Question 1

Which process restores the diploid chromosome number in the human life cycle, as shown in the first image?

Accepted Answer

Fertilization

Question 2

During which phase of meiosis does crossing over occur, as illustrated in the second image?

Accepted Answer

Prophase I

Question 3

The third image demonstrates independent assortment. What is the result of this process?

Accepted Answer

Gametes have random combinations of maternal and paternal chromosomes

Question 4

Based on the fourth image, what is the chromosome number in the cells after Meiosis II if the original cell was diploid with $$2n = 4$$?

Accepted Answer

$$n = 2$$

Question 5

Referencing the fifth image, what is the consequence of nondisjunction during Meiosis I?

Accepted Answer

All gametes are abnormal

Question 6

The sixth image shows a karyotype with three copies of chromosome 21. What condition does this represent?

Accepted Answer

Down syndrome (Trisomy 21)

Question 7

In the seventh image, what stage of cell division is depicted, given the separation of homologous chromosomes?

Accepted Answer

End of meiosis I

Question 8

According to the eighth image, what is the difference between homologous chromosomes and sister chromatids?

Accepted Answer

Sister chromatids are identical copies joined at the centromere; homologous chromosomes are similar but not identical

Question 9

The ninth image shows chromosome duplication. What happens to the chromosome number after DNA replication?

Accepted Answer

Chromosome number stays the same, but DNA content doubles

Question 10

Based on the tenth image, which phase of the cell cycle is the longest?

Accepted Answer

Interphase

Question 11

The eleventh image shows cell cycle checkpoints. What is the main function of the G1 checkpoint?

Accepted Answer

Checks for DNA damage and growth signals

Question 12

In the twelfth image, what is the role of Ras in the cell cycle?

Accepted Answer

Ras activates protein kinases that stimulate cell division

Question 13

The thirteenth image shows a mutated Ras protein. What is the result of this mutation?

Accepted Answer

Cell division occurs continuously, even without growth factor

Question 14

According to the fourteenth image, what is the function of p53 in response to DNA damage?

Accepted Answer

p53 inhibits the cell cycle to prevent replication of damaged DNA

Question 15

The fifteenth image shows a mutation in p53. What is the consequence of this mutation?

Accepted Answer

Cell division increases because inhibitory protein is absent

Question 16

In the sixteenth image, what is the effect of HER2 signaling on cell division?

Accepted Answer

HER2 signaling promotes cell division

Question 17

The seventeenth image shows Herceptin treatment. How does Herceptin affect HER2-positive breast cancer cells?

Accepted Answer

Herceptin binds to HER2 and blocks cell division

Cell Division: Meiosis, Mitosis, and Genetic Variation

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