Chapter 03 Lecture and Animation Outline

Vocabulary flashcards covering key cellular structures, organelles, transport mechanisms, genetic processes, and cell division concepts from the lecture notes.

Plasma membrane

Phospholipid bilayer that forms the cell boundary; selectively permeable; part of the fluid mosaic model with embedded proteins.

Cytoplasm

Fluid, jellylike substance between the plasma membrane and nucleus containing organelles.

Nucleus

Organelle that houses DNA and directs cell activities; enclosed by the nuclear envelope.

Nuclear envelope

Double membrane surrounding the nucleus with nuclear pores that regulate traffic.

Nucleolus

Darker region inside the nucleus that synthesizes ribosomal RNA (rRNA).

Chromatin

DNA packaged with histones; condenses to form chromosomes during cell division.

Euchromatin

Looser, transcriptionally active chromatin.

Heterochromatin

Highly condensed, transcriptionally inactive chromatin.

Nuclear pores

Protein channels in the nuclear envelope that allow small molecules and RNA to pass.

Endoplasmic reticulum (ER)

System of membranous tubules connected to the nuclear membrane and plasma membrane.

Granular (rough) ER

ER with ribosomes; site of protein synthesis and modification.

Agranular (smooth) ER

ER without ribosomes; involved in lipid metabolism and Ca2+ storage.

Golgi complex

Stacks of cisternae that modify, sort, and package proteins for secretion or delivery.

Ribosome

Ribonucleoprotein particle that synthesizes proteins; free or attached to ER.

Mitochondrion

Site of aerobic respiration; produces ATP; double membrane with cristae and matrix.

Lysosome

Organelle with digestive enzymes; digests ingested material and worn-out organelles.

Peroxisome

Organelle with enzymes for oxidative reactions; detoxifies harmful molecules.

Centrosome

Structure near the nucleus containing two centrioles; organizes spindle fibers during division.

Centriole

Paired organelles within the centrosome; role in organizing spindle apparatus.

Cytoskeleton

Network of microtubules and microfilaments that supports shape and transport.

Microtubule

Tubular protein filament forming part of cytoskeleton and spindle apparatus.

Microfilament

Actin filament involved in cell movement and shape changes.

Cilia

Hairlike projections; 9+2 axoneme; move substances across surfaces.

Flagellum

Long whip-like structure with 9+2 arrangement; enables cell propulsion (e.g., sperm).

Microvilli

Membrane folds that increase surface area for absorption and diffusion.

Phagocytosis

Bulk transport where cells engulf large particles using pseudopods.

Pseudopod

Temporary cytoplasmic extension used to engulf material during phagocytosis.

Endocytosis

Process of bringing large materials into the cell by membrane invagination.

Pinocytosis

Nonspecific endocytosis; uptake of fluids and dissolved substances.

Receptor-mediated endocytosis

Specific uptake via receptors that bind the substance to be internalized.

Exocytosis

Secretion of large cellular products; vesicles fuse with the plasma membrane to release contents.

Glycolipids

Carbohydrates attached to lipids in the membrane; function in antigenicity and signaling.

Glycoproteins

Carbohydrates attached to proteins in the membrane; involved in recognition and signaling.

Cholesterol

Sterol in the membrane that provides fluidity and stability.

Carbohydrates (membrane components)

Carbohydrate moieties on membrane proteins and lipids used in signaling and recognition.

Fluid mosaic model

Membrane structure where lipids and proteins float in a fluid bilayer; proteins move laterally.

Integral proteins

Proteins that span the lipid bilayer.

Peripheral proteins

Proteins attached to one face of the membrane, not spanning it.

Membrane receptors

Proteins that detect and respond to external signals (hormones, ligands).

Self markers

Membrane markers that help the immune system distinguish self from non-self.

Glycocalyx

Carbohydrate-rich zone on the cell surface involved in protection and signaling.

Nucleolus

Region within the nucleus where rRNA synthesis occurs.

DNA

Molecule containing genetic information; blueprint for protein synthesis.

Gene

DNA sequence that codes for a specific protein.

Transcription

Process of copying DNA into RNA (mRNA) using promoters and transcription factors.

Translation

Process of interpreting mRNA into a polypeptide at the ribosome.

