AS YOU COME IN, Materials: PICK UP A COPY OF THE LAB Notes pages and pencil The Plan: Macromolecule review Macromolecule Quiz Begin Eggcellent Lab Take Energy in a Cell notes The Assessment: Cell Organelle Quiz on Monday
Jan 19, 2016
AS YOU COME IN, Materials:
PICK UP A COPY OF THE LABNotes pages and pencil
The Plan:Macromolecule reviewMacromolecule QuizBegin Eggcellent LabTake Energy in a Cell notes
The Assessment:Cell Organelle Quiz on Monday
FLAGELLA AND CILIAMicrotubules that allow
these single-celled organisms (protists) to
move.
MACROMOLECULE REVIEW General Information:
Organic vs. inorganic moleculesMonomer vs. polymerDehydration synthesis vs. hydrolysisCarbohydrate monomer, function,
testLipid monomer, function, testProtein monomer, bonds, function,
testNucleic acid monomer, monomer
parts, function
ENERGY AND THE CELL
Energy of Chemical Reactions• Basics of Energy• Enzymes & Substrates
Movement of Substances• Passive Transport:
Diffusion & Osmosis• Active Transport:
Proteins, Exocytosis, & Endocytosis
Energy Organelles• Chloroplasts• Mitochondria
Energy is defined as the capacity to do work
All organisms require energy to stay alive
Energy makes change possible, for example chemical changes
Two types of energy:Kinetic Energy: energy that is actually doing work
Potential Energy: stored energy
BASICS OF ENERGY
First law of thermodynamics“Law of Conservation of Energy”Energy can be changed from one form to another
Energy cannot be created or destroyed
Second law of thermodynamicsEnergy changes are not 100% efficient
BASICS OF ENERGY
Cells carry out thousands of chemical reactions The sum of these reactions constitutes cellular metabolism
BASICS OF ENERGY
There are two types of chemical reactions:1. Endergonic reactions absorb energy and
yield products rich in potential energy AKA: Endothermic reactions
Reactants
Po
ten
tia
l en
erg
y o
f m
ole
cule
s Products
Amount of energy INPUT
BASICS OF ENERGY
2. Exergonic reactions release energy and yield products that contain less potential energy than the reactants
AKA: Exothermic reactions
Reactants
Po
ten
tia
l en
erg
y o
f m
ole
cule
s
Products
Amount of energy OUTPUT
BASICS OF ENERGY
ENZYMESBiological catalysts
Lower activation energy needed for a chemical
reaction in the cell
11
Most enzymes are proteins (tertiary and quaternary structures)
Act as catalyst to accelerate a reaction
Not permanently changed in the process
ENZYMES
12
Are specific for what they will catalyze
Are reusable End in –ase
SucraseLactaseMaltase
ENZYMES
ENZYME
13
Enzymes work by weakening bonds which lowers activation energy
ENZYMES
14
FreeEnergy
Progress of the reaction
Reactants
Products
Free energy of activation
Without Enzyme
With Enzyme
ENZYMES
15
The substance (reactant) an enzyme acts on is the substrate.
EnzymeSubstrate Joins
ENZYMES
Forms an Enzyme-Substrate Complex
16
Active Site: A restricted region of an enzyme molecule which binds to the substrate.
EnzymeSubstrate
Active Site
ENZYMES
17
Enzymes are specific. The shape of the active site only fits a certain substrate.An enzyme that hydrolyzes protein will not
act on starch.
EnzymeSubstrate
Active Site
ENZYMES
18
Induced fit: A change in the shape of an enzyme’s active site
Induced by the substrate
ENZYMES
19
WHAT AFFECTS ENZYME ACTIVITY?
Environmental ConditionsExtreme temperatures are most dangerous
(high temp can denature (unfold) the enzyme)pH (need to remain 6-8)Tonic concentration (salt ions)
Enzyme InhibitorsCompetitive Inhibitors: chemicals that look like
the normal substrate and compete for the active site
Noncompetitive Inhibitors: chemicals that do not enter the active site but bind to another part of the enzyme causing the enzyme to change shape.
