Tag: botany

Questions Related to botany

Gametic maps of chromosomes are based on

botany chromosomal basis of inheritance linkage and crossing over linkage and recombination genetics: inheritance

  1. Non disunction

  2. Tranlocation

  3. Dominance

  4. Genetic recombination

  5. Chromosomal aberrations.

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Correct Option: D
Explanation:

A linkage or genetic chromosome map is a linear graphic representation of the sequence and relative distance of the various things present in a chromosome. A chromosome app is also called a linkage map or the genetic map. The percent of crossing over between two genes is directly proportional to the distance. The unit of crossing over has been termed as centiMorgan.


So, the correct option is 'Genetic recombination'.

Out of three characters on chromosome no. 4, two characters indicate linkage and not mentioned by Mendel. These characters were

botany chromosomal basis of inheritance linkage and crossing over linkage and recombination genetics: inheritance

  1. Pod form - stem length

  2. Pod form - pod position

  3. Pod form - pod colour

  4. Pod position - stem length

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Correct Option: A
Explanation:

The chromosome no. 4 of pea plant carries genes for flower position, pod form and plant height. Out of these three genes, the two genes namely the gene for pod form and the one for plant height are closely placed on the chromosome that they show linkage. However, the gene for flower position is located far apart from the other two genes and do not show linkage. Hence, option A is correct. 

How many linkage groups are present in human male?

botany chromosomal basis of inheritance linkage and crossing over linkage and recombination genetics: inheritance

  1. 24

  2. 23

  3. 46

  4. 22

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Correct Option: A
Explanation:
Humans can have 2 linkage groups based on gender. 
Male have 22 pairs of autosomes and 1X and 1Y. So, in all 24 linkage groups. 
While females have 22 pairs autosomes and 1X pair. So, total 23 linkage groups
Thus, the correct answer is '24'.

Lack of independent assortment between two genes A and B would be due to

botany chromosomal basis of inheritance linkage and crossing over linkage and recombination genetics: inheritance

  1. Crossing over

  2. Linkage

  3. Recombination

  4. None of the above

Show answer
Correct Option: B
Explanation:
Crossing over is the process of exchange of genetic material between non-sister chromatids of homologous chromosomes to produce new genetics combinations or variations; it does not interfere with an independent assortment of genes. Option A is incorrect. The linkage is the tendency of closely placed genes on a chromosome to stay together during inheritance and do not assort independently; it produces more parental combination and less/no new combinations of the gene. The linkage is indirectly proportional to the distance between genes; the less the distance between the genes, the more linkage due to lack of independent assortment between them. Option B is correct. Recombination is new arrangements of genes on chromosomes which is carried out by independent assortment and crossing over; thus recombination is the result of independent assortment which makes option D is incorrect. Option B is correct.

Number of linkage groups in Pisum sativum is 

botany chromosomal basis of inheritance linkage and crossing over linkage and recombination genetics: inheritance

  1. 4

  2. 5

  3. 7

  4. 10

Show answer
Correct Option: C
Explanation:

The total number of linkage groups in an organism equals to the number of autosomes in its haploid cell. Pisum sativum has seven pairs of chromosomes which mean that the number of autosomes in its haploid cell is 7. Hence, a total number of linkage groups will be 7 provided all the genes are mapped. So, the correct answer is option C.

Linkage was first observed in

botany chromosomal basis of inheritance linkage and crossing over linkage and recombination genetics: inheritance

  1. Field pea

  2. Sweet pea

  3. Pea

  4. Grass pea

Show answer
Correct Option: B
Explanation:

The phenomenon of linkage was first observed by Bateson and Punnet in 1906 in sweet pea (Lathyrus odoratus). Linkage describes the way in which two genes that are located close to each other on a chromosome are often inherited together. Hence option B is correct.

In a long-term study of a population of a self-pollinated plant, it was observed that an allele, which significantly enhanced vegetative growth and production of flowers in the plant, did not expand in distribuation over subsequent generations in the population. This could be because the allele is

botany chromosomal basis of inheritance linkage and crossing over linkage and recombination genetics: inheritance

  1. Dominant lethal in nature

  2. Tightly linked to a gene that allows formation to large number of seeds in each plant

  3. Linked to a gene that suppresses development of axillary branches

  4. Tightly linked to a gene that suppresses development of pollen mother cells in the plant

Show answer
Correct Option: D
Explanation:

In the case of self pollinated plants, the self pollen pollinates on the stigma. The allele involved in the production of pollen affects the progeny plants in the subsequent generations. The allele for the formation of pollen from pollen mother cells and the allele for vegetative growth and production of flowers are tightly linked. So, when the plants did not show enhanced growth and flowering, it can be said that this gene also suppresses development of pollen mother cells which will thereby affect the distribution in the next generations. 

Thus, the correct answer is option D.  

Linkage gene do not show

botany chromosomal basis of inheritance linkage and crossing over linkage and recombination genetics: inheritance

  1. independent assortment

  2. 9:3:3:1

  3. segregation

  4. All of the above

Show answer
Correct Option: D
Explanation:

Linked gene do not show :

Correct option is (D) All of the above .
Linked gene violates independent assortment , having the phenotype ratio 9;3;3;1. Linked gene is also influenced by the segregation.
Hence, option D is correct.

Genes located very close to one another on same chromosome tend to be transmitted together and are called as

botany chromosomal basis of inheritance linkage and crossing over linkage and recombination genetics: inheritance

  1. Allomorphs

  2. identical genes

  3. Linked genes

  4. recessive genes

Show answer
Correct Option: C
Explanation:

Genes that are sufficiently close together on a chromosome will tend to "stick together," and the alleles of those genes that are together on a chromosome will tend to be inherited as a pair more often than not. This phenomenon is called genetic linkage. These genes are called as linked genes that are likely to be inherited together because they are physically close to one another on the same chromosome.

So, the correct answer is 'Linked genes'.

In the resting state of the neutral membrane, diffusion due to concentration gradients, if allowed, would drive.

botany plant water relation active transport and passive transport types of plant transport atp

  1. $K^+$ into the cell

  2. $K^+$ and $Na^+$ out of the cells

  3. $Na^+$ into the cells

  4. $Na^+$ out of the cell

Show answer
Correct Option: A