DNA, Genes & Biotechnology Essentials

33 vocabulary flashcards covering DNA structure, mutations, protein synthesis, DNA fingerprinting, gel electrophoresis, and PCR.

DNA (Deoxyribonucleic Acid)

The double-stranded molecule inside the cell nucleus that stores the genetic instructions for development, metabolism, and reproduction.

Nucleotide

The basic building block of DNA, composed of a phosphate group, a pentose sugar, and a nitrogenous base.

Base-Pairing Rule

Specific hydrogen bonding in DNA where Adenine pairs with Thymine, and Guanine pairs with Cytosine.

Adenine (A)

A purine nitrogenous base in DNA that forms two hydrogen bonds with thymine.

Thymine (T)

A pyrimidine nitrogenous base in DNA that pairs exclusively with adenine.

Guanine (G)

A purine nitrogenous base in DNA that forms three hydrogen bonds with cytosine.

Cytosine (C)

A pyrimidine nitrogenous base in DNA that pairs exclusively with guanine.

Gene

A specific DNA sequence that encodes a functional RNA or protein product.

Chromatin

The DNA-protein complex that packages DNA inside the nucleus; it condenses to form chromosomes during cell division.

Chromosome

A highly condensed structure of chromatin carrying part of an organism’s genetic material; humans have 46 in each somatic cell.

Somatic Mutation

A DNA change that occurs in non-reproductive (body) cells and cannot be inherited by offspring.

Germline Mutation

A DNA change occurring in reproductive cells that can be passed on to the next generation.

Point Mutation

A mutation involving a single nucleotide change—substitution, insertion, or deletion.

Insertion Mutation

Addition of one or more nucleotides into a DNA sequence, potentially causing a frameshift.

Deletion Mutation

Removal of one or more nucleotides from a DNA sequence, often resulting in a frameshift.

Substitution Mutation

Replacement of a single nucleotide with another, possibly altering one codon.

Frameshift

A reading-frame change in mRNA caused by insertion or deletion, altering every downstream codon.

Protein Synthesis

The cellular process of building proteins via transcription and translation.

Transcription

First step of protein synthesis in which a DNA template is copied into complementary mRNA inside the nucleus.

Translation

Second step of protein synthesis where ribosomes read mRNA codons and assemble amino acids into a polypeptide chain in the cytoplasm.

Messenger RNA (mRNA)

Single-stranded RNA that carries the copied genetic code from DNA to the ribosome for translation.

Codon

A sequence of three mRNA nucleotides that specifies one amino acid or a stop signal.

Amino Acid

Organic molecule that links together to form proteins; 20 standard types exist in biology.

Ribosome

Cellular organelle that reads mRNA and joins amino acids to form proteins during translation.

DNA Fingerprinting (DNA Profiling)

Technique that distinguishes individuals by analyzing unique patterns of DNA fragments.

Banding Pattern

The visible arrangement of DNA fragments on a gel that represents fragment sizes for comparison.

Gel Electrophoresis

Laboratory method that separates DNA fragments by size using an electric field through a gel matrix.

DNA Ladder

Mixture of DNA fragments of known lengths loaded on a gel to estimate sizes of sample fragments.

Polymerase Chain Reaction (PCR)

Technique that amplifies specific DNA segments, producing millions of identical copies from tiny samples.

Denaturation (PCR)

First PCR step at ~94-95 °C where double-stranded DNA is heated to separate into single strands.

Annealing (PCR)

Second PCR step at ~50-56 °C where primers bind to complementary sequences on single-stranded DNA.

Extension (PCR)

Third PCR step at ~72 °C where DNA polymerase synthesizes new strands starting from primers.

Primer

Short single-stranded DNA sequence that provides a starting point for DNA polymerase during PCR or replication.

DNA Polymerase

Enzyme that adds nucleotides to synthesize new DNA strands using a template during replication or PCR.