Lecture 3 Cellular organisation II: protein synthesis and mitosis | EPBIOL259 Introductory BioScience

Vocabulary flashcards covering key terms and concepts from Lecture 3: Protein synthesis and mitosis.

amino acid

A small organic molecule with a central carbon, an amino group (-NH2) and a carboxyl group (-COOH); building block of proteins.

polypeptide

A chain of amino acids linked by peptide bonds; longer chains form proteins.

protein

A macromolecule built from one or more polypeptide chains; performs a wide range of cellular functions.

peptide bond

Covalent bond linking amino acids in a protein chain via a condensation reaction.

keratin

A tough structural protein that strengthens nails, hair and skin.

collagen

Structural protein providing foundational support in bones, cartilage, teeth and skin.

hormone

Protein that acts as a chemical messenger in the body.

receptor

Protein that binds signaling molecules to trigger a cellular response.

channel protein

Membrane protein that forms a pore allowing specific solutes to pass.

gated channel

Channel that opens or closes to regulate solute flow at specific times.

cell-identity marker

Glycoprotein that marks a cell as part of the body, distinguishing self from foreign cells.

CAM (cell-adhesion molecule)

Protein that binds cells to each other or to extracellular matrix.

enzyme

Protein that acts as a biological catalyst to speed up chemical reactions.

antibody

Protein that recognizes and neutralizes foreign toxins and pathogens.

clotting protein

Proteins that help seal broken blood vessels and reduce blood loss.

molecular motor

Proteins that convert chemical energy into mechanical work for movement.

endoplasmic reticulum

Membrane network where ribosome-bound proteins are synthesized and processed.

rough ER

Endoplasmic reticulum studded with ribosomes; site of synthesis for proteins destined for secretion or lysosomes.

Golgi apparatus

Organelle that sorts, modifies and packages proteins for transport in vesicles.

vesicle

Small membrane-bound sac that transports proteins between organelles or to the membrane.

exocytosis

Process by which vesicles fuse with the plasma membrane to release contents outside the cell.

ribosome

Ribonucleoprotein complex that reads mRNA and assembles amino acids into a polypeptide.

nucleus

Organelle housing DNA and the site of transcription.

DNA

Deoxyribonucleic acid; genetic material; double helix; resides in the nucleus.

RNA

Ribonucleic acid; single-stranded; carries genetic orders from DNA; three types involved in protein synthesis.

nucleotide

Monomer units of nucleic acids consisting of a sugar, phosphate and nitrogenous base.

nitrogenous base

Organic base; purines (A, G) or pyrimidines (C, T in DNA, U in RNA).

purines

Double-ring bases: adenine (A) and guanine (G).

adenine

Purine base that pairs with thymine in DNA and with uracil in RNA.

guanine

Purine base that pairs with cytosine.

pyrimidines

Single-ring bases: cytosine (C), thymine (T) and uracil (U).

cytosine

Pyrimidine base that pairs with guanine.

thymine

Pyrimidine base that pairs with adenine in DNA.

uracil

Pyrimidine base that pairs with adenine in RNA.

deoxyribose

Five-carbon sugar in DNA.

ribose

Five-carbon sugar in RNA.

double helix

Two nucleotide chains wound around each other to form DNA.

chromatin

DNA-protein complex that condenses into chromosomes during cell division.

chromosome

Condensed DNA structure carrying genes; consists of two sister chromatids joined at the centromere.

centromere

Region where sister chromatids are held together and where spindle fibers attach during mitosis.

chromatids

Two identical copies of a replicated chromosome held together at the centromere.

spindle fibres

Microtubule structures that separate chromosomes during mitosis.

prophase

First mitotic phase; chromosomes condense; nuclear envelope breaks down; spindle forms.

metaphase

Mitotic phase where chromosomes align at the cell’s equator and spindle attaches to kinetochores.

anaphase

Mitotic phase; centromeres split and sister chromatids move to opposite poles.

telophase

Mitotic phase; chromosomes arrive at poles; nuclei reform and chromatin decondenses.

cytokinesis

Division of the cytoplasm; results in two genetically identical daughter cells.

cleavage furrow

Indentation of the cell surface during cytokinesis leading to cell division.

meiosis

Cell division that produces reproductive cells (eggs and sperm) with half the chromosome number.

mitosis

Nuclear division producing two identical nuclei; followed by cytokinesis.

mRNA

Messenger RNA; carries genetic code from DNA to ribosome for protein synthesis.

tRNA

Transfer RNA; brings amino acids to the ribosome; contains an anticodon.

rRNA

Ribosomal RNA; structural component of ribosome.

codon

Three-nucleotide sequence on mRNA that codes for one amino acid.

anticodon

Three-nucleotide sequence on tRNA complementary to a codon.

start codon

AUG; initiation codon that starts translation and codes for methionine.

stop codon

Codon signaling termination of translation.

translation

Process of converting an mRNA sequence into a polypeptide (protein).

transcription

Process of copying a DNA sequence into a complementary mRNA sequence.

mature mRNA

Processed mRNA with introns removed and exons joined; ready for translation.

splicing

Editing step removing introns and joining exons to form mature mRNA.

introns

Noncoding segments of a gene removed during mRNA processing.

exons

Coding segments of a gene that remain in mature mRNA after splicing.

helicase

Enzyme that unwinds the DNA double helix during transcription.

RNA polymerase

Enzyme that reads DNA and synthesizes RNA during transcription.

base pairing DNA

A pairs with T; C pairs with G in DNA.

base pairing RNA

A pairs with U; C pairs with G in RNA.

sugar–phosphate backbone

The repeating sugar and phosphate groups forming the structural framework of DNA/RNA.

interphase

Phase between cell divisions where cell grows and DNA is replicated.

G1

First gap phase; cell growth and normal tasks; preparation for DNA replication.

S phase

Synthesis phase; DNA replication occurs.

G2

Second gap phase; preparation for cell division; centriole replication finishes.

M phase

Mitotic phase; includes mitosis and cytokinesis; nucleus divides and cytoplasm splits.

cell cycle

The life cycle of a cell from one division to the next, including G1, S, G2 and M phases.