Cellular Form and Function & Genes and Cellular Function (Dr. Olivey P261)

Vocabulary flashcards covering the major topics from the lecture notes: cellular organelles and cytoskeleton, nucleus and genetic material, ribosomes and protein synthesis, ER/Golgi/lysosomes/peroxisomes/proteasomes, mitochondria and energy production, cell division, aging, differentiation, and basic genetics.

Nonmembranous organelles

Organelles not enclosed by a membrane and always in contact with the cytosol (examples: cytoskeleton, microvilli, centrioles, cilia, ribosomes, proteasomes).

Membranous organelles

Organelles enclosed by lipid membranes (examples: nucleus, endoplasmic reticulum, Golgi apparatus, lysosomes, peroxisomes, mitochondria).

Cytoskeleton

Structural framework of the cell giving strength, shape, and organization; composed of microfilaments, intermediate filaments, thick (myosin) filaments, and microtubules.

Microfilaments

Smallest cytoskeletal elements made of actin; form terminal web near cell surface; anchor proteins; interact with myosin to enable movement.

Intermediate filaments

Cytoskeletal elements of intermediate size; composed of various proteins (e.g., collagen, elastin, keratin) providing structural support.

Thick filaments

Large cytoskeletal bundles of myosin found in muscle cells involved in contraction.

Microtubules

Largest cytoskeletal elements made of tubulin; form centrioles and cilia; transport with kinesin and dynein; form the spindle apparatus during cell division.

Cilia

Hair-like cell surface projections that beat rhythmically to move fluids; anchored by basal bodies.

Basal body

Organelle that anchors a cilium or flagellum to the cell surface and nucleates the axoneme.

Axoneme

Core microtubule structure of a cilium/flagellum, typically arranged as 9+2.

Nucleus

Center of cellular operations; genetic control center surrounded by a nuclear envelope; contains nucleoplasm with DNA, RNA, and proteins; communicates with cytoplasm via nuclear pores.

Nucleolus

Nuclear subregion where ribosomal RNA (rRNA) synthesis and ribosome assembly occur.

Nucleoplasm

Fluid within the nucleus containing DNA, RNA, and proteins.

Nuclear envelope

Double membrane surrounding the nucleus with nuclear pores for transport.

Chromosome

DNA-protein complex containing genetic material; consists of chromatids held at the centromere during division.

Chromatin

Relaxed combination of DNA and proteins (histones) in the nucleus; becomes tightly packed during cell division.

Nucleosome

Basic unit of chromatin; DNA wrapped around a histone protein core.

Centromere

Region of a chromosome where sister chromatids attach; site for kinetochore attachment during division.

Chromatid

One of the two identical halves of a duplicated chromosome after DNA replication.

Histone

Protein around which DNA winds to form nucleosomes; essential for chromatin structure.

Ribosome

Ribosomal particle responsible for protein synthesis; composed of large and small subunits; can be free in cytoplasm or fixed on rough ER.

Ribosomal RNA (rRNA)

RNA component of ribosomes essential for protein synthesis.

Messenger RNA (mRNA)

RNA carrying genetic instructions from DNA to the ribosome for protein synthesis.

Transfer RNA (tRNA)

RNA that carries amino acids to the ribosome; contains an anticodon that pairs with mRNA codons.

Endoplasmic reticulum (ER)

Intracellular membrane network involved in synthesis, storage, transport, and detoxification; forms cisternae.

Rough endoplasmic reticulum (rER)

ER with attached ribosomes; synthesizes and processes proteins; forms transport vesicles to the Golgi.

Smooth endoplasmic reticulum (sER)

ER lacking ribosomes; involved in lipid synthesis, detoxification, and calcium storage.

Cisternae

Flattened membrane-bound sacs that form the structure of both rough and smooth ER.

Golgi apparatus

Organelle that modifies, sorts, and packages proteins for secretion or delivery; forms vesicles (secretory, membrane renewal, lysosome).

Secretory vesicles

Vesicles that carry proteins to the plasma membrane for exocytosis.

Membrane renewal vesicles

Vesicles that supply new membrane components to replenish the plasma membrane.

Lysosomes

Organelle filled with digestive enzymes for intracellular digestion and autophagy; autolysis of injured cells.

Peroxisomes

Organelles with enzymes that neutralize toxins and break down lipids; formed from ER or other peroxisomes.

Proteasome

Protein-degrading complex that removes damaged or abnormal proteins; targets proteins tagged with ubiquitin.

Mitochondrion

Organelle producing ATP via aerobic respiration; contains outer and inner membranes, matrix, and cristae.

Matrix

Fluid inside the mitochondrion where metabolic reactions occur, including the TCA cycle.

Cristae

Folds of the inner mitochondrial membrane that increase surface area for ATP production.

