Biology

Biology

science of life

Deductive reasoning

applies general principles to predict specific results

• takes big ideas and deducts it to get results

• ex. all mammals have hair, ants don’t have hair, so ants aren’t mammals

Inductive reasoning

specific observations are used to construct general principles

• small evidence that infers a principle

• ex. terrier, poodle, lab has hair so conclude all dogs have hair

Scientific Method Steps

1. observation

2. question

3. hypothesis

4. experiment

5. conclusion

Experimental group

group that differs by 1 key factor

Control group

group compared to the experimental group

Independent variables

factor that differs or is changed in the experimental group

Dependent variables

factor that will change because of the independent variable

Controlled variable

factors that remain the same with both groups

Atomic number

number of protons in a nucleus

Atomic mass

protons and neutrons combined measured in amu which is the weighted average of isotopes

Isotopes

atoms of the same element but different masses

Radioactive isotopes

unstable nuclei of isotope because of an incorrect balance of protons and neutrons

Half-life

rate of decay or release of neutron

used to identify age of objects

Electrons

give elements their chemical properties

can be shared, lost, or gained

usually the number of electrons = protons

Ions

electrically charged atom

Cation

positive charged ion

• more protons than electrons

• caused by loss of electron

Anion

negatively charged ion

• more electrons than protons

• caused by a gain of electrons

Oxidation reaction

loss of electrons

Reduction reaction

gain of electrons

Ionic Bond

ionizes elements where charges are opposite and the same magnitude

force of attraction between 2 opposite charges

elements on opposite sides of table

NaF, NaCl, KCl

Covalent Bond

strong, sharing of electrons

O=O, H-H, N-=N

Nonpolar Covalent Bond

electrons are shared equally

C-H or anything bound to itself

Polar Covalent

electrons are shared unequally

O-H, N-H, S-H

Hydrogen Bond

weak force of attraction between 2 opposite partial charges of oxygen on one molecule to hydrogen on another

Adhesion

water adheres to items, climb up items

binding of unlike molecule

capillary action of water transport in plants

transport H2O against force of gravity

Cohesion

water binds to water itself

creates water tension

why water is liquid at moderate temps

Specific heat

water has a high specific heat

• how much energy is needed to raise 1g of substance 1 degree C

• more polar = higher specific heat

• need to break H-bonds to raise temp

helps organisms maintain constant temp

High heat of vaporization

heat of vaporization - energy needed to change substance from liquid to gas

H bonds need to broken

Cools surrounding surface - sweating cools the body

Density of solid water

ice is less dense than liquid water

ice floats - water reaches maximum density at 4 degrees Celsius, H bonds space water molecules farther apart

Solvent

substances that dissolve another (H2O)

Solute

substance that gets dissolved (Kool-Aid)

Solubility

polar and ionic compounds dissolve easily in water

like dissolves like - substance with similar properties will dissolve well with like substances (polar with polar)

Hydrophobic

water fearing

• nonpolar molecules

• fats and oils

• clump together to get away from water

Hydrophilic

water loving

• polar molecules

• H-bonds form between substance and water

Acid

higher concentration of H+ ions (lower pH)

Basic

lower concentration of H+ ions (higher pH)

Buffers

help resist the changes in pH

contains pairs of substances - one acid, one basic

ex. carbonic acid/bicarbonate

Ecosystems

all organisms that live in a particular place plus the abiotic environment in which they live/interact

Biogeochemical cycles

chemicals moving through ecosystems

biotic and abiotic processes

Carbon cycle

major constituent of the bodies of organisms

aerobic cellular respiration releases CO2

Carbon Fixation (photosynthesis)

metabolic reactions that make nongaseous compounds from gaseous ones

Methanogens

produce methane by anaerobic cellular respiration

Greenhouse gasses

CO2, H2O, CH4

absorb infrared radiation emitted by Earth

re-emit radiation in all directions (back to Earth)

Earth temp rises

Earth would be cold at night without it

Water cycle

all life depends on the presence of water

60% of adult human weight is water

amount of water available determines the nature/abundance of organisms present

can be synthesized and broken down

• synthesized during cellular respiration

• broken down during photosynthesis

Ocean Acidification

bridge of water and carbon cycle

carbonic acid/bicarbonate get into water

lowers pH of ocean systems making them acidic

shelled organisms breakdown shells

Basic water cycle

liquid water evaporates from surface into atmosphere

• also evaporated by plants

water in atmosphere is a gas and cools and falls to surface as precipitation

Transpiration

water loss through plant’s stomata

Percolation

water goes through rocks/ground and creates groundwater

Aquifers

permeable, underground layers of rocks, sand, and gravel saturated with water

95% of fresh water in US

two subparts:

