3.3 IB Meiosis

What phase is shown in the picture?

• anaphase I

• anaphase II

• metaphase I

• telophase II

Answer explanation

It is obviously anaphase as they are moving away, but they are still in sister chromatid form, so it must be anaphase I, as the sisters get pulled apart during anaphase II.

What phase is shown in the picture?

• Metaphase I

• Metaphase II

• Prophase I

• Anaphase II

Answer explanation

Two cells, sister chromatids being pulled apart, must be anaphase II.

What phase is shown in the picture?

• metaphase I

• metaphase II

• anaphase I

• anaphase II

Answer explanation

Obviously metaphase, but there is only one chromosome on each spindle fiber, so it must be metaphase II.

What phase is shown in the picture?

• metaphase I

• metaphase II

• anaphase I

• anaphase II

Answer explanation

Obviously metaphase, but there are 2 homologous chromosomes per spindle fiber, so it is metaphase I.

What phase is shown in the micrograph?

• Anaphase I

• Anaphase II

• Telophase I

• Telophase II

Answer explanation

It is at the end of meiosis II, 4 daughter cells are present, so it must be telophase II.

In mitosis cells are genetically _______, but in meiosis cells are genetically ______.

• diverse, identical

• identical, diverse

• diverse, diverse

• identical, identical

Answer explanation

Mitosis is making identical cells to do specific jobs, meiosis makes diverse cells to increase variation in offspring.

Which of the following is true about the structure in the diagram? (2)

• The structures labeled (a) are identical.

• The diagram represents pre-S phase.

• The diagram shows homologous chromosomes.

• The diagram consists of sister chromatids

• This structure is comprised of DNA from both parents.

Answer explanation

Learn your chromosome structures peeps!

Chromosome pairs 1- 22 are known as

• sex chromosomes

• homologous chromosomes

• autosomes

• gametes

Answer explanation

Again, just another term you must know!

Why do we need meiosis?

• To double the number of chromosomes going into sex cells

• To halve the number of chromosomes going into sex cells

• To triple the number of chromosomes going into sex cells

• To not change the number of chromosomes going into sex cells

Answer explanation

Meiosis creates sex cells with only one set of chromosomes so when it joins with another sex cell a two sets of chromosomes are present for the offspring.

Unlike mitosis, meiosis in male mammals results in the formation of.....

• one haploid gamete

• three diploid gametes

• four diploid gametes

• four haploid gametes

Answer explanation

Yep, meiosis results in 4 cells.