bio exam 1

biology

Scientific study of life

Scientific method

Observation/ exploration → question → hypothesis _→ experiments → conclusion

Theory

Comprehensive & well sustained explanation, much broader in scope than a hypothesis

A theory …

a. Is only accepted by scientists if there is large, varied, and growing body of evidence

b. Can be used to explain many observations, used to devise other hypotheses

c.Must be refined, or even abandoned if new and contradictory evidence is discovered

Variables

Factors that change in an experiment

Controlled experiment

Compares 2 or more groups that differ in only 1 variable that the experiment is looking to test.

Control group

Lacks or does not receive the specific factor being tested

Experimental group

Receives the specific factor being tested

Independent variable

What is being manipulated as a potential cause, the object under investigation

Dependent variable

The response, output, or effect that is under investigation that is used to judge the outcome of the experiment. The dependent is affected by the independent

Placebo

Medically ineffective treatment that allows for this group to serve as a control group

Double blind

Researcher and participant don't know which group either is in.

Pseudoscience

Any field of study that is falsely presented as having a scientific basis

Relationship of structure to function

Ex. The indentations of red blood cells increase the surface area through which oxygen can diffuse

Information flow

Ex. Info. About the amount of glucose in the bloodstream is received by organs such as your pancreas

Pathways that transform energy and matter

Ex: sunlight is captured by plants and other photosynthetic organisms (producers). This energy is then converted into chemical energy, stored, as chemical bonds within sugars and other complex molecules.

Interactions within biological systems

Ex: At each new level, the complexity increases and novel properties emerge that are absent from the preceding one. These emergent properties are due to the specific arrangement an interactions of many parts of an increasingly complex system.

Evolution

The process of change that is transformed life on earth from its earliest forms to the east array of organisms living today

Anecdotal evidence

An assertion based on a single or a few examples that do not support a generalized conclusion

Biosphere

All environments on earth that support life everything from soil to the lower atmosphere

Cells

Smallest unit that can display all characteristics of life.

Genes

Hereditary units of info consisting of specific sequences of DNA passed on from previous generations

Biological system: smallest to largest

Atom → molecules → organelles → cells → tissues → organs → organ systems → organisms → populations → communities → ecosystems → biosphere

Major themes in biology.

1. Relationship of structure and function

2. Info flow

3. Pathways that transform energy and matter

4. Interactions within biological systems

5. Evolution

Matter

Anything that occupies space and has mass

Mass

Measure of the amount of material in an object

Element

Substance that cannot be broken down into other substances by chemical reactions

Trace elements

Required in only small amounts and are essential for life.

Elements combine to…

Form compounds substances that contain 2 or more elements in a fixed ratio

Atom

Smallest unit of matter that still retains the properties of an element

What are the subatomic particles

Protons, neutrons, electrons

Proton

Positively charged

Electron

Negatively charged

Neutron

Electrically neutral; no charge

Atomic number

Same unique number of protons

Atomic mass

Sum of the number of protons and neutrons in its nucleus

Isotopes

Have the same #of protons and behave identically in chemical reactions, but they have dif.. Numbers of neutrons

Radioactive isotope

Nucleus decays spontaneously

Chemical reactions enable

Atoms to transfer or share electrons

Ions

Atoms or molecules that are electrically charged as a result of gaining on losing electrons

Ionic bonds

Formed between oppositely charged ions

Covalent bonds

2 atoms share one or more pair of electrons

Which is the strongest type of bond?

Covalent bonds; hold atoms together in a molecule

Hydrogen bonds

Weak electrically attractions with hydrogen. Ex: H2O

How much of your cells is water?

70 -95%

Characteristics of water

Evaporation cooling/ temperature regulation, ice floats, universal solvent, cohesion, surface tension

Acid

Compound that releases h+ to a solution

Base

Compound that accepts H+ and removes them from the solution

Buffers

Minimize change in pH

When water is a solvent the result is

An aqueous solution

Chemical reactions

Rearranging of matter, No loss or gain

Polar molecules

Different electronegativits

Non-polar molecules

Same electronegativity

Electronegativity

The pull formed between chem. Bonds

Octet rule

The valence (outer) shell must hare 8 electrons

Solvent

Dissolving agent

Solute

The dissolved substance

Organic compounds consist of:

Hydrogen and carbon

How many bonds can carbon have?

4

Functional groups

In an organic compound, the group of atoms directly involved in chemical reactions

Macromolecules are

Polymers

What are the 4 functional groups

Amine, phosphate, carboxyl, hydroxyl

Isomer

Molecules with same molecular formula, but dif. Structure.

4 biological molecules

Complex carbohydrates, lipids, proteins, nucleic acid

Dehydration synthesis

From monomer → polymer, building something up. Water in the product

Hydrolysis

Polymer → monomer, water in the reactant

Carbohydrates

Structure, energy, storage,

Carbs include which elements

Carbon (C), hydrogen ( h), oxygen (o) in a fixed 1:2:1 ratio

Monosaccharides

Monomers of carbs and cannot be broken down into smaller sugars. Ex: glucose

Monosaccharides in water…

Form rings

Disaccharide

Double sugars ex: sucrose

Oligosaccharides

Short chains

Polysaccharides

Complex carbohydrates, long chain ex: starch

Lipids

Diverse function/ energy, hormones; fats, phospholipids, steroids, waxes

Fatty acid

Long hydrocarbon chain w/ a carboxyl group

Fats /

Glycerol with 1,2,3 fatty acids

Phospholipids

Make belayer in aqueous solutions

Steroids

Lipid molecule with no fatty acids

Proteins

Provide structure, support, movement, transportation, and enzymes

Monomers of proteins

Amino acids

4 elements in every protein

Carbon, hydrogen, oxygen, nitrogen

What makes a functional protein

One or more polypeptide chain precisely twisted, folded, and coiled into a molecule with unique shape ; shape determines function

Denatured

Proteins losing their function ; heat, salt, acid

Nucleic acid

Macromolecules that store info and provide instructions for building proteins

The 2 types of Nucleic acid

DNA and RNA

Monomers of nucleic acid

Nucleotides

3 parts of nucleotides

A 5-carbon sugar, phosphate group, nitrogen containing base

Nitrogenous bases in DNA

Adenine, guanine, thymine, cytosine

Nitrogenous bases in RNA

Adenine, guanine, cytosine, uracil