1. upper layers constitute water table

2. lower layer can be tapped by wells

Nitrogen cycle

nitrogen is a component of all proteins and nucleic acids

uses the element in shortest supply

nitrogen in atmosphere cannot be uses

can use NH3 and NO-3

nitrogenous wastes and fertilizer us radically alters global nitrogen cycle

humans have doubled rate of transfer of N2 in usable forms into soil and H2O

Phosphorus Cycle

required by all organisms

• occurs in nucleic acids, membranes, ATP

exists as inorganic phosphate

plants and algae use free inorganic phosphorus, animals eat plants to obtain their phosphorus

Weathering

phosphates stuck in rock become soluble by rain and goes into river, soil, lakes, ponds

Carboxyl

acid functional group

Amino

base functional group

Polymer Macromolecules

made of repeating units called monomers

Dehydration Synthesis (condensation)

building of polymer from monomer subunits

done by removing H2O molecule

forming polymer requires release of water

Hydrolysis

breaking polymer into monomer

done by inserting water molecule

Carbohydrates

monosaccharides are monomer subunits

all have a C:H:O ratio of 1:2:1

Disaccharides

2 monosaccharides

Ex. sucrose, maltose

Oligosaccharides

few monosaccharides (less than 20)

Polysaccharides

many monosaccharides

ex. starches, cellulose, chitin

Nucleic acids

monomer subunits are nucleotides

Nucleotide

consists of 5 carbon sugar, phosphate, nitrogenous base and carbohydrate inside the structure

Proteins

amino acids are monomer subunits

Amino acids

will ionize in water, backbone has nothing to do with properties

polar group in amino acid is dominant

Peptide bonds

joined through condensation reaction

bond between 2 or more amino acids

Intramolecular bond

within 1 protein structure

Primary protein structure

number and sequence of amino acids in a chain

Secondary protein structure

alpha-helix and beta plated sheets

Tertiary protein structure

primary and secondary structures put into a 3D showing

Quaternary protein structure

protein forms bond with other proteins

2 or more tertiary proteins bonded together

Intermolecular bonds

bonds that are between proteins

Protein function

determined by it’s structure and if misshaped it will not function correctly

• incorrect amino acid sequence

• wrong environmental conditions

Denatured

protein that has been damaged, unfolded, and doesn’t work

could be due to an H+ ion bonding to protein or raise in temperature

Functions of proteins

enzyme catalyst, defense, transport, support, motion, regulation, and storage

Saturated fatty acids

organized and can be solid at room temperature

all single bonds

animal fats and considered bad

Unsaturated fatty acid

liquid at room temperature

have one or more double bonds

plant fat like oil or fish and considered good

Amphipathic

2 sides; one nonpolar hydrophobic (tail) and one polar hydrophilic (head)

Lipids in water

micelle (come together to form a ball like shape)

form phospholipid bilayer

Phospholipid bilayer

2 layers

main separating layer from inside and outside the cell

1. nonpolar

2. fluid-mosaic

3. selectively permeable

Transmembrane protein

transport across membrane

cell communication

enzymes

Interior protein network (peripheral protein)

provide shape

works with cytoskeleton to move cell

Polysaccharides in phospholipid bilayer

help cells stick together

Oligosaccharides in phospholipid bilayer

act as cell identity markers

Cholesterol in phospholipid bilayer

help support and give structure to bilayer

hydrophobic

make cell membrane more flexible when cold and more rigid when warm

Simple Diffusion

passive transport - stuff easily passes through membrane

high to low concentration

small, non polar molecules

ex. oxygen, CO2, and steroids

Facilitated Diffusion

passive transport - transport things that cannot go easily through membrane

high to low concentration

larger items and ions

need use of proteins - channels and transport proteins

Osmosis

movement of water through a semipermeable membrane

passive transport

facilitated transport

• protein is called aquaporin

• some of the membrane is “leaky”

Hypotonic

lower solute concentration as the cell

i.e. higher water amount

Hypertonic

higher solute concentration as the cell

i.e. lower water amount

Isotonic

same solute concentration as the cell

Active Transport

low to high concentration

requires energy

requires protein

ex. Na+/K+ pump

Coupled transport (secondary active transport)

use stored energy in concentration to move other molecules against their concentration

Endocytosis

bring something into the cell

cell eating (taking in big substance) = phagocytosis

form of active transport

Exocytosis

release something from the cell

Why are cells so small

cells need to interact with their environment

surface area to volume ratio

• if too small cell cannot interact with environment

• the bigger the cell, the smaller the ratio

All Cells contain

genetic material, plasma membrane, and cytoplasm

Nucleoid

not membrane-bound, circular chromosomes, usually 1

prokaryotic (mostly bacteria)

Nucleus

membrane-bound, linear chromosomes, multiple chromosomes

eukaryotic (everything but bacteria)