T10. INTRODUCTION TO MOLECULAR BIOLOGY Flashcards
(43 cards)
What is Molecular Biology?
Molecular Biology is the study of the molecular basis of a cell’s life, including how molecules interact to enable growth, maintenance, and division of cells.
What is the central dogma of Molecular Biology?
It describes the flow of genetic information from DNA to RNA to Protein.
Why is the central dogma of Molecular Biology not completely correct?
Because much of DNA does not encode proteins but encodes various types of functional RNAs.
When do transcription and translation occur?
They can occur at any time throughout the cell’s life and only within the cell.
When does DNA replication occur?
It only occurs when cells are going to divide and can happen within the cell or from cell to cell.
Does replication occur before transcription?
No, replication does not necessarily take place before transcription.
Can RNA be transformed into DNA?
Yes, by reverse transcription, which is a reversible reaction.
What does the genome include?
All the genetic information in the organism—the total DNA sequences.
Does the genome include epigenetic information?
No, epigenetic information is not included in DNA sequences.
What does epigenetic information explain?
It explains the differences between living organisms and depends on genome organization.
What are the main types of DNA regions?
Protein-coding regions, transcribed non-coding regions, and untranscribed regions.
What determines the difference between species?
Mainly the transcribed non-coding regions.
What is a gene?
A basic heritable unit that is any segment of chromosomal DNA transcribed into functional RNA.
Does a gene always get translated into protein?
No, it may or may not be translated into protein.
How is DNA structurally organized?
Into highly-organized and topologically-constrained (supercoiled) structures.
What are DNA topoisomers?
Forms of DNA with different degrees of supercoiling created by adding or deleting twists.
What are examples of topological DNA forms?
Relaxed (+Lk), supercoiled, contracted or unlinked, knotted or unknotted.
How is circular DNA usually found?
As supercoiled DNA with plectonemic or solenoidal supercoiling.
What does Topoisomerase I do?
Introduces transient single-strand breaks in DNA to relieve torsional strain and allow rotation.
Why is Topoisomerase I important?
It helps unwind DNA and release accumulated tension.
What does Topoisomerase II do?
Creates transient double-strand breaks and helps in decatenation and chromosome segregation.
What is decatenation?
The unlinking of intertwined DNA molecules.
Why is Topoisomerase II essential?
It maintains DNA structure and ensures proper chromosome distribution during cell division.
Why are both topoisomerases vital?
They manage DNA’s structural changes for proper function, replication, and genetic transmission.
