Chromatin

Structure of DNA

The arrangement that enables DNA to serve as genetic material, consisting of a sugar-phosphate backbone and nitrogenous bases.

Components of DNA and RNA

1. Pentose sugar 2. Phosphate group 3. Nitrogenous base.

Primary structure of DNA

A long chain of repeating units that form the backbone of DNA, composed of nucleotides.

Nitrogenous Bases in DNA

Include adenine (A), thymine (T), guanine (G), and cytosine (C). A pairs with T and G pairs with C.

Directionality of DNA and RNA

DNA and RNA strands have directionality; one end is 5' and the other end is 3'.

DNA replication

Can only proceed in the 5' to 3' direction due to the need for DNA polymerase to attach to the 3' hydroxyl group.

Euchromatin

A form of chromatin that is loosely packed and generally transcriptionally active.

Constitutive heterochromatin

Tightly condensed chromatin that is usually transcriptionally inactive.

Facultative heterochromatin

Can switch between a relaxed and condensed state, influencing gene expression under specific conditions.

Restriction enzymes

Proteins that cut DNA at specific sequences, crucial for genetic engineering.

Gel electrophoresis

A technique used to separate DNA fragments based on size, allowing visualization of nucleic acids.

Southern blotting

Technique used to detect specific DNA sequences in DNA samples using hybridization with probes.

Northern blotting

Technique used to detect specific RNA sequences in RNA samples.

Western blotting

Technique used to detect specific proteins in a sample.

Nucleosome

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

Histones

Small, positively-charged proteins that assist in the packaging of DNA into chromatin.

Supercoiling of DNA

The additional twisting of DNA which allows it to compact and facilitates strand separation.

Chromosome

A DNA molecule that contains genetic material and is organized to fit within cells.

Genome

The complete set of genes or genetic material present in a cell or organism.

Prokaryotic vs. Eukaryotic cells

Prokaryotes have a simpler structure without a nucleus, while eukaryotes have a defined nucleus and organelles.

Antiparallel strands

The orientation of the two strands in DNA, running in opposite directions (5' to 3' and 3' to 5').

Hydrogen bonding in DNA

A weak bond between nitrogenous bases that hold the two strands of DNA together.

Gene expression

The process by which information from a gene is used to synthesize a functional gene product, typically a protein.

Transcription

The process of copying a segment of DNA into RNA.

Translation

The process where ribosomes synthesize proteins using mRNA as a template.

DNA-histone interactions

The bonds and associations that allow DNA to be compacted in the form of chromatin.

RNA stability

RNA is generally less stable than DNA due to the presence of an additional hydroxyl group.

Polymerase

An enzyme that synthesizes nucleic acids by adding nucleotides to a growing chain.

Gene control sequences

DNA sequences that regulate the transcription of genes.

Repetitive DNA

DNA sequences that are present in multiple copies in the genome, making up a significant portion of the genome.

Quantitative aspects of DNA interactions

Refers to the measurements and calculations concerning the associations of DNA with histones.

Blotting techniques

Methods used to transfer macromolecules onto membranes for detection and study.

Plasmids

Small, circular DNA molecules that are separate from chromosomal DNA and can replicate independently.

RNA primers

Short RNA sequences that provide a starting point for DNA synthesis during replication.

Origin of replication

The specific location on the DNA where replication begins.

Telomeres

Repeat sequences at the ends of linear chromosomes that protect them from degradation.

Genetic variance

Differences in genes among individuals of the same species, caused by mutations.

Polymerase Chain Reaction (PCR)

A technique used to amplify specific segments of DNA.

DNA sequencing

Determining the precise order of nucleotides within a DNA molecule.

Genome editing

Techniques that allow direct manipulation of an organism's DNA.

DNA repair mechanisms

Biochemical processes that fix damaged DNA, ensuring genomic stability.

Antisense RNA

RNA that is complementary to a given mRNA and can regulate gene expression.

MicroRNA

Small RNA molecules that regulate gene expression by binding to mRNA.

DNA methylation

The addition of methyl groups to DNA, which can regulate gene expression by altering chromatin structure.

Functional genomics

The study of gene functions and interactions using genomic technologies.

Proteomics

The large-scale study of proteins, particularly their functions and structure.

Central Dogma of Molecular Biology

The concept that genetic information flows from DNA to RNA to proteins.

Haploidy

The condition of having a single set of chromosomes.

Diploidy

The condition of having two complete sets of chromosomes, one from each parent.

Transgenic organisms

Organisms that have been genetically modified to contain genes from other species.

Gene therapy

A technique that uses genes to treat or prevent disease.

Nucleotide

The basic structural unit of nucleic acids, consisting of a nitrogenous base, a sugar, and a phosphate group.

Adenine (A)

A purine nitrogenous base in DNA and RNA that pairs with thymine in DNA and uracil in RNA.

Cytosine (C)

A pyrimidine nitrogenous base that pairs with guanine in DNA and RNA.

Thymine (T)

A pyrimidine nitrogenous base found only in DNA that pairs with adenine.

Uracil (U)

A pyrimidine nitrogenous base found only in RNA that replaces thymine.

Gene knockout

A genetic technique in which one of an organism's genes is made inoperative.

DNA ligase

An enzyme that facilitates the joining of DNA strands together by forming a phosphodiester bond.

Codons

Three-nucleotide sequences in mRNA that specify particular amino acids.

Start codon

The codon (AUG) that signals the start of translation.

Stop codon

Codons that signal the termination of protein synthesis (UAA, UAG, UGA).

Epigenetics

The study of changes in organisms caused by modification of gene expression rather than alteration of the genetic code itself.

Eukaryotic genome organization

The structure of eukaryotic genomes that include chromosomes composed of chromatin.

Gene regulation

The mechanisms that regulate the expression of specific genes within the genome.

Microbial genetics

The study of the genetics of microorganisms.

Chromatin remodeling

The dynamic modification of the structure of chromatin that enables access to DNA.

Nuclear envelope

The double membrane surrounding the nucleus that separates it from the cytoplasm.

Cell cycle

The series of events that take place in a cell leading to its division and duplication.

Meiosis

The process of cell division that produces reproductive cells (gametes) with half the number of chromosomes.

Mitosis

A part of the cell cycle where replicated chromosomes are separated into two new nuclei.

Genetic drift

A mechanism of evolution that refers to random changes in allele frequencies.

Hybridization

The process of combining different varieties of organisms to create a hybrid.

Transcription factors

Proteins that bind to specific DNA sequences, modulating gene expression.

Histone modification

Chemical modifications to histone proteins that influence gene expression.

Genetic counseling

A process to evaluate and understand genetic disorders.