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What is anecdotal evidence?
an informal observation that has not been systmatically tested
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What is the significance of peer review in science?
you can trust it; independent and unbgiased experts have critiqued the soundness of the study before it was published
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What is a hypothesis?
a testable and falsifiable explanation for a scientific observation or question
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What are the characteristics of a good hypothesis?
specific and testable
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What is the difference between the independent and dependent variable?
- independent: the variable that is changed in a systematic way
- dependent: the variable that is measured in the experiment
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What is the control group?
the group in an experiment that experiences no experimental intervention or manipulation
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What is the experimental group?
the group in an experiment that experiences the experimental intervention or manipulation
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How does sample size influence the validity of results in a scientific experiment?
- can stregthen our confidence in the results of the study
- the number of experimental subjects or the number of times an experiment is repeated
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What is a placebo?
a fake treatment given to control groups to mimic the experience of the experimental groups
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Why do scientists use placebos?
- to avoid a placebo effect
- mind over matter
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What does correlation between two varriables indicate?
consistent relationship between the variables; doesn't prove one causes the other
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What is epidemiological study?
the study of patterns of disease in populations including risk factors
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Why are epidemiological studies used in science?
- to answer questions that could not be tested through experiments for ethical or practical reasons
- ex: Does smoking cause cancer?
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What is the scientific theory?
A hypothesis that is supported by many years of rigorous testing and thousands of experiments
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What are the 5 functional traits that all living things share in common?
- growth
- reproduction
- homeostasis
- sense and respond to stimuli
- obtain and use energy
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What is energy?
the ability to do work
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How do all organisms obtain energy?
sunlight or food
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What is an atom?
the smallest unit of an element that cannot be chemically broken down into smaller units
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What is a proton?
a positively charged particle located in the nucleus of an atom
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What is a neutron?
a neutral charged subatomic particle located in the nucleus of an atom
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What is an electron?
a negatively charged subatomic particle with negligible mass
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What is a nucleus (atom)?
the dense core of an atom
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How many electrons are found on each shell or orbital?
- 2 on the first
- 8 on the rest
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What is atomic mass?
the number of protons and neutrons
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How many partners can carbon form bonds with?
4
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What is a covalent bond?
a strong chemical bond resulting from the sharing of a pair of electrons between 2 atoms
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What is a hydrogen bond?
a weak electrical attraction between a partially positive hydrogen atom and another atom with a partial negative charge
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What is an ionic bond?
a strong electrical attraction between oppositely charged ions
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what is homeostasis?
the maintenance of a relatively constant internal environment
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What makes an atom charged?
when there are more protons than electrons; or more electrons than protons
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How can atom become charged?
by loosing or gaining electrons in an attempt to achieve octet
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What forms cell membranes?
a phospholipid bilayer
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What characteristic of phospholipid bilayers makes them suited for their task?
its semipermeable
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What is an ion?
an electrically charged atom, the charge resulting from the looss or gain of electrons
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What does pH measure?
concentration of H+ in a solution
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How does the pH scale work?
- 0= acidic pH
- 7= neutral pH
- 14= basic pH
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What is an acid?
a substance that increases the hydrogen ion concentration of solutions, making them more acidic
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What is a base?
a substance that reduces hydrogen ion concentration of solutions, making them more basic
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What makes up protein?
amino acids
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What makes up carbohydrates?
polymers made of monomers; monosaccharides
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What is the unifying feature of lipids?
hydrophobic molecules (dont mix with water)
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What are examples of complex sugars?
starch
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What are examples of simple sugars?
glucose
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What is a polar molecule?
a molecule in which electrons are not shared equally between atoms causing a partial neg. charge at one end and a partial pos. charge at the other; for example water.
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What did Alexander Fleming discover?
antibiotics
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How did Fleming make his discovery?
he was throwing away a petri plate when he noticed that wherever mold was growing there was a zone of inhabbition where bacteria did not grow
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What is an antibiotic?
a chemical that can slow or stop the growth of bacteria; many are produced by living organisms
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What is penicillin?
antibacterial substance
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Where does penicillin come from?
Penicillium notatu; mold
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What is the cell theory?
the concept that all living organisms are made of cells and that cells are formed by the reproduction of existing cells.
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What is the difference between a prokaryotic and eukaryotic cells?
prokaryotic cells don't have organelles
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What structures are found in prokaryotic cells?
cell membrane, cytoplasm, ribosomes, DNA
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What structures are found in eukaryotic cells?
Nucleus, cell membrane, cytoplasm, ribosomes, DNA, mitochondria, lysosomes, chloroplasts, Golgi, ER, cytoskeleton... ect.
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Why do antibiotics kill bacterial cells and not human cells? Specificallly in the case of penicillin?
peptidoglycan
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What are bacterial cell walls made of?
peptidoglycan, a polymer made of sugars and amino acids
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Describe the cell membrane and the orientation of phospholipids in the membrane.
Phospholipids assemble into bilayers in water. Water-hatingtails congregate betweenwater-loving heads, forming a lipid sandwich
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What is diffusion?
the movement of particles from an area of high concentration to an area of lower concentration
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What is osmosis?
the diffusion of water across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration
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What happens to a cell in a hypertonic solution?
cells shrink
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What happens to a cell in a hypotonic solution?
cells expand
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What happens to a cell in an isotonic solution?
cells remain the same
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Why are transport proteins needed by the cell?
provide a passageway for large or hydrophillic molecules to move across the membrane
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What is facilitated diffusion? Does it require energy?
the process by which large or hydrophobic solutes move across a membrane from an area of higher concentration to an area of lower concentration with the help of transport proteins. DOES NOT REQUIRE ENERGY
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What is active transport? Does it require energy?
process by which solutes are pumped from an area of lower concentration to an area of higher concentration with the help of transport proteins. REQUIRES ENERGY
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What are ribosomes and what do they do?
a complex of RNA and protein that carries out protein synthesis in all cells
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What is the function of chloroplasts?
site of photosynthesis
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What is the function of lysosomes?
filled with enzymes that can degrade worn-out cellular structures
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What is the function of mitochondria?
membrane-bound organelles responsible for important energy conservation ractions in eukaryotes
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What is the function of the nucleus?
stores genetic material
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What is the function of the cytoskeleton?
a network of protein fibers in eukaryotic cells that provides strucuture and facilitates cell movement.
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What is the endosymbiotic theory?
the theory that freeliving prokaryotic cells engulfed other freeliving prokaryotic cells billions of years ago forming eukaryotic organelles such asw mitochondria and chloroplasts
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What are the four macronutrients?
proteins, carbohydratesw, fats, nucleic acids
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How do human bodies utilize macronutrients?
nutrients, including proteins, carbohydrates, and fats, that organisms must ingest in large amounts to maintain health
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What is an essiential amino acid?
eight amino acids in the human body cannot synthesize and must be obtained from food
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What is a non-essential amino acid?
amino acids that our body can produce itself
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What are enzymes?
a protein that speeds up the rate of chemical reactions
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What do enzymes do?
accelerate chemical reactions
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How do enzymes work?
reduce the activation energy
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What is activation energy?
the energy required for a chemical reaction to proceed.
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What is substrate?
a compound or molecule that an enzyme binds to and on which it acts
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What is a catabolic reaction?
any chemical reaction that breaks down complex molecules into simpler molecules
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What is an anabolic reaction?
any chemical reaction that combines simple molecules to build more complex molecules
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What is the difference between type 1 and type 2 diabetes?
- type 1: cannot make insulin
- type 2: the receptors on their cells respond poorly to insulin
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