Scientific Method
Steps of the Scientific Method |
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1) Observation |
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2) Question |
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3) Hypothesis |
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4) Prediction |
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5) Experiment |
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6) Record and Analyze data |
Types of Variables
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Controlled Variable The variable that stays constant throughout the experiment
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Independent Variable The variable that you are changing ( I-vary)
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Dependent Variable The variable that responds to the changes from the independent variable
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Negative Control Variable A control variable that does not result in any changes
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Positive Control Variable A control variable that results in a change
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Single Blind v.s Double Blind Experiment
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Single-Blind When the participants of the experiment do not know which group they are in
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Double-Blind When both the researcher and the participants do not know which group they are in
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Why is this important? It helps eliminate bias in an experiment and help obtain honest results
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Prokaryotic Cell Structure
Eukaryotic Cell Structure
Phospholipids
A phospholipid has 2 parts:
1) Polar region (hydrophilic)
2) Non-polar (hydrophobic) |
Phospholipids form a bilayer in the membrane (phospholipid bilayer) |
Passive transport
-> requires no energy
-> Spontaneous movement of a substance across a membrane from an area high concentration to an area of low concentration (spreading out)
ex: a ball rolls down a hill |
-> Non-polar substances can dissolve through the non-polar lipid bilayer.
-> (sex hormones, pesticides)
-> Small, unchanged molecules: O2 & the CO2 |
Active transport
-> REQUIRES AN INPUT OF ENERGY
-> The movement of a substance across a membrane from an area of low concentration to an area of high concentration
-> LOWER CONCENTRATION TO HIGHER CONCENTRATION
-> ex: we must work to roll the ball back uphill |
Active transport v.s Passive transport
Active |
Passive |
Molecules need energy to move across the membrane
ex: requires transport proteins |
Molecules move spontaneously (no imput of energy)
ex: Diffusion & Osmoisis |
What is excluded from passing the membrane?
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Ions (Ca2+, H+, Na+, Cl-) -> even though they are small, their charges cause them to be repelled by the hydrophobic tails of te membrane
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Large polar molecules (gluclose & amino acids) cannot pass the hydrophilic tails of the membrane
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Transport membranes help these molecules pass through the lipid bilayer
-> Facilitated Diffusion: is when the passive movement of a substance with the help of membrane transport proteins: channels
carriers
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Hydrophilic v.s Hydrophobic
Hydrophilic |
Hydrophobic |
Attracts Water Molecules |
Repels Water Molecules |
What is the monomer unit of a protein?
What is the main component of the plasma membrane?
Membrane
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What charateristic makes a membrane semi-permeable Substances move in & out of the cell through proteins or btwn phospholipids
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Characteristics of All Living things
1) Are made up of 1 or more cells |
2) Can reproduce using DNA |
3) Obtain energy from the environment around them |
4) Able to grow & develop |
5) able to evolve as a group |
Prokaryotic v.s Eukaryotic
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Prokaryotic(Unicellular) The entire organism is made up of one cell
This cell carries out all the functions for survival
ex: Bacteria & Archea
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Eukaryotic(Multicellualr) Are composed of many specialized cells working together
ex: small plants and animals
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Prokaryotic v.s Eukaryotic
DNA v.s RNA
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DNA -> deoxyribosose nucleic acid
-> gene carry an ATCG code
-> are the blueprint for protein molecules
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RNA -> ribonucleic acid
-> acts as a messenger carrying out orders from the DNA
-> controls synthesis of protein
-> The genetic code is AGCT
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Macromolecules comparison
Size Ranges of Biological Structure
Cell Structures; to real life ex
Nucleus = Town Hall ( controls the cell)
Golgi = USPS/ UPS (packages and delivers
ER= Factories (make lipids/ Proteins
Ribosomes = Factory workers (makes lipids proteins)
Chloroplast= Solar Panel ( Captures light)
Mitochondria = Power House ( Convert Energy)
Lysosomes = break down bacteria and worn out (sanitation)
Vacuoles = Break down bacteria etc.and store energy (sanitation)
Cell membrane = to regulate what gets in and out of the cell (Bouncer )
Cytoskeleton = structures and movement of chromosomes (infrastructure of town/ highway)
Cytoplasm = holds all the organelles together & cellular respiration (air)
Vesicles = storage and move things around move proteins out of the cell ( mailman/ mail truck) |
Diffusion
-> Diffusion= substances moving spontaneously
-> Diffusion stops when the substance is equally distributed -Equilibrium
-> There is no net movement of molecules, even though the molecules are still moving
-> They are moving in a space at the same rate as they are leaving the space |
What factors can affect the rate of diffusion?
