Answer:
The correct answer is option B, that is, promoter, operator, gene.
Explanation:
In a prokaryote, just in front of the operator, the promoter is located, and just in front of the structural genes, the operator is located. All these in combination give rise to an operon.
Any gene, which codes for an enzyme or a structural protein is termed as a structural gene, in the lac operon, a structural gene codes for three distinct kinds of enzymes. A short sequence of DNA is situated just in front of the structural gene, which is known as the operator. An operator functions as a switch for transcription, that is, it monitors whether the process of transcription will take place or not.
Just in front of an operator, a sequence of a promoter is present, and for the transcription and translation of all the structural genes, the RNA polymerase needs to combine first with the promoter. In case, if no transcription is to take place, then the operator allows the repressor to bind with it and prevent the attachment of RNA polymerase with the promoter. Hence, the correct sequence of a prokaryotic operon is a promoter, operator, and gene.
Answer:
Mitotic phase
Explanation:
Cell cycle is composed of interphase and mitotic phase. Interphase is aphase of cell preparation. It is subdivided into:
- G1 (gap 1 phase)-the cell grows and becomes larger
- S phase- replication of DNA, duplication of centrosomes
- G2 (gap 2 phase)-proteins and oranelles are made
Mitotic phase is phase of cell division, chromosomes are separated, daughter cell get identical sets of chromosomes. It is followed by cytokinesis-separation of cytoplasm. Stages of mitosis are:
- prophase-condensation of chromatin into chromosomes, the nuclear envelope breaks down, mitotic spindle formation
- metaphase-the chromosmes line up (metaphase plate)
- anaphase-the siste chromatides move toward opposite cell poles
- telophase-the nuclear envelope forms again, cell division is almost complete
Answer: A PEDIGREE is a family-tree like representation of how organisms are related based on ANCESTRY. It shows genetic relatedness or blood relationship between individuals or organisms.
Explanation: Pedigree can be used to determine
1. Family history or genealogy.
2. Genetic or blood relationship.
3. Coefficient of relationship.
4. Degree of relationship.
5. Proportions of shared genes.
6. Mode of transmission of diseases.
7. Risk evaluation or determination.
Genetic counseling.
8. Linkage analysis.
Pedigree symbols are used in constructing pedigree.
