Transcript Sci7-Chapter3-Chemistry

DO NOW: Write what you see…
Chemicals for Life
• Which objects come from living things?
• Which objects contain substances that
were never alive?
• Name three substances your body
needs to survive that were never alive.
Matter
EVERYTHING!
• Anything that has mass and takes up
space
STATES OF MATTER
solid
• _______
— have rigid shape, fixed volume.
• _______ — have no fixed shape and may not
fill a container completely.
liquid
gas
• _______
— expand to fill their container.
plasma
• _______ — similar to gas, loses electrons.
States of Matter
Chapter 2:
Composition of Matter
• Matter
– Anything that occupies space and has
mass
• Mass
– the property of a body that causes it to
have weight in a gravitational field
• Difference between mass and weight?
• Atom
– Simplest form of an element that retains
the properties of that element
– Atoms of different elements are different
– Draw example.
Atom
• Matter (solids, liquids, gases) is made of
atoms
Structure of an atom
• Nucleus
– Protons (+)
– Neutrons (-)
• Outside of nucleus
– Electrons (-)
Electron Cloud Model
Atom ALWAYS has equal number of protons and electrons
Electron Cloud Model
Energy of opposite forces hold the atom together
Therefore an atom’s charge is ________.
Atoms
• If an atom gains an electron it has a
negative
___________
charge.
• If an atom loses an electron it has a
positive
___________
charge.
• Ion
– Charged particle (+/-)
Atomic Structure
• HW: Draw the
atomic structures of
Oxygen, Nitrogen,
Hydrogen, & Carbon
Do Now: Word up!
• Take out your periodic tables.
• How many words can you make?
• You cannot use these three words.
• 3 letter words – 1pt
• 4 letter words – 2pts
• 5 or more letter words – 4 points
The Elements
• Element:
– A substance that cannot be broken down into other
substances by chemical methods
• Analogy:
– English has 26 letters
Elements
• Made up of one kind of atom
• Cannot be broken down into simpler
substances via chemical reactions
Oxygen atoms
Element
Elements
• Language like the alphabet
• Letters + letters --> word
• Element + element --> compound
How to read an Element
• Example = oxygen
• O = elemental symbol
• 8 = atomic number
(protons &/or electrons)
• 16 = mass number
(protons + neutrons)
You try…
7
N
14.00
Symbol?
Mass number?
Atomic number?
• Atoms of different elements are different
oxygen
Draw.
Hydrogen
Carbon
nitrogen
Elements in the Human Body
Oxygen
Carbon
Hydrogen
O
C
H
Nitrogen
N
Calcium
Phosphorus
Potassium
Sulfur
Sodium
Chlorine
Magnesium
Ca
P
K
S
Na
Cl
Mg
Metals
• Properties:
– Conduct heat and electricity
– Bendable
– Shiny
Nonmetals
• At room temp are gases,
liquids, & solids
Metalloids
• Combination of metals and
non-metals
• substance made of atoms of two or more
different elements joined
Compounds
Molecule
• Group of atoms held together by a
chemical bond
Now get this…
• All atoms of the same element have the
same number of protons and electrons
• But…
• ***Atoms of the same element can have
a different number of neutrons! ***
Isotopes
• Isotope– atoms with the same number of protons,
but different number of neutrons
Carbon Isotopes
The outermost electron shell is referred to
as the valence shell.
RULES ABOUT ELECTRONS!
1. First energy shell - 2 electrons
2. Second energy shell - 8 electrons
3. Third energy shell - 8 electrons
**An atom is most stable when the
valence (outer) shell contains
8 electrons =
OCTET RULE
BONDING
IONIC BONDING
COVALENT BONDING
Ionic bonds
• Between atoms of metals and nonmetals
• Bond formed by transfer of electrons
• Examples; NaCl, CaCl2, K2O
Covalent bond
• Two atoms share 1 or more pairs of electrons
• Examples; O2, CO2, C2H6, H2O, SiC
DRAW on board
examples with bonds
Si--C
Oxygen Atom
Oxygen Atom
Oxygen Molecule (O2)
Do Now: Atoms, Elements, & Compounds
• What is the purpose of mixing the ingredients?