Glycolysis

Glucose breakdown in the cytosol to pyruvate; yields ATP and NADH (anaerobic phase of respiration).

TCA cycle (Krebs cycle)

Metabolic cycle in the mitochondrial matrix producing NADH and FADH2 and ATP; releases CO2.

Electron transport system (ETS) / oxidative phosphorylation

The mitochondrial inner membrane system that uses NADH/FADH2 to drive ATP synthesis via a proton gradient.

Mitochondrial ribosome

Ribosome located in the mitochondrial matrix that synthesizes some mitochondrial proteins.

Centrioles

Paired structures that organize microtubules during cell division and form basal bodies of cilia/flagella.

Centrosome

Organization center for microtubules; surrounds the pair of centrioles.

Mitotic spindle

Structure composed of microtubules that separates chromosomes during mitosis.

Inclusions

Storage products or other materials in the cytoplasm; not membrane-bound.

Plasma membrane

Phospholipid bilayer that encloses the cell; regulates material exchange and provides protection.

Microvilli

Short, dense projections on the cell surface that increase absorptive surface area.

Desmosomes

Cellular junctions that bind adjacent cells together to resist mechanical stress.

Hemidesmosomes

Junctions that attach epithelial cells to the basement membrane.

Kinetochore

Protein structure at the centromere where spindle fibers attach during mitosis.

Golgi vesicles

Vesicles formed from the Golgi that carry cargo to various destinations (secretory, lysosomal, membrane renewal).

Genetic code

Triplet code of 64 codons in mRNA that specify amino acids or stop signals during protein synthesis.

Triplet

Three-nucleotide sequence in DNA that codes for a specific amino acid or stop.

Codon

Three-nucleotide sequence in mRNA that codes for an amino acid or stop signal.

Allele

Variant form of a gene.

Mutation

Change in the genetic code that can alter gene function.

Promoter

DNA region where RNA polymerase binds to initiate transcription.

RNA polymerase

Enzyme that synthesizes RNA from a DNA template during transcription.

Introns

Noncoding sequences within a gene that are removed during mRNA processing.

Exons

Coding sequences that remain in mature mRNA after splicing.

mRNA

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

Pre-mRNA

Initial RNA transcript containing both introns and exons before processing.

Post-transcriptional modification

Processing of pre-mRNA to mature mRNA (splicing, capping, polyadenylation).

Alternative splicing

Process by which different exons are joined to produce multiple mRNA variants from a single gene.

Translation

Process by which ribosomes synthesize protein from mRNA.

Initiation

First phase of translation where the ribosome assembles at the start codon.

Elongation

Phase of translation where amino acids are added to the growing polypeptide chain.

Termination

Phase of translation where a stop codon is reached and the polypeptide is released.

Start codon

AUG; signals the beginning of translation and codes for methionine.

Stop codon

UAA, UAG, or UGA; signals termination of translation.

Anticodon

Three-nucleotide sequence on tRNA that pairs with a complementary mRNA codon.

Polyribosome / polysome

A group of ribosomes translating a single mRNA simultaneously.

Posttranslational modification

Chemical changes to a protein after translation (e.g., glycosylation) often in the Golgi.

Interphase

Non-dividing phase of the cell life cycle consisting of G1, S, and G2; cell growth and DNA replication occur here.

G1 phase

First gap phase; cell growth and metabolic activity.

S phase

DNA synthesis phase; replication of the genome.

G2 phase

Second gap phase; preparation for mitosis and cell division.

G0

Phase where terminally differentiated cells exit the cell cycle and stop dividing.

Mitosis

Nuclear division of somatic cells, producing two identical daughter nuclei.

Meiosis

Reduction division producing sex cells (gametes) with half the chromosome number.

Apoptosis

Programmed cell death; genetically controlled elimination of cells.

Telomeres

TTAGGG repeats at chromosome ends; shorten with each cell division; protect genome.

Telomerase

Enzyme that extends telomeres; activity declines with aging.

Differentiation

Process by which cells become specialized; involves gene activation/deactivation.

Stem cells

Cells capable of repeated division and differentiation into various cell types.

Growth factors

Proteins that stimulate cell division, growth, and development.

Oncogenes

Genes that promote cell growth; when mutated or overexpressed can contribute to cancer.

Benign tumor

Non-cancerous growth that does not invade neighboring tissues.

Malignant tumor

Cancerous tumor capable of invasion and metastasis.

Metastasis

Spread of cancer cells from the primary site to distant locations.

Dominant gene

Allele that masks another allele in a heterozygous organism.

Recessive gene

Allele whose effect is masked by a dominant allele in a heterozygote.

Sex-linked genes

Genes located on sex chromosomes; often show different patterns in males and females.

Codominance

Both alleles contribute to phenotype; e.g., AB blood type.

Incomplete dominance

Heterozygous phenotype is intermediate between two alleles.