Characteristics of Living Things

Living Things Share the Following Characteristics Made of Cells Reproduce: sexually or asexually Based on the Universal Genetic Code: DNA

Obtain & use materials and energy Grow & Develop Obtain & use materials and energy Metabolism – the combination of chemical reactions through which an animals builds up or breaks down materials

Respond to the environment Stimulus: external signal; light or temp Maintain stable internal environment Homeostasis – like a thermostat; shiver As group, change over time Evolution

Levels of Biology Biosphere: part of the earth that contains al of the ecosystems Ecosystem: community and its nonliving surroundings

Levels Cont. Community: group of organisms of different types living in the same area Population: group of organisms of one type living in the same area Organisms – individual living thing

Levels of Biology Group of Cell: tissues, organs, and organ systems Cells: smallest functional unit of life Molecules: group of atoms; smallest unit of most chemical compounds

Microscopes

Types of Microscopes Light Microscopes: produce magnified images by focusing visible light rays Electron Microscopes: produces magnified images by focusing beams of electrons

The Microscope Cell Culture - develops from a single original cell used to test cell responses under controlled conditions Cell Fractionation - technique to separate different parts of a cell

Microscope Parts A. Eyepiece contains the ocular lens B. Nosepiece Holds the high and low power objective lenses; can be rotated to change magnification C. Objective Lenses Magnification ranges from 10X to 40X

Microscopes D. Stage Clips - hold the slide in place E. Stage supports the slide being viewed F. Light Source projects light upwards through the diaphragm, the specimen, and the lenses G. Base supports the microscope

Microscopes H. Diaphragm regulates the amount of light on the specimen I. Fine adjustment knob moves the stage slightly to sharpen the image J. Course adjustment knob moves the stage up and down for focusing K. arm used to support the microscope when carried

What happens as the power of magnification increases? Power: Ocular x Objective = Total Magnification 10x4=40 10x10=100 10x40=400

The Metric System

The Metric System Metric System: decimal system of measurement whose unit are based on certain physical standards and a scale of 10. International System of Units or SI: revised version of the metric system

Common Metric Units Length: meter (m) Mass: gram (g) Volume: liter (l) Temperature: Celsius (ºC)

Common Prefixes kilo (k) 1 kilo =1000 units centi (c) 1 unit =100 centi-units Milli (m) 1 unit =1000 milli- units micro (µ) 1 unit =106 micro-units nano (n) 1 unit =109 nano-units

Example 1 gram = 100 centigrams 1 liter = 1000 milliliters 1000 meters = 1 kilometer

Conversion Convert 10 grams to milligrams. What is the conversion factor? 1g = 1000 mg Problem: 10 grams x (1000mg/1g) = 10,000mg

More Examples Convert 200 mL to L. Convert 50 µg to g. Convert 10 km to cm.

More Examples Convert 200 mL to L. Convert 50 µg to g. Convert 10 km to cm.