Biology For Dummies®

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Living things grow and develop. You started life as a single cell. That cell divided to form new cells, which divided again. Now your body is made of approximately 100 trillion cells. As your body grew, your cells received signals that told them to change and become special types of cells: skin cells, heart cells, liver cells, brain cells, and so on. Your body developed along a plan, with a head at one end and a tail at the other. The DNA in your cells controlled all of these changes as your body developed. (For the scoop on the changes that occur in animal cells as they grow and develop, see Chapter 19.) During the Krebs cycle, acetyl-coA breaks down into carbon dioxide (CO 2). The conversion of pyruvate to acetyl-coA produces two molecules of NADH. Energy transfers during the Krebs cycle produce an additional six molecules of NADH, two molecules of FADH 2, and two molecules of ATP.

Hypothesis-based science: When scientists test their understanding of the world through experimentation, they’re engaging in hypothesis-based science, which usually calls for following some variation of a process called the scientific method (see the next section for more on this). Modern biologists are using hypothesis-based science to try and understand many things, including the causes and potential cures of human diseases and how DNA controls the structure and function of living things. We use some of the familiar For Dummies icons to help guide you and give you new insights as you read the material. Here’s the scoop on what each one means.Hemoglobin is an example of the other major type of proteins: globular proteins. Globular proteins serve a larger variety of functions than the fibrous proteins. For example, the globular proteins include such useful proteins as enzymes, antibodies, and transport proteins. Stems support leaves and reproductive structures and also transport sugars and water throughout the plant. Inductive reasoning uses specific observations to generate general principles, like those in a hypothesis. different types of structures you'll see in some cells versus others, this right here is eukaryotic cell which we will talk more Reproductive system: Is responsible for sexual reproduction. Made up of ovaries, fallopian tubes, a uterus, a cervix, a vagina, and a vulva if you’re female, and testes, a scrotum, vas deferens, a prostate gland, seminal vesicles, and a penis if you’re male (see Chapter 19). Comparing Plants to People

Digestive system: Takes up nutrients and water and eliminates wastes. Made up of your stomach, intestines, liver, and pancreas (see Chapter 16). Delve into the details of how cells get energy. Chapter 1 Exploring the Living World IN THIS CHAPTERAn enzyme is a protein used to speed up the rate of a chemical reaction. Because they regulate the rate of chemical reactions, they also are called catalysts. There are many, many, many different types of enzymes, because for each chemical reaction that occurs, an enzyme specific to that reaction must be made. Metabolic processes don’t just automatically happen; they need enzymes. And, a reason that you must consume protein is so that you can make more enzymes so that your processes will occur. Chemical reactions control the metabolism and life of living things. Angiosperms (or flowering plants) have vascular tissue and produce both flowers and seeds. Scientists divide the most familiar flowering plants into two groups based on the number of cotyledons they contain in their seeds: When gas exchange occurs between the lungs and a blood cell, it is the iron that binds (attaches to) the oxygen. Then, the iron-oxygen complex releases from the hemoglobin molecule in the red blood cell so that the oxygen can cross cell membranes and get inside any cell of the body. How much exercise do you get? Regular exercise uses your musculoskeletal system and strengthens your heart so it doesn’t have to pump as hard, which lowers your blood pressure.

The root system, located below ground, absorbs water and minerals from the soil. Roots make up the root system. Proteins are long chains of polypeptides, and thus, so are enzymes. However, some enzymes contain parts that are not made up of proteins but assist the enzyme in its function. These are called coenzymes. Vitamins often act as coenzymes. The name of an enzyme usually reflects the name of the chemical on which the enzyme acts (that is, the chemical substrate). For example, an enzyme that acts on a fat (fat being the substrate) is called a lipase (remember, lip = fat). remember A system is a group of related parts that work together. As an example, consider your own body. You are a system. You have a boundary (your skin) that keeps all of you separate from the outside world. Within your body, you have many smaller systems like your nervous system or your cardiovascular system that work together so that your whole body functions. To truly understand how one of your organ systems works to help keep you healthy, we need to look not just at that system, but also how it interacts with the other parts of your body.Biology wouldn’t have gotten very far as a science if biologists hadn’t used organized processes to conduct their research or if they hadn’t communicated their research results with others. This chapter explores the characteristics that distinguish living things from the nonliving materials in the natural world. It also introduces you to the methods scientists (whether they’re biologists, physicists, or chemists) use to investigate the world around them and the tools they use to communicate what they’ve discovered. Living Things: Why Biologists Study Them and What Defines Them

remember Your genes are found in your DNA, which is in turn found in your chromosomes. Each chromosome consists of hundreds of different blueprints that contain the instructions for your cells’ worker molecules (which are mostly proteins). Each type of cell in your body uses the blueprints found in your genes to build the proteins it needs to do its particular job. So what exactly does all that mean? Here it is, plain and simple: DNA determines your traits because it contains the instructions for the worker molecules (proteins) that make your traits happen. Every genetics problem, from those on an exam to one that determines what coat color your dog’s puppies may have, can be solved in the same manner. Here’s a simple approach to any genetics problem: remember Any scientific experiment must be repeatable by other scientists so they can confirm or challenge the original scientist’s work. Conclusions from scientific experiments only become part of the scientific knowledge base after they’ve been supported by repeated testing. Bryophytes are plants, such as mosses, that don’t have a vascular system and don’t produce flowers or seeds. Bryophytes also don’t have a true root system. Instead, many rely upon delicate anchoring structures called rhizoids. After fertilization of the eggs by sperm, the ovules within a flower become seeds, and the ovary becomes a fruit. Seeds protect the embryo, and fruits help scatter the seeds away from the parent plant.

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technicalstuff The Technical Stuff icon marks extra information that isn’t necessary to understanding the material in the chapter. If you want to take your understanding of biology to a higher level, or if you just want to build your knowledge base of interesting facts, incorporate these paragraphs into your reading. If you just want the basics and don’t want to bother with nonessential information, skip them.