The mother's lymphocytes.

• The mother's cheek cells.

• The cells from the chorionic villi.

• The fetal hair root cells.

What causes the presence of three chromosomes 21 in Down syndrome?

• Crossing over

• Allele change

• Non-disjunction

• Gene mutation

Tags

NGSS.HS-LS3-2

What is a characteristic of the human Y chromosome?

• It is made of DNA and histones covered by phospholipids.

• It contains some genes that are not present on the X chromosome.

• It is the largest chromosome in the human karyotype.

• It has a condensed length of approximately 100 µm.

What is the name given to a heritable factor which controls a specific characteristic?

• Allele

• Chromosome

• Gene

• Mutation

Tags

NGSS.HS-LS3-2

NGSS.HS-LS1-1

What is a gene mutation?

• Failure of chromosome pairs to separate properly during cell division

• Changes to genes caused by natural selection

• Changes to the nucleotide sequence of the genetic material

• Changes in karyotypes

Tags

NGSS.HS-LS3-2