Chapter 4 and 12.5

Nucleotide

A building block of DNA and RNA containing a phosphate group, a sugar (deoxyribose in DNA), and a nitrogenous base.

Nucleoside

A nitrogenous base attached to a sugar, without a phosphate group.

Phosphodiester bond

A strong covalent bond linking nucleotides together in DNA or RNA.

Double helix

The three-dimensional structure of DNA, consisting of two intertwined strands.

Griffith's experiment

An experiment that demonstrated the phenomenon of transformation in Streptococcus pneumoniae.

Avery, MacLeod, McCarty

Scientists who identified DNA as the genetic material.

Watson & Crick

The researchers who proposed the double helix model of DNA structure.

Franklin's X-ray crystallography

Techniques used to determine the structure of DNA, providing crucial data for DNA modeling.

Chargaff’s rules

Rules stating that in DNA, adenine (A) pairs with thymine (T) and guanine (G) pairs with cytosine (C).

Base pairing rule

Describes how A pairs with T and G pairs with C in DNA, ensuring accurate replication.

Antiparallel strands

The orientation of DNA strands, where one runs 5' to 3' and the other runs 3' to 5'.

RNA World Hypothesis

The theory that RNA was the first molecule of life, due to its catalytic functions.

Central Dogma

The flow of genetic information from DNA to RNA to protein.

Transcription

The process of synthesizing RNA from a DNA template.

Translation

The process of synthesizing proteins from an RNA template.

RNA Polymerase

The enzyme responsible for catalyzing the synthesis of RNA during transcription.

Promoter

A DNA sequence that signals the start of transcription.

Template Strand

The DNA strand used as a guide for RNA synthesis.

Coding Strand

The strand of DNA that has the same sequence as the RNA (with T replaced by U).

Transcription Factors

Proteins that help regulate the transcription of genes by assisting RNA polymerase.

5′ cap

A modified guanine nucleotide added to the 5' end of mRNA to protect it and assist in ribosome binding.

Poly-A tail

A sequence of adenine nucleotides added to the 3' end of mRNA, enhancing stability and export.

Intron

Non-coding regions of RNA that are removed during splicing.

Exon

Coding regions of RNA that are retained during splicing.

Splicing

The process of removing introns and joining exons in pre-mRNA.

Euchromatin

Less condensed chromatin that is accessible for transcription.

Heterochromatin

Tightly packed form of DNA that is generally transcriptionally inactive.

Nucleosome

The structural unit of chromatin, consisting of DNA wrapped around histone proteins.

Histone

Proteins that package and order DNA into structural units called nucleosomes.

Genome Packaging

The organization and compaction of DNA within the nucleus to fit inside a cell.

Prokaryotes

Single-celled organisms without a nucleus, often with a circular genome.

Eukaryotes

Organisms made up of cells that have a nucleus and other membrane-bound organelles.

Transcription bubble

The unwound section of DNA where RNA synthesis occurs.

Initiation of transcription

The stage where RNA polymerase binds to the promoter and begins RNA synthesis.

Elongation in transcription

The stage during transcription when RNA strands are synthesized.

Termination of transcription

The process of ending transcription and releasing the newly synthesized RNA.

RNA stability

The lifespan and degradation of RNA within a cell influenced by various modifications.

Alternative Splicing

A process that enables a single gene to code for multiple proteins by including or excluding specific exons.

Catalytic ability of RNA

RNA's capability to act as an enzyme and facilitate biochemical reactions.

Gene expression

The process by which information from a gene is used to synthesize functional gene products.

Mutation resistance

The ability of DNA to maintain its integrity and minimize errors during replication.

Template strand RNA transcript

The RNA sequence that is complementary to the DNA template strand during transcription.

5′-AUGCCAUGC-3′

The RNA transcript produced from the DNA template strand 3′-TACGGTACG-5′.

Post-transcriptional modification

Changes made to RNA after transcription but before translation, crucial for mRNA functionality.

Energy for RNA polymerization

The energy required for RNA synthesis derived from the phosphate bonds in incoming nucleotides.

Transcription factors' role

Proteins that bind to specific DNA sequences to regulate the transcription of genes.

Impact of 5′ cap on mRNA

The 5′ cap enhances mRNA stability and facilitates translation initiation.

Consequences of enhancer mutation

Mutations in enhancer regions can lead to abnormal transcription levels.

DNA replication fidelity

The accuracy of DNA replication, which is crucial for maintaining genetic information.

Role of nucleosomes in gene expression

Nucleosome positioning can influence the accessibility of DNA to transcription machinery.