The Chemical Basis of Life II: Organic Molecules

A total of 40 vocabulary flashcards covering key concepts from the chapter on the chemical basis of life, specifically focusing on DNA structure, replication, and the molecular mechanisms involved.

What is DNA?

Deoxyribonucleic acid, a molecule that stores the information needed to produce proteins.

Nucleotide

The basic building block of nucleic acids, consisting of a phosphate group, a five-carbon sugar, and a nitrogenous base.

What are purines?

Nitrogenous bases with a double-ring structure; includes adenine (A) and guanine (G).

What are pyrimidines?

Nitrogenous bases with a single-ring structure; includes cytosine (C), thymine (T), and uracil (U).

Sugar-phosphate backbone

The structural framework of nucleic acids, consisting of sugar and phosphate groups.

Transformation principle

The concept that genetic material can be transferred from one organism to another, as shown in Griffith's experiment.

RNA polymerase

An enzyme that synthesizes RNA from a DNA template during transcription.

Transcription

The process of copying the gene's sequence from DNA to mRNA.

Translation

The process of synthesizing a protein based on the sequence encoded in mRNA.

Griffith's experiment

A study that revealed the transforming principle of DNA by showing how heat-killed bacteria could transform live bacteria.

DNA replication

The process of copying DNA to produce two identical DNA molecules.

Leading strand

The DNA strand that is synthesized continuously toward the replication fork.

Lagging strand

The DNA strand that is synthesized discontinuously away from the replication fork in short segments called Okazaki fragments.

Okazaki fragments

Short segments of DNA synthesized on the lagging strand during DNA replication.

DNA helicase

An enzyme that unwinds and separates the two strands of the DNA double helix during replication.

Single-strand binding proteins

Proteins that stabilize single-stranded DNA during replication to prevent it from re-forming a double helix.

Topoisomerase

An enzyme that relieves the twisting tension ahead of the replication fork during DNA replication.

RNA primase

An enzyme that synthesizes a short RNA primer to initiate DNA synthesis.

DNA polymerase

An enzyme that adds nucleotides to a growing DNA strand during replication.

DNA ligase

An enzyme that connects Okazaki fragments on the lagging strand by forming phosphodiester bonds.

Hydrolysis reaction

A chemical reaction involving the addition of water that breaks down polymers into monomers.

Dehydration reaction

A chemical reaction that removes water to join monomers into polymers.

Antiparallel strands

Refers to the opposite orientation of the two strands of DNA, where one strand runs 5' to 3' and the other runs 3' to 5'.

Telomeres

Repeating nucleotide sequences at the ends of chromosomes that protect them from deterioration.

What role does telomerase play in cells?

Telomerase adds repetitive nucleotide sequences to telomeres, maintaining chromosome length and stability during cell division.

Genome

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

Chromosomes

Structures composed of DNA and protein that contain genetic information.

Nuclease

An enzyme that cleaves the chains of nucleotides in nucleic acids into smaller units.

Euchromatin

Less compacted form of chromatin that is accessible for transcription.

Heterochromatin

Highly compacted form of chromatin that is generally transcriptionally inactive.

Nucleosome

The fundamental unit of chromatin, consisting of a segment of DNA wound around histone proteins.

Covalent bond

A chemical bond that involves the sharing of electron pairs between atoms.

Hydrogen bonding

A weak bond between two molecules resulting from an electrostatic attraction.

Genome stability

The maintenance of the integrity of genetic information over time.

Gene expression

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

What is the role of DNA in the cell?

DNA stores genetic information and serves as a template for the production of RNA and proteins.

RNA structure vs DNA structure

RNA is typically single-stranded and contains ribose sugar; DNA is double-stranded and contains deoxyribose sugar.

What is the function of DNA polymerase?

To synthesize new DNA strands by adding nucleotides to a growing chain during replication.

Genetic material

Material such as DNA or RNA that carries genetic information.

Cell division

The process by which a parent cell divides into two or more daughter cells.

Loop domains

Regions of DNA that fold into loops to facilitate gene regulation and chromatin structure.

What impacts telomere length?

Telomere length is affected by factors such as cell division, aging, and telomerase activity.