Biology 101 - Exam #1

Atoms

Atoms

Building blocks of all living and non-living things

Molecules

An association of 2 or more atoms

Cells

Smallest unit of life

Organisms

An individual; consists of many cells

Population

All members of a single species within an area

Community

All populations of all species within a given area

Ecosystem

A community interacting with its environment

Biosphere

All ecosystems of earth

Properties of Life: Order

Organisms are complex beings organized into one or more cells

Properties of Life: Homeostasis (Homo: Same; Stasis: Unchanging environment)

Tendency to maintain a stable, constant internal environment (Ex: Body temperature and Osmoregulation)

Properties of Life: Response to Stimulus

Ex: Plant phototaxis (Plants face toward the sun on their own; they are attracted to light)

Properties of Life: Energy Processing

Running metabolic reactions (Ex: Photosynthesis and Respiration)

Properties of Life: Growth and Development

Our genetic code determines how we are put together (Ex: Embryonic Development and Germination)

Properties of Life: Reproduction

Survival and reproduction is the ultimate goal (Pass genetic material from parent to offspring)

Properties of Life: Adaptation

The fit of an organism in relation to it’s environment or ecological niche (Ex: Camouflage and Coloration in butterflies, moths, etc)

Properties of Life: Evolution

Change over time; Descent with modification; based on the pressures of natural selection)

Phylogeny

Evolutionary history of a species or a group of species

Systematics

Study of evolutionary relationships among organisms

Taxonomy

Founded by Carl Linneas, an 1800s scientist. Ranges from broad to specific. Order as follows:

Domain (3; Bacteria, Archaea, Eukarya)

Kingdom

Phylum

Class

Order

Family

Genus

Species

How is the name of a species determined?

Genus species: Scientific name (Ex: Homo Sapiens = Human. Canis Lupus = Wolf. Canis Lupus Familiarus = Domesticated Wolf/Dog)

Basic Science

“Pure Science” ; Seeks to know

Applied Science

“Technology” ; Aims to Solve

What is the story of penicillin?

In 1928, Alexander Fleming left dirty dishes in the sink while on vacation. Penicillin prevented staph bacteria. It was difficult to illustrate. Limited drug development. Until 1943 in Peoria, Illinois, when there was a moldy cantaloupe.

Steps of the Scientific Method

1. Observe some aspect of nature

2. Ask a question

3. Form a hypothesis: testable (potentially falsifiable) explanation of the observation. A good hypothesis has a rich predictive value

4. Make a prediction

5. Test your prediction!

6. Analyze results

7. Hypothesis support or hypothesis not supported?

8. If the hypothesis isn’t supported, return to the “form a hypothesis” step

9. If the hypothesis is supported, publish your results

Scientific Theory

A broad, well supported explanation with rich predictive value. It leads to many accurate predictions. (Ex: Germ Theory)

Scientific Law

A description of an observed phenomenon (Ex: Law of Gravity)

Variable

Something that can be changed or altered for an experiment

Independent Variable

Variable that is manipulated (Ex: Amount of sunlight on a flower)

Dependent Variable

The outcome that is tested for (Ex: Plant growth)

What is the control group used to do?

Make a comparison

Electrons

Negative charge

Protons

Positive Charge

Atomic Number

Number of protons, determines the element

Neutrons

No charge

Atomic Mass

Protons + Neutrons

Isotopes

Forms of an element that differ in the number of neutrons their atoms carry. Has a change in the atomic mass but NOT the charge

Radioactive Isotope

Lose subatomic particles (Ex: Carbon-14. Every 5,730 years, looses ½ life. In 50,000 years it becomes Nitrogen-14)

Where are electrons found?

Traveling around the nucleus in different orbitals (shells)

What is the max number of electrons that can fit in the 1st shell?

2

What is the max number of electrons that can fit in the 2nd shell?

8

What is the max number of electrons that can fit in the 3rd shell?

