IB BIO DNA FLASHCARDS

Virus

A microscopic infectious agent that can only replicate inside the living cells of an organism.

DNA

Deoxyribonucleic acid, the molecule that carries the genetic instructions for life.

RNA

Ribonucleic acid, a molecule that plays several roles in the coding, decoding, regulation, and expression of genes.

Nucleotide

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

Sugar-phosphate backbone

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

Nitrogenous base

A molecule that contains nitrogen and has the chemical properties of a base; examples include adenine, thymine, guanine, and cytosine.

Complementary base pairing

The pairing of nitrogenous bases in DNA and RNA where adenine pairs with thymine (or uracil in RNA) and guanine pairs with cytosine.

Semiconservative replication

The process by which DNA is replicated in all cellular organisms, where each new double helix consists of one old strand and one newly synthesized strand.

Helicase

An enzyme that unwinds the DNA double helix by breaking the hydrogen bonds between the complementary bases.

DNA polymerase

An enzyme that synthesizes new DNA strands by adding nucleotides to a pre-existing strand.

Primers

Short strands of RNA or DNA that provide a starting point for DNA synthesis.

Taq polymerase

A heat-stable DNA polymerase used in polymerase chain reaction (PCR) for amplifying DNA.

Polymerase chain reaction (PCR)

A technique used to amplify a specific DNA segment by repeating cycles of denaturation, annealing, and extension.

Gel electrophoresis

A laboratory method used to separate mixtures of DNA, RNA, or proteins according to their size and charge.

Transcription

The process of synthesizing RNA from a DNA template.

RNA polymerase

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

Translation

The process by which a ribosome synthesizes proteins using mRNA as a template.

mRNA

Messenger RNA, a type of RNA that conveys genetic information from DNA to the ribosome.

Ribosomes

Molecular machines composed of rRNA and proteins, serving as the site of protein synthesis.

tRNA

Transfer RNA, a type of RNA that carries amino acids to the ribosome during protein synthesis.

Codon

A sequence of three nucleotides on mRNA that corresponds to a specific amino acid.

Anticodon

A sequence of three nucleotides on tRNA that is complementary to an mRNA codon.

Degeneracy

The redundancy in the genetic code whereby multiple codons can code for the same amino acid.

Universality

The principle that the genetic code is consistent across all known forms of life.

Genetic code

The set of rules by which information encoded in genetic material is translated into proteins.

Point mutation

A change in a single nucleotide base pair in a DNA sequence.

Mutation

A change in the DNA sequence, which can lead to altered genetic information.

Substitution mutation

A type of mutation where one base pair in DNA is replaced by another.

Insertion mutation

A mutation involving the addition of one or more nucleotide base pairs into a DNA sequence.

Deletion mutation

A mutation involving the loss of one or more nucleotide base pairs from a DNA sequence.

Single-nucleotide polymorphism (SNP)

A variation at a single position in a DNA sequence among individuals.

Frameshift change

A mutation caused by a deletion or insertion that shifts the reading frame of the genetic message.

Mutagens

Agents that can cause mutations in DNA, such as chemicals or radiation.

Germ cell

A reproductive cell that gives rise to gametes.

Somatic cell

Any cell of the body excluding germ cells.

Cytokinesis

The process during cell division in which the cytoplasm of a mother cell is divided into two daughter cells.

Oogenesis

The process of formation of ova (egg cells) in the ovaries.

Meiosis

A type of cell division that reduces the chromosome number by half, creating four haploid cells.

Diploid

A cell or organism that has two sets of chromosomes.

Haploid

A cell or organism that has only one set of chromosomes.

Nondisjunction

An error in cell division that causes chromosomes to not separate properly.

Crossing over

The exchange of genetic material between homologous chromosomes during meiosis.

Differentiation

The process by which unspecialized cells develop into specialized cells.

Totipotent

Stem cells that can differentiate into any type of cell, including embryonic tissues.

Pluripotent

Stem cells that can differentiate into almost any cell type but not into entire organisms.

Multipotent

Stem cells that can develop into a limited range of cell types.

Surface area-to-volume ratio

A ratio that describes how the surface area of an object relates to its volume, affecting efficiency of material exchange.