Think you can tell a yam from a yak? Examine these still images of typical plant and animal cells from Biology by Kenneth R. Miller and Joseph Levine. What similarities and differences can you find?

This 21-minute video lesson examines parts of a cell: nucleus, ribosomes, endoplasmic reticulum, Golgi bodies, mitochondria, chloroplasts, vacuoles, and vesicles. [Biology playlist: Lesson 35 of 71].

In this lesson, the students look at the components of cells and their functions. The lesson focuses on the difference between prokaryotic and eukaryotic cells. Each part of the cell performs a specific function that is vital for the cell's survival. Bacteria are single-celled organisms that are very important to engineers. Engineers can use bacteria to break down toxic materials in a process called bioremediation, and they can also kill or disable harmful bacteria through disinfection.

Is it possible to identify species using a standard piece of DNA? Liza Gross summarizes original research published by PLoS Biology that investigates this question.

Read how DNA was used to solve the mystery of the Romanov family's execution.

This illustration from Biology by Kenneth R. Miller and Joseph Levine describes the steps of the electron transport chain, the second stage in the process of cellular respiration.

A colorful study guide summarizing the electron transport chain in the mitochondria of eukaryotic organisms.

In this exercise, students use fluorescence microscopy to look at organelles (mitochondria, Golgi apparatus, endoplasmic reticulum) and the cytoskeleton in PtK2 cells. In both cases, DNA stains allow students to observe changes in organelle and cytoskeleton morphology as the cell undergoes mitosis. In addition to revealing the cellular structures in a dramatic fashion, the exercise shows students that the distributions, sizes, and shapes of the structures are not always as they imagine them. Finally, observation of tobacco cells with green fluorescent protein (GFP) targeted to mitochondria demonstrates the use of GFP reporters for tracking cellular structures in living cells.

This illustration from Biology by Kenneth R. Miller and Joseph Levine describes the steps of the Krebs cycle, the critical first stage in the process of cellular respiration.

Often referred to as the powerhouses of the cell, mitochondria provide the energy that powers nearly every cellular process. This essay by John Ross describes in detail the structures and functions of these amazing organelles.

This essay by Owen Anderson describes the effects of physical exercise on the number and function of mitochondria inside muscle cells.

Honeybees provide a convenient source of insect flight muscle, a tissue especially rich in mitochondria. These organelles are easily isolated using simple laboratory equipment and their metabolic activity readily measured colorimetrically with the dye 2,6-dichloroindophenol, which changes from blue to colorless when reduced by the electrons produced during respiration. This system is well-suited for studying cell fractionation, experimental isolation of the major subcellular components responsible for glycolysis and the Krebs cycle, and the role of oxygen in respiration. It can also be used for simple enzymology experiments using the Krebs cycle enzyme succinic dehydrogenase.

In this activity, mitochondria are isolated from the California blackworm, Lumbriculus variegatus, by homogenization and differential centrifugation. A modified plasmid miniprep procedure (alkaline lysis) is then used to isolate DNA from these mitochondria. Single and double enzyme restriction digests of mitochondrial DNA (mtDNA) are analyzed by agarose gel electrophoresis. Sizes of mtDNA restriction fragments are estimated from gel results and are used to determine the total size of the L. variegatus mitochondrial genome. Issues involved in creating a restriction map of mtDNA from this organism are discussed.

Cells contain many specialized structures known as organelles which perform a variety of specific functions. To obtain precise information about the structure and functions of subcellular organelles, it is imperative to isolate them free from contaminating organelles. Marker enzymes are known to be localized exclusively in specific organelles and are used to monitor the separation of these organelles. In this exercise the homogenate of Dictyostelium discoideum will be fractionated by differential centrifugation to separate mitochondria, lysosomes, and contractile vacuoles. The fractions will be assayed for their marker enzymes: acid phosphatase for lysosomes, succinate dehydrogenase for mitochondria, and alkaline phosphodiesterase for the contractile vacuoles. This exercise presents two fundamental concepts to the students: organelle isolation and enzyme assays.

In this video segment from An Introduction to the Living Cell, explore the inner workings of a cell, including some of its most important organelles.

The primary role of mitochondria is to produce 90% of a cell's energy in the form of ATP through a process called oxidative phosphorylation. A variety of clinical disorders have been shown to include "mitochondrial dysfunction," which loosely refers to defective oxidative phosphorylation and usually coincides with the occurrence of excess Reactive Oxygen Species (ROS) production, placing cells under oxidative stress. A known cause and effect of oxidative stress is damage to and mutation of mitochondrial DNA. We will use this class to explore issues relating to mitochondrial DNA integrity and how it can be damaged, repaired, mutated, and compromised in human diseases. This course is one of many Advanced Undergraduate Seminars offered by the Biology Department at MIT. These seminars are tailored for students with an interest in using primary research literature to discuss and learn about current biological research in a highly interactive setting. Many instructors of the Advanced Undergraduate Seminars are postdoctoral scientists with a strong interest in teaching.

This video segment describes the critical role that mitochondria play in nearly every cellular process in your body.

This course will start with a survey of basic oxygen radical biochemistry followed by a discussion of the mechanisms of action of cellular as well as dietary antioxidants. After considering the normal physiological roles of oxidants, we will examine the effects of elevated ROS and a failure of cellular redox capacity on the rate of organismal and cellular aging as well as on the onset and progression of several major diseases that are often age-related. Topics will include ROS-induced effects on stem cell regeneration, insulin resistance, heart disease, neurodegenerative disorders, and cancer. The role of antioxidants in potential therapeutic strategies for modulating ROS levels will also be discussed.This course is one of many Advanced Undergraduate Seminars offered by the Biology Department at MIT. These seminars are tailored for students with an interest in using primary research literature to discuss and learn about current biological research in a highly interactive setting. Many instructors of the Advanced Undergraduate Seminars are postdoctoral scientists with a strong interest in teaching.