Biology Study Guide

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Biology Midterm Outline
* Topic One: Chemistry of Living Things (p2-4)
* Topic Two: The Cell (p5-6)
* Topic Seven: Evolution (p23-27)
* Topic Ten: State Labs (37-40)
Topic One: Chemistry of Living Things
I. All living things must maintain homeostasis in order to stay alive. A) Homeostasis: A balanced state in an organism’s body.
B) Failure to maintain homeostasis results in disease or death. C) Homeostasis is often maintained using feedback mechanisms. 1. Feedback mechanisms are cycles in which the product of one reaction causes another to start or stop. D) While organisms are balanced, they are not unchanging. The term used to describe the balanced state is dynamic equilibrium. 1. Dynamic Equilibrium: A balanced state created by many small, opposing changes. II. Life Processes: All living things carry out the same basic chemical processes. Taken together, these processes make up an organism’s metabolism.

A) Metabolism: All the chemical processes that take place in an organism. 1. Nutrition: Using nutrients for growth, synthesis, repair and energy. 2. Respiration: Converts energy in food into a usable form (ATP). 3. Synthesis: Making complex chemicals from simple substances. 4. Transport: Absorbing and distributing materials throughout the body. 5. Regulation: The control and coordination of life processes. 6. Excretion: Removing of wastes produced by metabolic activities. 7. Reproduction: Passes on genes to offspring.

III. Inorganic Chemicals: Simple compound
A) Acids and Bases:
 Measured by the pH scale
 Very high and very low pHs are usually lethal.
 pH can affect rates of chemical reactions; for example, digestive enzymes work fastest in acidic environments, which is why we make stomach acid (hydrochloric acid, or HCl).4
IV. Organic Compounds: Larger, more complex chemicals. Always contain the elements carbon (C)and hydrogen (H). Synthesized from simpler substances (building blocks). A) Carbohydrates: Sugars and starches

1. Building blocks: Simple sugars
2. Functions:
 Main source of energy for living things.
 Stores energy in plants (starch) and animals (glycogen).  Serves as structural material in plants and some animals. B) Lipids: Fats, oils and waxes
1. Functions:
 Stores energy (animal fat)
 Insulation
 Cell membrane
C) Proteins: Complex compounds that carry out all the body’s activities. 1. Building blocks: Amino acids
2. Have many different functions as determined by their shape. 3. Lock and Key Model: Proteins must have the right shape to “fit” with other molecules.  Changing the shape of a protein will change what it can interact with its function.

4. Important types of proteins:
 Hormones and neurotransmitters – carry messages through the body.  Cell receptors – in cell membrane; receive hormones and neurotransmitters.  Antibodies – attack foreign pathogens
 Enzymes- act as catalysts, controlling all chemical reactions in the body.  High temperatures will cause enzymes to denature (lose their shape) and stop functioning. This is why high fevers are dangerous.

D) Nucleic Acids (DNA and RNA): Make up genes and chromosomes. 1. Building blocks: Nucleotides; molecular bases (ATCGU) A starch (A) is broken down by an enzyme (B) into two simple sugars (C, D). This is also a good example of the lock and key model. 1. Topic Two: The Cell

I. Definition: The basic unit of structure and function in all living things. II. Cell Theory has three parts:
1. All living things are made of one or more cells.
 Unicellular – single celled organisms (amoeba, paramecium)  Multicellular – have more than 1 cell; may be only a few cells, or many trillions of cells . Almost all structures in multicelled organisms are made of or by cells. 2. Cells carry out all life processes.

 Everything you do is the result of the work of your cells – walking, talking, even thinking and feeling. When you get sick, it is because your cells are not working correctly....
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