WEST-E Science Certification Test Study Guide
Terms in this set (81)
Within an atom there are two regions, the nucleus and outer region. Which holds the protons, neutrons, and electrons?
Nucleus: protons and neutrons.
Outer region: electrons.
What does the atomic number and mass number mean?
Atomic number: # of protons
Mass number: sum of # of protons and neutrons.
Define electromagnetic forces
oppositely charged particles attracting each other.
What is the difference between a mixture and a solution?
Mixture: two or more substances that are not chemically combined.
Solution: mixture that appears to be a single substance.
Examples of physical and chemical properties of matter
Physical: color, density, volume, mass, boiling point nd melting point.
Chemical: heat of combustion, chemical stability, flammability, and oxidation state.
Four types of chemical bonds
Covalent: two atoms with small differences in electronegativity.
Polar covalent: fall between ionic and covalent bonds.
Ionic: two atoms with large difference in electronegativity.
Hydrogen: only form between H and O,N, or S
What does left to right on the periodic table mean?
What does bottom to top on the periodic table mean?
Example of physical and chemical changes in matter
o Chemical: production of one or more new substances.
Ex. Iron rusting: iron oxide forms.
o Physical: ex. Melting a sugar cube is physical change because the substance is still sugar.
Define radioactivity and radioactive decay.
Radioactivity: particles are emitted from nuclei as a result of nuclear radiation.
Radioactive decay: spontaneous breakdown of an atomic nucleus resulting in the release of energy and matter from the nucleus.
Law of Conservation
o The law of conservation of mass or principle of mass conservation states that for any system closed to all transfers of matter and energy, the mass of the system must remain constant over time, as system mass cannot change quantity if it is not added or removed. Hence, the quantity of mass is "conserved" over time.
Common ion effect
decrease in solubility of an ionic compound when a salt that contains an ion that already exists in the chemical equilibrium is added to the mixture.
Factors that affect reaction rate of chemical reactions
- the reaction rate usually increases as the concentration of the reactants increases.
- Increasing the temperature of a system increases the average kinetic energy of its constituent particles. As the average kinetic energy increases, the particles move faster and collide more frequently per unit time and possess greater energy when they collide.
- A catalyst is a substance that participates in a chemical reaction and increases the reaction rate without undergoing a net chemical change itself.
Characteristics of a system that is at equilbrium
the rate of the forward reaction equals the rate of the reverse reaction, such that the concentrations of reactants and products remain fairly stable, in a chemical reaction.
First and second law of thermodynamics
o The first law, also known as Law of Conservation of Energy, states that energy cannot be created or destroyed in an isolated system.
o The second law of thermodynamics states that the entropy of any isolated system always increases.
Newton's 3 Laws of Motion
♣ 1. Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it.
♣ 2. The relationship between an object's mass m, its acceleration a, and the applied force F is F = ma. Acceleration and force are vectors (as indicated by their symbols being displayed in slant bold font); in this law the direction of the force vector is the same as the direction of the acceleration vector.
♣ 3. For every action there is an equal and opposite reaction.
Newton's Law of Gravitation
♣ Newton's law of universal gravitation states that any two bodies in the universe attract each other with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.
Three forces that can act on an object in any given situation
o Normal: the support force exerted upon an object that is in contact with another stable object.
o Gravity: the force with which the earth, moon, or other massively large objects attracts another object toward itself.
o Friction: force exerted by a surface as an object moves across it or makes an effort to move across it.
o Work: energy that is transferred by a force that moves an object a certain distance.
♣ W = force x distance moved.
o Power: rate of work performed over time.
♣ P = work/time
o Efficiency: e = work out/work in x100%
o quantity that measures how much a machine multiplies that force or distance.
♣ F out/F in = d in/ d out.
Three different types of waves
o Longitudinal wave*s - Movement of the particles are parallel to the motion of the energy. Sound waves moving through the air is an example of this type of wave.
o Transverse wave*s - movement of the particles are at right angles (perpendicular) to the motion of the energy. Movement of a wave through a solid object like a stretched rope or a trampoline is an example of this type of wave.
o Surface wave*s - particles travel in a circular motion. These waves occur at interfaces. Examples include waves in the ocean and ripples in a cup of water. One consequence of occurring at an interface is that the motion of the particles diminish with distance from the interface. The further from the interface the smaller the rotation of the particles until as some distance from the surface, there is no more movement or energy propagation.
