To start a chemical reaction, one needs to weaken the chemical bonds found in the reactants. This process requires that the molecules be able to absorb energy and it is known as activation energy. One way to weaken the chemical bonds is to heat it up, some cellular reactions use something known as catalysts, which speed up the chemical reaction. The main catalysts of chemical reactions are known as enzymes which are specialized proteins. An enzyme catalyzes only one type of reaction by specific reactions only allow enzyme of a certain shape and a specific reactant acted upon by an enzyme is called the enzyme's substrate. The substrate only fits into a certain region of an enzyme known as the active site.
Concept Check
1. Explain the role of activation energy in a reaction. How does an enzyme affect activation energy? The role of activation energy in a reaction is that this is the initial energy with which a reaction starts. This energy activates reactants to start a chemical reaction. An enzyme lowers the activation energy, thus speeding up the chemical reaction.
2. Describe how a subtrate interacts with an enyzme. A subtrate interacts with an enzyme by entering the active site of the enzyme. The fit between the subtrate and the enzyme is not rigid, but instead the enzyme's active sight slightly changes shape to fit the subtrate.88
Tuesday, September 9, 2008
Thursday, September 4, 2008
5.4 summary
Proteins function in our cells.
-A protein is a polymer that is constructed from a set of 20 different monomers known as amino acids.
-An amino acid monomer consists of a central carbon atoms that is covalent bonds to four other atoms or molecules.
-Polypeptide is a chain of proteins linked by amino acids. Most polypeptide chains are at least 100 amino acids in length.
-Denaturation is a process in which an unfavorable change in the environment has caused a protein to unravel and loose its normal shape.
Picture of protein foods, from http://www.dkimages.com/discover/ previews/836/965507.JPG
Concept Check
1. Give at least two example of proteins you can "see" in the world around you. What are their functions?
Two examples of proteins that you can see around you is hair/fur and muscles. Hair/fur keeps an animal warm and gives it texture. Muscles help you move to catch prey and find foods.
2. Relate amino acids, polypeptides, and proteins.
Amino acids is a central carbon atom bonded to four different atoms through covalent bonds, polypeptides are chains of amino acids and proteins are polymers also made of amino acids.
3. Explain how heat can destroy a protein.
It can destroy a protein by changing the environment around a protein causing it to unravel and loose its normal shape.
4. Which parts of an amino acid's structure are the same in all amino acids? Which part is unique?
Two examples of proteins that you can see around you is hair/fur and muscles. Hair/fur keeps an animal warm and gives it texture. Muscles help you move to catch prey and find foods.
2. Relate amino acids, polypeptides, and proteins.
Amino acids is a central carbon atom bonded to four different atoms through covalent bonds, polypeptides are chains of amino acids and proteins are polymers also made of amino acids.
3. Explain how heat can destroy a protein.
It can destroy a protein by changing the environment around a protein causing it to unravel and loose its normal shape.
4. Which parts of an amino acid's structure are the same in all amino acids? Which part is unique?
Three of the carbon's partners are the same in all amino acids.
Tuesday, September 2, 2008
5.3 summary
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-Lipids are water avoiding compounds that are unable to mix with water, compounds like these are hydrophobic meaning "water fearing".
-Fat consists of a three carbon backbone called glycerol that is attached to three fatty acids.
-Saturated fat contains the maximum number of hydrogen atoms in all three fatty acid chains.
-Unsaturated fat contains less than the maximum number of hydrogen atoms in one or more f it's fatty acid chains because some of it's carbon atoms are double bonded.
-Steroids are lipid molecules which the carbon skeleton forms four fused rings, but steroids are different from fats in structure and funtion. Steroids go around your body and acts as chemical signals.
-Cholestrol is an essential molecule found in the membrane that surrounds your cells.
Picture of fatty foods, from http://upload.wikimedia.org/wikipedia/commons/7/74/McDonald's_French
Concept Check
1.What property do lipids share?
Lipids are hydropholic meaning avoid water molecules.
2.What are the parts of a fat molecule?
A fat molecule consists of a three-carbon backbone called glycerol that is attached to three fatty acids.
3.Desribe two ways that steroids differ from fats.
Two ways that steroids differ from fats are that have different structures, steroids' carbon skeleton is a four fused ring structure, where as a fat is three carbon backbone. And steroids functions different from fats by working as chemical signals.
