Chapter 8: Cell Structure and Function

Vocabulary practice flashcards covering cell theory history, prokaryotic vs. eukaryotic differences, plant vs. animal organelles, cytoskeleton structures, and plasma membrane dynamics from Biology Chapter 8.

Anton von Leeuwenhoek

A Dutch drapery store owner who ground lenses as a hobby, constructed his own microscope, and became known as the "Father of Microbioilogy" after being the first to describe microscopic organisms and living cells.

Robert Hook

A British scientist who examined cork under a microscope, observed its empty chambers, and named them "cells."

Matthias Schleiden

A German scientist who discovered in 1838 that all plants are composed of cells.

Theodore Schwann

A German zoologist who discovered in 1839 that all animals are composed of cells.

Rudolph Virchow

A German physician who discovered in 1855 that animals arise from animals and plants arise from plants.

Cell Theory

The foundational biological theory formulated from the work of Schleiden, Schwann, and Virchow stating that: 1. Cells are the basic unit of life; 2. All organisms are made up of one or more cells; 3. All cells arise from preexisting similar cells.

Prokaryotes

Organisms that do not have membrane-bound organelles or a nuclear membrane, have cell walls containing murein, lack mitochondria, and are mostly unicellular.

Eukaryotes

Organisms that possess a well-defined nucleus surrounded by a nuclear membrane, contain mitochondria, have cell walls lacking murein, and are mostly multicellular.

Murein

A substance found in the cell walls of prokaryotes that is absent in the cell walls of eukaryotes.

Cellulose

The primary structural carbohydrate component found in the cell walls of plants.

Chloroplasts

Plastids found in plant cells that convert sunlight, $CO_2$, and $H_2O$ into sugars and chemical energy.

Chlorophyll

The pigment embedded in the inner series of thylakoid membranes within chloroplasts that traps light energy and gives plants their green color.

Vacuoles (Plant Cell)

A large membrane-bound sac that occupies a large amount of space within a plant cell, storing proteins, ions, water, wastes, or poisons.

Cytoskeleton

An internal framework that maintains the three-dimensional structure of the cell and assists in cellular movement.

Microtubules

Hollow tubes composed of the protein tubulin that help maintain cell shape and act as tracks for intracellular movement.

Cilia

Short, hairlike projections formed by microtubules that function in movement, such as those lining nasal passages and fallopian tubes.

Flagella

Long, whiplike projections made of microtubules that aid in motility, such as the tail of a sperm cell.

Microfilaments

Solid (not hollow) protein filaments structured like a rope made of two twisted chains of proteins.

Centrioles

Microtubule structures found in animal cells that play an important role during cell division.

Organelles

Small, specialized structures within a cell that carry out specific functions; literally meaning "tiny organs."

Cell Wall

A rigid boundary structure located outside the plasma membrane that provides extra support and protection; found in plant cells.

Cell Membrane

A boundary structure located on the outside of animal cells, and inside the cell wall in plant cells, that allows substances to pass through.

Nucleus

The control center of the eukaryotic cell, enveloped by a double membrane with large holes termed nuclear pores.

Chromatin

Strands of DNA located in the nucleus that contain the master set of instructions for synthesizing proteins.

Nucleolus

A prominent structure located inside the nucleus responsible for the production of proteins.

Ribosomes

The specific sites where the cell produces proteins according to instructions provided by DNA.

Cytoplasm

The clear, gelatinous fluid within a cell that suspends and holds all the organelles.

Golgi Apparatus

A flattened stack of tubular membranes looking like a side view of a stack of pancakes that modifies, sorts, and packages proteins into vesicles.

Vesicles

Small membrane-bound spherical sacs involved in the packaging and transport of proteins.

Lysosomes

Organelles containing digestive enzymes that break down excess or worn-out organelles, food particles, viruses, and bacteria.

Endoplasmic Reticulum

A complex network of folded membranes within the cytoplasm of eukaryotic cells serving as the site of cellular chemical reactions.

Rough Endoplasmic Reticulum

The portion of the endoplasmic reticulum that is studded with attached ribosomes.

Smooth Endoplasmic Reticulum

The portion of the endoplasmic reticulum that lacks attached ribosomes.

Plastids

A group of plant organelles that includes chloroplasts.

Mitochondria

Granular, rod-shaped organelles known as the "powerhouse" of the cell, possessing a heavily folded inner membrane to assist energy production.

Homeostasis

The internal balance and proper physiological conditions that a cell must actively maintain within itself to ensure survival.

Selective Permeability

The functional property of a cell membrane that allows certain molecules to pass into or out of the cell while keeping others out.

Phospholipid Bilayer

The two-layered structural framework of the plasma membrane, composed of a glycerol backbone with two nonpolar fatty acid tails facing inwards and a polar phosphate head facing outwards.

Hydrophilic

Water-loving; describes polar molecules, such as the phosphate head groups of phospholipids, that attract and interact with water.

Hydrophobic

Water-fearing; describes nonpolar molecules, such as the fatty acid chains of phospholipids, that repel and do not interact with water.

Fluid Mosaic Model

The model that describes the plasma membrane as dynamic and flexible, composed of phospholipids, embedded proteins, and cholesterol.

Cholesterol (Membrane Component)

A lipid embedded within the plasma membrane that prevents the nonpolar fatty acid tails from sticking together.

Transport Proteins

Proteins spanning the entire plasma membrane that regulate the entry and exit of specific substances through recognition.

Facilitated Diffusion

A form of passive membrane transport that uses carrier proteins to move molecules along their concentration gradient without cellular energy expenditure.

Active Transport

A membrane transport process that utilizes carrier proteins and metabolic energy to move materials against their concentration gradient.

Pinocytosis

A type of endocytosis where the cell brings in liquid droplets from the extracellular environment.

Phagocytosis

A type of endocytosis where the cell engulfs solid particles from the extracellular environment.

Exocytosis

The cellular process of exporting or releasing materials out of the cell via vesicle fusion with the plasma membrane.