Big Idea 2

Big Idea 2: 1. Adhesion of water

Adhesion is the property of two substances to cling to one another. In this picture, water has been flung onto a mirror, but the water does not all slide off; some of it adheres to the mirror.

Big Idea 2: 3. ATP

ATP, or adenosine triphosphate, is used in cells as a coenzyme. It transports chemical energy, and therefore facilitates an organism's use of energy. This squirrel needs ATP to maintain its ability to scamper around and climb trees.

Big Idea 2: 4. Autotroph

An autotroph, in simple terms, is an organism that makes its own food (the root auto means "self," and troph means "food.") Autotrophs are the producers of a food chain. This tree is an autotroph because it takes in energy from sunlight and uses that energy to produce its own organic compounds.

Big Idea 2: 5. Calvin cycle

These plants are of various species, but they all undergo photosynthesis (simply because they are plants) and thus undergo the Calvin cycle, the second part of photosynthesis. The Calvin cycle uses ATP and NADPH from light reactions to convert water and carbon dioxide into organic compounds. It is necessary to these plants because, like animals, they need food.

Big Idea 2: 6. Carbohydrate

This picture is an example of a carbohydrate because pasta is rich with carbohydrates. Carbohydrates are compounds that only consist of carbon, hydrogen, and oxygen. They are made up of monosaccharides such as glucose. Carbs are used often for short-term energy.

Big Idea 2: 7. Catabolic

Catabolism is the set of pathways that breaks down complex pathways into much simpler ones, releasing energy. Catabolic pathways can be found in all organisms, such as this red panda.

Big Idea 2: 9. Chitin

Big Idea 2: 10. Cohesion of water

Cohesion is a phenomenon in which hydrogen bonds hold a substance together. In this photo, water is actually above the rim of the cup, but it is not spilling because it is cohesive.

Big Idea 2: 12. Ectothermy

Ectothermic animals are animals that cannot produce their own body heat and therefore must absorb external heat to warm their bodies. They are often referred to as "cold-blooded." All reptiles, such as this snake, are ectotherms.

Big Idea 2: 13. Endothermy

Endothermy is the opposite of ectothermy; endotherms can produce their own body heat and do not need to take it up from their surroundings. They are commonly referred to as "warm-blooded." Nearly all mammals, such as this gibbon, are endothermic.

Big Idea 2: 15. Enzyme

This *delightful* spit represents an enzyme. An enzyme is a catalytic protein (a protein that acts as a chemical agent to speed things up in a reaction.) Enzymes are found in saliva because they begin the process of digestion.

Big Idea 2: 16. Fermentation

Fermentation is a catabolic process occurring in without the use of oxygen. It only partially degrades sugars (in other words, it does not break them down to monomers.) Yeast convert the sugars of wine grapes into ethanol and carbon dioxide. Humans manipulate this conversion and use yeast to ferment wine, as shown in this photograph.

Big Idea 2: 19. Heterotroph

A heterotroph is an organism that is unable to make its own food and must rely on compounds produced by other organisms (hetero means "other.") Heterotrophs are always the consumers of a food chain. This lion exemplifies heterotrophy because it feeds on other animals.

Big Idea 2: 23. Hydrophilic

A hydrophilic substance is one that has an affinity for water, such as salt. In this picture, the shaker on the left is full of table salt. I then dumped a teaspoon of salt into the glass of water on the right and stirred it up. The salt dissolved in the water, demonstrating hydrophilic behavior.

Big Idea 2: 24. Hydrophobic

A hydrophobic substance is one that repels water, like oil. I filled a cup halfway with water and then poured a few tablespoons of oil in. The oil all gathered in a layer at the top. I mixed the solution up, and after letting it settle, the oil moved to the top again, demonstrating its hydrophobia.

Big Idea 2: 26. Kinesis

The ants in this picture illustrate kinesis. Kinesis is a change in activity in response to a stimulus. As a result of the cold weather outside, the ants moved indoors and infested my bathroom.

Big Idea 2: 30. Phloem

Phloem is the living tissue of a plant that conducts sugar (in particular, sucrose,) to all parts of the plant where needed. It is found in trees as the innermost layer of bark. In this picture, we can see all of the layers of the tree, including the place where the phloem would be if the tree were living.

Big Idea 2: 32. Saturated fat

A saturated fat is a fatty acid with the maximum possible number of hydrogen atoms bonded to the carbon skeleton. At room temperature, a saturated fat is a solid, such as this stick of butter.

Big Idea 2: 37. Unsaturated fat

An unsaturated fat is a fatty acid without the maximum possible number of hydrogen atoms bonded to the carbon skeleton. It is unsaturated because the fatty acid has at least one double-bonded carbon. At room temperature, unsaturated fats are liquids, like this extra virgin olive oil.

Big Idea 2: 38. Xylem

Xylem is a type of vascular tissue found in plants. It conducts most of the water and minerals in the plant. The most obvious type of xylem is wood, as shown by the branch in the photo.