Leptotene

Q.

Difference between chromatin and chromatids ?

Q.

What is the difference between chromatids and chromosome?

Q. A human has 46 chromosomes. How many chromosomes will be present after S phase?

1. 23
2. 46
3. 92
4. 84

Q. To make a karyotype, chromosomes are photographed during

1. s-phase
2. fertilization
3. mitosis
4. meiosis

Q. Assertion: Number of chromosomes in one genome is equal to number of linkage groups.

Reason: Linkage groups give important information about the location of genes in the chromosomes.

1. Both assertion and reason are true and reason is the correct explanation of assertion
2. Both assertion and reason are true but reason is not the correct explanation of assertion
3. Assertion is true but reason is false
4. Both assertion and reason are false

Q. Given figure shows a pair of homologous chromosomes during meiosis.
Maximum crossing over will take place between genes

1. A and a, D and d
2. C and d, c and D
3. B and c, b and C
4. A and d, a and D

Q.

Match the following stages during Prophase I with their key changes:

$$\begin{array}{cc}\text{Column I}& \text{Column II}\\ \text{i. Leptotene}& \text{a. Bivalents separate and remain attached at Chiasmata.}\\ \text{ii. Zygotene}& \text{b. Pairing of opposite chromosomes.}\\ \text{iii. Pachytene}& \text{c.Bivalents divide and remain attached at Chiasmata.}\\ \text{iv. Diplotene}& \text{d. Bivalents are formed and crossing over is seen.}\\ \text{v. Diakinesis}& \text{e. Chromosomes are formed and in condensed stage.}\end{array}$$

1. i).➡ a., ii).➡ e., iii).➡ c., iv). ➡ d., v). ➡ b.

2. i).➡ c., ii).➡ d., iii).➡ a., iv). ➡ b., v). ➡ e.

3. i).➡ b., ii).➡ c., iii).➡ d., iv). ➡ e., v). ➡ a.

4. i).➡ d., ii).➡ b., iii).➡ e., iv). ➡ a., v). ➡ c.

Q. What is the best stage of cell division for studing chromosome under microscope?

Q. The chromosomes appears as long thin threads in

1. Leptotene
   
2. Zygotene
   
3. Pachytene
   
4. Diplotene

Q. The phenomenon of exchange of segments between non-sister chromatids/ paternal and maternal chromosomes is called

1. Linkage
2. Recombination
3. Segregation
4. Crossing over

Q. Match the following columns w.r.t. mitosis and select the correct option.

	Column I		Column II
(a)	Prophase	(i)	Re-appearance of nuclear membrane
(b)	Metaphase	(ii)	Condensation of chromatin
(c)	Anaphase	(iii)	Separation of chromatids
(d)	Telophase	(iv)	Chromosomes align on equator

1. (a) (b) (c) (d)
   (iii) (ii) (i) (iv)
2. (a) (b) (c) (d)
   (ii) (iv) (iii) (i)
3. (a) (b) (c) (d)
   (ii) (iv) (i) (iii)
4. (a) (b) (c) (d)
   (iv) (i) (iii) (ii)

Q. Explain the process of meiosis - I

Q. In the following statements identify the false statement:-

1. Pairing of maternal and paternal chromosome during zygotene is called synapse
2. Terminalization occurs completely during diplotene
3. Chiasmata are the site of crossing over of genetic material
4. Prophase -I is the most complicated and longest stage of meiosis (dividing phase)

Q. In which of the following stages the chromosomes appear as beaded structures?

1. Leptotene
2. Pachytene
3. Diakinesis
4. Telophase I

Q. In Meiosis-I, the pairing of homologous chromosomes take place during _______stage.

1. Leptotene
2. Diplotene
3. Zygotene
4. Pachytene

Q. Consider the following statements (A D) and select the correct option stating ones are true (T) and false (F)?
A. Genes located on different chromosomes always show linkage.
B. Homologous non-sister chromatids participate in crossing over during gamete formation.
C. The frequency of crossing over between any two genes is generally proportional to the distance between them on the chromosome
D. Two non-sister chromatids participating in crossing over at any given point will lead to the formation of one type of gamete.

1. A - T, B - F, C - F, D - T
2. A - F, B - T, C - F, D - T
3. A - F, B - T, C - T, D - F
4. A - T, B - F, C - T, D - F

Q. Which of the following is the first stage of Prophase of meiosis?

1. Leptotene
2. Zygotene
3. Pachytene
4. Diplotene

Q. Number of spindles formed in meiosis-I is?

1. $2$
2. $3$
3. $4$
4. $1$

Q. Maize has $10$ pairs of chromosomes. How many linkage groups does it have?

1. $5$
2. $40$
3. $20$
4. $10$

Q. What are polytene chromosomes?

Q. Leptotene chromosomes have?

1. Two chromatids
2. One chromatid
3. Four chromatid
4. No chromatid

Q. In which stage do chromosomes appear as thin long threads?

1. Zygotene
2. Leptotene
3. Pachytene
4. Prophose

Q. In the following statements identify the false statement:-

1. Terminalization occurs completely during diplotene
2. Prophase -I is the most complicated and longest stage of meiosis (dividing phase)
3. Chiasmata are the site of crossing over of genetic material
4. Pairing of maternal and paternal chromosome during zygotene is called synapse

Q. Chromosomes become visible during

1. Leptotene
2. Zygotene
3. Pachytene
4. Diplotene

Q. Crossing over in diploid organisms is responsible for

1. Dominance of genes
2. Linkage between genes
3. Segregation of alleles
4. Recombination of linked genes

Q. Exchange of segments between non-homologous chromosomes is

1. Translocation
2. Crossing over
3. Inversion
4. Tetrasomy

Q. A cell has 10 picogram of DNA which undergone meiosis. What will be the amount of DNA in the product of meiosis I and meiosis II?

1. 10 pg and 10 pg respectively
2. 10 pg and 5 pg respectively
3. 5 pg and 5 pg respectively
4. 5 pg and 10 pg respectively

Q. The linked characters would always inherit together till they are

1. Delinked due to segregation
2. Masked by dominance
3. Mutated
4. Separated due to crossing over

Q. Chromosomes appear beaded during___________.

1. Pachytene
2. Leptotene
3. Diakinesis
4. Diplotene

Q. The diagram shows a bivalent at prophase-I of meiosis. Which of the four chromatids can cross over?