Define reflection, diffraction, and refraction
Reflection: incident light hits an object and reflects almost all the incident light.
Diffraction: bending and spreading of waves around an obstacle.
Refraction: light waves change direction as they pass from one medium to another.
o the force on a charged point exerted by a second charge is proportional to the product of charges, and inversely proportional to the square of distance between the charges, and acts either directly towards each other or away from each other.
Define parallel and series circuits
o A circuit composed solely of components connected in series is known as a series circuit; likewise, one connected completely in parallel is known as a parallel circuit.
Contemporary theories of the origin and evolution of the solar system
nebular hypothesis, maintains that 4.6 billion years ago, the Solar System formed from the gravitational collapse of a giant molecular cloud which was light years across. Several stars, including the Sun, formed within the collapsing cloud. The gas that formed the Solar System was slightly more massive than the Sun itself. Most of the mass collected in the centre, forming the Sun; the rest of the mass flattened into a protoplanetary disc, out of which the planets and other bodies in the Solar System formed.
Effects of gravity on objects in the solar system
o Gravity holds all the planets and other objects in place.
What is a solar eclipse?
Moon passes between the Earth and sun.
What are the 5 stages of the water cycle?
1. Evaporation is the transfer of water from bodies of surface water into the atmosphere.
2. Condensation is the transformation of water vapor to liquid water droplets in the air, producing clouds and fog.
3. Advection is the movement of water—in solid, liquid, or vapor states—through the atmosphere.
4. Precipitation is water vapor that has condensed into clouds and falls to the Earth's surface. This mostly occurs as rainfall, but also includes snow, hail, fog drip, and sleet.
5. Runoff includes the variety of ways by which water moves across the land.
Define waves, tides, and currents.
1. Waves caused by underwater disturbances such as earthquakes, landslides, or volcanic eruptions are called tsunamis.
2. The ocean's surface rises and falls predictably due to changes in gravitational forces originating from the Moon and the Sun.
3. An ocean current is a continuous, directed movement of seawater generated by forces acting upon this mean flow, such as breaking waves, wind, the Coriolis effect, cabbeling, temperature and salinity differences, while tides are caused by the gravitational pull of the Sun and Moon.
Four different layers of the earth's atmosphere
o Troposphere: closest to Earth's atmosphere and contains 74% of atmosphere's mass.
o Stratosphere: layer directly above troposphere and 35 km deep.
Warmer at the top than at the bottom.
Ozone layer: thin layer of ozone molecules in the stratosphere.
Directly above the stratosphere extending from 50-80 km above the Earth's surface.
Extends 80 km above the earths surface to outer space.
Cause of global climate changes
o Carbon pollution is the main reason our planet is getting hotter, increasing the chances of weather disasters, drought and flood and hurting our health.
Structure an composition of the earth
Define the layers in the crust and what they're made out of.
♣ The thin oceanic crust is composed of primarily of basalt and the thicker continental crust is composed primarily of granite.
Define the two zones of the core.
♣ The outer core is a liquid because the temperatures there are adequate to melt the iron-nickel alloy.
♣ However, the inner core is a solid even though its temperature is higher than the outer core
Define igneous, metamorphic, and sedimentary rocks.
o Igneous rocks are crystalline solids which form directly from the cooling of magma.
o Sedimentary rocks are called secondary, because they are often the result of the accumulation of small pieces broken off of pre-existing rocks.
- Any rock can become a metamorphic rock.
♣ Quartz, Feldspar, Mica, Pyroxene, Amphibole, Olivine.
♣ Calcite, Clays, Magnetite, Pyrite.
How can you distinguish minerals?
These include features such as crystal form, hardness(relative to a steel blade or you finger nail), colour, lustre, and streak (the colour when a mineral is ground to a powder).
