Biology Module 2.01

DNA

contains an organism's genetic information and is usually found within a cell's nucleus The RNA molecules are also very important because they transport the genetic coding from the DNA to other parts of the cell where proteins are built.

Facts about Amino Acids

As amino acids bond together to form a large protein molecule, it naturally twists and bends into its unique shape. One thing that determines the natural shape of a protein is the side chains of the amino acids. The human body contains thousands of different proteins, and it is the shape and structure of the proteins that determine their unique function. Proteins can only function properly under specific conditions, such as a small range of temperature and pH. Changes in these conditions can break the chemical attractions within the protein and change the molecule's shape. When this happens, the protein is said to be "denatured" because it is unable to serve its function.

protein

Greek word proteios, meaning "first place." This indicates how important they are to living organisms. Proteins make up more than 50 percent of the dry weight of cells, and they are important to almost every function of a cell. They are used for structure, transporting other substances, storage, signaling from one part of an organism to another, movement, and defense against foreign substances.

hydrophobic

Not mixing well with water

Examples of Proteins

Protein Insulin enzyme - for sugar metabolism - 51 Cytochrome c enzyme -for cell respiration - 104 Growth Hormone - used in antiaging treatment - 191 Hemoglobin - oxygen transport in blood - 574 Hexokinase enzyme - for glycolysis - 730 Gamma Globulin - part of immune system in blood 1320 Myosin - muscle action - 6100

Facts about proteins

Proteins are large biological macromolecules that are made up of smaller molecules called amino acids. There are 20 different amino acids that all share the same basic structure. Proteins are made up of 50 or more amino acids bonded together. A difference of only one amino acid in the protein chain can cause a big difference in the protein's function within a cell. The number and arrangement of amino acids in the chain determines the properties and functions of the protein. The table below lists some proteins and their functions. Notice the difference in the number of amino acids in the various proteins, as well as the variety in the functions of these proteins.

RNA

RNA molecules are also very important because they transport the genetic coding from the DNA to other parts of the cell where proteins are built

The Main Players

Reactants: Glucose (C6H12O6): An organic compound found in many foods. It will be broken down into smaller carbon-based compounds, such as pyruvate and citric acid, as energy is released. Oxygen (O2): A reactant required for this process to occur (this is why cellular respiration is called an aerobic process). Electron Carrier: NAD+ and NADH: NAD+ is an electron carrier that accepts a pair of high-energy electrons to become NADH. The NADH carries the high-energy electrons to the electron transport chain where they are used to build high-powered ATP molecules. FAD and FADH2: FAD is another electron carrier. It accepts a pair of high-energy electrons to form FADH2, which carries high-energy electrons to the electron transport chain. Products: Carbon Dioxide (CO2): A product given off during cellular respiration, containing the carbon atoms from the glucose molecule. The carbon dioxide gas that is released during cellular respiration can be used as a reactant for photosynthesis. Water (H2O): At the end of the electron transport chain, electrons, hydrogen ions, and oxygen bond together to form water molecules. Energy: ADP and ATP: Some of the energy released during cellular respiration is used to convert ADP to ATP. The ATP molecule can then be used to power various cell functions.

ATP

The immediate source of energy that drives the functions of a cell is a molecule called adenosine triphosphate, or ATP. ATP is made up of adenine, a five-carbon sugar called ribose, and a chain of three phosphate groups. The bond between the second and third phosphate groups is broken down easily. When one phosphate is broken off of ATP, the remaining molecule is called adenosine diphosphate, or ADP. Water molecules and a small amount of energy are needed to remove a phosphate from ATP, but the amount of energy released in the process is significantly greater than amount needed to break the bond. That energy that is released is used by the cell to power processes such as movement, active transport, or protein synthesis. The cell can store or release energy by adding or removing the phosphate group. The ability to form or break this bond makes ATP a renewable resource within the cell. Our food contains large molecules, such as fats, carbohydrates, and proteins. During digestion, those large macromolecules are broken down into smaller molecules. As the chemical bonds are broken, energy is released. That released energy can be used by cells to regenerate ATP molecules. In turn, the energy stored in ATP can then be used to power most of the cell's functions. Unfortunately, ATP is best suited for short-term energy storage because it is too unstable for long-term storage. When cells need to store chemical energy in a more stable form, they use the energy from ATP to build more stable molecules. If plants have excess energy that needs to be stored for later use, they will then use the energy of the ATP molecules to build sugar and starch molecules. These sugar and starch macromolecules are very stable and can be stored for a long time. Animal cells can store excess energy in fat molecules, which are a stable macromolecule for long-term storage. Starch and fat molecules in our food can be broken down to release energy. Cells use that released energy to build ATP molecules, which can then be used to power a variety of functions within the cell.

