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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
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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
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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A phospholipid has 2 parts:
1) Polar region (hydrophilic) 2) Non-polar (hydrophobic) |
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Phospholipids form a bilayer in the membrane (phospholipid bilayer)
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-> 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 |
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-> Non-polar substances can dissolve through the non-polar lipid bilayer.
-> (sex hormones, pesticides) -> Small, unchanged molecules: O2 & the CO2 |
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-> 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 |
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Active
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Passive
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Molecules need energy to move across the membrane
ex: requires transport proteins |
Molecules move spontaneously (no imput of energy)
ex: Diffusion & Osmoisis |
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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
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Hydrophobic
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Attracts Water Molecules
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Repels Water Molecules
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Answer: Amino Acids
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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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1) Are made up of 1 or more cells
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2) Can reproduce using DNA
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3) Obtain energy from the environment around them
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4) Able to grow & develop
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5) able to evolve as a group
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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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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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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) |
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-> 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 |
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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 |
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-> 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 |
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-> 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 |
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Intracellular: located Inside of the cell
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Extracellular: located outside of the cell
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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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1) Proteins
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2) Lipids
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3) Carbohydrates
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4) Nucleic Acids
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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
-> 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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DNA -> RNA -> Protein
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-> 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 |
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-> 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 |
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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 |
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Macromolecules
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Building Blocks
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Functions
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Examples
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Lipids
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Fatty acids & glycerol
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to provide cells with long-term energy & make-up biological membranes
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Fats, Phospholipids, waxes, oils, grease, steroids
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Nucleic acids
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Nucleotides
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to store and pass on genetic info
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DNA & RNA
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Carbohydrates
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Monosaccharides (simple sugars)
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to provide cells with short term energy & source of fiber
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Glucose, Sucrose, Starch, Cellulose, Chtin
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Proteins
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Amino Acids
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to provide cell structure, send chemical signals, speed up chemical reactions, & more
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Keratain(found in hair & nails), Hormones, Enzymes, Antibodies
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Answer: The plasma membrane plays a key role in communication btwn cells & their environment
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Ion Channels
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Intergral pores that allow specific ions to get in/out of the cell
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Transporters
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Integral proteins that selectively move a polar substance/ion to one side of the membrane
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Receptors
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Integral proteins that serve as recognition sites. Each binds to a specific type of molecule
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Ligand
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A specific molecule that binds to a receptor
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Enzymes
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Intergral proteins that catalyze specific chemical reactions at the cell surface
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Linkers
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Intergral proteins that hold down proteins in the plasma membrane. Helps form structure of cells and link cells together
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A series of steps linking a mechanical/chemical stimulus to a specific cellular response
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Local
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Both
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Long
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target only specific target cells recognize & respond to a given signal molecule
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Panacrine Signaling
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A secreting cell acts on nearby target cells by discharging molecules of a local regulator into extracellular fluid
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Synaptic Signaling
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A nerve cell releases nuerotransmitter molecules into a synapse stimulating the target cell
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Hormonal Signaling
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Specialized endocrine cells secrete hormones into body fluids, often blood Hormones may reach virtually all body cells
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Local Regulators: a secreted molecule that influences cells near where it was secreted
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G-protein-coupled receptors: a signal receptor protein that responds to the binding of a signal molecule by activating a G-protein
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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
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-> are organic molecules with carboxyl and an amino acid group
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-> at the center of the small molecules is the carbon atom called " Alpha Carbon"
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-> surrounded by amino group, carboxyl group, a hydrogen group with a "-R" group
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-> A functional protein consists of 1 or more polypeptides
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3 Levels of Structure:
1) Primary Structure 2) Secondary Structure 3) Teritary Structure 4) Quaternary Structure |
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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) |
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-> Nuclear Envelope
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-> Endoplasmic Reticulum
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-> Golgi Body
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-> Lysosomes
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-> Plasma Membranes
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-> Vacuoles
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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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having both hydrophillic & hydrophobic parts
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oocurs when the concentration of particle in one area than another.s is higher
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allowing cells/ions to pass through
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Swollen or congested
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Solvent: able to dissolve other solutions
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Solution: a homogenous (balanced) mixture of solvent or solute molecules
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Solute: is a substance that can be dissolved by a solvent to create a solution
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