Messenger RNA (mRNA)

RNA that carries genetic code from DNA to the ribosome for protein synthesis.

Transfer RNA (tRNA)

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

Ribosomal RNA (rRNA)

RNA component of ribosomes; structural and catalytic role in protein synthesis.

Pre-mRNA

Initial RNA transcript containing introns and exons before processing.

Spliceosome

Molecular complex that removes introns and joins exons during RNA splicing.

Introns

Noncoding segments of a gene that are removed during RNA processing.

Exons

Coding segments of a gene that are retained in mature mRNA.

Alternative splicing

Process by which multiple mRNA variants are produced from one pre-mRNA.

Promoter

DNA sequence where RNA polymerase and transcription factors bind to start transcription.

Transcription factors

Proteins that regulate transcription by binding to DNA.

RNA polymerase

Enzyme that synthesizes RNA from a DNA template during transcription.

Codon

Three-nucleotide sequence in mRNA that specifies an amino acid or stop/start signal.

Anticodon

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

Polyribosome

A cluster of ribosomes translating a single mRNA simultaneously.

Translation factors

Components involved in assembling amino acids into a polypeptide at the ribosome.

Protein

Polypeptide chain that folds into a functional molecule.

Posttranslational modifications

Chemical modifications after translation (e.g., methylation, phosphorylation, glycosylation).

Methylation

Addition of methyl groups to DNA or histones affecting gene expression.

Phosphorylation

Addition of phosphate groups to proteins regulating function.

Ubiquitin

Small protein tag marking proteins for degradation by the proteasome.

Proteasome

Protein complex that degrades ubiquitinated proteins.

Genome

All genes of an organism or species; humans ≈ 25,000 genes.

Proteome

All proteins produced by the genome; over 100,000 in humans.

Epigenetic inheritance

Heritable changes in gene expression without changes to DNA sequence.

Histone

Positively charged protein around which DNA wraps to form chromatin.

Nucleosome

DNA wrapped around a histone; basic unit of chromatin structure.

Chromatin

DNA-histone complex that becomes chromosomes during cell division.

Telomeres

DNA sequences at chromosome ends; shorten with replication; protect ends.

Telomerase

Enzyme that extends telomeres in some cells, enabling continued division.

p53

Tumor suppressor transcription factor; can halt the cell cycle, repair DNA, or induce apoptosis.

Cyclin D

Protein driving progression through G1; overactivity linked to cancer.

Cell cycle

Ordered sequence of growth and division: interphase (G1, S, G2) and mitosis (M).

Interphase

Phase of the cell cycle where growth and DNA replication occur.

G1 phase

First gap phase; cell growth and metabolic activity before DNA replication.

S phase

DNA synthesis phase where replication occurs.

G2 phase

Second gap phase; preparation for mitosis; chromosome condensation begins.

Mitosis

Nuclear division through prophase, metaphase, anaphase, and telophase.

Prophase

Chromosomes condense; nuclear envelope breaks down; spindle forms.

Metaphase

Chromosomes align at the cell equator; spindle fibers attach to centromeres.

Anaphase

Sister chromatids separate and move to opposite poles.

Telophase

Nuclei re-form around chromosomes; cytokinesis typically overlaps.

Cytokinesis

Division of the cytoplasm to form two separate cells.

Meiosis

Reduction division to form gametes; two rounds of division with crossing-over.

Homologous chromosomes

Pairs of chromosomes with the same genes from each parent.

Crossing-over

Exchange of genetic material between homologous chromosomes during meiosis I.

Meiosis I

First meiotic division; homologous chromosomes separate; reduction to haploid.

Meiosis II

Second meiotic division; sister chromatids separate; produces four haploid cells.

Tetrad

Pair of homologous chromosomes (each with two chromatids) formed in Prophase I.

Random assortment

Independent orientation of chromosome pairs at Metaphase I, increasing variation.

Chromatid

One of two identical copies of a replicated chromosome held at the centromere.

Sister chromatids

Two identical chromatids of a duplicated chromosome that separate during anaphase.

Centromere

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

Spindle fibers

Microtubules that separate chromosomes during mitosis and meiosis.

Cleavage furrow

Indentation that forms during cytokinesis in animal cells as the cell divides.