Genetics and Cell Function Vocabulary

Vocabulary flashcards covering DNA structure, RNA types, chromatin organization, and protein synthesis stages based on Chapter 4 lecture notes.

Deoxyribonucleic Acid (DNA)

A double-helix nucleic acid polymer containing genetic instructions, composed of $46$ molecules in most human cells with a uniform diameter of $2\,nm$ and average length of approximately $2\text{ in.}$

Nucleotide

The structural monomer of nucleic acids, consisting of a sugar (deoxyribose or ribose), a phosphate group, and a nitrogenous base.

Purines

Two-ring nitrogenous bases found in nucleic acids, comprising Adenine (A) and Guanine (G).

Pyrimidines

Single-ring nitrogenous bases found in nucleic acids, comprising Cytosine (C), Thymine (T, found only in DNA), and Uracil (U, found only in RNA).

Law of Complementary Base Pairing

The structural pairing rule in DNA where Adenine pairs with Thymine (A-T) and Cytosine pairs with Guanine (C-G) held together by hydrogen bonds.

Gene

A sequence or segment of DNA that carries code for one polypeptide or closely related proteins.

Genome

All the genes of one individual person, consisting of an estimated $25,000$ to $35,000$ genes which constitute about $2\%$ of human DNA.

Chromatin

Filamentous material in the interphase nucleus consisting of DNA and proteins that forms $46$ chromosomes.

Nucleosome

A segment of chromatin arranged like beads on a string, consisting of DNA wrapped around a core particle of histone proteins and connected by linker DNA.

Sister Chromatids

Two identical parallel strands of coiled chromatin joined at a centromere to form a chromosome during cell division.

Messenger RNA (mRNA)

A single-stranded RNA molecule containing over $10,000$ bases that carries transcribed genetic code from DNA in the nucleus to the cytoplasm.

Transfer RNA (tRNA)

The smallest RNA molecule, composed of $70$ to $90$ bases, that delivers specific amino acids to ribosomes during translation.

Transcription

The protein synthesis process in which messenger RNA (mRNA) is synthesized from an activated DNA gene inside the nucleus.

Translation

The process of protein synthesis in which ribosomes read mRNA codons in the cytoplasm to assemble amino acids into a polypeptide chain.

Base Triplet

A sequence of three consecutive nucleotides on a DNA molecule that codes for one specific amino acid.

Codon

A mirror-image sequence of three nucleotides on mRNA that codes for an amino acid, featuring start codon AUG and stop codons UAG, UGA, and UAA.

Anticodon

A loop sequence of three nucleotides on tRNA that pairs complementarily with a corresponding codon on mRNA.

P (Peptidyl) Site

The site on the large subunit of a ribosome where initiator tRNA attaches and where tRNA holding the growing peptide chain resides.

A (Acceptor) Site

The site on the large subunit of a ribosome that receives an incoming tRNA carrying its specific amino acid.

E (Exit) Site

The site on the large subunit of a ribosome where uncharged tRNA exits after transferring its amino acid to the growing peptide chain.