What are the cornerstones of scientific thought? Explain each.
Questions: inquiring about the world around you/being skeptical
Observations: using senses to experience the environment
What are the differences and similarities between control and experimental groups?
Similarities: both needed for an experiment
Differences: Control is what is measured against. Experimental: one variable changes
What is the definition of biology?
Study of life
Name and describe the seven properties of life.
Cellular Organization: all living things have one or more cells
Metabolism: sum total of all chemical reactions; require energy
Heredity: passing of traits
Reproduction: continuation of life
Growth; developing and getting bigger
Responsiveness: reacting to the environment
What are the steps in the scientific method? Describe each.
Observations: taking note of the world
Questions: inquiring about how or why
Hypothesis: statement of predicted results
Experimentation: using control and experimental to test
Data Collection: writing down measurements and observations
Analysis: making sense of data
Conclusions: sharing results, identifying errors
What is the difference between an independent variable and a dependent variable?
IV: controlled by experimenter
DV: changes as a result of changes in IV
What is the relationship between a community, a habitat, and an ecosystem?
A community and habitat make up an ecosystem
Community: variety of organisms living together
Habitat: where organism lives
Ecoystem: all living and non-living factors
What is biodiversity? Why is it important to an ecosystem? What would be considered "good" biodiversity?
Biodiversity: measure of the variety of organisms in an ecosystem
It determines how well an ecosystem can withstand change
More biodiverse= BETTER
What is the difference between biotic and abiotic? Also, give two examples of each.
Biotic: living factors. Ex: plants and animals
Abiotic: nonliving factors. Ex. Availability of water, amount of sunlight
List and then briefly describe the three major groups of terrestrial biomes.
Tropical biomes: near equator
Temperate biomes: wide range of temps; areas between equator and poles High-latitude biomes: near poles
List and then briefly describe the four major groups of aquatic ecosystems.
Marine ecosystem; Oceans Freshwater ecosystem: lakes, streams Estuary; where ocean meets freshwater Wetland: link between land and fully aquatic ecosystems
What is the difference between a producer and a consumer? How are they related?
Producer: makes own food/energy Consumer: eats to get energy Consumers get energy from producers
Describe the ten percent rule.
Only 10% of an organisms consumed or made energy stays with them; the other 90% is used and released as heat
Describe what happens in the water cycle. Be sure to describe each part. Why is the water cycle important?
Water cycle moves water between the land, air, and oceans Ocean water is evaporated, condensates, precipitates, and process starts all over Evaporation: water is heated into gas into the atmosphere
Condensation: the water vapor condenses into cloud Precipitation: falls to the ground All life requires water
Describe what happens in the carbon cycle. Be sure to describe each part. Why is the carbon cycle important?
Carbon moves between the air, ground, and living organisms Plants take in carbon from the atmosphere. The carbon is in the atmosphere due to respiration, decomposition, and combustion. Respiration: plants and animals release carbon dioxide as a product of cellular respiration. Decomposition: carbon returns to the ground as dead organisms decay. This carbon is used by plants for photosynthesis. Combustion: burning of fossil fuels All organisms need carbon; part of all biomolecules
Describe what happens in the nitrogen cycle. Be sure to describe each part. Why is the nitrogen cycle important?
Nitrogen gas is converted to usable form by bacteria. Then taken in by plants through the soil. Organisms eat plants to get nitrogen then die and nitrogen returns to soil.
Needed to make proteins
What is succession? What is the purpose?
Replacement of one community by another Occurs after major change in ecosystem; needed to fill niche
What is the purpose of an energy pyramid? Why is it shaped as a triangle?
Triangular diagram that shows movement of energy through an ecosystem Shaped like triangle because energy as lost as we move up the pyramid. Gets narrower as there is less energy.
What are trophic levels? Which kinds of organisms are in each level? Describe each.
Trophic levels are layers of the energy pyramid. Producers: 1st level (make own energy) Consumers: remaining levels; includes herbivores, carnivores, omnivores Herbivores: eat only plants Carnivores: eat only meat Omnivores: eat plants and meat
What are the differences and similarities between a food chain and a food web?
