Science SOL Review

cell membrane

-flexible and allows cell to change shape

-boundary of a cell

-semipermeable

-controls which molecules enter (food oxygen) and leave (water and waste)

cell wall

-outer covering found only in plants

-thicker than membrane and gives shape and support

cytoplasm

-clear gel-like fluid where organelles are found

-place where life processes occur

vacuole

-storage for water and other substances

-one large in plant and multiple small ones in animal

nucleus

-largest organelle in a cell "the brain"

-contains necessary information to control the functions of a cell (DNA)

mitochondria

-organelle that uses oxygen to release energy from food molecules during respiration in both plants and animals

chloroplast

-found only in plants that are exposed to light and contains green chlorophyll which transforms energy from sunlight to make food during photosynthesis

Van Leeuwenhoek

invented the first simple microscope

The Cell Theory

1. All organisms are made up of one or more cells

2. A cell is the basic unit of life that can perform the processes necessary for life

3. All cells come from cells that already exist

Cell Cycle phases

interphase, mitosis, cytokinesis

Interphase

Phase were cell grows and carries out life functions. Changes in this phases prepares it or cell division.

Mitosis

Prophase, metaphase, anaphase, and telophase. Result is each new cell produced has the same number and type of chromosomes as the parent cell

Cytokinesis

Daughter cells are separated and each is surrounded by membranes. The new daughter cells later enter phases and repeat the cell cycle.

Meiosis

produces sex cells. Cells resulting from meisosis have only half the number of chromosomes body cells have (one of each original pair).

Levels of Organization in an Organism

cell, tissue, organ, system, organism

Passive transport

cell does not use energy to move molecules from areas of high concentration to lower concentration. movement of molecules do not stop even after equilibrium.

osmosis

passive transport of water molecules through a cell membrane

diffusion

passive transport of substances other than water

Active transport

movement of molecules from area of low concentration to high concentration and uses energy to move substances across the membrane.

Chromosomes

Found in the nucleus of a cell and are made of toightly wound strands of DNA

Allele

Code to produce a particular form of a trait (a variation of a gene). One allele can mask another variation of the same trait (dominant and recessive)

Genotype

genetic make up of the organism

Phenotype

the visible trait

Rosalind Franklin

helped discover the structure of DNA

Watson and Crick

Constructed a double helix model of DNA and received the Nobel Prize

Fossils

Older rock layers are deeper in earth's crusts therefore contain older fossils.

Prokaryotic

Organisms that have no nucleus

Eukaryotic

Organisms with a nucleus

Biological Classification

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

Domains

Archae, Bacteria, Eukarya

Eukarya

Protista, Fungi, Animalia, Plantae

Binomial Nomenclature

two-part naming system for sceinctific names that combines the genus and species.

Carbon Cycle

Carbon used by plants to perform photosynthesis. This carbon is then consumed through the plants by animals who later cycle it back into the air through respiration. When organisms die decomposers break down the carbon containing matter and carbon dioxide is also released into the air for later use by green plants.

Symbiosis

relationships between two or more different species

Mutualism

no organisms are harmed

Commensalism

one organism is not harmed while the other benefits

Parasitism

one benefits and the other is harmed

Succession

the gradual replacement o one community by another as environmental conditions change.

Primary Succession

begins when living thing move into a barren environment (no soil. usually scoured by glacier or destroyed by lavel from a volcano) and overtime the community becomes stable.

Secondary succession

Takes place after a community is destroyed by a natural disaster and soil remains.

Eutrophication

When water becomes so depleted of oxygen it can no longer support plant or animal life. Begins when excess nutrients are brought in causing an abundant growth of algae. Algae uses all the oxygen and cover all the sunlight.

Why is water a universal solvent?

a large number of substances are able to dissolve in water due to its polar nature

Turbidity

the amount of particles found in he water

wetlands

wetlands improve water quality by absorbing and storing floodwaters and slowing down runoff which prevents erosion. Also filters sediments, trap nutrients, break down pollutants, and refill groundwater supplies.

