About This Chapter
Chapter Summary and Learning Objectives
The cell is the basic unit of life. Thus, when we ask how life began, we're also asking what conditions gave rise to the first cells. We'll tackle this question with biology videos looking at an origin of life hypothesis that will give you a better idea of the transition from non-biological molecules to biological molecules. You'll also see how membranes make life possible for cells. From the phospholipid bilayer to active transport, you'll understand how marvelous membranes allow cells to control what moves in and out of their internal environments. We'll also look at how endocytosis and exocytosis are used for trafficking larger molecules.
The earliest cells were so successful that their close ancestors, archaea and bacteria, still thrive in almost every conceivable environment today. They are the prokaryotes, and we'll show you how their cells differ from eukaryotic cells in size and complexity. Compared to prokaryotes, eukaryotes, with their membrane-bound organelles, are relative newcomers on the evolutionary timescale. By the end of our lessons, you'll be an expert on these cells and their individual components.
As for the individual components, or organelles, their primary purpose is to keep the cell alive and functioning. Each organelle is a piece of well-oiled machinery that keeps the factory of the cell up and running. We'll start with the nucleus to show how it functions as a command center for cell activity. Next, we'll examine ribosomes, and see how the endomembrane system partitions the cell into functional compartments. We won't stop there; you'll also navigate the microtubules and microfilaments that make up the cytoskeleton.
Eukaryotic cells can vary from organism to organism. You'll get to know the differences between plant cells and animal cells when we study mitochondria, chloroplasts and cell walls. Finally, we'll explore what it really means to be alive by comparing a virus with a bacteriophage too see which one is considered living. Thanks for watching!
1. How a Phospholipid Bilayer Is Both Hydrophobic and Hydrophilic
In this lesson, we will learn what gives phospholipids a dual personality. How can this molecule be both hydrophobic and hydrophilic, and why is this important to a cell?
2. The Fluid Mosaic Model of the Cell Membrane
In this lesson, we will discuss the components of the cell membrane and why the fluid mosaic model paints the best picture of its structure. We'll learn about the roles of the phospholipid bilayer, cholesterol, proteins and carbohydrates.
3. Passive Transport in Cells: Simple and Facilitated Diffusion & Osmosis
A cell membrane is selectively permeable - not permeable to everything. In this lesson, we'll talk about methods of passive transport along a concentration gradient, including simple and facilitated diffusion and osmosis.
4. Active Transport in Cells: Definition & Examples
In this lesson, we'll learn how substances are transported across the cell membrane against the concentration gradient. This might seem like an uphill battle for the cell, but all it takes is a little chemical energy and a few integral membrane proteins to kick off some active transport!
5. Endocytosis and Exocytosis Across the Cell Membrane
In this lesson, we'll discover how some cells can eat, drink, and digest their dinner through the process of endocytosis and a structure called the lysosome. In addition, we'll learn how a cell can throw out the leftovers across the cell membrane during exocytosis.
6. Structure of the Nucleus: Nucleolus, Nuclear Membrane, and Nuclear Pores
In this lesson, we'll discuss the organization and importance of the nucleus in your cells. This is the membrane-bound structure responsible for containing all the genetic material essential to making you who you are.
7. The Ribosome: Structure, Function and Location
The ribosome is the cellular structure responsible for decoding your DNA. In this lesson, we'll learn about ribosome structure, function and location - characteristics that make it a very good genetic translator.
8. The Endomembrane System: Functions & Components
In this lesson, we'll learn about the endomembrane system, which consists of the endoplasmic reticulum and the Golgi apparatus. This system is important in making, packaging, and shipping all sorts of goodies for the cell to use!
9. The Cytoskeleton: Microtubules and Microfilaments
In this lesson, we'll learn about the cytoskeleton of your cells. This network of microtubules, intermediate filaments, and microfilaments helps different types of cells maintain a unique set of characteristics, including shape and movement.
10. Mitochondria Structure: Cristae, Matrix and Inner & Outer Membrane
If you want to make it through the day, you're going to need some energy. In this lesson, we'll learn about the organelle that supplies this energy, the mitochondrion, and why this cell structure appreciates the time you took to eat breakfast this morning!
11. Chloroplast Structure: Chlorophyll, Stroma, Thylakoid, and Grana
In this lesson, we'll explore the parts of the chloroplast, such as the thylakoids and stroma, that make a chloroplast the perfect place for conducting photosynthesis in plant cells.
12. Plant Cell Structures: The Cell Wall and Central Vacuole
In this lesson, we'll talk about some of the things that make plant cells so different from our cells. In addition to being mean, green photosynthesizing machines, plant cells have cell walls and central vacuoles to make them unique!
13. Eukaryotic and Prokaryotic Cells: Similarities and Differences
In this lesson, we discuss the similarities and differences between the eukaryotic cells of your body and prokaryotic cells such as bacteria. Eukaryotes organize different functions within specialized membrane-bound compartments called organelles. These structures do not exist in prokaryotes.
14. Viruses: Bacteriophage Lytic and Lysogenic Cycles
Viruses are generally not only our enemy but also the enemy of many other organisms. Bacteriophages are viruses that infect specific bacteria. In this lesson, we'll discuss their basic structure and infection cycle.
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Other chapters within the CLEP Biology: Study Guide & Test Prep course
- Scientific Principles
- Review of Inorganic Chemistry For Biologists
- Introduction to Organic Chemistry
- How Enzymes Work
- Basics of DNA & RNA
- Process of DNA Replication
- The Transcription and Translation Process
- Basics of Gene Mutations
- Basics of Metabolic Biochemistry
- Overview of Cell Division
- Plant Biology
- Plant Reproduction and Growth
- Physiology I: The Circulatory, Respiratory, Digestive, Excretory, and Musculoskeletal Systems
- Physiology II: The Nervous, Immune, and Endocrine Systems
- Animal Reproduction and Development
- Biology of Genetics
- Principles of Ecology
- Speciation & Evolution
- The Origin and History of Life On Earth
- Phylogeny and the Classification of Organisms
- Social Biology
- Analyzing Scientific Data