Similar: show movement of energy through an ecosystem Different: food chain shows only one direct path; food web shows that energy can move in many directions at once
How is a population different from a community? How are they the same?
Differences - population: group of same species living together & interbreeding. Community - group of various species livining in the same habitat & interacting
Similarities - all interact with one another & affect population growth
What is population growth?
How the population size increases or decreases over time
Explain the two types of population growth.
Exponential Grouwth - growth increases at a contant rate due to lack of competition & unlimited resources
Logistic Growth - growth starts out at a small number & increases to a maximun number depending on the carrying capacity of the of the habitat
What makes the two types of population growth different?
The amount of available resources & the amount of competiton for those resources
What is predation?
The act of one organism killing another for food
What is symbiosis? Name and describe the different types.
A relationship where 2 species live in close association with each other
Parasitism - 1 organism feeds on another, usually harming but not killing it
Mutualism - 2 species live in close association with each other & both are benefited
Commensalism - 1 species benefits from interaction & the other is neither harmed nor helped
What are the differences between a realized and a fundamental niche?
Fundamental Niche - entire range where an organism can survive
Realized Niche - actual area in which an organism lives due to competition of resources
What is the difference between density dependent and density independent factors? Give an example of each.
Density dependent factors - variables affected by number of organisms present in the area. Example - availabilty of food, nesting sites
Density independent factors - variables that affect a population regardless of population density. Example - weather, natural disasters
What is competition? When might it occur?
The act of competing for the same resources
Occurs when different species require the same resources & resourcecs are limited
What is a keystone species? Why is it important?
A species that is criticla to an ecosystem because it affects the survival & number of many other species
Without them an ecosystem would not be able to maintain its homeostasis
What are the parts of an atom? Give the name, location, and charge.
Protons - in nulceus, positive charge
Nuetrons - in nucleus, no charge/neutral charge
Electrons - souround the nucleus, negative charge
What is an ion? How is it formed?
An atom or group of atoms that has an electrical charge
Formed when electrons are either gained/lost
What are the similarities and differences between an ionic and a covalent bond?
Similarities - both bonds form a compond made of 2 or more elements to become stable
Differences - ionic compound: 1 atom loses an electron from its valence shell & 1 element gains an electron from its valence shell. Covalent bonds: share valence electrons
Explain what makes a molecule polar.
Unequal sharing of valence electrons in a covalent bond
What kind of relationship do polar molecules have with water?
Polar molecules are attacked to water because water is polar
Explain what makes a molecule non-polar.
When valence electrons are shared equally, moving around each nucleus for equal time
What kind of relationship do non-polar molecules have with water?
Non-polar molecules are repeled by water because they have no charge to atract the polar water molecules
Describe the four properties that make water unique.
Ice floats - when water freezes the hydrogen bonds make empty spaces, making the solid form of water (ice) less dense.
Water absorbs & retains heat - hydgrogen bonds are contstantly breaking & forming allowing water to absorb large amounts of heat & water to stay liquid over a large range of temperature. (Allows organisms to maintain homeostasis with changing temperatures)
Cohesion - hydrogen bonds cause water molecules to be polar so they stick to each other forming droplets. Crucial part of the water cycle
Adhesion - polar water miolecules are attracted to other polar substances causing them to stick together
What is an organic compound? Give two other names for organic compounds.
Organic compond is any compound that contains carbon, also called carbon componds or biomolecules
Name the four organic compounds. Describe the role of each and the building blocks of each.
Carbohydrates - function: energy supply, structural support of cell & cell recognition. Building Block: single sugar
Lipids - function: water barrier & back up energy supply. Building block: carbon & hydrogen
Proteins - function: provides structure & support, allows for movement of materials into/out of the cell, aids in cellular communication & aids in chemical reactions. Building Blocks: amino acids
Nucleic Acids - function: contains hereditary information & contains instructions for making proteins. Building Block: nucleotides
What is an enzyme? What three things does an enzyme do that causes chemical reactions to speed up?
