DNA: The Chemical Nature of the Gene

A comprehensive set of vocabulary flashcards summarizing key concepts about DNA and genetic material as covered in Chapter 10 of the lecture.

Genetic material

Must contain complex information for traits and functions of an organism.

Replication

The process through which genetic material must be duplicated faithfully.

Phenotype

The observable characteristics of an organism encoded by genetic instructions in DNA.

Genetic variation

The differences in DNA sequences among individuals, leading to diversity within and between species.

Nucleotide structure

Consists of a phosphate group, a sugar, and a nitrogenous base.

Tetranucleotide hypothesis

An early incorrect proposal that four repeating nucleotides were insufficiently complex to be genetic material.

Nuclein

A term used by Johann Friedrich Miescher for the substance isolated from the nuclei of white blood cells.

Chargaff's rules

Adenine equals thymine (A = T) and guanine equals cytosine (G = C) in DNA composition.

Transformation

The process by which non-virulent bacteria acquire virulence from dead virulent bacteria.

The Transforming Principle

The notion that a compound from dead bacteria can change the genetic identity of living bacteria.

Avery-MacLeod-McCarty experiment

Demonstrated that DNA is the transforming agent responsible for bacterial transformation.

Hershey-Chase experiment

Showed that DNA is the genetic material in bacteriophages by labeling DNA and protein.

X-ray diffraction

A technique used to study the structure of DNA, notably by Rosalind Franklin.

Double helix

The structure of DNA comprising two complementary and antiparallel nucleotide strands.

Deoxyribose

The sugar component of DNA nucleotides.

Purine

A type of nitrogenous base that includes adenine (A) and guanine (G).

Pyrimidine

A type of nitrogenous base that includes cytosine (C), thymine (T), and uracil (U).

Phosphodiester bonds

Covalent bonds that connect nucleotides in the sugar-phosphate backbone of DNA.

Base pairing

The specific hydrogen bonding between adenine and thymine (2 H bonds) and guanine and cytosine (3 H bonds).

Antiparallel strands

The opposite orientation of the two nucleotide strands in a DNA double helix.

Hairpin structure

Structure formed when complementary sequences within the same strand of RNA or DNA invite folding.

DNA methylation

The addition of methyl groups to nucleotide bases, affecting gene expression.

B-DNA

The common right-handed double helix structure of DNA.

A-DNA

A right-handed helical structure of DNA that is more compact than B-DNA.

Z-DNA

A left-handed helical form of DNA with a zig-zag shape.

Nucleoside

A molecule consisting of a nitrogenous base and a sugar, without a phosphate group.

Nucleotide monophosphate

A nucleotide containing one phosphate group.

Deoxyadenosine

A nucleoside made up of adenine and deoxyribose.

Epigenetic gene silencing

The process through which certain genes are turned off without changing the DNA sequence.

Hydrogen bonds

Weak bonds that hold together complementary bases on opposite DNA strands.

Covalent bonds

Stronger bonds that form the backbone of the DNA strand by linking nucleotides.

Structure of DNA

Comprised of two polynucleotide chains wound around each other to form a double helix.

Nitrogenous bases

Components of nucleotides, responsible for the genetic information they carry.

Prokaryotic DNA methylation

Process used by bacteria to differentiate their own DNA from foreign DNA.

Molecular structure of nucleic acids

The chemical structure that enables nucleic acids like DNA and RNA to function.

Nobel Prize in Chemistry 1962

Awarded to Watson, Crick, and Wilkins for their discovery of the molecular structure of nucleic acids.