Study Guide 1 BIOS 1063-601, Fall 1998

1. What is the composition and biological function of the following?
   • Carbohydrate
     Any of the group of organic compounds composed of carbon, hydrogen, and oxygen. Some examples include, starch, sugar and cellulose. Used for energy.
   • Monosaccharide
     Simple sugar. Some examples include glucose and ribose.
   • Disaccharide
     Two sugars. Combining glucose and glucose yields maltose. Combining glucose and fructose yields sucrose. galactose+glucose=lactose.
   • Polysaccharide
     Many sugars. These include: Starch which is the principal carbohydrate storage for plants, glycogen, the primary carbohydrate storage product for animals and cellulose, the major supporting material for plants.
   • Starch
     A polysaccharide, starch is the principal carbohydrate storage product for higher plants.
   • Amino Acid
     The basic building block of protein. The structure of a protein is determined by the sequence of amino acids.
   • Protein
     A string of amino acids and composed of carbon, hydrogen, oxygen and nitrogen, proteins are responsible for structural maintenance of the organism and biochemical reactions.
   • Enzyme
     Catalysts which are made up of proteins. Enzymes control biochemical reactions.
   • Glycogen
     The primary carbohydrate storage product for animals.
   • Cellulose
     The major supporting material for plants.
   • Nucleotide
     A five carbon sugar made up of C, H, O, P and N. They are the basis for DNA.
   • DNA
     The molecule of life. DNA provides the blueprint for proteins which act as catalysts for biochemical reactions.
   • Chromatin
     The uncondensed chromosomal strands, made of protein and DNA.
   • Chromosomes
     Condensed chromatin located in the cell nucleus or nucleoid along which genes are located.
   • Lipids
     Combinations of carbohydrates and energy bonds which can build cell structures or be used for energy.
2. What is the composition, structure and function of biological membranes? How do substances cross these membranes?
   Biological membranes are composed a bilipid layer and proteins. They are composed of hydrophyllic and hydrophobic molecules. It serves to give shape and some protection to the cell as well as regulating the movement of substances into and out of cells. Substances Substances pass through it via the process of diffusion, a movement of ions or molecules from an area of high to an area of low concentration.
3. Identify the structure and function of each of the following:
   
   • Cytoplasm
     A gel-like substance or matrix inside of the cell membrane that allows the flow of materials.
   • Mitochondrian
     Described as "the powerhouse of the cell," the mitichondrian has an outer membrane composed of lipids and proteins and an inner membrane composed of christae. It is the site of cellular respiration.
   • Endoplasmic Reticulum
     Composed of lipids and proteins, it is a net-like substance located inside of the cell. There are two types of ER, rough and smooth. The "bumps" on the rough ER are ribosomes. It functions to increase the surface area of the cell.
   • Flagella
     Composed of protein fibers, this "whip" propels the cell through the fluid medium.
   • Nucleolus
     A dense body within the nucleus, it contains copies of the genes for rRNA.
   • Exocytosis
     The reverse of endocytosis, exocytosis is the expelling of wastes to the periphery of the cell.
   • Golgi Body
     The Golgi modify molecules and packs them in to small sacs called vesicles.
   • Cell Wall
     Only in plant cells, it is a peptidoglycan, a polymer of amino acids and sugars. It gives the cell wall strength and rigidity.
   • Chromatin
     A combination of protein and DNA located in the nucleus.
   • Ribosomes
     Sites of protein synthesis within the cell. mRNA and tRNA combine to make proteins.
   • Central Vacuole
     Inside of a plant cell, the vacuole acts as a large "balloon" that fills with water pressure to provide internal support.
   • Nucleus
     Inside of the cell, the nucleus contains a nuclear membrane, chromatin and a nucleolus.
   • Lysosome
     A "suicide bag" inside of the cell which contains enzymes capable of digesting cells.
   • Chloroplasts
     Only found in plant cells, they are the containers of thylakoids, the photosynthetic apparatus and may contain chlorophyll.
   • Vesicles
     Prepared sources of nourishment for cells. Produced by Golgi.
   • Endocytosis
     The "pinching off" of the cell around molecules, it requires an expenditure of energy.
4. What are the major differences between plant and animal cells?
   
   • Animal cells do not have cell walls.
   • Animal cells do not contain chloroplasts.
   • Animal cells do not have central vacuoles.
5. What are the two major groups of prokaryotes? What are the primary differences between prokaryotic and eukaryotic cells? What organisms are eukaryotic?
   The two major groups of prokaryotes are bacteria and blue green algae. Eukaryotic cells have specialized organelles which are membrane bound and prokaryotes have not compartmentalized their processes. prokaryotic cell have no nucleus. Animals as well as all other organisms than bacteria and blue green algae are eukaryotic.
   see also: BIOS-1053 Study Guide One
6. Explain various mechanisms involved in the movement of materials across biological membranes.
   
   • Osmosis is the movement of water molecules from an area of high to an area of low concentration through a differentially permeable membrane. It is termed a type of passive transport and requires no expenditure of energy.
     
   • Endocytosis, pinocytosis and phagocytosis are forms of active transport, and are differentiated primarily by the size of the molecules they are encountering. They utilize ATPs from cellular respiration for energy to move against a diffusion gradient.