Safety review

CHAPTER 1THE SCIENCE OF LIFE

Lets play a game…

Am I alive? How can you tell?

Characteristics of Life?

Organization Response to stimuli Homeostasis metabolism Growth and Development Reproduction Change through time

Organization

High degree of order between internal and external parts

Interactions with the living world Examples?

Response to stimuli

Ability to respond to changing environment

Homeostasis

ability to maintain a stable internal condition.

No matter the changes in environment.

Metabolism

Use of energy to power life processes

Growth and Development

Growth? increase in amount of living material Development? process ending in adulhood Ie. Frog

Reproduction

Production of Offspring Coded information is passed on to the

offspring Like Produces Like

Change through time

evolution

Science as a process

Scientific method

Organized approach to learn how the natural world works

Scientific method

1. Observation / question: 2. Hypothesis: tries to

answer question; proposed explanation

3. Prediction: guesses what will happen

4. Experiment: tests hypothesis

5. Collect and analyze data6. Supports or disputes

hypothesis

Scientific theory

When a set of confirmed hypotheses is confirmed to be true many times

Examples?

Tools of the trade

Microscopes1. Compound light microscope Uses light through a specimen Electron microscpes use a stream of

electrons to visualize a specimen2. Scanning (SEM) electron microscope 3-D surface view3. Transmission (TEM) electron microscope 2-D internal view

Compound Light Microscope

Scanning Electron Microscope

SEM

Transmission Electron Microscope

TEM

Light vs. Electron

SEM or TEM

SEM TEM

TEM SEM

SEM or TEM

SEM TEM

TEM SEM

More SEM

More SEM

More SEM

The Metric System

Common Metric Units

Length (meters) Mass (grams)1 meter (m) = 100 centimeters (cm)1 meter = 1000 millimeters (mm)1000 meters = 1 kilometer

1 kilogram (kg) = 1000 grams (g)1 gram = 1000 milligram (mg)1000 kilograms = 1 metric ton (t)

Volume (liters) Temperature (Celcius)1 liter (L) = 1000 milliliters (mL)1 liter = 1000 cubic centimeters (cm3)

0o Celsius (C) = freezing point of water100o C = boiling point of water

•System of measuremnt in science. •Based on multiples of ten = easy conversion

Ch 1 Vocab quiz next class

1. Biology2. Compound light

microscope3. Electron

microscope4. Gene 5. Hypothesis

1. Metabolism2. Metric

system3. Organization4. Scientific

method5. Theory

CH 2CHEMISTRY OF LIFE

Matter

Everything is made of matter (?) Has mass and occupies space

Elements and atoms

Element: substances that cannot be broken down into simpler substances

Atoms: smallest particle of an element that retains the properties of that element

Atomic structure

Nucleus makes up most of mass of an atom

Consists of protons (positive) and neutrons (no charge)

Number of protons = atomic number Number of protons + neutrons = mass number

Atomic structure

Electrons: negatively charged particles Balance out with positive charge of

protons Very small mass Move around the nucleus in orbitals

Isotopes

Atoms of same element have equal number of protons but not necessarily neutrons

Isotopes: atoms of the same element that have a different number of neutrons

Compounds

Made of atoms of two or more elements H2O CO2

CH4

A Covalent Bond occurs when atoms

share electrons

Covalent Bonds

Ionic Bonds

Example: Sodium Chloride

Oppositely charged atoms, attracted to each other

Note: they do not share electrons

Energy and Matter

Energy: ability to do work Many types of energy

Electrical Radiant (light) Thermal (heat) Chemical mechanical

Chemical reactions

One or more substances change to produce one or more different substances

Reactants: on the left side of the equation

Chemical reactions

One or more substances change to produce one or more different substances

Products: on the right side of equation

Activation energy

Energy needed to start a reaction

Catalysts reduce activation energy Example: enzymes

Water and solutions

Properties of water are necessary for life Many of water’s functions come from it’s

chemical structure Polarity: uneven distribution of charges Water is polar Polar nature allows water to dissolve

polar substances

Hydrogen bonding

Polar nature allows water to be attracted to one another

+ region of one moleculue attracted to the – region on another

Cohesion and adhesion

Cohesion: attractive force between molecules of a single substance Water attracted to water

Adhesion: attractive force between molecules of different substances Water attracted to other stuff

Quick cohesion and adhesion lab HOW MANY DROPS OF WATER CAN I PUT

ON LINCOLN’S HEAD? Get in lab groups. Send one member up to the front to get

a penny and a cup Count the number of drops that you can

put on the head of a penny

Temperature moderation

Water has a high heat capacity Water can absorb or release large

amounts of energy with only a slight change in temperature

This allows water to absorb heat during the summer to keep air cool w/o increasing the temp.

And at night, water cools and warms the air

Density

Is ice more or less dense than water?

Discuss with your partner and write your ideas down in your notes

Solutions

Solution: mixture of two or more substances

Solute: substance that dissolves in a solvent

Solvent: substance in which the solute is dissolved

Acids and bases

pH scale is used to measure acidity or alkalinity

Scale from 0 14 06.9: acid 7 neutral (water) 7.114: base Buffers: chemical substances that

neutralize small amounts of acids or base added to a solution They keep the pH from changing greatly