Q. Describe how the polarity of the water molecule results in hydrogen bonding.
A. The electropositive hydrogen atoms are attracted to the electronegative oxygen atom.
Q. Describe the role of water as a solvent, temperature regulator, and lubricant.
A. Only substances that can dissolve in water can enter cells, helps maintain temperature in living organisms, and lubricates joints due to its high surface tension.
Q. Distinguish among acids, bases, and buffers and indicate the importance of pH to biological systems.
A. Acids have a pH of 0-7 and have more H+ ions than OH- ions. Bases have a pH of 7-14 and have more OH- ions than H+ ions. Buffers absorb both ions and help maintain the pH of blood to prevent enzymes from denaturing.
Biological Molecules
Q. Demonstrate a knowledge of dehydration synthesis and hydrolysis as applied to organic polymers.
A. Dehydration synthesis is the process by which monomers (such as amino acids) are linked to create polymers (such as a protein) by removing a OH- and H+ ion to make water. Hydrolysis is the process by which polymers are broken down into monomers by adding water and enzymes.
Q. Distinguish among carbohydrates, lipids, proteins and nucleic acids with respect to chemical structure.
A. The ratio of Carbon, Hydrogen, and Oxygen in carbohydrates is 1:2:1. Proteins have an amino group, carboxyl group, and a variable "R"group. Lipids are split into fatty acids, triglycerides, phospholipids, and steroids. Unsaturated fatty acids have double bonds between carbons and the saturated fatty acids do not.
Nucleic Acids are made of monomers called nucleotides which are made of a sugar, phosphate group, and a nitrogen base.
Q. Recognize the empirical formula of a carbohydrate.
A. CH2O (1:2:1).
Q. Differentiate among monosaccharides, disaccharides, and polysaccharides.
A. A monosaccharide is just a glucose or fructose molecule. A disaccharide is two monosaccharides that have joined to form sucrose. A polysaccharide is hundreds or thousands of monosaccharides joined together
to form starch, glycogen, or cellulose.
Q. Differentiate among starch, cellulose, and glycogen.
A. Starch is stored glucose which can be broken down for energy by cells. Glycogen is excess glucose that is stored in the liver and muscles and is also used for energy. Cellulose is used by plants to keep their cells rigid, and it cannot be digested by humans and is essential to our diet.
Q. List the main functions of carbohydrates.
A. Carbohydrates are used as sources of energy and as building materials.
Q. Compare and contrast saturated and unsaturated fats in terms of molecular structure.
A. Saturated Fatty Acids do not have double bonds between carbons. Unsaturated Fatty Acids do have one or more double bonds between carbons in the chain.
Q. Describe the location and explain the importance of the following in the human body: neutral fats, steroids, phospholipids.
A. Neutral Fats act as energy storage and are found in the thighs and torso. Steroids can be chemical messengers and form many hormones. They are found in every cell in your body. Phospholipids form an important part of cell membrane and are found in all cells.
Q. Draw a generalized amino acid and identify the amino, acid, and R groups.
A. R group
H R O
\ l =
N - C - C
/ 1 \
H H OH
Amino group Acid group
Q. Differentiate among the primary, secondary, tertiary, and quaternary structure of proteins.
A. Primary structure is just a line of amino acids. Secondary has a spiral or helix shape. Tertiary is the alpha helix shape folded into an irregular shape. Quaternary is a specific arrangement of 2 or more polypeptide chains.
Q. List the major functions of proteins.
A. 1. Structure in cartilage, bone, muscle cells, etc. 2. Enzymes 3. Immunity against foreign invaders 4. Hormones ( chemical messengers in the body) 5. Transport (through protein channels for example)
Q. Relate the general structure of the ATP molecule to its role as the "energy currency" of cells.
A. ATP has a three phosphate group. During hydrolysis, a special enzyme will remove a phosphate molecule from ATP. This releases energy that the cell can use. The ATP is then recycled so it can used again.
Cell Structure
Q. Describe the following cell structures and their functions.
A. Cell Membrane -Bilipid layer of phospholipids and cholesterol. Regulates what goes in and out of a cell and protects the cell.
Mitochondria - Double membrane bound organelle. Produces energy (ATP) for the cell activities, such as cellular respiration.
Ribosomes - Made of rRNA and protein, floats free. Site of protein synthesis. Reads RNA code and translates into amino acid sequence.
