Chapter 11 - Nucleic Acids, DNA Replication, and Chromosomes

This set of flashcards contains key vocabulary terms and definitions related to nucleic acids, DNA replication, and chromosomes, helping students review vital concepts for their upcoming exam.

Nucleic Acids

Biomolecules essential for all known forms of life, which include DNA and RNA.

DNA

Deoxyribonucleic acid, the molecule that carries genetic information.

RNA

Ribonucleic acid, a molecule essential for various biological roles, including coding, decoding, regulation, and expression of genes.

DNA Replication

The process by which DNA makes a copy of itself during cell division.

Chromosome

A structure composed of DNA and proteins that carries genetic information.

Nucleotide

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

Double Helix

The structure of DNA, consisting of two strands twisted around each other.

Chromatin

The complex of DNA and proteins found in the nucleus of eukaryotic cells.

Genome

The complete set of genetic material within an organism.

Nitrogenous Base

A molecule that contains nitrogen and as a base, it includes adenine, guanine, cytosine, thymine, and uracil.

Purines

A class of nitrogenous bases with a double-ring structure, including adenine (A) and guanine (G).

Pyrimidines

A class of nitrogenous bases with a single-ring structure, including thymine (T), uracil (U), and cytosine (C).

Covalent Bond

A chemical bond formed by the sharing of electron pairs between atoms.

Phosphodiester Bond

A type of covalent bond that links nucleotides in a DNA strand.

Antiparallel Orientation

Refers to the opposite direction of the two strands of DNA.

5' End

The end of a DNA strand that has a phosphate group attached to the fifth carbon of the sugar.

3' End

The end of a DNA strand that has a hydroxyl (-OH) group attached to the third carbon of the sugar.

DNA Polymerase

An enzyme responsible for synthesizing new DNA strands by adding nucleotides.

Leading Strand

The DNA strand that is synthesized continuously during replication.

Lagging Strand

The DNA strand that is synthesized in short bursts, known as Okazaki fragments.

Okazaki Fragments

Short DNA fragments synthesized on the lagging strand during DNA replication.

DNA Ligase

An enzyme that joins Okazaki fragments together on the lagging strand.

Telomeres

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

Telomerase

An enzyme that extends telomeres, preventing chromosome shortening.

Replication Fork

The area where the DNA helix is unwound during replication.

DNA Primase

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

Bidirectional Replication

Refers to DNA replication that occurs simultaneously in two directions from the origin of replication.

Enzymatic Activity

The function or action performed by an enzyme.

Chromosomal Territory

The distinct location occupied by a chromosome within the nucleus.

Euchromatin

Less condensed form of chromatin which is actively being transcribed.

Heterochromatin

Highly condensed form of chromatin that is generally not transcribed.

Histones

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

Nucleosome

The basic unit of DNA packaging, consisting of a segment of DNA wound around a core of histone proteins.

RNA Primer

A short strand of RNA used to initiate DNA synthesis.

Base Pairing Rules

Rules that dictate the pairing of nitrogenous bases, specifically A with T and G with C.

Mutation

An alteration in the DNA sequence that can lead to changes in traits.

Fidelity of DNA Replication

The high degree of accuracy associated with DNA replication.

Topoisomerase

An enzyme that alleviates the twisting tension in DNA during replication.

Single-Strand Binding Protein

A protein that stabilizes unwound single DNA strands to prevent them from re-annealing.

DNA Replication Accuracy

High precision in DNA replication due to specific base pairing and proofreading mechanisms.

Chromosome Shortening

The gradual reduction in length of chromosomes after each replication cycle.

Radial Loop Domains

Structural organization of chromatin in the nucleus, anchoring DNA to the nuclear matrix.

Chromatin Fiber

Compressed and packaged form of chromatin, further condensing DNA for packaging into chromosomes.

Centromere

The region of a chromosome where sister chromatids are joined and where spindle fibers attach during mitosis.

Hydrogen Bonds

Weak bonds between nitrogenous bases that hold the two strands of DNA together.

Covalent Linkage

The strong connections formed between nucleotides in a DNA strand.

Nuclear Matrix

The network of fibers found throughout the inside of a cell nucleus that helps maintain its shape.

Chromosomal Compaction

The process of condensing chromatin into chromosomes during cell division.

Duplication of DNA

The process of copying the DNA before cell division.

Gene Expression

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

RNA Structure

The specific arrangement and composition of RNA molecules, important for their functionality.

Cell Division

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

Evolutionary Processes

Natural phenomena that lead to changes in the hereditary characteristics of biological populations.