Mrs. Jackson’s Absolute Bare Minimum Module 1 Review

You need to study more. This is better than nothing.

– 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.

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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.

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+)

Carbon atoms have unique bonding properties.

1. Carbon forms covalent bonds (strong bonds) with up to four other atoms, including other carbon atoms2. 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

Monomer  monosaccharide

Polymer disaccharide (dimer), polysaccharide 

Examples Monosaccharide:  glucose, fructoseDisaccharide: sucrose (table sugar)

Polysaccharide: starch & cellulose (cell wall in plants),

glycogen (in animals)

Unique - Provide a quick source of energy

Lipids

Monomer  glycerol & fatty acids; polar heads & fatty acid tails

Polymer  triglycerides; phospholipidsExamples Fats, oils, cholesterol, steroids, waxes,

phospholipidsUnique - Nonpolar

- Broken down to provide energy- Used to make steroid hormones (control

stress, estrogen, testosterone)- Phospholipids make up all cell

membranes  - Fats and oils contain fatty acids bonded to

glycerol

LIPIDS

ProteinsMolecule Proteins

Monomer Amino acid Polymer Polypeptide (protein) Examples Enzymes,  hemoglobin (in blood), muscle

movement, collagenUnique - 3D structure makes them active 

- Peptide bonds hold amino acids together- Have a side group (R) that makes each

amino acid (and therefore protein) different

- Sometimes may contain sulfur

Nucleic acidsMolecule Nucleic acids

Monomer  Nucleotide (5-carbon sugar, phosphate group, & base)

Polymer Nucleic acid Examples DNA & RNA Unique  - Order of the bases makes every living thing

unique- DNA stores genetic information

- RNA builds proteins

Chemical reactions release or absorb energy.

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

A catalyst lowers activation energy.• Catalysts are substances that speed up chemical

reactions– Decrease activation energy– Increase 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.•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

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.

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• 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 Functions

See attached list

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.

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

low concentration– Osmosis: diffusion of water

Diffusion and osmosis are types of passive transport.

• 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

• 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

3.5 Active Transport, Endocytosis, & Exocytosis

• Key Concept:– Cells use energy (ATP) to transport materials that

cannot diffuse across a membrane.

Active Transport

• 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)

Sodium-Potassium 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

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)

Starch molecule

Glucose molecule

This is how it works

phosphate removed

4.2 & 4.3 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 and organelle called the chloroplast.

• 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.

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.

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

Glycolysis• Takes place in cytoplasm (eukaryotes and prokaryotes do

this step since all cells have cytoplasm)• Splits one glucose molecule into two pyruvate molecules

–Costs the cell 2 ATP molecules to do this• 4 ATP molecules are produced (only gain 2 ATP)• This portion of CR does NOT require oxygen (anaerobic)

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

in eukaryotes)• 2 pyruvate (made during glycolysis) enter the mitochondrion• Each pyruvate is broken down to create 1 ATP• Total products of Kreb’s cycle (because of 2 pyruvates):

– 2 ATP

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• Oxygen and hydrogen ions combine to form water (released as

a waste product)• 32 ATP are made

ATP from Cellular Respiration

• 4 from Glycolysis (uses up 2, so really only gain 2 ATP)• 2 ATP from Kreb’s cycle• 32 ATP from ETC• GAIN 36 ATP from one glucose molecule

Equation for Cellular RespirationC6H12O6 + 6O2 6CO2 + 6H2O + 36ATP

Like the reverse of photosynthesis

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