Topics: Signal transduction, Protein, DNA replication Pages: 8 (2158 words) Published: February 27, 2013
Physiology Linder

Unit 1 Possible Essay Questions

Chapter 1
1. Describe the concept of homeostasis. Explain how negative feedback and positive feedback loops effect the homeostatic condition. Use examples to explain your answer.

Homeostasis can be described as maintaining a relatively internal environment even though the external environment is variable. Negative feedback loops effect the homeostatic condition by controlling it by bringing you back to your set point. An example of this would be blood pressure or heart rate. Positive feedback loops effect the homeostatic condition by using amplification to increase the change and stimulus. For example, labor, platelate plugs, and action potentials are all positive feedbacks loops.

2. Describe the four physiological themes discussed in the book that apply to all living organisms.

Theme 1: Structure and function are closely related: by dividing space into compartments (structure) it allows cells, tissues, organs, etc to specialize and isolate functions such as molecular interactions (function) which is the ability of individual molecules to bind to or react with other molecules. Theme 2: Living organisms need energy: growth, reproduction, movement, homeostasis, etc all require the input of energy. Theme 3: Information flow coordinates body functions: gene transfer from generation to generation, transcription and translation with a single organism to produce proteins, cell to cell communication involving neurotransmitters, hormones, action potentials, etc. and chemical communication where some molecules will cross the membranes and other must bind to receptors. Theme 4: Homeostasis maintains internal stability: maintaining a relatively internal environment even though the external environment is variable.

Chapter 2
1. Explain chemical bonding in terms of covalent, ionic, and hydrogen bonds as well as discuss Van der Waals forces.

Chemical bonding involves the interaction of valence electrons between 2 or more atoms. Covalent: atoms that share their valence electrons from covalent bonds. Take most energy to make and break. Ionic: formation of ions (atoms that have lost or gained an electron)-receive electrons Hydrogen: when hydrogen forms a polar covalent bond with another atom it gains a slight +charge –strong bond Van der Waals forces: weak, nonspecific attractions between the nucleus of an atom and the electrons of nearby atoms allowing atoms to pack closely together and occupy minimum amounts of space.

2. Describe dehydration synthesis and hydrolysis. Give examples of each type of reaction.

Dehydration synthesis (ex. condensation): 2 monosaccharides covalently bonded together producing maltose, sucrose, or lactose. Hydrolysis (reverse of dehydration synthesis): a digestion reaction to free-up the sugars for energy. Ex: the breakdown of triglycerides to form glycogen and fatty acids.

3. Explain what a lipid is. Be able to describe triglycerides, ketone bodies, phospholipids, steroids, and prostaglandins.

Lipids: Insoluble in polar solvents because they consist of hydrocarbon chains and rings that are nonpolar Triglycerides: true lipids/fats and oils, formed by condensation of glycerol and 3 fatty acids which consist of nonpolar hydrocarbon chain with a carboxyl end. saturated- single bond/ unsaturated-double bonds, bent. Ketone Bodies: hydrolysis in adipose tissue release free fatty acids into the blood. Phospholipids: a number of different categories of lipids that contain a phosphate group. Nonpolar end is hydrophobic, polar end is hydrophilic. Water inside and outside. Steriods: nonpolar and insoluble in water, lipid, three 6-carbon rings joined to a 5-carbon ring. Prostaglandins: fatty acid with a cyclic hydrocarbon group; serve a variety of regulatory functions (blood clotting, inflammation, ovulation, etc).

4. Explain the structure of a protein and explain primary structure, secondary structure,...
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