Advertisements
Advertisements
प्रश्न
State how does meiosis maintains chromosome number in a species.
उत्तर
The gametes are formed by meiosis. During meiosis the number of chromosomes is reduced to half i.e. the gametes contain haploid number of chromosomes. The male and female gametes fuse to form a diploid zygote. In this way meiosis maintains chromosome number in a species.
APPEARS IN
संबंधित प्रश्न
Name the sex chromosomes in human males and females
The term “chromosomes” literally means ______.
Choose the correct answer:
During mitosis which of the following disintegrate ___________
Write a sentence of the following:
Sheath
Label the lettered parts of the given figure and answer the following questions:
(i) What does this diagram represent?
(ii) What is the importance of'd'?
(iii) What are the 'staining' properties of 'b' and 'c'?
(iv) Who gave the term used for this structure today?
(v) What is a?
(vi) Is 'e' present in all chromosomes?
Enumerate the various changes that occur in the nucleus of the cell during prophase.
Explain the Term Chromosomes
Give Technical Terms
The stage at which chromosomes occurs reach the opposite poles.
Complete the following sentence with appropriate word :
The pairing of homologous chromosomes is called _______.
Name the following:
Pairs of chromosomes, present in human egg cells.
Give Technical Term:
Transmission of characters through generations.
Compare X chromosome and Y chromosome.
The centromere is found at the centre of the ______ chromosome.
The loss of one or more chromosomes in ploidy is called ______.
Identify the TRUE statements with respect to aneuploidy.
- When the chromosome number is not the exact multiple of the haploid set, it is described as aneuploidy.
- Aneuploidy is only addition of one or more chromosome(s) to the total number of chromosomes in a cell.
- Aneuploidy is further classified as hypoploidy and hyperploidy.
Read the following statements and select the correct option.
Statement I: The densely packed transcriptionally active, light staining region of chromatin is known as 'Heterochromatin'.
Statement II: The loosely packed, dark staining transcriptionally inactive region of chromatin is known as 'Euchromatin'.
Normally, genes occur in a pair of chromosome, but genes of X and Y chromosomes shows different gene loci indicating ______.
Differentiate between X-chromosome and Y-chromosome with reference to –
- length of non-homologous regions
- type as per the position of the centromere
Define Aneuploidy.