18 (Typically only holds 8 because of the Octet Rule 2-8-8)

How do atoms get rid of vacancies?

Gaining or losing electrons or by sharing electrons with other atoms

Ions

A charged atom. Atoms carry a charge due to an unequal number of protons and electrons. Negative charge balances a positive charge. Changing the number of electrons may fill the outer-shell, but it changes the charge of the atom. (Ex: Sodium is naturally positive ion, or cation, and Chloride is a negative ion, or anion.) Group 17 will take on an electron, while Group 18 (Noble Gases) is “full” and won’t interact with eachother.

Chemical Bonds

An attractive force that arises between 2 atoms when their elements (electrons) interact

Compound

A type of molecule that has atoms of more than one element

Glucose

C6H12O6

Ionic Bond

A strong mutual attraction formed between ions of opposite charge (Ex: NaCl)

Covalent Bond (More common)

Two atoms sharing a pair of electrons

Equal sharing

Nonpolar-covalent

Unequal sharing

Polar-covalent

Hydrogen Bonds

• A water molecule (H2O) has 2 polar covalent bonds.

• Hydrogen bonds form when a covalently bonded hydrogen atom is attracted to another atom taking part in a separate covalent bond.

• Hydroden bonds form and break more easily than other bonds.

• DNA is held together by hydrogen bonds

• H2O is polar covalent

• Interactions between H2O molecules = hydrogen bond

Unique properties of water

• Capacity to dissolve many substances

• Polar H2O molecules hydrogen-bond to other polar (hydrophilic) substances and repel nonpolar (hydrophobic) substances

• Hydrophilic substances dissolve easily in H2O

• Hydrophobic substances resist dissolving in water

• Water is excellent solvent for salts, sugars, and other polar molecules

• Temperature Stability

• Important for Homeostasis

• Water absorbs more heat than other liquids before temperature rises (Temperature = a measure of molecular motion)

• H-bonds hold ice together in a rigid pattern that makes ice float

• Evaporation - Transition of liquid to gas, absorbs heat energy

• Boiling point → evaporation

• Movement of molecules = kinetic

• Cohesion

• Surface Tension- Property that helps to sustain multi celled bodies and resist evaporation

• Cohesion - Tendency of water molecules to stick together

Acids and bases

Water molecules seperate into hydrogen ions (H+ and OH-)

PH

Measure of hydrogen ions (H+) in solution

The more H+ ions…

Lower PH (PH<7) More acidic

PH of water

Neutral; 7

Carbonic Acid

H2CO3

Bicarbonate

HCO3 (basic)

Organic Molecules

• Molecules of life- Carbohydrates, proteins, lipids, and nucleic acids

• Consist primarily of carbon and hydrogen atoms

• Carbon atoms bond covalently with up to 4 other atoms (can form rings or long chains)

• Macromolecules

• Biomolecules

Enzyme

Driven reactions construct large molecules into smaller ones

Metabolism

All enzyme-mediated chemical reactions by which cells acquire and use energy in processing molecules

Monomers

building blocks = subunits of polymers

Polymers

Macromolecules = Molecules of multiple monomers

Condensation Reactions

• “Water forms”

• Building large molecules from smaller subunits

Hydrolysis Reactions

• “Water is used”

• Break large molecule into smaller subunits

Carbohydrates

• Consist primarily of carbon, hydrogen, oxygen atoms (1:2:1 ratio)

• Cells use carbohydrates for energy and structural materials

• The principle source of energy for most organisms

Simple carbohydrates

Monosaccharides or sugar

Complex Carbohydrates

Polysaccharides

Monosaccharides

• Fructose

• Galactose

• Glucose (Glucose monomers can bond in different patterns to form complex carbohydrates)

Polysaccharides

• Starch (Main energy reserve in plants)

• Glycogen (Energy reserve in animals)

• Cellulose (Structural Component in plants)

Lipids

• Consist primarily of carbon, hydrogen, oxygen atoms (many more hydrogen atoms and many fewer oxygen atoms)