Processes and consequences of weathering and erosion.
o Weathering is the breakdown and alteration of rocks and minerals at or near the Earth's surface into products that are more in equilibrium with the conditions found in this environment.
o Soil erosion is perceived as a major and widespread form of soil degradation and it has large environmental and economic impacts at different scales, especially in agricultural areas.
Three tenets to the cell theory
♣ All living organisms are composed of one or more cells.
♣ The cell is the basic unit of structure and organization in organisms.
♣ Cells come from preexisting cells.
Differences between prokaryotic and eukaryotic cells.
o Eukaryotic cells contain membrane-bound organelles, such as the nucleus, while prokaryotic cells do not.
o Differences in cellular structure of prokaryotes and eukaryotes include the presence of mitochondria and chloroplasts, the cell wall, and the structure of chromosomal DNA.
Function of specialized cells in animals.
♣ RBCs, nerve cells, reproductive cells,
Function of specialized cells in plants.
♣ Root hair cells (absorb water and minerals)
♣ Leaf cells (absorb sunlight for photosynthesis)
4 building blocks of life
carbohydrates, fats, proteins, and nucleic acids
Basic chemical processes of a cell
o Chemical bonds in the reacting molecules are broken; this takes in energy
o New chemical bonds form to make the products; this gives out energy
Phases of mitosis
- Prophase: the complex of DNA and proteins contained in the nucleus, known as chromatin, condenses.
- Metaphase: pair of chromosomes line up in the middle.
- Anaphase: the chromosomes separate.
Telophase: the process that separates the duplicated genetic material carried in the nucleus of a parent cell into two identical daughter cells.
Difference between mitosis and meiosis
Mitosis: chromosomes of parent cell are duplicated and equally distributed into two daughter cells.
Meiosis: One diploid (2n) cell divide in a special way to generate haploid cells (n).
o process used by plants and other organisms to convert light energy, normally from the Sun, into chemical energy that can be later released to fuel the organisms' activities (energy transformation).
Define cellular respiration
o Cellular respiration is the process of oxidizing food molecules, like glucose, to carbon dioxide and water. C6H12O6 + 6O2 + 6H2O → 12H2O + 6 CO2. The energy released is trapped in the form of ATP for use by all the energy-consuming activities of the cell.
Order of taxonomic groups
o Domain, kingdom, phylum, class, order, family, genus, species.
Three domains that all living things are categorized in
Bacteria, archaea, eukaryotes.
Life cycles strategies of plant, fungi, and animals
Animal: gametic life cycle
Fungi: zygotic life cycle
Plant: sporic life cycle.
Systems within a plant
♣ Root system: underground, anchors the plant in the soil, absorbs water and nutrients, food storage.
♣ Shoot System: above ground, elevates plant above soil, photosynthesis, reproduction, food and water conduction.
Systems within an animal
♣ Control systems: coordinating and synchronizing the functions of their millions of individual cells.
♣ Nervous system, circulatory system, immune, respiratory, digestive, excretory, reproductive.
Explain the components of the circulatory system
consists of the heart, blood, and blood vessels. There are three types of blood vessels: arteries, veins and capillaries.
How does the nervous system work?
o The nervous system responds to stimuli by sending electrical action potentials along neurons, which in turn transmit these action potentials to their target cells using neurotransmitters, the chemical messenger of the nervous system. This response to stimuli is near instantaneous.
Define the main function of the endocrine system
o Endocrine system brings about longer-term adaptations by sending out chemical messengers (hormones) into the bloodstream.
What do the nervous and endocrine systems work together to achieve?
Functions of the skeletal system.
The most basic function of the skeletal system is to support and provide structure for the body.
o A second major function of the skeletal system is to provide protection for vital organs like the brain, heart and lungs, which are protected by the skull and rib cage.
Function of digestive system
to break down our food into small particles so they are able to diffuse into our cells easily.
Function of excretory system
way for humans to get rid of chemical wastes, which plays a role in maintaining homeostasis.
What are the two levels of immunity?
Specific and non-specific immunity.
Non-specific: innate immunity - human body protects itself against foreign materials.
Specific: allows for a targeted response against a specific response.
