DNA lecture 11

DNA

Nucleic acid storing genetic information.

Nucleic Acid

Biomolecule essential for genetic information.

Replication

Process of copying DNA for cell division.

Transcription

Process of converting DNA to RNA.

Translation

Process of synthesizing proteins from RNA.

Deoxyribonucleic Acid

DNA, the genetic material in organisms.

Ribonucleic Acid

RNA, involved in protein synthesis.

Nucleotide

Monomer unit of nucleic acids.

Phosphate Backbone

Structural framework of DNA strands.

Phosphodiester Bond

Covalent bond linking nucleotides in DNA.

5-carbon Sugar

Sugar component in nucleotides, deoxyribose for DNA.

Nitrogenous Base

Component of nucleotides; A, T, C, G.

Antiparallel Strands

DNA strands run in opposite directions.

Chargaff's Rule

Base pairing: A-T and G-C.

Double Helix

Structure of DNA, resembling a twisted ladder.

Telomeres

Protective ends of chromosomes, linked to aging.

Proofreading

Error-checking process during DNA replication.

Eukaryotes

Organisms with complex cells and nuclei.

Prokaryotes

Single-celled organisms without a nucleus.

Rosalind Franklin

Pioneered X-ray diffraction to study DNA.

Watson and Crick

Discovered DNA structure; awarded Nobel Prize.

5' end

Attached to a phosphate group in DNA.

3' end

Attached to a hydroxyl (OH) group.

Nitrogenous Bases

Four types: A, T, C, G in DNA.

Thymine

A pyrimidine base pairing with adenine.

Adenine

A purine base pairing with thymine.

Cytosine

A pyrimidine base pairing with guanine.

Guanine

A purine base pairing with cytosine.

Hydrogen Bonds

Connect complementary base pairs in DNA.

Pyrimidines

Single ring structure; includes T and C.

Purines

Double ring structure; includes A and G.

Chargaff's Rule

Amount of A = T; C = G in DNA.

Double Helix

Structure of DNA; twisted ladder formation.

Sugar-Phosphate Backbone

Alternating phosphate and deoxyribose sugar.

Phosphodiester Bonds

Covalent bonds linking nucleotides in DNA.

Complementary Base Pairs

A-T and G-C pairings in DNA.

Eukaryotic DNA

Linear, stored as chromatin in the nucleus.

Prokaryotic DNA

Circular, located in nucleoid region.

DNA Replication

Process of creating identical DNA copies.

Semiconservative Replication

Each new DNA has one original strand.

Helicase

Enzyme that unwinds DNA during replication.

DNA Polymerase

Enzyme synthesizing new DNA strands.

DNA Ligase

Enzyme that seals gaps in DNA strands.

Initiation

Starting point of DNA replication process.

Origin of Replication

Specific nucleotide sequence where replication begins.

Helicase

Enzyme that unwinds DNA by breaking hydrogen bonds.

RNA Primer

Short RNA sequence allowing DNA polymerase attachment.

Replication Forks

Active sites where DNA is unwound by helicase.

Elongation

Phase where new DNA strands are synthesized.

DNA Polymerase

Enzyme that synthesizes new DNA strands.

Leading Strand

Continuously synthesized DNA strand towards replication fork.

Lagging Strand

Synthesized in short segments called Okazaki fragments.

Okazaki Fragments

Short DNA pieces on the lagging strand.

DNA Ligase

Enzyme that seals gaps between Okazaki fragments.

Termination

Final phase where RNA primers are replaced with DNA.

Telomeres

Protective ends of linear chromosomes in eukaryotes.

Telomerase

Enzyme that extends telomeres during replication.

Mismatch Repair

Corrects mismatched nucleotides immediately after replication.

Proofreading

DNA polymerase checks and corrects its own errors.

DNA Damage Repair

Mechanisms to fix DNA damage from various sources.

Thymine Dimer

Distortion caused by adjacent thymine bases bonding.

Base Excision Repair

Removes single mismatched nucleotides from DNA.

Nucleotide Excision Repair

Fixes distortions in DNA double helix structure.

Gaps in Lagging Strand

Spaces between Okazaki fragments needing sealing.

Active Telomerase Cells

Present in germ cells, stem cells, and cancers.

Aging and Telomeres

Shortening telomeres linked to cellular aging.