History Bookmarks Window Help drive.google.com Raven Biology of Plants.pdf-Googl

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History Bookmarks Window Help drive.google.com Raven Biology of Plants.pdf-Google Drive Genetics Ga df Open with Google Docs 1. During meiosis : ) the number is reduced by four non-homologous chromosomAs symapse dyads form all of the above . In an organisa with a diploid number of 12, how many tetrads n are visible during melosis ? b) 24 c). 12 3. In Drosophila, a bristle mutation called singed is inherited as an X-linked recessive. If a female showing the singed phenotype is crossed with a wild type male, the ottspring will be composed of phenotypically a) all wild types g) 1/2 wild type ma Des: Elies. 1/2 singed males:l/2 wild type Eemales 1/2 inged females d all singed 1/4 wild type males: 1/4 sLnged males: 1/4 wild type Cenales:1/4 singed females 4. Eomologous chromosomes are not necessarily identical in their: a) overall size c) centromere placement e) arm ratio placement of genes alleles 5. In diseases exhibiting genetic anticipation: a) The disease is most severe in the tirst generation and decreases in severity in subsequent generations. ) The disease exhibits the same severity in all generations . d) There is NO genetic component to the disease. a) difterent genes CThe disease is milder in the first generation and incfeases in severity in subsequent generations. 6. involves interaction between: b) alleles at one gene locus Page 19Q+ Live MacBook Pro

Explanation / Answer

Answer

1) D) crossing over occurs

Explanation :

Crossing over occrus in pachytene of prophase I of meiosis I

-Regarding option a, homologous chromosome number is reduced to half in meiosis I

-option b, synapes occurs between homologous chromosomes

2) D) 6

Explanation : 1 tetrad is formed by 1 pair of homologous chromosomes i.e 2 chromosomes

Hencr 12 chromosomes means 6 pairs will form 6 tetrad

3) B) 1/2 singed male, 1/2 wild type female

Explanation :

Xd for mutant

XD for wild type

Therefore male genotype will be XDO

Female genotype XdXd

XDO x XdXd

Offsprings will be

2 XDXd

2 XdO

4) d) alleles

Explanation :

Homologous chromosomes are morphological and genetically identical chromosomes.

They will have same type of gene at same position but type of alleles for that gene may be different.

5) B) The disease exhibits same severity in all generations

Explanation : genetic anticipation of a disease just determine the presence or absence of disease in th individual. Disease severity depends on underlying process of the disease.

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