Define mRNA, rRNA, tRNA
♣ mRNA: carries DNA's message out of the nucleus to the ribosomes in the cytoplasm.
♣ rRNA: helps in protein synthesis by decoding mRNA into amino acids.
♣ tRNA: delivers individual amino acids to the ribosomes during protein synthesis.
o segments of DNA encoding information that direct the production of RNA molecules.
What are the components of genes?
♣ Contains introns that are spliced out before RNA is translated into protein.
♣ Flanking regions: plays role in regulation of gene expression.
Disadvantage of asexual compared to sexual reproduction
Asexual has no variation. Whatever the parent has, the offspring will have as well.
Processes that contribute to genetic variability
♣ Meiosis produces haploid gametes that are genetically different. This is due to two processes: independent assortment and crossover.
♣ Essentially, these processes shuffle alleles during gamete formation and create genetic variation. In addition, sexual reproduction randomly combines gametes from two different parents.
o Crossing Over:
♣ Chromosomal crossover (or crossing over) is the exchange of genetic material between homologous chromosomes that results in recombinant chromosomes during sexual reproduction.
♣ Changes in DNA. A single mutation can have a large effect, but in many cases, evolutionary change is based on the accumulation of many mutations.
Principle of segregation
♣ during reproduction, alleles are separated in reproductive cells through meiosis and randomly reunite during fertilization.
Principle of independent assortment
♣ genes located on different chromosomes will be inherited independently of each other.
Define gene flow
any movement of genes from one population to another and an important source of genetic variation and evolutionary change.
o differential survival and reproduction of individuals due to difference in phenotype.
♣ Key mechanism of evolution, the change in heritable traits of a population over time.
♣ Certain traits will be more ideal for certain environments which will lead to the survival of the fittest.
o feature that is common in a population because it provides some improved function.
♣ Well fitted to their function and are produced by natural selection.
• Many different forms: behaviors, proteins, anatomical feature.
Difference between biotic and abiotic
o Biotic: living parts of an ecosystem: animals, plants, microorganisms.
o Abiotic: non living parts of ecosystem.
Factors that affect evolution of species
♣ Migration is the movement of populations, groups or individuals. In genetic terms, migration enables gene flow: the movement of genes from one population into another.
♣ Scientists think that geographic isolation is a common way for the process of speciation to begin: rivers change course, mountains rise, continents drift, organisms migrate, and what was once a continuous population is divided into two or more smaller populations.
♣ Speciation: the evolutionary process by which reproductively isolated biological populations evolve to become distinct species.
♣ Genetic mutations:
• Mutations are essential to evolution; they are the raw material of genetic variation. Without mutation, evolution could not occur.
• If hybrids are less fit, the geographical range of ecologically divergent populations may be limited, and prezygotic reproductive isolation may be reinforced.
Biotic and abiotic factors that affect the growth of organisms living in different types of ecosystems.
o Abiotic factors: light availability, water availability, nutrient availability, temperature.
o Biotic factors: competition (two animals fight for same resources), predation, mutualism (two organisms benefiting from each other), parasitism, commensalism.
Flow of energy and cycling within an ecosystem (different trophic levels)
1st: primary producers use solar energy to produce organic material through photosynthesis.
2nd: herbivores that feed slowly on plants
3rd: predators that feed on herbivores.
Decomposers break down wastes and dead organisms and return nutrients to soil.
What percent of energy production is passed to the next trophic level?
Relationships between organisms in an ecosystem
(ex. predation, parasitism)
o Predation: one species feeding on and killing another.
o Competition: multiple organisms fighting for the same resources.
o Parasitism: one species benefits from a second species that is disadvantaged, but generally not killed.
o Commensalism: one species benefits and the other is unaffected. Ex. Bird nesting in a tree.
o Mutualism: interaction characterized by mutual benefit, so both species benefit from relationship.
Human activities that affect on ecosystems.
o Overhunting: throws balance off and causes environmental stress.
o Deforestation: contributes to global warming due to natural air filter elimination.
o Pollution: plants and animals die from pollutants.
o Land conversion: urbanization displaces animals and increases environmental pollution from vehicles and factories.
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