4.What does the term unsaturated fat on a food label mean?
The term unsaturated fat on a food label mean that they might be healthier than saturated fat foods.
1.What property do lipids share?
Lipids are hydropholic meaning avoid water molecules.
2.What are the parts of a fat molecule?
A fat molecule consists of a three-carbon backbone called glycerol that is attached to three fatty acids.
3.Desribe two ways that steroids differ from fats.
Two ways that steroids differ from fats are that have different structures, steroids' carbon skeleton is a four fused ring structure, where as a fat is three carbon backbone. And steroids functions different from fats by working as chemical signals.
4.What does the term unsaturated fat on a food label mean?
The term unsaturated fat on a food label mean that they might be healthier than saturated fat foods.
5.2.summary
5.2 talks about carbohydrates that provide fuel and building materials.
-A carbohydrate is a type of organic compound made of sugar molecules.
-Monosaccharides are simple sugars that contain one sugar unit. Examples of monosaccharides are fructose, glucose, and galactose.
-Disaccharides are basically two monosaccharides joined together and the most common dissaccharide is sucrose.
-Polysaccharides are long polymer chains of simple sugar monomers, starch is a type of polysaccharide found in plant cells which consists of only glucose monomers.
-Animal cells are different they don't contain starch, so they store excess sugar in the form of a polysaccharide known as glycogen.
-Many carbohydrates are hydrophillic due to the many hydroxyl groups their sugar units.
Picture of carbohydrates, from http://invitrofertilitygoddess.com/wp-content/uploads/slow%20carbs.jpg
Concept Check
1. Explain the difference between a monosaccharide and a dissacharide. Give an example of each.
Monosaccharides are single sugar units dissacharides are double sugars that are made by two monosaccharides.
2. Compare and contrast starch, glycogen and cellulose.
Starch is a polysaccharide found in plants constructed entirely of glucose monomers. Glycogen is found in animals, and is used to store excess sugar in the form of a polysaccharide. Cellulose is a polysaccharide found in plants that serve as building materials.
1. Explain the difference between a monosaccharide and a dissacharide. Give an example of each.
Monosaccharides are single sugar units dissacharides are double sugars that are made by two monosaccharides.
2. Compare and contrast starch, glycogen and cellulose.
Starch is a polysaccharide found in plants constructed entirely of glucose monomers. Glycogen is found in animals, and is used to store excess sugar in the form of a polysaccharide. Cellulose is a polysaccharide found in plants that serve as building materials.
3. How do animals store excess glucose molecules?
Animals store glucose as glycogen. Glycogen is usually stored as granules in liver and muscle cells.
Animals store glucose as glycogen. Glycogen is usually stored as granules in liver and muscle cells.
5.1 summary
Carbon is the main ingredient of organic molecules.
-Carbon atoms form with more carbon atoms creating carnbon based molecules called organic molcules non carbon based molecules are called inorganic molecules.
-Functional groups are a group of atoms that reacts in a predictable way to other molecules.
-Hydroxyl groups are hydrophic meaning they attract water molecules. Larger molecules are made of many smaller molecular units called monomers.
-Long chains of monomers are called polymers. Organisms have to build and break down polymers.
Picture of functional groups, from http://kvhs.nbed.nb.ca/gallant/biology/functional_groups.jpg
Concept Check 5.1
1. Draw a molecule that has a three-carbon skeleton and a hydroxyl group on the middle carbon.
1. Draw a molecule that has a three-carbon skeleton and a hydroxyl group on the middle carbon.
picture from, http://littlezhelovesmarshmallows.blogspot.com/2. Explain the connection between monomers and polymers.
Polymers are made of 2 monomers.
3. What molecule is released during the construction of a polymer? What is this reaction called?A water molecule is released after the construction of a polymer in a reaction called a dehydration reaction.
4. Draw at least three ways in which five carbon atoms could be joined to make different carbon skeletons.
3. What molecule is released during the construction of a polymer? What is this reaction called?A water molecule is released after the construction of a polymer in a reaction called a dehydration reaction.
4. Draw at least three ways in which five carbon atoms could be joined to make different carbon skeletons.
pictures from http://littlezhelovesmarshmallows.blogspot.com/
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