Mrs. Jackson’s Absolute Bare Minimum Module 1 Review

– All need energy for metabolism.• Metabolism: All of the chemical processes in an organism that build up or break down materials.

• An organism is any individual living thing.

• Living things share some common characteristics:

– All are made of one or more cells.

– All respond to their environment.– Stimuli, or physical factors, include light, temperature,

and touch.– All have genetic material (DNA) that they pass on to

offspring (universal code)

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Life depends on hydrogen bonds in water.

• Water is a polar molecule.– Polar molecules have slightly charged regions.

– Nonpolar molecules do not have charged regions.

1. Hydrogen bonds

form between slightly positive hydrogen atoms and slightly negative atoms. (oxygen)

Atom: OxygenCharge: Slightly negative

Atom: HydrogenCharge: Slightly positive

• Hydrogen bonds are responsible for important properties of water.– High Specific Heat: water resists changes in temp.

– Provides stability of temperature for land masses surrounded by water & for the temperature of the human body, & makes it an effective cooling agent.

– Cohesion: water molecules stick to each other.– Adhesion: water molecules stick to other things.– Ice floats on water: one of the only solids to float

on its liquid form – due to arrangement of water molecules due to charged regions. Provides insulation for water below (stays at about 4 degrees C – freezing point is 0 C)

Many compounds dissolve in water.

• A solution is formed when one substance dissolves in another. A solution is a homogeneous mixture.– Solvents dissolve other substances.– Solutes dissolve in a solvent.

solution

• “Like dissolves like.”

–Polar solvents dissolve polar solutes.–Nonpolar solvents dissolve nonpolar

solutes.–Polar substances and nonpolar

substances generally remain separate.–Example: Oil (non-polar) and

water (polar)

Maintaining homeostasis*Buffer: Helps to maintain pH.

pH<7=Acid (more H+)7=Neutral>7=Base (less H+)

Speaking of homeostasis…

• Homeostasis refers to your body maintaining stable, constant internal conditions.

• This may include:– Regulation of temperature (thermoregulation) Ex.:

sweating during exercise– Regulation of pH (i.e. buffers)– Regulation of oxygen delivery (for cellular respiration!). Ex:

heart beating faster during exercise– Regulation of water (osmoregulation - regulation of water

concentrations in the bloodstream, effectively controlling the amount of water available for cells to absorb.)

Control systems work together through feedback

• Feedback: Information from sensor that allows a control center to compare current conditions to a set of ideal values.– Feedback loop: Sensorcontrol centertargetsensor….

• Negative feedback loops: control system counteracts any change in the body that moves conditions above or below a set point (reversing change to return conditions to their set points)-most functions in the body are regulated this way.– Ex.: Thermostats, holding your breath

• Positive feedback loops: Control center uses information to increase rate of change away from set points.– Ex.: Cut finger increases clotting factors in blood.

Carbon atoms have unique bonding properties.

1. Carbon forms covalent bonds (strong bonds) with up to four other atoms, including other carbon atoms (has 4 unpaired electrons in its outer energy level)2. They can form large, complex molecules

3. Carbon can form single, double, or triple bonds4. Carbon forms isomers

– Isomers are compounds that have the same chemical formula, but different structural formulas

• Example: C4H10

• Only carbon has these 4 characteristics

Carbon atoms have unique bonding properties – Slide 2

Many carbon-based molecules are made of many small subunits bonded together.

• Monomers are the individual subunits.• Polymers are made of many monomers.

Carbohydrates

Polymer polysaccharide (or disaccharide if there are only 2 monomers)

Structure: Monomer: Monosaccharide (glucose, fructose)Made of atoms C, H, O

Function - Provide a quick source of energy- -Makes up cell wall in plants (cellulose)

- -Energy storage (starch in plants, glycogen in animals)

Lipids

Monomer (structure)

 glycerol & fatty acids; polar heads & fatty acid tails made of atoms C, H, O, sometimes P,

sometimes NPolymer  triglycerides; phospholipids

Examples Fats, oils, cholesterol, steroids, waxes, phospholipids

Function - Broken down to provide energy (takes longer than carbs)

- Used to make steroid hormones (control stress, estrogen, testosterone)

- Phospholipids make up all cell membranes  - (tend to be non-polar)

LIPIDS

ProteinsMolecule Proteins

Monomer (structure)

Monomer: Amino acid connected by peptide bonds

Atoms: C,H,O, N, sometimes SPolymer Polypeptide (protein) 

Function Enzymes (catalyze biochemical reactions),  hemoglobin (transports oxygen in blood),

muscle movement, collagenMore function

- Have a side group (R) that makes each amino acid (and therefore protein)

different- -3D structure makes them active – change

of structure (denature) = change of function

Nucleic acidsMolecule Nucleic acids

Monomer (Structure)

 Nucleotide (5-carbon sugar, phosphate group, & base) made of atoms C, H, O, N, P

Polymer Nucleic acid 

Examples DNA & RNA

Function  - Order of the bases makes every living thing unique

- DNA stores genetic information- RNA builds proteins

• How are polymers made from monomers?• This is dehydration synthesis. During this type of

reaction, a water molecule is removed (an –OH from one simple monomer and an –H from another to form a water molecule. This joins two monomers together to form a polymer. When adding another monomer to the dimer, another water molecule needs to be removed.