-> Temperature(heat/cold): Heat causes particles to move faster
Cold slows down the movement of particles
-> Size of particles: Small molecules will move faster than the large ones |
Osmosis
-> is the movement of water across a selectively permeable membrane
-> Through polar, water molecules are small enough to weave through the lipid bilayer
-> If a large amount of water is needed, the movement is done through a protein channel -Aquaporin |
-> The diffusion of water across the membrane is PASSIVE
-> NO INPUT OF ENERGY IS REQUIRED
-> Water moves from an area of high concentration to an area of low concentreation
-> Water moves from areas of low solute (salt,sugar) to high solute |
Solution types
Isotonic = having the same/equal
Hypotonic = having a lower concentration of solute than the other solution{
Hypertonic = having higher osmotic pressure than the comparison solution
Intracellular v.s Extracellular
Intracellular: located Inside of the cell |
Extracellular: located outside of the cell |
Producers v.s Consumers
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Producer -> Plants obtain energy from the non-living part of the environment
-> Autotrophs = Producers
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Consumer -> Animals obtain energy from the living part of the environment
Hetrotrophs =Consumers
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Linnean Hierarchy of Classification
8 category system
Top to bottom = Least specific to most
Bottom to the top = Most specific to least
4 Biological Molecules
1) Proteins |
2) Lipids |
3) Carbohydrates |
4) Nucleic Acids |
Monomer v.s Polymer
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Monomer -> is any molecule that contains atleast 1 C-H bond
->Small Building Blocks
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Polymer -> are small organic molecules that are used as repeating links together via covalent bonds to form a macromolecule (polymers)
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Dehydration Reaction v.s Hydrolysis Reaction
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Dehydration Reaction -> connects a monomer to another monomer or a polymer
-> In a dehydration reaction the 2 reactants(monomer/polymer) contributes a part of the water molecule released in the reaction
-> one contributes the -OH(hydroxyl group) & the other H (Hydrogen)
-> Continuous reaction
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Hydrolysis -> breaks down polymers into monomers
The bond btwn the monomers attaching to one monomer and the hydroxyl attaching to the other monomer
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The Order of Making Protein
The Plasma Membrane
-> Forms the external boundary of all types of cells
-> Seperates the inside contents of the cell from the outside
-> Controls communication and exchange of some materials |
-> Is Selectively Permeable
the membrane regulates the passage of materials
-> Membrane allows some substances to pass through, more easily than others.
-> Some molecules can enter and exit the cell freely
Some molecules can pass under some circumstances
-> Others have some trouble |
Functions of a Plasma Membrane:
-> They keep toxic substances out of the cell
-> They contain receptors and channels that allow molecules such as ions, nutrients, waste, and metabolic product
-> Regulates the transport of substances in and out of the cell
-> Protects the cell by acting as a barrier |
4 Macromolecules Functions & Examples
Macromolecules |
Building Blocks |
Functions |
Examples |
Lipids |
Fatty acids & glycerol |
to provide cells with long-term energy & make-up biological membranes |
Fats, Phospholipids, waxes, oils, grease, steroids |
Nucleic acids |
Nucleotides |
to store and pass on genetic info |
DNA & RNA |
Carbohydrates |
Monosaccharides (simple sugars) |
to provide cells with short term energy & source of fiber |
Glucose, Sucrose, Starch, Cellulose, Chtin |
Proteins |
Amino Acids |
to provide cell structure, send chemical signals, speed up chemical reactions, & more |
Keratain(found in hair & nails), Hormones, Enzymes, Antibodies |
Active Transport & Channels
Ion Channels |
Intergral pores that allow specific ions to get in/out of the cell |
Transporters |
Integral proteins that selectively move a polar substance/ion to one side of the membrane |
Receptors |
Integral proteins that serve as recognition sites. Each binds to a specific type of molecule |
Ligand |
A specific molecule that binds to a receptor |
Enzymes |
Intergral proteins that catalyze specific chemical reactions at the cell surface |
Linkers |
Intergral proteins that hold down proteins in the plasma membrane. Helps form structure of cells and link cells together |
Regulators
Local Regulators: a secreted molecule that influences cells near where it was secreted |
G-protein-coupled receptors: a signal receptor protein that responds to the binding of a signal molecule by activating a G-protein |
Ion Channel receptors: a ligand-gated ion channel is a type of membrane receptor containing a region that can act as a "gate" when the receptor changes shape |
Local v.s Long Distance(animal cells)
Local |
Both |
Long |
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target only specific target cells recognize & respond to a given signal molecule |
Panacrine Signaling |
A secreting cell acts on nearby target cells by discharging molecules of a local regulator into extracellular fluid |
Synaptic Signaling |
A nerve cell releases nuerotransmitter molecules into a synapse stimulating the target cell |
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Hormonal Signaling |
Specialized endocrine cells secrete hormones into body fluids, often blood Hormones may reach virtually all body cells |
Signal Transduction Pathway
A series of steps linking a mechanical/chemical stimulus to a specific cellular response |
key role in cell communication
Answer: The plasma membrane plays a key role in communication btwn cells & their environment |
mono v.s di v.s poly (saccharides)
Amino Acid Monomers
-> are organic molecules with carboxyl and an amino acid group |
-> at the center of the small molecules is the carbon atom called " Alpha Carbon" |
-> surrounded by amino group, carboxyl group, a hydrogen group with a "-R" group |
Protein Structure & Function
-> A functional protein consists of 1 or more polypeptides |
3 Levels of Structure:
1) Primary Structure
2) Secondary Structure
3) Teritary Structure
4) Quaternary Structure |
Primary Structure: is the proteins linear sequence
Secondary Structure: is when polypeptide chains coil or fold to the backbone of the polypeptide interact and form bonds
Teritiary Structure: happens through the interactions of the amino acids. Determines the overall shape of the polypeptide
Quaternary Structure: is when 2 or more polypeptides combine (aggregate) |
Endomembrane System
-> Nuclear Envelope |
-> Endoplasmic Reticulum |
-> Golgi Body |
-> Lysosomes |
-> Plasma Membranes |
-> Vacuoles |
Plasma membrane
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What macromolecule makes up the majority of the plasma membrane of cells? A) Proteins
B) Carbohydrates
C) Lipids -->> Phospholipids
D) Nucleic Acids
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Proteins and carbohydrates also compose the membrane
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Amphipathic
having both hydrophillic & hydrophobic parts |
Concentration Gradient
oocurs when the concentration of particle in one area than another.s is higher |
Permeable
allowing cells/ions to pass through |
Solution vocab
Solvent: able to dissolve other solutions |
Solution: a homogenous (balanced) mixture of solvent or solute molecules |
Solute: is a substance that can be dissolved by a solvent to create a solution |
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