Easy Notes – Chapter 3: Cells (with Pictures)

Vocabulary flashcards covering key concepts about cells from the notes.

Cell

The basic unit of structure and function in living organisms; measured in micrometers.

Nucleus

Control center of the cell; contains DNA (chromatin) and the nucleolus.

Cytoplasm

Internal environment of the cell containing cytosol and organelles.

Cell membrane

The phospholipid bilayer that encloses the cell, protecting it and regulating entry/exit and signal transduction.

Phospholipid bilayer

Two-layer arrangement with hydrophilic heads facing outward and hydrophobic tails inward.

Hydrophilic heads

Part of the phospholipid bilayer that faces the watery exterior and interior.

Hydrophobic tails

Part of the phospholipid bilayer that faces inward, away from water.

Selective permeability

Property of the cell membrane that allows only certain substances to cross.

Cholesterol

Stabilizes the membrane and modulates fluidity.

Proteins (in membrane)

Membrane proteins act as pores, channels, receptors, enzymes, and cell ID markers.

Carbohydrates

Carbohydrate chains on the membrane used for cell recognition (self markers).

CAMs

Cell adhesion molecules that guide cell movement and adhesion.

Ribosome

Organelle where protein synthesis occurs.

Rough Endoplasmic Reticulum

ER with ribosomes; synthesizes proteins destined for export or membranes.

Smooth Endoplasmic Reticulum

ER without ribosomes; synthesizes lipids.

Golgi apparatus

Packages and ships proteins to their destinations.

Mitochondrion

Powerhouse of the cell; produces ATP.

Lysosome

Digestive organelle; breaks down waste ('garbage disposals').

Peroxisome

Breaks down lipids, alcohol, and toxins.

Cytoskeleton

Network of microfilaments and microtubules that give shape and enable movement.

Centrosome

Microtubule organizing center; helps form spindle fibers for division.

Centrioles

Paired structures within the centrosome that organize spindle fibers during cell division.

Cilia

Short, numerous projections that move mucus or eggs across the cell surface.

Flagellum

Long, single projection that propels a cell (e.g., sperm tail).

Chromatin

DNA material inside the nucleus (uncondensed form).

Nucleolus

Site of ribosome production inside the nucleus.

Diffusion

Movement of particles from high to low concentration; passive process.

Osmosis

Diffusion of water across a selectively permeable membrane toward higher solute concentration.

Facilitated diffusion

Passive transport using membrane channels or carrier proteins.

Filtration

Movement of substances through a membrane due to pressure; does not require energy.

Active transport

Movement against a concentration gradient; requires ATP.

Endocytosis

Process of taking material into the cell; includes phagocytosis, pinocytosis, and receptor-mediated endocytosis.

Exocytosis

Vesicles fuse with the membrane to export material out of the cell.

Transcytosis

Transport of material across the cell from inside to outside (in→out).

Interphase

Cell growth and DNA replication between divisions.

Mitosis

Division of the nucleus into two genetically identical nuclei.

Prophase

Chromosomes appear; the nucleus breaks down.

Metaphase

Chromosomes line up in the middle of the cell.

Anaphase

Chromosomes are pulled apart toward opposite poles.

Telophase

Nucleus reforms and chromosomes uncoil.

Cytokinesis

Cytoplasm divides, yielding two identical daughter cells.

Telomeres

'Mitotic clock' at chromosome ends that shorten with each cell division.

Contact inhibition

Cells stop dividing when they become crowded.

Cancer

Loss of control of cell division leading to tumor formation.