Nucleic Acids & Karyotyping

DNA (Deoxyribonucleic Acid)

A molecule that carries genetic information in living organisms and is composed of two strands forming a double helix.

Deoxyribose

A five-carbon sugar that is a component of DNA.

Nucleotide

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

Adenine

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

Thymine

A nitrogenous base found in DNA that pairs with adenine during DNA replication.

Guanine

A nitrogenous base found in DNA and RNA that pairs with cytosine in both DNA and RNA.

Cytosine

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

Purines

A family of nitrogenous bases including adenine and guanine, which have a double-ring structure and are found in both DNA and RNA.

Pyrimidines

A family of nitrogenous bases including cytosine, thymine, and uracil, characterized by a single-ring structure and present in both DNA and RNA.

Hydrogen Bonds

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

Complementary Base Pairing

The phenomenon where adenine pairs with thymine (or uracil in RNA) and cytosine pairs with guanine, ensuring accurate DNA replication.

Chromosome

A thread-like structure made of DNA and proteins that carries genetic information in the form of genes. Found in the nucleus of eukaryotic cells and are visible during cell division.

Histone

A type of protein that helps package and organize DNA into structural units called nucleosomes, facilitating the compaction of DNA into chromosomes.

Nucleosome

A structural unit of DNA composed of a segment of DNA wound around a core of 8 histone proteins, playing a key role in the organization and compaction of chromatin within the nucleus.

Gene

A series of nucleotides along the length of a DNA molecule that codes for the production of a protein.

Genome

The entire set of chromosomes of an organism. For the human, this includes the 3 billion base pairs that comprise our 46 chromosomes.

Somatic Cells

Any cells forming the body excluding gametes, which contain a complete set of chromosomes and are responsible for growth and maintenance.

Gametes

Reproductive cells that unite during fertilization to form a zygote, containing half the number of chromosomes as somatic cells.

Diploid

A cell or organism that contains two complete sets of chromosomes, one from each parent, and is characterized by the presence of homologous chromosome pairs. (2n)

Haploid

Cells with one set of chromosomes, typically found in gametes. (n)

Sex chromosomes

Chromosomes that determine an individual's sex, typically designated as X and Y in humans. They play a crucial role in reproduction and inheritance.

Homologous Chromosomes

A pair of chromosomes, one inherited from each parent, that have the same genes but may carry different alleles.

Karyotype

A visual representation of an individual's complete set of chromosomes, organized by size and shape, used to identify chromosomal abnormalities.

DNA Replication

The process by which a cell duplicates its DNA, resulting in two identical DNA molecules. This occurs during the S phase of the cell cycle.

Mitosis

The process of cell division that produces two identical daughter cells, involving stages such as prophase, metaphase, anaphase, and telophase.

Meiosis

The process of cell division that reduces the chromosome number by half, resulting in the formation of four haploid gametes.

Mutation

A change in the DNA sequence of an organism that can lead to alterations in their traits or functions.

Apoptosis

The programmed cell death process that regulates cell turnover and helps eliminate damaged or unnecessary cells.

Cancer

A disease characterized by uncontrolled cell growth and division, often leading to the formation of tumors.

Genetic Disease

A mutation that affects the structure or function of proteins, often resulting in inherited disorders or increased susceptibility to disease.

RNA (Ribonucleic Acid)

A molecule that is used as a copy of DNA/gene (mRNA), and a carrier of amino acids during protein synthesis (tRNA). In addition, it helps to form ribosomes (rRNA).

Ribose

A 5-carbon sugar molecule that is a component of RNA.