MItosis & Meiosis - IB Biology

The graph shows the incidence of trisomy resulting from non-disjunction in pregnancies at different maternal ages.

• The incidence of three copies of a chromosome increases directly in proportion with the age of the mother.

• The incidence of three sets of chromosomes increases from age 20.

• The incidence of three copies of a chromosome increases the most from age 35.

• The incidence of three sets of chromosomes increases the most from age 30.

The diagram shows a stage in cell division.

What is the stage shown?

• Anaphase I of mitosis

• Anaphase II of mitosis

• Anaphase I of meiosis

• Anaphase II of meiosis

Look at the parent cell.

Which diagram represents a cell from the same species in anaphase II of meiosis?

• A

• B

• C

• D

How does mitosis produce two genetically identical nuclei?

• By separation of homologous chromosomes

• By separation of sister chromatids

• By division of the cytoplasm into two equal cells

• By division of the nuclear membrane into two equal parts

What happens during meiosis I and meiosis II?

• A

• B

• C

• D

What forms when two different chromatids of the same homologous pair cross over?

• Daughter centromere

• Chiasma

• Chromosome mutation

• Telomere

Which process could cause non-disjunction if it occurred during meiosis?

• Sister chromatids do not align in metaphase I.

• Homologous chromosomes do not separate in anaphase I.

• Sister chromatids do not align in metaphase II.

• Homologous chromosomes do not separate in anaphase II.

What occurs during meiosis but not mitosis?

• Spindles are formed from microtubules.

• Chromosome number is conserved.

• Homologous chromosomes pair up.

• Centromeres split.

Which diagram(s) represent(s) processes used in asexual reproduction?

• I only

• I and II only

• II only

• I, II and III

The micrographs show four different phases from meiosis II.

What is the correct order?

• 3-4-2-1

• 2-3-4-1

• 4-3-2-1

• 4-2-3-1