Cell Biology and Structure Lecture Notes

Vocabulary and terminology flashcards covering cell history, theory, organization levels, and organelle functions based on lecture notes.

Main Characteristics of Organisms

Made of cells, require energy (food), reproduce (species), maintain homeostasis, organized, respond to environment, grow and develop, and exchange materials with surroundings.

Levels of Organization (Nonliving)

Atom (element), Molecule (compounds like carbohydrates and proteins), and Organelles (nucleus, ER, Golgi).

Levels of Organization (Living)

Cell (makes up all organisms), Tissue (cells working together), Organ (heart, brain, stomach), and Organ Systems (respiratory, circulatory).

Robert Hooke

In $1665$, he used a microscope to examine a thin slice of cork and named the small rooms he saw "cells."

Anton van Leeuwenhoek

A Dutch microscope maker who, in $1673$, was the first to view living organisms in pond water and teeth scrapings.

Matthias Schleiden

A German botanist who concluded in $1838$ that all plants were made of cells; he is a cofounder of the cell theory.

Theodore Schwann

A German zoologist who concluded in $1839$ that all animals were made of cells; he is a cofounder of the cell theory.

Rudolph Virchow

A German medical doctor who observed cells dividing in $1855$ and reasoned that all cells come from other pre-existing cells.

Cell Theory

All living things are made of cells, cells are the basic unit of structure and function in an organism, and cells come from the reproduction of existing cells.

Endosymbiotic Theory

Proposed by Lynn Margulis in $1970$, it provides evidence that some organelles (like chloroplast and mitochondria) were once free-living cells.

Typical Cell Size

Cells range from $5$ to $50$ micrometers (microns) in diameter.

Differentiation

The process by which cells in a multicellular organism become specialized by turning different genes on and off.

Prokaryotes

Cells that lack a nucleus or membrane-bound organelles; includes bacteria and contains a single, circular chromosome.

Eukaryotes

More complex cells that possess a nucleus and membrane-bound organelles; includes protists, fungi, plants, and animals.

Cell Membrane

A living layer composed of a double layer of phospholipids and proteins that controls what enters or leaves the cell.

Phospholipid Bilayer

A structure where hydrophilic heads (glycerol and phosphate) point out and hydrophobic tails (fatty acids) point inward.

Glycoproteins

Proteins with carbohydrate tails that act as markers for cell recognition.

Cell Wall

A nonliving layer found in plants (cellulose), bacteria (peptidoglycan), and fungi (chitin) that supports and protects the cell.

Nucleus

The control organelle that contains DNA, is bounded by a nuclear envelope with pores, and is usually the largest organelle.

Chromatin

DNA that is spread out in non-dividing cells.

Chromosomes

DNA that is condensed and wrapped around proteins in dividing cells.

Nucleolus

Found inside the nucleus, it disappears during cell division and is responsible for making ribosomes.

Cytoskeleton

A protein-based structure consisting of microfilaments (actin) and microtubules (tubulin) that maintains cell shape and moves organelles.

Centrioles

Paired structures found only in animal cells, made of microtubules, that help pull chromosome pairs apart during cell division.

Mitochondrion

The "powerhouse" of the cell that generates ATP through cellular respiration; contains its own DNA and an inner membrane called cristae.

Rough Endoplasmic Reticulum

A network of hollow membrane tubules with ribosomes on its surface that makes membrane proteins and proteins for export.

Smooth Endoplasmic Reticulum

Lacks ribosomes; makes membrane lipids (steroids), regulates calcium in muscle cells, and destroys toxic substances in the liver.

Ribosomes

The "protein factories" of the cell made of proteins and rRNA; they join amino acids through protein synthesis.

Golgi Bodies

Stacks of flattened sacs that modify, sort, and package molecules from the ER for storage or transport.

Lysosomes

Contain digestive enzymes to break down food, bacteria, and worn-out cell parts; programmed for cell death (autolysis).

Cilia and Flagella

Organelles made of microtubules in a $9 + 2$ arrangement; used for movement of the cell or movement of fluids across the cell surface.

Central Vacuole

A large fluid-filled sack in plant cells that stores cell sap, including sugars, proteins, and wastes.

Chloroplasts

Found in producers, these use sunlight energy to make glucose; contain thylakoids (sacs), grana (stacks), and stroma (gel).

Surface Area and Volume Relationship

Volume ($L \times W \times H$) increases faster than surface area ($L \times W$), which eventually triggers a cell to divide.