Chapter 8 - Nutrients and Enzymes & Disgestive System Flashcards
Define carbohydrate
A molecule composed of sugar subunits that contain carbon, hydrogen, and oxygen in a 1:2:1 ratio
Define polymer
A molecule composed of three or more subunits
Define monosaccharide
A single sugar unit
Define isomer.
One of a group of chemicals that have the same chemical formula but different arrangements of atoms
Define disaccharide.
A sugar formed by the joining of two monosaccharide subunits.
Define dehydration synthesis.
The process by which larger molecules are formed by the removal of water from two smaller molecules. (Water is formed from the two smaller molecules)
Define hydrolysis.
The process by which larger molecules are split into smaller molecules by the addition of water. (Water molecule is used to break the bond of the disaccharide)
What are the 5 chemicals of life?
Vitamins and Minerals, Lipids (fats), Carbohydrates, Proteins, and Nucleic Acids.
What are the roles of carbohydrates?
Carbohydrates are the primary source of energy for cells, and are the structural material of plant cells.
Why should you not eat excess amounts of carbohydrates?
It will be stored as fat.
What is the source of carbohydrates for humans? Why are they a source?
The main source of carbohydrates come from plants. Humans rely on plants because humans cannot make carbohydrates.
How can you identify a sugar?
You can identify sugars by the -ose suffix.
Define polysaccharide.
A carbohydrate composed of many single sugar subunits.
What is starch? What is it composed of?
Starch is a plant polysaccharide/carbohydrate used to store energy in the starch molecule. It is composed of many subunits of glucose.
What are the 2 forms of starch? What do they have in common? Describe them both.
Amylose and amylopectin. Both molecules tend to bend in the shape of a helix or coil.
1) Amylose: Contains up to 1000 or more glucose units. The first carbon of a glucose molecule is linked to the fourth carbon of the next molecule.
2) Amylopectin: Contains between 1000 and 6000 glucose subunits and have short branching chains of between 24 and 36 glucose units extending from the main branch.
Define glycogen. What form of starch does it resemble?
Glycogen is the form of carbohydrate storage in animals. It resembles a amylopectin starch molecule, except that it’s branching structures only contain 16 to 24 glucose units.
Define cellulose. What is it made of? How is it formed?
Cellulose is a plant polysaccharide that makes up plant cell walls. Over 50% of all organic carbon in the biosphere is cellulose. Cellulose is made of glucose subunits. Cellulose does NOT form coiled structures. The layers of cellulose are attracted to one another by hydrogen bonds between the -OH groups.
Are lipids polar or non-polar? What are most lipids composed of?
Non polar. Most lipids are composed of 2 structural units: glycerol and fatty acids.
What is a triglyceride? How are they formed?
What are monoglycerides and diglycerides?
A triglyceride is a lipid composed of glycerol and three fatty acids. They are formed by dehydration synthesis.
Monoglycerides and diglycerides are the joining of glycerol with one or two fatty acids.
What are the functions of lipids?
Lipids are energy storage compounds, structural components of cell membranes and insulation.
What are fats?
Fats are lipids composed of glycerol and saturated fatty acids. (Fats are triglycerides that are solid at room temperature.)
What are oils?
Oils are lipids composed of glycerol and unsaturated fatty acids. (Oils are triglycerides that are liquid at room temperature.)
What are saturated fats? What type of fats are mostly saturated?
Saturated fats are fats where only single bonds exist between the carbon atoms. Most of the fatty acids in animal fats are saturated. Because single covalent bonds tend to be stable, animal fats are hard to break down.
What are unsaturated fats? What fats are mostly unsaturated?
Unsaturated fats contain double bonds between the carbon atoms. The fatty acids of most plants are unsaturated. The unsaturated double bonds are somewhat reactive so plant oils are more easily broken down.
What is it called when the fatty acid contains only one double bond? What is it called when the fatty acid contains two or more double bonds?
If it contains one double bond, it is monounsaturated. If it contains two or more double bonds, it is polyunsaturated.
Define phospholipids.
A lipid with a phosphate molecule attached to the glycerol backbone, making the molecule polar. Phospholipids are the major component of cell membranes. O= (diagram) O is the polar phosphate molecule, = is the non polar glycerol backbone.
What are waxes?
Waxes are a long-chain fatty acids that is insoluble in water. The long-chain lipids are joined to long-chain alcohols or to carbon rings.
What is a protein? When are proteins manufactured?
A chain of amino acids that form the structural parts of cells or act as antibodies or enzymes. Whenever cells are damaged and require repair, proteins are manufactured.
What is an amino acid?
A chemical that contains nitrogen, can be linked together to form proteins.
What is a peptide bond?
A bond that joins amino acids.
What is a polypeptide?
A chain of three or more amino acids.
What are essential amino acids? How many essential amino acids are there? What happens when there is a lack of an amino acid?
An amino acid that must be obtained from the diet, as your body cannot synthesize them. There are 8 essential amino acids. The lack of any of them call lead to specific diseases and deficiencies.
___________ are polypeptides. What shapes are they?
Proteins are polypeptides that are folded into specific 3D shapes. Some proteins contain more than one polypeptide.
What determines a structure of a protein?
It’s sequence of amino acids.
What determines a protein’s function?
A protein’s shape, or structure determines it’s function.
What are the levels of protein structure?
Primary, secondary, tertiary, and quaternary.
Describe the four levels of proteins.
- Primary structure: is the sequence of amino acids in the polypeptide strand.
- Secondary structure: hydrogen bonds form with nearby amino acids, and coil and fold the polypeptide into a helices and B-pleated sheets.
- Tertiary structure: the polypeptide folds further. The tertiary structure forms because of interactions between the R groups of different amino acids.
- Quaternary structure: the clustering of two or more polypeptides in the tertiary structure makes up the quaternary structure.
Define denaturation. What are factors that can denature a protein?
Denaturation is the process that occurs when the bonds of a protein molecule are disrupted, causing a temporary change in shape. Factors include excess heat, radiation, or a change in pH.
Define coagulation.
Coagulation is the process that occurs when the bonds of a protein molecule are disrupted, causing a permanent change in shape.
Define catalyst.
A chemical that increases the rate of chemical reactions without altering the products or being altered itself.
Define enzyme.
A protein catalyst that permits chemical reactions to proceed at low temperatures by reducing the reaction’s activation energy.
Define substrate.
A molecule on which an enzyme works.
Define active site.
The area of an enzyme that combines with the substrate.