Tributaries

small streams that join river systems alon ght eway

Six largest rivers in the Cheapeake Bay Watershed

Susquehana, Potomac, James, Appomattox, Rappahannock, and Patuxent

Atoms move faster at

higher temperature

Acids

acids produce hydrogen ions when dissolved in water. They taste sour and can conduct electricity. Less than 7 on the pH scale

Bases

Produce hydroxide ions in solution. They taste bitter and conduct electricity. Greater than seven on the pH scale

Neutralization

When a acid reacts with a base and produces an ionic compound: NaCl (Salt) and water

Physical Property

any characteristic that can be observed without changing the identity of the material. Ex. shape, density, solubility, boiling point, melting point, odor, and color

characteristic property

unique to the substance and can be used to identify an unknown sample of matter. Same no matter the size of the sample

Chemical property

a substance's ability to be involved in a chemical reaction to produces a new substance and undergo a chemical change. Ex. Combustibility, reactivity, acidity, basicity

Dalton

Found that all atoms in a given element are exactly alike. Different elements have different atomic weight.

Thompson

discovered small particiles exist inside an atom and found negatively charged electrons.

Rutherford

Atom has a central positive nucleus surrounded by negative orbiting electrons. Most of the atom was empty space.

Bohr

Electrons travel outside the atoms nucleus in fixed pathways

Schrodinger and Heisenburg

Electrons travel in an electron cloud

Isotopes

difference in neutrons

ion

difference in electron

covalent bond

a reaction between two nonmetals where elctrons are shared

ionic bond

reaction between nonmetal and metal. Electrons are transferred from one atom to another.

Physical change

change in appearance only

chemical change

new substances are formed

exothermic reaction

energy is released

endothermic reaction

requires energy to be put in. this reaction results in a decrease in temperature (medical cold packs!)

Nuclear fission

process when the large nucleus of an element splits into two smaller nuclei and energy is released

nuclear fusion

two or more nuclei that have small masses combine to form a larger nucleus

Kelvin

zero degrees kelvin is the temperature at which there is no molecular movement. also known as absolute zero

conduction

the transfer of thermal energy from warmer matter to colder matter with direct contact. Ex. a put in contact with a hot stove gets hot

convection

the transfer of thermal energy by the movement of molecules within a fluid (liquid or gas). The hot air rises and the cold sinks because of the different densities. Circular patterns of this movement are called concvection currents.

Radiation

transmission of energy in the form of electromagnetic radiation Ex. Sun gives radiation to the earth

Interference

the addition of two or more waves which results in a new wave pattern. Can be constructive or destructive

Refraction

when a wave passes through a substance which causes it to change direction or speed

Longitudinal Wave

Sound waves! Has compressions and rarefactions. The amplitude of a longitudinal wave is the largest distance the particles vibrate from their rest positions.

Transverse Waves

Light waves! transmits energy through space

Insulator

a nononductor

semiconductors

they are neither good conductors nor good insulators

Electromagnet

created when there is a magnetic field around a wire containing moving electric charges.

Motor

Transforms electrical energy into mechanical energy

Generator

transforms mechanical energy into electrical energy

Climate

a long term weather pattern

Convection currents

the rising of warm air and falling of cool air

Hurricanes

form over warnm tropical water. Convection plays a key role in the formation of severe thunderstorms.

Warm Front

a boundary formed when warm air replaces cold air. This results in long periods of precipitation and formation of clouds

Cold Front

boundary between air masses when cold air replaces warm air and results in much heavier precipitation than warm fronts

occluded front

formed when a storm reaches its later stages and the storm begins to weaken.

Stationary front

does not move. Bounday between to different air masses which neither is strong enough to replace th other. Results in cloudy wet weather.

Cloud Formation

Warm air rises and releases thermal energy as it cools. when it reaches saturation point vapor condenses around particles in the air and tiny droplets form.