Acts as a catalyst to speed up chemical reactions. By: lowering the amount of activation need for reaction to take place, holding the molecules in the correct alignment & holding them close together
What is a hydrogen bond? Where are hydrogen bonds found?
Bond that includes the sharing of a hydrogen electron causing them to be slightly charged/polar, found in water & DNA
shape reveals function
. cell size
smaller is better because the cell is able to maintain a greater surface area to volume ratio which enables the cell to exchange substances more efficiently
four structures that all cells share
cytoplasm, the fluid and most of the structures within a cell, ribosomes, site of protein synthesis, cell membrane, outermost boundary of a cell and DNA, the genetic material providing instructions for making proteins, regulating cell activities and enabling cells to reproduce
prokaryotes and eukaryotes
similarities are they both have cytoplasm, cell membrane, ribosomes and DNA. Differences pro-no nucleus, no membrane bound organelles, no multicellularity. Eu, true nucleus, true membrane bound organelles true multicellularity (and unicellularity)
1) all living things are made up of one or more cells 2) cells are the basic units of structure and function in living things 3) all cells arise from the reproduction of existing cells
a structure that carries out specific tasks/functions within a cell. Eukaryotes only
Ribosomes, Smooth ER, Rough ER, Golgi apparatus, Mitochondria, Chloroplasts, Cell membrane, Nucleus:
ribosomes - site of protein synthesis in cells, either free or bound to the rough ER smooth ER - responsible for making lipids, breaking down toxins rough ER - embedded with ribosomes that produce proteins, ER pinches off to form vesicles around these proteins and transport them to the Golgi Apparatus, Golgi Apparatus- modifies, sorts, packages and transports cell products by forming vesicles around them (like UPS for the cell) Mitochondria - powerhouse of the cell, uses energy from organic molecules to make ATP during cellular respiration Chloroplasts - uses light energy to make sugar from CO2 and H2O during photosynthesis Cell membrane - outer boundary of a cell acts as a barrier between the outside and inside of the cell Nucleus - control center of an eukaryotic cell, contains DNA and nucleolus which is where ribosome parts are made
maintains homeostasis by acting as a gatekeeper allowing certain materials to pass into or out of the cell, provides structural support to the cytoplasm, recognizes foreign material, and communicates with other cells
structure of the cell membrane
made of two layers of phospholipid molecules, the outer and inner parts are polar and the middle is non polar
when one area has a concentration of particles than another area, related to passive transport because particles move from area of higher concentration to lower on passive transport
diffusion of water from an area of higher concentration to lower concentration across a membrane. Hypertonic solution - concentration of particles is higher outside the cell than inside, H2O moves out of the cell, cell shrinks Hypotonic solution - concentration of particles is lower outside the cell than inside the cell H2O moves into the cell, cell expands, Isotonic solution - no net movement of water as concentration is the same inside and outside the cell, cell stays the same size
cells communicate by sending signals either chemical or electrical that are sent from a signaling cell to a target cell
cell surface markers - act like a name tag to identify the cell, receptor proteins - enable cells to sense their surroundings, enzymes - catalyze important biochemical reactions within the cell, transport proteins - aid transport of substances across the cell membrane
move substances down their concentration gradient without the use of energy by the cell to reach equilibrium
passive and active transport
passive transport does not use from the cell in the form of ATP while active transport does. Passive with/down the gradient active against/up the gradient.
