Question

9. The fusion of a and a _produces a zygote with 46 (2n) chromosome number. 10. During meiosis, the chromosome number: a) is doubled b) is reduced c) remains the same d) becomes diploid 11. Meiosis produces haploid (#) reproductive cells called _ 12. Name the 2 human gametes & tell their chromosome number. 13. Cells starting mitosis & meiosis begin with a (haploid or diploid) set of chromosomes. 14. How many times do cells divide during meiosis? 15. What are the stages of meiosis called? Meiosis I: Meiosis II: 16. What is a tetrad? 17. Which of the following best describe the term "crossing over"? a.) An exchange of information between two homologous chromosomes b.) A molecular interaction between two sister chromatids c.) A molecular interaction between two non-sister chromatids d.) A separation of two sister chromatids 18. What type of material is exchanged during crossing-over? 19. Crossing-over can be found in the stage of a.) Prophase I b) Prophase II c) Anaphase I d) Anaphase II

Answer 1

QUESTION 9

The fusion of a sperm (n=23) and egg (n=23) produces a zygote with 46 (2n) chromosome number

QUESTION 10

Remember that during meiosis, the gametes are produced. These gametes are the sperm and egg which has the half of the genetic charge. So, During meiosis, the chromosome number is reduced

QUESTION 11

Meiosis produced haploid reproductive cells called gametes (the sperm and the egg)

QUESTION 12

As I already told you, the gametes are the sperm and the egg. Each gamete posses 23 chromosomes

QUESTION 13

In the case of mitosis, the cell starts with an haploid genetic charge. However, the genetic material is duplicated in order to produce two daughter cells with the same genetic charge. On the other hand, in meiosis the cells starts at diploid. At the end of the meiosis, the genetic charge will be reduced

QUESTION 14

During meiosis, the cells will divide two times, while in mitosis, the cell will divide only one time

QUESTION 15

MEIOSIS I:

•Prophase I

•Metaphase I

•Anaphase I

•Telophase I

MEIOSIS II:

•Prophase II

•Metaphase II

•Anaphase II

•Telophase II

QUESTION 16

In this context, a tetrad is a set of chromosomes that contains 4 chromatids

QUESTION 17

During crossing over, the genetic charge of the two parental cells is exchange. For this, chromosomes with the same genes are paired (homologues chromosomes) and one part of the newly cell will posses one half of each parent. So, the correct answer is An exchange of information between two homologous chromosomes

QUESTION 18

The DNA of the homologue chromosomes

QUESTION 19

Crossing over occurs during prophase I