Monomer called Glucose

Dimer called Maltose

monomer-OH + monomer-H polymer + H2O

Hydrolysis• A polymer needs to break apart (the carbs,

proteins, and lipids we ingest are too big for us to use)– Water breaks apart into (-OH) and (-H) and

splits the polymer into monomers– The (-OH) and (-H) bond to each monomer to

make them stable molecules

• polymer + H2O monomer-OH + monomer-H

Chemical reactions release or absorb energy.

• Activation energy is the amount of energy that needs to be absorbed to start a chemical reaction

Catalysts are substances that speed up chemical reactionsDecrease activation energyIncrease reaction rate

Enzymes allow chemical reactions to occur under tightly controlled conditions.

• Enzymes are catalysts in living things.–Enzymes are needed for

almost all processes.–Most enzymes are proteins.

Disruptions in homeostasis can prevent enzymes from functioning.

• Enzymes function best in a small range of conditions.–Changes in temperature or pH can

break hydrogen bonds – DENATURES enzyme (changes 3D structure)•An enzyme’s function depends on its structure.

An enzyme’s structure allows only certain reactants to bind to the enzyme.

• Substrates: reactants that bind to an enzyme• Active site: area on the enzyme where substrates bind

What else can affect enzyme activity?• Enzyme ConcentrationIf we keep the concentration of the substrate constant and increase the concentration of the enzyme, the rate of reaction increases linearly.

(That is if the concentration of enzyme is doubled, the rate doubles.)

This is because in practically all enzyme reactions the molar concentrationof the enzyme is almost always lower than that of the substrate.

• Substrate ConcentrationIf we keep the concentration of the enzyme constant and increase the concentration of the substrate, initially, the rate increases with substrate concentration, but at a certain concentration, the rate levels out and remains constant So at some point, increasing the substrate concentration does not increase the rate of reaction, because the excess substrate cannot find any active sites to attach to.

Exothermic reactions release more energy than they absorb.

• Excess energy is released by the reaction.– Energy “exits” the reaction. (Exo = exit)

Endothermic reactions absorb more energy than they release.

• Energy is absorbed by the reaction to make up the difference.– Energy goes into the reaction. (Endo = “into”)

• The Cell Theory:–All organisms are made of

cells.–All cells come from other

cells.–The cell is the basic unit of

structure & function in living things.

All cells share certain characteristics.

• Cells tend to be microscopic.• All cells are enclosed by a

membrane.• All cells are filled with cytoplasm.• All cells have ribosomes.• All cells have genetic material (DNA)

There are two cell types:

• Eukaryotic cells– Have a nucleus– Have membrane-

bound organelles

• Prokaryotic cells – Do not have a nucleus

(still have DNA)– Do not have membrane-

bound organelles

Review

Eukaryotes

• Have nucleus (DNA)• Have membrane-bound

organelles• Larger size because of

organelles (Organelles divide up the functions of the cell and allow eukaryotic cells to have more volume.)

• More complex• Unicellular or multicellular

Prokaryotes

• No nucleus (still have DNA)• No membrane-bound

organelles• Smaller size because of lack of

organelles• Less complex• Unicellular

Organelles and FunctionsSee 3.1/3.2 PowerPoint!

How do membrane-bound organelles facilitate the transport of materials within the cell?The rough ER works with the Golgi…• Vesicle: Small membrane-bound sacs that divide some materials

from the rest of the cytoplasm and transport these materials within the cell.

• Proteins (such as secretory & membrane proteins) made by ribosomes on the rough ER are packaged in vesicles and sent to the cell membrane or Golgi Apparatus.

• The Golgi Body processes & sorts the proteins, then packages them into vesicles for storage, transport, or secretion from the cell membrane in new vesicles.

Levels of Organization

• OrganellesCellsTissuesOrgans Organ SystemsOrganisms

There are advantages to being multicellular rather than unicellular. These include allowing:• Allows the organism to be larger & have more

efficient movement• Cell differentiation (having different types of

cells with different functions) – specialization of cells, tissues, organs, organ systems allows for efficient performance of a variety of functions.

• The organisms to be more complex

Cell membranes are composed of two phospholipid layers.

• The cell membrane has two major functions1. Forms a boundary between inside and

outside of the cell2. Controls passage of materials in & out of cell

Phospholipid Bilayer

• Forms a double layer surrounding a cell

• Head is polar (attracted to water) and forms hydrogen bonds with water

• Tails are nonpolar (repelled by water)

Passive transport does not require energy (ATP) input from a cell.

• Molecules can move across the cell membrane through passive transport.

• Three types of passive transport:– Diffusion: movement of molecules from high to

low concentration– Osmosis: diffusion of water– Facilitated diffusion (see slide)

Diffusion and osmosis are types of passive transport (NO ENERGY)

• Molecules diffuse down a concentration gradient.– High to low concentration

How do different solutions affect cells?

