Anatomy lecture - chapter 2

A comprehensive set of vocabulary flashcards covering cell structure, organelles, membrane function and transport, the nucleus and DNA, the cell cycle and mitosis, and cellular diversity.

Cell

The smallest living unit of the body that obtains nutrients, makes molecules, disposes of wastes, maintains its shape, and can reproduce.

Organelles

Subunits of cells with specific functions; most cells contain the same basic organelles, though abundance varies.

Plasma membrane

The outer boundary of the cell that separates intracellular from extracellular fluid; selectively permeable; built from a lipid bilayer with integral and peripheral proteins.

Glycocalyx

A sugar coat formed by carbohydrate chains attached to integral proteins on the cell surface.

Integral proteins

Proteins firmly embedded in or attached to the lipid bilayer; may have carbohydrate chains attached.

Peripheral proteins

Proteins that attach to the membrane surface from the cytoplasmic side and help support the membrane.

Lipid bilayer

The double layer of phospholipids that forms the core of the plasma membrane.

Membrane transport

The process by which substances move across the cell membrane, either passively or actively, to maintain homeostasis.

Cytoplasm

Internal to the plasma membrane; consists of cytosol, organelles, and inclusions.

Cytosol

Jellylike fluid containing water, ions, and enzymes.

Plasma membrane

The selective barrier surrounding the cell, composed of a phospholipid bilayer that regulates the movement of substances in and out of the cell.

Nucleus

Control center of the cell; contains DNA and directs cellular activities.

Nuclear envelope

Two membranes surrounding the nucleus, perforated by nuclear pores.

Nuclear pores

Openings in the nuclear envelope that allow large molecules to pass in and out of the nucleus.

Nucleolus

A structure within the nucleus where ribosomal subunits begin to assemble.

Chromatin

DNA packaged with proteins; forms a threadlike material that becomes chromosomes during division.

Chromosome

A condensed, long DNA molecule; humans typically have 46 chromosomes in each cell.

DNA

Deoxyribonucleic acid; double helix composed of nucleotides A, T, C, G; carries genetic information.

Nucleotide

The basic building block of DNA; consists of a sugar, phosphate, and a base.

Ribosome

Site of protein synthesis; composed of proteins and rRNA; free ribosomes in cytosol and bound ribosomes on rough ER.

Rough endoplasmic reticulum

ER with ribosomes on its surface; synthesizes proteins destined for membranes or secretion.

Smooth endoplasmic reticulum

A type of endoplasmic reticulum that lacks ribosomes and is involved in the synthesis of lipids and metabolism of carbohydrates. It also plays a role in detoxifying certain chemicals and storing calcium ions.

Golgi apparatus

Stacks of cisterns that sort, modify, and package proteins for delivery; flows from cis to trans.

Lysosome

Membrane-walled sacs with digestive enzymes that digest unwanted substances.

Mitochondrion

Double-membrane organelle that generates most of the cell’s energy (ATP); powerhouse of the cell.

Peroxisome

Membrane sacs with oxidase or catalase enzymes; neutralize free radicals and break down fatty acids; abundant in liver and kidneys.

Cytoskeleton

Cell skeleton — a network of rods: microfilaments (actin), intermediate filaments, and microtubules. It provides structural support, maintains cell shape, and facilitates cell movement and division.

Microfilaments

filaments of contractile protein actin, thinnest. They are part of the cytoskeleton and play crucial roles in cell shape, motility, and division.

Intermediate filaments

are part of the cytoskeleton and provide structural support to the cell. They are essential for maintaining cell shape and integrity.

Microtubules

cylindrical structures made of proteins, stiff but bendable

Centrosome

Spherical structure near the nucleus; contains the matrix and centrioles; organizes microtubules.

Centrioles

Paired cylindrical bodies made of microtubules; role in forming cilia/flagella and the mitotic spindle.

Cilia

hair-like projections on cell surfaces that aid in movement and sensation.

Flagella

Thread-like structures that enable motility in certain cells, particularly sperm cells and some bacteria. They are composed of microtubules and use whip-like movements to propel the cell.

Mitotic spindle

A structure composed of microtubules that segregates chromosomes during cell division.

Interphase

Cell life-cycle phase when the cell grows and carries out normal metabolic activities; includes G1, S, and G2.

G1 phase

Growth 1; first part of interphase; cell grows and synthesizes proteins; centrioles begin replication.

S phase

DNA replication stage; ensures daughter cells receive identical copies.

G2 phase

Growth 2; centrioles finish copying; enzymes needed for division are synthesized.

Mitosis

Nuclear division that distributes chromosomes into two daughter nuclei; followed by cytokinesis.

Prophase

Early stage of mitosis where chromatin condenses into chromosomes and the mitotic spindle forms.

Metaphase

Chromosomes align at the cell’s equator with centromeres at the metaphase plate.

Anaphase

Centromeres split and sister chromatids are pulled to opposite poles.

Telophase

Chromosomes arrive at poles; nuclear envelope reforms; nucleolus reappears.

Cytokinesis

Division of the cytoplasm, resulting in two separate daughter cells.

Fluid mosaic model

Model of the plasma membrane: a fluid phospholipid bilayer with embedded, moving proteins.

Simple diffusion

Movement of molecules down their concentration gradient directly through the lipid bilayer or via channels.

Osmosis

Diffusion of water across a membrane.

Facilitated diffusion

Diffusion of solutes down their gradient through a membrane-integral protein.

Active transport

Movement of substances across the membrane against their gradient, powered by ATP.

Endocytosis

Process by which particles enter cells via vesicle formation.

Phagocytosis

Cell eating; engulfment of large particles into a phagosome.

Pinocytosis

Cell drinking; nonspecific uptake of extracellular fluid in vesicles.

Receptor-mediated endocytosis

Endocytosis triggered by binding of substances to specific receptors in coated pits.

Exocytosis

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

SNAREs

Vesicle (v-SNARE) and target (t-SNARE) proteins that mediate vesicle fusion during exocytosis.

Phagosome

Vesicle formed when a particle is engulfed during phagocytosis; fuses with a lysosome for digestion.

Epithelial cell

Cell type with shape that allows tight packing, forming linings and coverings.

Fibroblast

Connective tissue cell that synthesizes and secretes fibers.

Erythrocyte

Red blood cell; biconcave shape increases surface area for gas exchange.

Fat cell

Adipocyte; contains a large fat droplet and stores lipids.

Macrophage

Immune cell that moves through tissue to reach infection sites.

Neuron

Nerve cell with long processes for receiving and transmitting signals.

Sperm cell

Male reproductive cell with a long tail for swimming to the egg.

Skeletal and smooth muscle

tissue types that facilitate movement in the body, with skeletal muscle being under voluntary control and smooth muscle being involuntary.

centrosome matrix

The centrosome matrix is a structure composed of proteins and microtubules that organizes the microtubules in a cell, playing a critical role in cell division and the maintenance of cell structure.