Golgi Bodies - Stacked flat sacs. Modifies proteins and lipids. Stores and packages molecules.
Vesicles - Membrane bound sac. Transports materials around the cell.
Vacuoles - Membrane bound sac.Contains liquids or solids, bigger than vesicles.
Lysosomes - Membrane bound sacs, contain digestive enzymes. Garbage disposal. Breaks down bacteria and worn-out organelles.
Nuclear envelope - Double membrane, has pores. Protects nuclear contents, allows communication with cell via RNA molecules.
Nucleus - Bound by double porous membrane. Stores genetic information, controls cell division, directs functioning of the cell.
Nucleolus - Found in nucleus. Creates ribosomes.
Smooth Endoplasmic Reticulum - Network of tubules, lacks ribosomes. Packages proteins, detoxifies drugs in liver. Synthesizes lipids, triglycerides, and steroids.
Rough Endoplasmic Reticulum - Network of tubules, ribosomes on surface. Produces protein at ribosomes, transports them to smooth ER for packaging.
Chromosomes - Double stranded DNA molecules in nucleus. Genetic blueprint in bases. Cell division, RNA transcription.
Q. Identify the functional interrelationships of cell structures.
A. Mitochondria provide the energy for the cells activities. In the nucleus, DNA in the chromosomes are copied and a strand of RNA (from the nucleolus) leaves through the nuclear envelope. The RNA then goes to a ribosome that is attached to the rough endoplasmic reticulum. The ribosome reads the RNA and assembles amino acids into polypeptide chains. Then the smooth ER modifies and packages them and sends them to the golgi body. The golgi body makes some final modifications to the proteins and packages them into a vesicle which then takes them through the cell membrane and out of the cell. Other proteins are used as digestive enzymes in lysosomes.
Q. Identify the cell structures in diagrams & electron micrographs.
A.
1. Nucleolus - Produces ribosomes, made of RNA.
2. Nucleus - Stores genetic information, controls cell division, directs functioning of cell.
3. Ribosome - Site of protein synthesis, reads RNA code, translates into amino acid sequence.
4. Vesicle - Membrane bound sacs that transport materials around and out of cell.
5. Rough Endoplasmic Recticulum - Produces proteins and transports them to Smooth ER.
6. Golgi Body - Modifies proteins and lipids. Stores and packages molecules.
7. Cytoskeleton - Maintains cell shape, helps with transport in cell.
8. Smooth Endoplasmic Recticulum - Packages proteins, synthesizes membrane phospholipids, detoxifies drugs in liver cellls.
9. Mitochondria - Produces ATP, site of cellular respiration.
10. Vacuole - Maintains structure in plant cells. Acts as storage.
11. Cytoplasm - Gel-like substance that contains all the organelles.
12. Lysosome - Acts as garbage disposal, breaks down bacteria entering cell and worn out organelles.
13. Centrioles - Help the cell during mitosis and meiosis.
DNA
Q. Name the four bases in DNA and describe the structure of DNA using the following terms:
Nucleotide, Complementary base pairing, Double helix, Hydrogen bonding.
A. A nucleotide is made of 3 parts: sugar, phosphate group, nitrogen base.
The nitrogen base can be adenine, thymine, guanine, or cytosine. In complimentary base pairing, adenine goes with thymine, and guanine goes with cytosine. The bases are held together by hydrogen bonds. DNA is twisted into a double helix.
Q. Describe DNA replication with reference to three basic steps: "unzipping", Complementary base pairing, joining of adjacent nucloetides.
A. DNA replication starts with DNA helicase "unzipping" the strand of DNA. Then a strand of RNA lines up with the DNA and uses complementary base pairing to copy the strand of DNA. The joining of adjacent nucleotides is conducted by DNA ploymerase, which forms bonds between the sugar and the phosphate to hold the nucleotides together.
Q. Define recombinant DNA.
A. Recombinant DNA is DNA that has been opened up and has had a gene (such as insulin) added to it to enhance its abilities.
Q. Describe three uses for recombinant DNA.
A. Recombinant DNA has been used to create insulin-producing bacteria. It can also be used to make disease-resistant plants and it can help diagnose and treat genetic disorders.
Q. Compare and contrast the general structural composition of DNA and RNA.
A. DNA is double-stranded and cannot leave the nucleus, while RNA is single stranded and can leave the nucleus.
