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Climate Change- Concept

JoVE 10609

The certainty of climate change remains a public controversy despite the consensus among approximately 97% of active climate researchers, who not only agree that the Earth’s climate is changing but also state that this change is intensified by human activity, predominantly carbon emissions 1. The disconnect between the public and the experts is partly due to poor understanding of the…

 Lab Bio

Photosynthesis- Concept

JoVE 10565


Almost all living organisms on Earth depend on photosynthesis, which is the process that converts sunlight energy into a simple sugar called glucose. This molecule can be used as a short-term energy source or to build more complex carbohydrates like starches for long-term energy storage. Autotrophs are organisms that capture light energy using photosynthesis. Also known …

 Lab Bio

Drosophila Maintenance

JoVE 5084

Drosophila melanogaster, commonly known as fruit flies, are a frequently used model organism for life science research. Although starting a collection of these critters may seem as easy as leaving a banana on your kitchen counter for too long, a productive fly colony in the lab requires careful husbandry and maintenance.

This video demonstrates the necessary steps for…

 Biology I

Products of the Citric Acid Cycle

JoVE 10977

The cells of most organisms—including plants and animals—obtain usable energy through aerobic respiration, the oxygen-requiring version of cellular respiration. Aerobic respiration consists of four major stages: glycolysis, pyruvate oxidation, the citric acid cycle, and oxidative phosphorylation. The third major stage, the citric acid cycle, is also known as the Krebs cycle or tricarboxylic acid (TCA) cycle. For every glucose molecule that undergoes cellular respiration, the citric acid cycle is carried out twice; this is because glycolysis (the first stage of aerobic respiration) produces two pyruvate molecules per glucose molecule. During pyruvate oxidation (the second stage of aerobic respiration), each pyruvate molecule is converted into one molecule of acetyl-CoA—the input into the citric acid cycle. Therefore, for every glucose molecule, two acetyl-CoA molecules are produced. Each of the two acetyl-CoA molecules goes once through the citric acid cycle. The citric acid cycle begins with the fusion of acetyl-CoA and oxaloacetate to form citric acid. For each acetyl-CoA molecule, the products of the citric acid cycle are two carbon dioxide molecules, three NADH molecules, one FADH2 molecule, and one GTP/ATP molecule. Therefore, for every glucose molecule (which generates two acetyl-CoA molecules), the citric acid cycle yi

 Core: Biology

C4 Pathway and CAM

JoVE 10754

Some plants, like sugar cane and corn, that grow in hot conditions, use an alternative process called the C4 pathway to fix carbon. The cycle begins with CO2 from the atmosphere entering mesophyll cells where it is used to generate oxaloacetate—a four-carbon molecule—from phosphoenolpyruvate (PEP). Oxaloacetate is then converted to malate and transported to bundle sheath cells, where the oxygen concentration is low. There, CO2 is released from malate and enters the Calvin Cycle where it is converted into sugars. The CAM pathway is carried out in plants like cacti that also need to conserve water during the day. CAM plants let CO2 into the leaves at night and produce malate that is stored in vacuoles until the following day. The malate is then released from vacuoles and processed in the Calvin Cycle. The C4 pathway separates the different processes locally, while the CAM pathway separates them chronologically. Some plants, like corn and sugarcane, have evolved alternative ways to fix carbon that help avoid water loss in hot, dry environments. One such method is the C4 pathway. In the first step, CO2 enters mesophyll cells, and the enzyme phosphoenolpyruvate (PEP) carboxylase adds it to the 3-carbon compound PEP to form the 4-carbon compound oxaloacetate. Oxaloacetate is then converted

 Core: Biology

Diagnostic Necropsy and Tissue Harvest

JoVE 10294

Source: Kay Stewart, RVT, RLATG, CMAR; Valerie A. Schroeder, RVT, RLATG. University of Notre Dame, IN

Many animal experiments rely on final data collection time points that are gathered from the harvesting and testing of organs and tissues. The use of appropriate methods for the collection of organs and tissues can impact the quality of…

 Lab Animal Research

Photosynthesis - Prep Student

JoVE 10623

Plant Pigment Chromatography and Floating Leaf Discs in a Vacuum
On the day before the experiment, fill a container with water.
Place the spinach leaves into the water and make sure they are submerged.
Leave the spinach leaves to soak overnight at room temperature.
Wearing gloves, prepare and measure out 18 cm x 304 cm sections of…

 Lab Bio

Gas Absorber

JoVE 10436

Source: Michael G. Benton and Kerry M. Dooley, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA

Gas absorbers are used to remove contaminants from gas streams. Multiple designs are used to accomplish this objective1. A packed bed column uses gas and liquid streams running counter to each other in a column…

 Chemical Engineering

Passaging Cells

JoVE 5052

Cell lines are frequently used in biomedical experiments, as they allow rapid culture and expansion of cell types for experimental analysis. Cell lines are cultured under similar conditions when compared to freshly-isolated, or primary, cells, but with some basic important differences: (i) cell lines require their own specific growth factor cocktails and (ii) their growth must be more closely…

 Basic Methods in Cellular and Molecular Biology

Responses to Heat and Cold Stress

JoVE 11119

Every organism has an optimum temperature range within which healthy growth and physiological functioning can occur. At the ends of this range, there will be a minimum and maximum temperature that interrupt biological processes.

When the environmental dynamics fall out of the optimal limit for a given species, changes in metabolism and functioning occur – and this is defined as stress. Plants respond to stress by initiating changes in gene expression - leading to adjustments in plant metabolism and development aimed at attaining a state of homeostasis. Plants maintain membrane fluidity during temperature fluctuations Cell membranes in plants are generally one of the first structures that are affected by a change in ambient temperature. These membranes primarily constitute phospholipids, cholesterol, and proteins, with the lipid portion comprising long chains of unsaturated or saturated fatty acids. One of the primary strategies plants can adopt under temperature change is to alter the lipid component of their membranes. Typically, plants will decrease the degree of unsaturation of membrane lipids under high temperature, and increase it under low temperature, maintaining the fluidity of the membrane. Heat Shock Proteins The exposure of plant tissue or cells to sudden high-temperature stress res

 Core: Biology
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