• When the mixture is finished/cooked, can you change it back into
the original ingredients?
• If you forgot an ingredient, what may happen to the final product?
Do Now:
Chemical Rxns
• How does this show a chemical
rxn?
• What are the reactants to create
fire?
• What are the products?
Chemical Reactions
• Allow living things to grow, develop, & reproduce
• Occur around us
• Occur in our bodies
Physical change
• Properties of substance are not
changed
– Examples?
Chemical Change
• substances are converted into different
substances.
Examples?
Rate of Reactions
• speed at which reaction happens
– Slow rate:
• Molecules have few collisions
– Fast rate:
• Molecules have many collisions
Catalysts
• Enzyme
– speeds up chemical reactions
Energy & Chemical Rxns
• Demonstration: Glow sticks: Reaction
Speed & heat
Yummy
Sugar
Cookies
• 1 cup Flour
• ½ cup Sugar
• 1 teaspoon Vanilla
• 2 eggs
___________________________________
– Following a recipe is similar to writing chemical
reaction.
• Sugar + Flour + Vanilla + Eggs  Cookies
• The ingredients are my reactants
• The cookies are my products
• HOW DO I GET TO THE COOKIES?
• What do you need
to start any
reaction?
• Activation energy!
What do you need for a
chemical change to occur?
• Energy!
– Can be absorbed to break chemical bonds
– Can be released to form chemical bonds
Mixture
• two or more different substances are
mixed together but not combined
chemically
Solution
Mixture composed of two substances that are
spread out equally
Suspension
When substances don’t mix.
Water
Properties of Water
• Cohesion and
adhesion
• Density
• Solvent
Cohesion
Water molecules hydrogen bonding to each
other
Adhesion
• Attractive forces between two different
substances
– Example: Water and glass
Density
• Ice floats on water
Properties of Water
Water
Water is the solvent of Life!
Solute – substance dissolved in
a solvent to form a solution
Solvent – fluid that dissolves
solutes
Acids and Bases
pH
[H+]= 10-1M
10x fold
[H+]= 10-9 M
4 molecules of Life
•
•
•
•
Carbohydrates
Proteins
Lipids
Nucleic Acids
• Aka: macromolecules
Do Now: Relate the kangaroo to organic molecules.
What monomers make up
the Biological Molecules?
Monomer
Polymer
Simple Sugar (glucose)
monosaccharide
3 Fatty Acids
1 Glycerol
Amino Acids
Carbohydrates
Nucleotides
Nucleic Acids
Lipids
Proteins
Carbohydrates
• Contain Carbon, hydrogen, and oxygen.
• Store energy for cells.
– Animals store it as glycogen
– Plants store it as starch
• Make cellulose
– Important for cell wall stability
Proteins
• Contains the elements carbon, hydrogen,
oxygen, and nitrogen
• Made up of long chains of amino acid
monomers
– Note* There are 20 different amino acids that
all share a similar structure
Proteins
• Examples of proteins
– Muscles
– Skin
– Enzymes
• Shape is very important in proteins
• Shape predicts function
R groups
• The different R groups in amino acids is
what gives proteins different shapes.
• The different shapes allow proteins to
perform different functions.
Enzymes
Are organic molecules (proteins) that act
as catalysts.
– Catalyst- something that speeds up a
chemical reaction.
– Enzymes speed up reactions by lowering
the activation energy (Ea)
Enzyme Action
• Enzymes bind to the substrate in chemical
reactions.
• Substrate: the reactant
• Active Site: The area where the enzymes binds to
substrate
Lipids
• 3 fatty acids bonded to one glycerol
• Non-polar molecules
– do not dissolve in water
Fatty Acids
• Fatty acids are carbon/hydrogen chains that
make up most lipids
• Tail (-CH) chain is hydrophobic
• Head- carboxyl group is hydrophobic
Types of Lipids
• Triglyceride: Most common lipid that are found in
foods
• Phospholipids: Lipids which make up the cell
membrane
• Wax: Structural lipid found in plants.
