Chapter 9 Information of Life, DNA and RNA structure, DNA replication.

Criteria for Genetic Material

Information, replication, transmission, variation.

Griffith’s Experiment

Showed that live R bacteria transformed into S bacteria by dead S bacteria.

Transforming Principle

Substance from dead S cells that can transform R cells into S cells.

Avery, MacLeod, and McCarty

Identified DNA as the genetic material through purification methods.

Nucleotides

Building blocks of nucleic acids containing a phosphate, sugar, and base.

Structure of DNA

Consists of nucleotides, strands, double helix, chromosomes, and genome.

Directionality of DNA Strand

5' end has a phosphate, and 3' end has a hydroxyl group.

Complementary Base Pairing

The specific pairing of A with T and C with G in DNA.

X-ray Diffraction

Technique used to determine the helical structure of DNA.

Chargaff’s Rule

Amount of adenine equals thymine, and cytosine equals guanine.

Ball-and-Stick Models

Used by Watson and Crick to deduce DNA structure.

Semiconservative Replication

Each new DNA double helix contains one old and one new strand.

DNA Replication Fork

A site where DNA strands are unwound for replication.

DNA Helicase

Enzyme that unwinds DNA strands by breaking hydrogen bonds.

DNA Polymerase

Enzyme that synthesizes new DNA strands by adding nucleotides.

Leading Strand

Synthesized continuously in the direction of the replication fork.

Lagging Strand

Synthesized in short Okazaki fragments in the opposite direction of the fork.

Replication Origins

Sites in chromosomes where DNA replication begins.

Nucleosomes

Formed by DNA wrapping around histone proteins, compacting DNA.

30-nm Fiber

Higher-order structure formed by nucleosomes compacting together.

Heterochromatin

Highly compacted regions of chromatin, generally inactive genes.

Euchromatin

Less condensed form of chromatin with active genes.

Maximum Compaction

Occurs during cell division, transforming chromatin into visible chromosomes.

Okazaki Fragments

Short segments of DNA synthesized on the lagging strand.

Isolation of Base Composition

Evidence revealing the specific ratios of bases in DNA.

DNA Replication Accuracy

High fidelity due to stable base pair hydrogen bonds, proofreading capability of DNA polymerase.

AT/GC Rule

Specifies the base pairing rules in DNA replication.

Biochemical Basis of Heredity

Early theory postulating that hereditary information is stored in a biochemical form.

Alfred Hershey and Martha Chase

Their experiments confirmed DNA is the genetic material in viruses.

Topoisomerase

Enzyme that alleviates the stress ahead of the replication fork.

Primase

Enzyme that synthesizes short RNA primers for DNA synthesis.

Chromatin Structure

The combination of DNA and proteins in eukaryotic chromosomes.

Chromosome Territories

Discrete regions in the nucleus that contain non-overlapping chromosomes.

Replication Bubble

Formed as DNA strands are unwound at the origin of replication.

Single-Strand Binding Proteins

Proteins that stabilize unwound DNA during replication.

CCCTC Binding Factor (CTCF)

Protein that helps define loop domains in DNA structure.

Structural Maintenance of Chromosomes (SMC) Proteins

Proteins involved in the maintenance of chromosome structure during division.