types of active transport
cell membrane pumps - carrier proteins that use ATP to move substances against the gradient across the cell membrane Na+-K+ pump, Proton pump are examples, vesicles - lipid bilayer that enables large molecules to pass through the cell membrane, endocytosis - use of a vesicle to move large substances into the cell, exocytosis - use of a vesicle to move large substance out of a cell
simple diffusion - move of substances from an area of high concentration to an area of low concentration, osmosis - diffusion of H2O from an area of high concentration to an area of low concentration across the cell membrane, facilitated diffusion - use of carrier proteins to move substance s across the cell membrane, ALL of these do not require the cell to expend energy in the form of ATP
active transport and facilitated diffusion
both allow movement of substances across the membrane that would not be able to get through otherwise by either being too big or having polarity or a charge. Both can use carrier proteins, active needs energy in the form of ATP passive does not
using sunlight/radiant energy to make organic compounds such as sugars from CO2 and H2O
autotrophs are able to make their own food through the process of photosynthesis, examples of autotrophs are algae, certain bacteria, and plants, heterotrophs need to consume other organisms to get their food
adenosine tri phosphate is the energy currency of living things because it can be made in one place and used in another. Energy is stored in the high energy bonds between the phosphates, when the bonds between the 2nd and 3rd phosphates are broken energy is released for metabolic activities
photosynthesis begins when light is harvested by the chlorophyll molecules located on the thylakoid membrane of the chloroplast which produces ATP and NADPH, these two high energy molecules are used in the Calvin cycle which takes place in the stroma of the chloroplast to produce sugar
chlorophylls A and B are the pigments responsible for absorbing light energy in photosynthesis
rate of photosynthesis
3 factors that affect the rate of photosynthesis are CO2 concentration light intensity and temperature
oxygen released during photosynthesis
comes from the splitting of H2O during the first steps of photosynthesis
two ETC's of photosynthesis
products produced are ATP and NADPH which are both used during the Calvin Cycle
purpose is produce sugar through the process of CO2 fixation
series of steps that break down glucose to produce ATP, begins with glycolysis, breaks glucose down into two pyruvates produces (2 ATP) which are broken down more through aerobic respiration if O2 is present by Krebs cycle (2ATP) and electron transport chain (max of 32 ATP) or glycolysis is kept going by fermentation pathways if O2 is not available
organisms that use cellular respiration
all organisms use cellular respiration either aerobically or anaerobically
process of recycling NAD+ which is necessary for glycolysis to continue, both lactic acid fermentation and alcoholic fermentation recycle NAD+
most ATP produced
most ATP is produced during the electron transport chain of aerobic respiration
a hereditary unit that codes for a protein or RNA
most of cells time
cells spend most of their time in Interphase
Interphase consists of G1 phase a period of rapid cell growth, S phase which is when DNA is copied and G2 phase where the cell grows more and prepares for division followed by cell division which consists of mitosis and cytokinesis
G1 checkpoint occurs at the end of the G1 phase before DNA is copied to ensure conditions are favorable to continue and to ensure the cell is healthy enough, G2 checkpoint occurs at the end of the G2 phase to ensure that DNA was copied correctly and if not enzymes correct the mistakes also other enzymes check to make sure the cell is large enough to divide, Mitosis checkpoint occurs during metaphase of mitosis and ensures the chromosomes are properly attached to the spindle fibers to make sure each daughter gets the exact same amount and type of genetic material
because they get too large and because the organism needs more cells as it grows or to repair/replace cells damaged or old.
DNA is packaged into highly condensed chromosome structures by many proteins. The first is a histone protein which has DNA wrap around it to form a nucleosome, 30 nm fibers called the nucleosome cord form loops that are attached to a protein scaffold. These looped domains then coil into the most highly condensed form of the chromosome
sister chromatids are held together
at a region called the centromere
mitosis consists of four stages, prophase where chromatids condense, the nuclear membrane dissolves, the centrosomes move to opposite poles and the spindle begins to form, metaphase - where the condensed chromosomes line up on the equator and the spindle fibers attach the chromatids of each chromosome to opposite poles, anaphase - the spindle shortens and the chromatids are pulled towards the poles and telophase - where the nuclear membrane reforms, spindle disappears, and the chromosomes uncoil
end result of mitosis
the final products of mitosis are two genetically identical daughter cells
difference between plant and animal cell cytokinesis is animal cells have the cell membrane pinch together to form two new cell and in plant cells a cell plate forms which cuts the cell into two identical cells