• Steroids: hormones and cholesterol
Nucleic Acids
• Nucleic Acid
– Phosphorous & Nitrogen containing
compounds
• Two kinds
– DNA
– RNA
Deoxyribonucleic Acid (DNA)
• Found in the nucleus
• Heredity material passed on during
reproduction
Ribonucleic Acid (RNA)
• Found in the cytoplasm
• Found on ribosomes
– Ribosomes are made in nucleolus
Chargaff’s rule
• “the amount of adenine present always
equals the amount of thymine, and the
amount of guanine always equals the
amount of cytosine.” Erwin Chargaff
[A] = [T]
[C] = [G]
The double helix
DNA Characteristics
• Double helix
– A bonds with T
– G bonds with C
• Two strands are complimentary
• Strands are anti-parallel
– 5’- AGGTAGCGACCT -3’
– 3’- TCCAGCACTGGA -5’
DNA vs RNA
DNA
Double stranded
Nucleotides:
adenine
thymine
cytosine
guanine
DNA Replication
RNA
Single stranded
Nucleotides:
adenine
uracil
cytosine
guanine
Protein Synthesis
DNA coloring Activity!!!
Project!?
Or save for Chapter 4…
Chapter 5: Homeostasis &
Cell Transport
The Plasma Membrane and
Homeostasis
Homeostasis
• Balance between nutrients &
waste.
Plasma Membrane
• Selective Permeability controls
what enters & exits the cell
Structure
• Phospholipid bilayer
–Found around the cell
–Embedded with proteins
–strengthened with cholesterol
Cellular Transport!
• Molecules move from one
side of cell to the other
• Two Types
–Active
–Passive
Cellular Structure and Function
Passive Transport
 Move particles across cell membrane
without energy
Three Modes of Passive Transport
 Diffusion
 Facilitated Diffusion
 Osmosis
Cellular Transport
• Diffusion
– movement of particles from [high] to [low]
concentration
• Concentration gradient
– Driven by Kinetic Energy
• Put cube in hot water
• Set up carrots
Carrots
What do you think is going to happen?
Diffusion at work…
Cellular Structure and Function
Diffusion
 Movement of particles from an area of high
concentration to an area of lower
concentration
Initial Conditions
Sugar cube
Diffusion
Low
High
High
Low
Which way will the particles
move?
Which way will the particles
move?
Check Carrots
Do you notice anything different?
Osmosis
• Diffusion of water across a
selectively permeable membrane.
• Moves from [high] to [low]
• Occurs until equilibrium.
Osmosis… Which way will the
water flow?
Osmosis
• Solution
– 1. Solvent
• What the solute dissolves in
• Water is Universal Solvent
– 2. Solute
• What dissolves in/moves through the solvent
Cellular Structure and Function
Osmosis
 Diffusion of water across a selectively
permeable membrane
Three Types of Solutions
 Isotonic
 Hypotonic
 Hypertonic
Cell Concentrations
• Hypertonic
– more dissolved solute outside of cell
• Hypotonic
– less dissolved solute inside of cell
• Isotonic
– the same dissolved solute in and out
Cellular Structure and Function
Isotonic Solution
 Water and dissolved substances diffuse
into and out of the cell at the same rate.
Plant Cell
Blood Cell
11,397x
Cellular Structure and Function
Hypotonic Solution
 Solute concentration is higher inside the
cell.
 Water diffuses into the cell.
Plant Cell
Blood Cell
13,000x
Cellular Structure and Function
Hypertonic Solution
 Solute concentration is higher outside the
cell.
 Water diffuses out of the cell.
Plant Cell
Blood Cell
13,000x
Back to the carrot
• Carrot in normal water
– Iso? Hypo? Hyper?
• Carrot in NaCl
– Iso? Hypo? Hyper?
Which on is hypotinic? Hypertonic? Isotonic?
DO NOW!
• What is the difference between A, B,
and C? (ie What processes do these
figures represent?)