Photosynthesis

The processes of photosynthesis and cellular respiration are both necessary for the survival of life on Earth. In comparing the two reactions, they appear to be opposites in many ways. Although the individual steps of each process are not opposites, the reactants of one overall process are the products of the other. Photosynthesis: 6 CO2 + 6 H2O + Energy (Solar) → C6H12O6 + 6 O2 Cellular Respiration: C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + Energy (ATP and Heat) Together, these two processes work together to harvest the energy from sunlight, package it into chemical molecules, and break down those molecules to power the growth, movement, and functions of all organisms and their cells. Photosynthesis converts solar energy to stored chemical energy, and cellular respiration converts that stored chemical energy to ATP, an energy molecule used directly by the cell. In addition to the energy conversions, these two processes also help cycle important molecules in our atmosphere. Photosynthesis removes carbon dioxide from the atmosphere and releases oxygen gas. Cellular respiration uses oxygen gas and releases carbon dioxide. Remember that photosynthesis happens in plants, algae, and some bacteria, whereas cellular respiration (or fermentation) occurs in all organisms. 6 CO2 + 6 H2O + Energy → C6H12O6 + 6 O2

Structure of monosaccharide

When dissolved in water, like inside a cell, monosaccharide molecules form a ring structure. Notice that glucose, fructose, and galactose all have the same chemical formula, C6H12O6. However, the differences in the arrangement of the atoms and bonds give each of the molecules a unique shape. The shape of a molecule determines how molecules function and react within a cell

macromolecules

bonding smaller molecules together into chains called polymers (from the Greek polys, "many," and meris, "part")

Disaccharides

carbohydrate molecules made up of two monosaccharide molecules bonded together. Monosaccharides and disaccharides are classified as simple carbohydrates. Most simple carbohydrates have a sweet taste, and they are collectively referred to as "sugars" in biology. Table sugar, called sucrose, is a disaccharide that you probably use every day. It is made up of one fructose molecule and one glucose molecule bonded together. Lactose, the major sugar in milk, is made of one glucose molecule and one galactose molecule bonded together. Maltose is a disaccharide produced during the digestion of starch. It is made of two glucose molecules.

Polysaccharides

carbohydrate polymers made up of hundreds to thousands of monosaccharide units bonded together produced and consumed by living organisms starch, cellulose, and glycogen, are all made up of the monomer glucose

nucleic acids

carry the genetic information needed to build organisms

Steroids

category of lipids - macromolecules in this category all share a similar structure of four linked rings of carbon atoms. Many steroids are hormones that control a number of the body's metabolic processes.

Facts about Nucleic acids

chain of nucleotides bonded together Each nucleotide is made up of a nitrogenous base, a sugar, and a phosphate group. A DNA molecule is actually made up of two nucleotide chains that spiral around an imaginary axis. This shape is called a double helix. A DNA molecule is very long and is made up of hundreds of thousands of genes

two major nucleic acids

deoxyribonucleic acids (DNA) and ribonucleic acids (RNA)

main categories of lipids

fats, phospholipids, and steroids *grouped together because they all have hydrophobic properties

Polymers

large molecules composed of many identical or similar subunits called monomers

lipids

macromolecules, they are not considered polymers because they are not made up of repeating structural units (monomers) such as the fat molecules in oil, do not dissolve well with water

Fat molecules

made up of carbon, hydrogen, and oxygen atoms

triglycerides

made up of smaller molecules, one glycerol and three fatty acids,

Cholesterol

most abundant steroid and is the starting material for most other types of steroids Cholesterol is found throughout your body and it is important for synthesizing other steroids, such as male and female hormones.

