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Mastering biology 1,3,4,5

Scientific Method

Steps of the Scientific Method
1) Observ­ation
2) Question
3) Hypothesis
4) Prediction
5) Experiment
6) Record and Analyze data

Types of Variab­les

Cont­rolled Variable
The variable that stays constant throughout the experiment
Inde­pendent Variable
The variable that you are changing ( I-vary)
Dependent Variable
The variable that responds to the changes from the indepe­ndent variable
Negative Control Variable
A control variable that does not result in any changes
Positive Control Variable
A control variable that results in a change

Single Blind v.s Double Blind Experiment

When the participants of the experiment do not know which group they are in
When both the researcher and the participants do not know which group they are in
Why is this import­ant?
It helps eliminate bias in an experiment and help obtain honest results

Prokar­yotic Cell Structure

Eukaryotic Cell Structure

Plant Cell Structure


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

-> The movement of a substance across a membrane from an area of low concen­tration to an area of high concentration
-> ex: we must work to roll the ball back uphill

Active transport v.s Passive transport

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?

Ions (Ca2+, H+, Na+, Cl-)
-> even though they are small, their charges cause them to be repelled by the hydrophobic tails of te membrane
Large polar molecu­les
(gl­uclose & amino acids) cannot pass the hydrop­hilic tails of the membrane
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

Hydrop­hilic v.s Hydrop­hobic

Attracts Water Molecules
Repels Water Molecules

What is the monomer unit of a protein?

Answer: Amino Acids

What is the main component of the plasma membrane?


What charateristic makes a membrane semi-permeable
Substances move in & out of the cell through proteins or btwn phospholipids

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

The entire organism is made up of one cell
This cell carries out all the functions for survival
ex: Bacteria & Archea
Are composed of many specia­lized cells working together
ex: small plants and animals

Prokar­yotic v.s Eukaryotic


-> deoxyr­ibosose nucleic acid
-> gene carry an ATCG code
-> are the blueprint for protein molecules
-> ribonu­cleic acid
-> acts as a messenger carrying out orders from the DNA
-> controls synthesis of protein
-> The genetic code is AGCT


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= 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


-> 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
-> 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

Solution differ­ences

Intrac­ellular v.s Extrac­ellular

Intr­ace­llu­lar: located Inside of the cell
Extracellular: located outside of the cell

Producers v.s Consumers

-> Plants obtain energy from the non-living part of the environment
-> Autotrophs = Producers
-> Animals obtain energy from the living part of the environment
Hetrotrophs =Consumers

Linnean Hierarchy of Classi­fic­ation

8 category system
Top to bottom = Least specific to most
Bottom to the top = Most specific to least

Biological Organi­zation

4 Biological Molecules

1) Proteins
2) Lipids
3) Carboh­ydr­ates
4) Nucleic Acids

Monomer v.s Polymer

-> is any molecule that contains atleast 1 C-H bond
->Small Building Blocks
-> are small organic molecules that are used as repeating links together via covalent bonds to form a macrom­olecule (polymers)

Dehydr­ation Reaction v.s Hydrolysis Reaction

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
-> breaks down polymers into monomers
The bond btwn the monomers attaching to one monomer and the hydroxyl attaching to the other monomer

The Order of Making Protein

DNA -> RNA -> 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

Building Blocks
Fatty acids & glycerol
to provide cells with long-term energy & make-up biological membranes
Fats, Phospholipids, waxes, oils, grease, steroids
Nucleic acids
to store and pass on genetic info
Monosaccharides (simple sugars)
to provide cells with short term energy & source of fiber
Glucose, Sucrose, Starch, Cellulose, Chtin
Amino Acids
to provide cell structure, send chemical signals, speed up chemical reactions, & more
Keratain(found in hair & nails), Hormones, Enzymes, Antibodies

key role in cell communication

Answer: The plasma membrane plays a key role in communication btwn cells & their environment

Active Transport & Channels

Ion Channels
Intergral pores that allow specific ions to get in/out of the cell
Integral proteins that selectively move a polar substance/ion to one side of the membrane
Integral proteins that serve as recogn­ition sites. Each binds to a specific type of molecule
A specific molecule that binds to a receptor
Intergral proteins that catalyze specific chemical reactions at the cell surface
Intergral proteins that hold down proteins in the plasma membrane. Helps form structure of cells and link cells together

Signal Transd­uction Pathway

A series of steps linking a mechanical/chemical stimulus to a specific cellular response

Local v.s Long Distance(animal cells)

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
Hormonal Signaling
Specialized endocrine cells secrete hormones into body fluids, often blood Hormones may reach virtually all body cells


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

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

Amino Acid Structure

20 amino acids

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

What macrom­olecule makes up the majority of the plasma membrane of cells?
A) Proteins
B) Carbohydrates
C) Lipids -->> Phos­pho­lip­ids
D) Nucleic Acids
Proteins and carboh­ydrates also compose the membrane


having both hydrophillic & hydrophobic parts

Concen­tration Gradient

oocurs when the concentration of particle in one area than another.s is higher


allowing cells/ions to pass through


Swollen or congested

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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