• Greasy/oily nonpolar organic molecules, often have one or more fatty acid tails

• Store large amounts of energy

• Fatty acid = monomer = long chain of carbon atoms with an acidic carboxyl group at one end

• Fat = lipid with 1, 2, 3 fatty acid tails

Triglyceride

3 fatty acid tails attached to a glycerol backbone

Saturated fat

Fatty acid, no double bonds in fatty acid tail (Ex: Animal fats)

Unsaturated Fat

One or more double bonds in fatty acid tail (Ex: Veg. oils)

Phospholipid

Lipid with phosphate group in its hydrophilic head and 2 nonpolar (hydrophobic) fatty acid tails

Wax

Water repellent lipid (long fatty acid tails) bonded to long-chain alcohols or carbon rings. Water repellent and lubricating secretions in plants and animals (Ex: Surfaces of feathers, fur, leaves, fruit)

Steroids

Lipid with 4 carbon rings and no fatty acid tails

Examples of lipids

• Hormones

• Testosterone

• Estradiol

• Bile salts

Proteins

• Organic compound that consists of one or more chains of amino acids (20 kinds)

• Diverse group of molecules (thousands of types in any given cell)

• Contain carbon, hydrogen, oxygen, nitrogen, and sulfur

• Exs: Enzymes, muscle fibers, some antibodies, some hormones, structural proteins (keratin, collagen)

• Amino acids are linked into chains by peptide bonds

Peptide bonds

Bond between the amine group of one amino acid and the carboxyl group of another

Polypeptide

Chain of amino acids linked by peptide bonds

Protein structure

• Changing the shape permanently alters the bond (and protein function)

• A proteins function depends on its structure, which consists of chains of amino acids that twist and fold into functional shapes

Nucleic Acids

• Nucleotide = monomer (building blocks) of nucleic acids

• DNA, RNA, coenzymes, energy carriers (ATP) messenger

• Deoxyribonucleic acid (DNA) carries hereditary material (double strand)

• Ribonucleic Acid (RNA) functions in protein synthesis (single strand)

What monomer makes up proteins?

Amino acids

Protein Structure: Primary

Sequence of a chain of amino acids

Protein Structure: Secondary

Local folding of the polypeptide chain into helices or sheets

Protein Structure: Tertiary

Three-dimensional folding pattern of a protein due to side chain interactions

Protein Structure: Quaternary

Protein consisting of more than one amino acid chain

Denatured

When a protein looses its shape, therefore loosing its function (Ex: frying/scrambling egg, the runny part becomes solid and opaque after cooking it). Cooler temperature does not typically denature, but hotter does. PH level can also denature a protein (really acidic or really basic)

What bases make up DNA

ATGC

What bases make up RNA

AUGC

What is the structure of DNA and RNA

• Sugar = Deoxyribose (Ribose for RNA) and Phosphate Group

• Nucleotide base

• This structure is repeated over and over

Tissue

Many cells interconnected and share a common function

Cell Theory

• Proposed in 1839

  1. The cell is the basic unit of life (structure and organization)

  2. All living things are made of one or more cells

  3. New cells arise from pre-existing cells

Light microscope

Most commonly used to view living and or stained cells

Electron microscopes

Use a beam of electrons for illumination (higher magnification)

Why is there no human sized bacteria?

• Ratio between surface area and volume [SA:V]

• More SA:V (Less volume) → More efficient

• Less SA:V (More volume) → Less efficient

• Volume increases at a much faster rate than surface area

• As cell size increases, the SA:V ratio decreases

• Materials are no longer able to efficiently pass in/out of the cell

How can cells maintain efficiency

• By becoming multicellular

• Spreading out the functions between all cells in an organism

• Can get big and remain efficient

What are considered Eukaryotes

Everything else (Plant cells, Animal Cells)

What are considered Prokaryotes

Bacteria and Archaea