Characteristics of Living Things Living Things Share the

Characteristics of Living Things

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

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

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

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

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

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

Microscopes

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

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

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

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

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

What happens as the power of magnification increases? Power: Ocular x Objective = Total Magnification 10 x 4=40 10 x 10=100 10 x 40=400

The Metric System

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

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

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

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

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

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

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