Starch

polysaccharide formed by plants as a way to store the large amounts of glucose produced during photosynthesis Animals are able to break down starch into individual glucose molecules, which makes starch an important food source.

Cellulose

polysaccharide made up of glucose, is a very strong material that serves as the primary structural component of plants Most animals are not able to break cellulose down into glucose. However, cellulose in the food that we eat is important because it serves as dietary fiber that regulates digestion

Glycogen

polysaccharide that animals and fungi use to store excess glucose molecules from their food. It serves as an energy reserve that can be broken down into individual glucose molecules when they are needed. Your athletic endurance is related to the amount of glycogen you have stored away, but even a significant supply of glycogen in an average human can be used up in a day if it is not replenished by carbohydrates from food

Cellular respiration

process that uses oxygen to harvest the chemical energy stored in organic molecules. Carbon dioxide is produced as the chemical energy is released from the organic molecules. The reaction below describes this process: C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + Energy Adenosine Triphosphate (ATP) The organic molecules in food contain stored energy that is released when their chemical bonds are broken. During cellular respiration, high-energy electrons are harvested from organic molecules and used to make adenosine triphosphate (ATP) molecules. ATP provides energy for most work done by the cell. Cellular respiration is very efficient, producing many ATP molecules for each organic molecule used. There are two types of respiration: aerobic respiration, which uses oxygen, and anaerobic respiration, which does not use oxygen. Anaerobic respiration will be examined in more detail later in the lesson. Let's first examine the steps of aerobic respiration. Organic Compounds + Oxygen → Carbon Dioxide + Water + Energy

Enzymes

proteins that increase the rate of a reaction by decreasing the amount of energy needed to get a reaction started - biological catalysts

biological macromolecules

provide energy and structure to living organisms and their cells

Facts about Enzymes

sensitive to temperature and pH like other proteins, so they can only speed up reactions when the conditions are right

Phospholipids

similar in structure to fat molecules. Instead of three fatty acids found in a fat molecule, phospholipids have two fatty acids and one phosphate group bonded to the glycerol molecule. Having a phosphate group instead of the third fatty acid gives phospholipids a hydrophilic-end and a hydrophobic end to the molecule

monosaccharide

smallest type of carbohydrate molecule most common being glucose and fructose important energy sources for cells carbon atoms in glucose can be used by the cells to build other important molecules, like fatty acids and amino acids they can be stored in larger carbohydrate molecules to be used later

Chitin

structural polysaccharide made up of glucose molecules. However, it is different than cellulose because it has amino groups (NH2) bonded to the glucose. It is found in the exoskeletons of arthropods such as insects, spiders, lobsters, and crabs. These protective exoskeletons, or anything else made of chitin, cannot be digested by animals

Enzyme inhibitors

substances that bind to an enzyme and change its shape or block its ability to interact with the chemical reaction

fat molecule

three fatty acids are each bonded to the glycerol. The fatty acid molecules may vary in the number of atoms, usually 16 to 18 carbons, and they may have single or double bonds between the carbon atoms Fats are stored in the body in fat deposits, which serve as stored energy for the organism. Fat deposits under the skin and can provide insulation for an animal, while fat surrounding vital organs provides protection and cushion for the organs. Although fats, carbohydrates, and proteins all serve as energy sources, digesting fat macromolecules releases much more energy than an equal amount of the others. One gram of fat can provide about 38 kilojoules of energy, compared to around 17 kilojoules of energy from one gram of carbohydrate or protein.

four categories of biological macromolecules

◾carbohydrates ◾lipids ◾proteins ◾nucleic acids