PCB 3023 Cell Bio Exam 2 Flashcards

Initiator tRNA

Special tRNA that starts translation, carrying methionine in eukaryotes.

Ribosome

Cellular machine that synthesizes proteins by translating mRNA.

Aminoacyl-tRNA-synthetase

Enzyme that attaches the correct amino acid to its corresponding tRNA.

Reading Frame

Three-way grouping of nucleotides used to translate mRNA into amino acids.

Codon

A sequence of three nucleotides that codes for a specific amino acid.

Alternative Splicing

Mechanism producing different mRNAs by varying exon inclusion during splicing.

Protease

An enzyme that degrades proteins by hydrolyzing peptide bonds.

Exon

Protein-coding region in a eukaryotic gene.

Intron

Noncoding intervening sequence removed during RNA splicing.

RNA Processing

Modifications like capping, splicing, and polyadenylation applied to primary RNA transcripts.

General Transcription Factors

Proteins required to initiate transcription at all eukaryotic promoters.

Noncoding RNA

Functional RNA molecule that is not translated into a protein.

Transcription

Synthesis of an RNA molecule using a DNA template.

RNA

Single-stranded nucleic acid containing ribose, uracil, and genetic information.

Proteasome

Large protein complex that degrades ubiquitinated proteins.

snRNP

Small nuclear ribonucleoprotein complexes that form the core of the spliceosome.

Translation initiation factor

Protein that helps assemble ribosomes on mRNA to start translation.

Ubiquitin

Small protein tag marking proteins for destruction by the proteasome.

snRNA

Small nuclear RNA involved in RNA splicing within the spliceosome.

RNA transcript

RNA molecule produced by transcription from a DNA template.

RNA polymerase

Enzyme that synthesizes RNA from a DNA template.

mRNA

Messenger RNA that carries genetic code from DNA to ribosomes.

Gene expression

Process by which a gene's information directs protein or RNA synthesis.

Promoter

DNA region where RNA polymerase binds to initiate transcription.

RNA capping

Addition of a methylated guanine nucleotide to the 5' end of mRNA.

Polyadenylation

Addition of a poly-A tail to the 3' end of mRNA.

RNA splicing

Removal of introns and joining of exons in a pre-mRNA.

Gene

Fundamental unit of heredity carrying instructions for a functional product.

Spliceosome

Large macromolecular complex that splices introns out of pre-mRNA.

Translation

Process converting mRNA nucleotide sequence into a polypeptide chain.

Genetic code

Set of rules translating nucleotide triplets into amino acids.

tRNA

Transfer RNA that delivers specific amino acids to ribosomes during translation.

anticodon

Three-nucleotide sequence on tRNA complementary to an mRNA codon.

rRNA

Ribosomal RNA forming core structural and catalytic components of ribosomes.

ribozyme

An RNA molecule with catalytic activity.

Gene expression

Process by which a gene's info directs cellular function and protein synthesis.

siRNA

Small interfering RNA guiding target mRNA destruction via RNAi.

miRNA

MicroRNA regulating gene expression by binding and silencing target mRNAs.

regulatory RNA

RNA molecules that regulate gene expression.

epigenetic inheritance

Transmission of heritable traits not caused by changes in DNA sequence.

cell memory

Ability of cells to maintain specialized patterns of gene expression.

iPS cell

Induced pluripotent stem cell reprogrammed from somatic cells.

transcriptional activator

Protein binding to DNA to enhance transcription initiation.

transcriptional repressor

Protein binding to DNA to decrease transcription initiation.

promoter

DNA sequence initiating transcription of a particular gene.

differentiation

Process where unspecialized cells develop specialized structures and functions.

long noncoding RNA

Non-coding RNA transcripts longer than 200 nucleotides with regulatory roles.

RNAi

RNA interference pathway silencing gene expression via small RNAs.

Post-transcriptional control

Regulation of gene expression after transcription has occurred.

DNA methylation

Addition of methyl groups to DNA bases, usually repressing transcription.

Positive feedback loop

Regulatory circuit where a component activates its own production.

Combinatorial control

Control of gene expression by combinations of multiple transcription regulators.

Transcription regulator

Protein binding to regulatory DNA sequences to control transcription.

Regulatory DNA sequence

DNA region determining when and where a gene is expressed.

Plasma membrane

Lipid bilayer enclosing the cytoplasm of a cell.

Lipid bilayer

Double layer of phospholipid molecules forming the basis of cell membranes.

Amphipathic

Having both hydrophilic and hydrophobic regions.

Fat droplet

Intracellular storage site for neutral fats and cholesterol esters.

Cholesterol

Sterol molecule modulating membrane fluidity and permeability.

Membrane protein

Protein associated with or embedded in a cell membrane.

Cell cortex

Meshwork of cytoskeletal proteins supporting the plasma membrane.

Glycocalyx

Carbohydrate-rich outer coat of a eukaryotic cell surface.

Phospholipid

Major membrane lipid consisting of polar head and fatty acyl tails.

Phosphatidylcholine

Most common phospholipid found in mammalian cell membranes.

Unsaturated

Containing one or more double bonds in hydrocarbon chains.

Saturated

Containing no double bonds in hydrocarbon carbon chains.

Detergent

Amphipathic molecule used to solubilize membrane proteins.

Bacteriorhodopsin

Light-driven proton pump found in Archaea plasma membranes.

membrane domain

Specialized region of a membrane with specific proteins and lipids.

endomembrane system

Interconnected network of internal membrane-bounded organelles in eukaryotic cells.

autophagy

Cellular degradation process clearing damaged organelles and proteins.

lysosome

Acidic organelle containing digestive enzymes for degradation.

pinocytosis

Cellular uptake of fluid and small molecules via tiny vesicles.

phagocytic cell

Specialized cell that engulfs large particles or microorganisms.

secretory vesicle

Vesicle storing products for release from the cell by exocytosis.

secretion

Process of releasing cellular products outside the cell.

exocytosis

Fusion of vesicles with the plasma membrane to release contents.

SNARE

Protein family mediating vesicle fusion with target membranes.

Clathrin

Protein forming coated pits and vesicles for receptor-mediated endocytosis.

coated vesicle

Vesicle surrounded by a protein coat during transport steps.

rough endoplasmic reticulum

ER region studded with ribosomes, synthesizing membrane and secretory proteins.

peroxisome

Organelle containing oxidative enzymes for metabolic breakdown.

nuclear pore

Protein complex perforating the nuclear envelope for molecular transport.

signal sequence

Amino acid sequence directing a protein to its correct cellular destination.

membrane-enclosed organelle

Intracellular compartment bounded by a distinct lipid membrane.

endosome

Membrane-bounded compartment sorting endocytosed materials.

receptor-mediated endocytosis

Selective uptake of specific molecules bound to cell-surface receptors.

phagocytosis

Engulfing of large particles or whole cells by specialized phagocytes.

endocytosis

Cellular uptake of extracellular material via plasma membrane invagination.

Golgi apparatus

Organelle modifying, sorting, and packaging proteins and lipids.

unfolded protein response

Cellular stress response triggered by misfolded proteins in the ER.

tethering protein

Protein capturing transport vesicles near target membranes.

Rab protein

Monomeric GTPase guiding vesicle targeting and docking.

vesicular transport

Transfer of materials between compartments via transport vesicles.

transport vesicle

Small membrane-bound vesicle moving cargo between cell compartments.

endoplasmic reticulum (ER)

Extensive membrane network involved in protein and lipid synthesis.

nuclear envelope

Double membrane enclosing the cell nucleus.