Molecular Biology

• The enzyme DNA polymerase plays a key role in DNA replication by catalyzing the addition of nucleotides to the growing DNA strand.
• The DNA double helix is held together by hydrogen bonds between complementary base pairs.
• RNA primers serve as templates for DNA synthesis until they can be replaced by DNA sequences during lagging-strand synthesis.
• During DNA synthesis, RNA primers are used as starting points for DNA synthesis, which are then removed and replaced by DNA sequences.
• DNA polymerases have an active site that binds to the incoming nucleotide, forming a phosphodiester bond with the previous nucleotide on the template strand.
• RNA polymerase binds to promoter sequences on the template strand and initiates transcription.
• DNA replication occurs through semiconservative replication, where the two strands separate and serve as templates for new nucleotides to be added.
• DNA replication produces two identical copies of DNA from a single original DNA molecule.
• DNA replication produces two identical copies of DNA from a single original DNA molecule.
• The DNA replication process requires the unwinding and separation of the two strands of the DNA double helix by an enzyme called helicase.
• DNA replication occurs semiconservatively, with one new strand being synthesized from free nucleotide triphosphates using the other parental strand as a template.
• RNA polymerases are responsible for transcribing genes into RNA molecules.
• Transcription involves the formation of an mRNA copy of a gene's sequence of bases.
• During leading-strand synthesis, DNA polymerases move continuously along the template strand, while during lagging-strand synthesis, RNA primers are used as starting points for Okazaki fragments that are later joined together.
• Leading-strand synthesis occurs continuously from the origin of replication towards the end of the chromosome, while lagging-strand synthesis involves multiple short fragments called Okazaki fragments that must be joined together.
• Replication fork movement involves unwinding the DNA double helix, separating the two strands, and synthesizing new DNA strands using the parental strands as templates.
• DNA polymerases require a primer to initiate DNA synthesis, but once initiated, they can continue elongating the new strand without further assistance from other proteins or factors.
• What Are The Stages Of Mitosis?

  Prophase, Metaphase, Anaphase, Telophase
• What Are The Stages Of Meiosis?

  Prophase I, Metaphase I, Anaphase I, Telophase I, Prophase II, Metaphase II, Anaphase II, Telophase II
• What Are The Differences Between Mitosis and Meiosis?


  Mitosis: produces two identical daughter cells, occurs in somatic cells, results in diploid cells and used for growth and repair. Meiosis: produces four genetically different daughter cells, occurs in germ cells, results in haploid cells and used to produce sex cells (gametes).
• What Occurs Before Both Mitosis And Meiosis?

  Interphase
• What Occurs In Interphase?

  Cell growth, DNA replication.
• What Are The Stages Of Interphase And What Occurs At Each Stage?

  G1 (Gap 1): Cell growth and normal functions. S (Synthesis): DNA replication. G2 (Gap 2): Preparation for cell division.
• What Are The Name Of The Major DNA Replication Enzymes?

  DNA polymerase, DNA helicase, DNA primase, DNA ligase and Topoisomerase.
• What Is The Function Of All The Major DNA Replication Enzymes?

  Helicase: Unwinds the DNA double helix. Primase: Synthesizes RNA primers. DNA Polymerase: Adds nucleotides to the growing DNA strand. Ligase: Joins Okazaki fragments on the lagging strand. Topoisomerase: Relieves tension in the DNA helix.
• What Does Semi-Conservative Mean For DNA Replication?

  Each new DNA molecule consists of one original strand and one newly synthesized strand.
• What Type Of Division Is Meiosis?

  Reduction
• What Is The Difference Of Prophase I and Prophase II?

  Recombination (Crossing over) occurs in Prophase I.
• What Is The Difference Between Metaphase I and Metaphase II?


  Homologous pair chromosomes align in Metaphase I, while individual chromosomes align in Metaphase II.
• Why Is Their A Leading Strand and Lagging Strand?

  The leading strand is synthesized continuously in the 5' to 3' direction, while the lagging strand is synthesized discontinuously in Okazaki fragments (more primers required).
• All Types Of RNA?

  mRNA, tRNA, rRNA
• Full Name And Function Of All RNA?

  mRNA - messenger RNA (carries genetic information from DNA to ribosomes for protein synthesis) rRNA - ribosomal RNA (part of the ribosome where protein synthesis occurs) tRNA - transfer RNA (transfers amino acids to the ribosome during protein synthesis)
• What Does RNA Polymerase Need To Begin?

  Promoter sequence
• What Does An Operon Need?

  Promoter, operator, structural genes
• Function Of A Repressor?

  Inhibition of RNA Polymerase
• Full Name Of All The Regions Of The Lac Operon?

  Promoter, Lac I, Promoter, Operator, Repressor, Lac Z, Lac Y, Lac A
• What Is The Function Of Lac I?

  Codes For The Repression of the lac operon.
• How To Stop The Repressor From Binding To The Operator In The Lac Operon?

  Lactose
• What Are The 3 Types Of DNA Polymerase?

  DNA Polymerase I, DNA Polymerase II, DNA Polymerase III
• What Are The Functions Of The 3 Types Of DNA Polymerase?

  1. DNA Polymerase I: Fills in the gaps in DNA repair, primer removal. 2. DNA Polymerase II: DNA repair (lagging strand). 3. DNA Polymerase III: Main enzyme for DNA replication.