• There are 3 types of solutions:1. Isotonic: solution has

the same concentration of solutes as the cell.

• Water moves in and out evenly

• Cell size stays constant

How do different solutions affect cells?

• There are 3 types of solutions:2. Hypertonic: solution

has more solutes than a cell

• More water exits the cell than enters

• Cell shrivels or dies

How do different solutions affect cells?

• There are 3 types of solutions:3. Hypotonic: solution

has fewer solutes than a cell

• More water enters the cell than exits

• Cell expands or bursts

Some molecules can only diffuse through transport proteins – this is FACILITATED DIFFUSION

• Some molecules cannot easily diffuse across the membrane– Ex: glucose (needed by cell to make energy)

• Facilitated diffusion is diffusion through transport proteins

• DOES NOT USE ENERGY

Video

Active Transport• Cells use energy (ATP) to transport materials that

cannot diffuse across a membrane.• Drives molecules across a membrane from

lower to higher concentration– Goes against the concentration gradient

TYPES OF ACTIVE TRANSPORT

• Endocytosis: Brings materials into cell (Endo=into)

• Exocytosis: Releases materials out of cell (Exo=Exit)

• Pumps (see next slide)

Sodium-Potassium Pump (A type of pump)

• Uses a membrane protein to pump three Na+ (sodium ions) across the membrane in exchange for two K+ (potassium ions)– ATP (energy) is needed to make the protein

change its shape so that Na+ and K+ can move through it and cross the membrane

• Helps the heart contract, helps regulate blood pressure, allows neurons to respond to stimuli and send signals

Scientific Terms

• Hypothesis: A proposed, testable answer to a scientific question.

• Observation: the use of our senses, computers, and other tools to gather information about the world.– Ex.: Studying the interactions between gorillas by

observing their behavior.

Other important science terms• Inference: A conclusion reached on the basis of evidence and

reasoning.

• Law: A law that generalizes a body of observations. At the time it is made, no exceptions have been found to a law. It explains things but does not describe them; serves as the basis of scientific principles.

• Theory: A proposed explanation for observations and experimental results that is supported by a wide range of evidence – may eventually be accepted by the scientific community.

• Principle: A concept based on scientific laws and axioms (rules assumed to be present, true, and valid) where general agreement is present.

• Fact: An observation that has been repeatedly confirmed.

Controlled experiments

• Only one independent variable should be changed in an experiment.

• Other conditions must stay the same and are called constants.

• Controlled experiments must have a control group – everything is the same as the experimental groups but the independent variable is not manipulated.– Example: When testing blood pressure medication,

control group receives none of the active ingredient.• A large number of test subjects or trials is ideal.

4.1 How do living things get ATP?

• ATP is the energy carrier in living things – it is usable energy for the cell.

• ATP stands for Adenosine triphosphate.• Living things get ATP from breaking down carbon

based molecules. (carbohydrates, lipids, proteins)• Needed for cellular activities (i.e. active transport)

Starch molecule

Glucose molecule

This is how it works

phosphate removed

Photosynthesis

• The process of photosynthesis captures energy from sunlight and converts it into sugar (glucose).

• This process happens in organisms called autotrophs or producers. (Need to make their own food)

• This process takes place in an organelle called the chloroplast (this is a plastid).

• The chloroplast has a green pigment in it called chlorophyll that is responsible for capturing the light energy.

So how does photosynthesis work?

The first stage of photosynthesis is called the Light Dependent Stage.• Light is captured by the chlorophyll in the

thylakoid of the chloroplast.

So how does photosynthesis work?

The second stage of photosynthesis is called the Light Independent Stage/ Calvin Cycle/ Dark Cycle.• This process takes place in the stroma of the

chloroplast.

The chemical formula for photosynthesis

• 6CO2 + 6H2O + light C6H12O6 + 6O2

(reactants)

(products)

Carbon dioxide plus water plus light yields Glucose and oxygen

Purpose of Cellular Respiration

• To make ATP from the energy stored in glucose– Glucose comes from an organism doing

photosynthesis themselves or from eating foods containing glucose

–Remember: the purpose of photosynthesis was just to get glucose

–Takes place mostly in mitochondria

Glycolysis• Takes place in cytoplasm (eukaryotes and prokaryotes do

this step since all cells have cytoplasm)• This portion of CR does NOT require oxygen (anaerobic)

Kreb’s Cycle (Citric Acid Cycle)• Takes place in matrix of mitochondria (only

in eukaryotes)

Electron Transport Chain (ETC)

• Takes place in inner membrane of mitochondria (cristae)– Folded to create more surface area for reactions to

produce more ATP in a small space

Equation for Cellular RespirationC6H12O6 + 6O2 6CO2 + 6H2O + 36ATPLike the reverse of photosynthesis

Energy transfers:Photo: LightCPE CR: CPECPE

What happens when there’s no/not enough oxygen or there are no mitochondria?

• Answer: Fermentation–Two Kinds:

• Lactic Acid Fermentation• Alcoholic Fermentation

• Allows glycolysis to continue making ATP without oxygen