Learn: Exam 1, Lab 3

Hypothesis

Suggests a possible explanation/The testable explanation

Theory

Explains why it happens

Law

Describes what happens

Scientific Method

Observation, Question, Hypothesis, Prediction, Experiment (Data Collection & Analysis), Conclusion

Observation

Notice something in the world

Question

Ask: Why is this happening?

Hypothesis

Suggests a possible explanation/The testable explanation

Prediction

If, then statement

Experiment (Data Collection & Analysis)

Record what happens

Conclusion

Support or Reject hypothesis?

Hypothesis - General Format Equation

If [the specific treatment], then [a predicted result].

Experimental Group

group being tested on

Control Group

group not being tested on

Independent variable

the variable that you are changing

Dependent variable

the variable that is being measured

Constant variable

variables that stay CONSTANT

Hypothesis must be

testable and falsifiable

Not blind

Test subjects and researchers both know which group is which

Single blind

Test subjects don't know which group is which, but researchers know which group is which

Double blind

Test subjects don't know which group is which, and researchers don't know which group is which

Biology

the scientific study of life

Characteristics of life

Order

Cells

Growth and development

Energy processing

Regulation

Response to the environment

Reproduction

Evolution

5 unifying themes in biology

1. Structure and function

2. Information flow

3. Pathways that transform Energy and Matter

4. Interactions with biological systems

5. Evolution

Ocular lens magnification

10X

Red lens

4X

Yellow lens

10X

Blue lens

40X

mega

M 10^6

kilo

k 10^3

hecto

H 10^2

deca

Da 10^1

deci

d 10^-1

centi

c 10^-2

milli

m 10^-3

micro

u 10^-6

Ocular lens

Head

Arm

Nosepiece

Objective Lens

Stage

Coarse Adjustment

Fine Adjustment

Condenser

Light

Stage controls

Base

Brightness adjustment

light switch

How to use microscope

Set microscope on 4X objective by rotating

nosepiece and set stage lowest position by

rotating coarse adjustment

Place the slide on stage by moving the metal

holders

Use the stage control to place the slide directly

on top of the light

Begin focusing on by rotating coarse

adjustment until clear

Once focused, draw what you see and write

the total magnification in Part II number 4

circle

Rotate the nosepiece until the 10X objective

lens and again focus using the coarse

adjustment until image is CLEAR

Rotate the nosepiece until the 40X objective

lens and again focus using the only fine

adjustment until image is CLEAR

Once finished, rotate nosepiece back to 4X

objective and remove the slide and return into

container

Proton

A subatomic particle that has a positive charge and that is found in the nucleus of an atom

Neutron

A subatomic particle that has no charge and that is found in the nucleus of an atom

Electron

A subatomic particle that has a negative charge

Atomic Number

the number of protons in the nucleus of an atom

Mass number

the sum of the number of neutrons and protons in an atomic nucleus

Isotopes

Atoms with the same number of protons but different numbers of neutrons

radioactive isotopes

Atoms that are unstable, meaning they decay, or break down, to form stable atoms of a different element

Ionic bond

Formed when one or more electrons are transferred from one atom to another

Covalent bond

A chemical bond that involves sharing a pair of electrons between atoms in a molecule

Polar Covalent Bond

A covalent bond in which electrons are not shared equally

nonpolar covalent bond

a covalent bond in which the electrons are shared equally by the two atoms

Hydrogen bond

Attraction between a slightly positive hydrogen atom and a slightly negative atom.

polar molecule

molecule with an unequal distribution of charge, resulting in the molecule having a positive end and a negative end

nonpolar molecule

molecule that shares electrons equally and does not have oppositely charged ends

Hydrophobic

Water fearing

Hydrophilic

water loving

polar molecules are

hydrophilic

nonpolar molecules are

hydrophobic

What type of bond joins individual water molecules to each other?

hydrogen bonds

How are the individual hydrogen and oxygen atoms inside each water molecule are joined?

polar covalent bonds

States of matter

solid, liquid, gas

What properties of water allow it to sustain life?

The cohesion of water

Water can moderate temperature

The biological significance of ice floating

Water as the solvent of life

The cohesion of water

Then tendency of molecules of the same kind to stick together

Water can moderate temperature

Hydrogen bonds gives water a stronger resistance to temperature change

Earth's giant water supply enables planet temperatures to stay within limits that permit life

The biological significance of ice floating

Each water molecule has 4 H-bonds holing it in place with neighboring water molecules

Makes ice less dense than water, floats

Allows life in the water to persist beneath frozen surface

Water as the solvent of life

Water can dissolve a large variety of necessary solutes for life

Provides a medium for chemical reactions

Solute

A substance that is dissolved in a solution.

Solvent

A liquid substance capable of dissolving other substances

Ion

An atom or group of atoms that has a positive or negative charge.

Hydrogen in water

slightly positive

Oxygen in water

slightly negative

pH scale

measurement system used to indicate the concentration of hydrogen ions (H+) in solution; ranges from 0 to 14

An increase of 1 on the pH scale represents

a tenfold (10 times) decrease in the concentration of hydrogen ions

a decrease in 1 on the pH scale represents what

A decrease of 1 unit on the pH scale represents a tenfold (10x) increase in hydrogen ion concentration and acidity

Acid

A substance that increases the hydrogen ion concentration of a solution.

Base

A substance that decreases the hydrogen ion concentration in a solution.

4 elements that make up 96% of humans

Oxygen (O)

Carbon (C)

Hydrogen (H)

Nitrogen (N)

How many elements are essential for humans?

25

DNA

deoxyribonucleic acid

DNA function

DNA is the code for making proteins and stores genetic information

What makes up DNA?

Adenine, Thymine, Guanine, Cytosine (ATGC)

Genes

stretches of DNA that code for the production of proteins

RNA

ribonucleic acid

RNA function

performs protein synthesis

What makes up RNA?

adenine, cytosine, guanine, uracil (ACGU)

Transcription

(genetics) the organic process whereby the DNA sequence in a gene is copied into mRNA

Translation

Process by which mRNA is decoded and a protein is produced

What is mRNA?

messenger RNA

Double bond

A chemical bond formed when atoms share two pairs of electrons

Single bond

a covalent bond in which two atoms share one pair of electrons