Cellular Transport
• Passive Transport Review
– Diffusion
– Osmosis
• Isotonic
• Hypertonic
• Hypotonic
– Facilitated Diffusion
Facilitated Diffusion is a type of Diffusion
Facilitated diffusion
• Movement of materials across the plasma
membrane using carrier proteins
• High to low
• Specificity
Facilitated Diffusion
• Facilitate
– “help” “ease”
• Used for molecules that cannot easily
pass through the membrane
– Not lipid soluble
– Too large
– Has a charge
Cellular Structure and Function
Carrier Proteins
Active Transport
 Movement of particles across the cell
membrane using energy (ATP)
Active Transport Using Carrier Proteins
Active Transport
• Requires energy
• Moves molecules from low to high
concentration
– Like pedaling up hill on a bike
Active Transport
• Endocytosis
– Cell “eating”, molecules move in
• Exocytosis
– Cell getting rid of waste, molecules move
out.
Endocytosis and Exocytosis
• passage of food and waste particles
Endocytosis
• Cells ingest (eat) external fluid,
macromolecules, large particles, & other
cells
Endocytosis
(endo- “inside”)
•
Membrane folds in and forms a vesicle
•
Contents are digested by cellular enzymes
• Pinocytosis
– fluids
• Phagocytosis
– large molecules or whole cells
Exocytosis - “excrete”
 Secretion of material out of the plasma
membrane
Exocytosis
1. Substance packaged into vesicle
2. Vesicle fuses with plasma membrane
3. Substance released from cell
Putting it all together
1. What is the difference
between passive and active
transport?
2. How do cells obtain the
materials they need to
perform life processes?
Putting it all together
Passive
Transport
Active
Transport
Add section 3 stuff on energy!
Edit Chapter 3 for Sci 7!!!
Do Now: How do organisms
obtain energy? (Ch. 8)
QuickTime™ and a
decompressor
are needed to see this picture.
Metabolism
 All of the chemical reactions in a cell
 Photosynthesis—light energy from the Sun
is converted to chemical energy for use by
the cell
 Cellular respiration—organic molecules are
broken down to release energy for use by
the cell
THE SUN: MAIN SOURCE OF
ENERGY FOR LIFE ON EARTH
First, a ‘lil bit about chloroplasts
Chloroplasts in leaves of plants perform photosynthesis
• A chloroplast
contains:
Outer
membrane
– stroma
• a fluid
– Grana
Granum
• stacks of
thylakoids
Inner
membrane
Stroma
Thylakoid
• The thylakoids contain chlorophyll
– Chlorophyll is green
– Chlorophyll captures light
Outer
membrane
Granum
Inner
membrane
Stroma
Thylakoid
WHY ARE PLANTS GREEN?
Plant Cells
have Green
Chloroplasts
Thylakoids have
chlorophylls
Electromagnetic Spectrum and
Visible Light
Gamma
rays
X-rays
UV
Infrared &
Microwaves
Visible light
Wavelength (nm)
Radio waves
The feathers of male cardinals
have carotenoid pigments.
Why are plants green?
Transmitted light
Do Now:
• A check vs. a $10 bill
Refresh…
• Write the photosynthesis equation:
– 6H2O + 6CO2 + light --> C6H12O6 + 6O2
• Autotrophs & heterotrophs
• Break organic compounds to release energy
– Some energy used to make ATP
– Energy (ATP) used to do work
Cellular Respiration
Cellular Respiration
• breakdown of
– fats,
– proteins,
– Carbohydrates
(glucose)
• Produces
– CO2,
– water,
– energy.
Aerobic Cellular Respiration
• Oxygen required=aerobic
• 2 more sets of reactions which occur in
the mitochondria
– 1. Kreb’s Cycle
– 2. Electron Transport Chain
Mitochondria
• matrix (inside inner
membrane)
– pyruvates broken
down to CO2 and
water
• cristae (folds of
inner membrane)
– where ATP is made
Different products:
ethanol & CO2
Lactic acid
Lactic Acid Fermentation
• Enzyme converts pyruvic acid into lactic
acid
• NADH gives one H to pyruvic acid
• NADH oxidized to NAD+
Milk, cheese, muscles
Alcoholic Fermentation
• Convert pyruvic acid into enthyl alcohol
• Two steps
Cellular Respiration
Fermentation in the Absence of Oxygen