ENZYMES
20
COMPETITIVE INHIBITOR
EnzymeSubstrate
21
Enzyme
active site altered
NoncompetitiveInhibitorSubstrate
NONCOMPETITIVE INHIBITOR
AS YOU COME IN, Materials:
Notes pages and pencilEggcellent Lab PICK UP 5 PIECES OF PAPER
The Plan:Macromolecule Quiz – return papersDay 1: Eggcellent LabTake Energy in a Cell notesStart Cell Organelle flipbook
The Assessment:Cell Organelle Quiz on Monday
MOVEMENT OF
SUBSTANCESMoving necessary molecules into and
out of the cell through the cell
membrane
24
Function: Cell membranes organize the chemical reactions making up metabolism by controlling the flow of substances into and out of the cell.
Membranes are selectively permeable.
CELL MEMBRANE
Phospholipids are the main structural components of membranes
Membrane phospholipids form a bilayer
They each have a hydrophilic (polar) head and two hydrophobic (nonpolar) tails
Head
Symbol
Tails
CELL MEMBRANE
In water, phospholipids form a stable bilayerThe heads face outward and the tails face
inward
Hydrophilicheads
Hydrophobictails
Water
Water
CELL MEMBRANE
The membrane is a fluid mosaic of phospholipids and proteins
Phospholipid molecules form a flexible bilayerCholesterol and protein molecules are
embedded in it Carbohydrates act as cell identification tags
CELL MEMBRANE
The plasma membrane of an animal cell
Fibers of the extracellular matrix
Glycoprotein Carbohydrate (of glycoprotein)
Microfilaments of the cytoskeleton
Phospholipid
Cholesterol
Proteins
CYTOPLASM
Glycolipid
Proteins make the membrane a mosaic of functionSome form cell junctionsOthers transport substances across the membraneSome are receptors for chemical messages
Transport
CELL MEMBRANE
Enzyme activity Signal transduction
Activated molecule
Messenger molecule
Receptor
FOCUS: Transport Passive transport Active transport
In passive transport, substances diffuse through membranes without work by the cell A type of diffusion Substances spread
from areas of high concentration to areas of lower concentration
EQUILIBRIUMMolecule of dye
Membrane
EQUILIBRIUM
CELL MEMBRANE
PASSIVE TRANSPORT = NO ENERGY NEEDED
Osmosis is the passive transport of water.
In osmosis, water travels from an area of lower solute concentration to an area of higher solute concentration
Hypotonicsolution
Solutemolecule
HYPOTONIC SOLUTION
Hypertonic solution
Selectivelypermeablemembrane
HYPERTONIC SOLUTION
Selectivelypermeablemembrane
NET FLOW OF WATER
Solute molecule with cluster of water molecules
Water molecule
CELL MEMBRANE
WATER MOVES TO WATER DOWN
ONE SIDE OF THE MEMBRANE.
Achieving water balance between cells and their surroundings is crucial.
Osmosis causes cells to shrink in a hypertonic solution and swell in a hypotonic solution The control of water balance
(osmoregulation) is essential for organismsISOTONIC SOLUTION
HYPOTONIC SOLUTION
HYPERTONIC SOLUTION
(1) Normal
(4) Flaccid
(2) Lysing
(5) Turgid
(3) Shriveled
(6) Shriveled
ANIMALCELL
PLANTCELL
Plasmamembrane
CELL MEMBRANE
ISOTONIC = CELL
AND SOLUTION
ARE ATEQUILIBRI
UM
NO
MOVEMENT OF
WATER
Transport proteins in the cell membrane facilitate diffusion across the membrane.Small nonpolar molecules diffuse freely through
the phospholipid bilayerMany other kinds of molecules pass through
selective protein pores by facilitated diffusion
Solutemolecule
Transportprotein
CELL MEMBRANE
WILL ENERGY BE NEEDED?
In active transport, cells use energy.Transport proteins can move solutes across a
membrane against a concentration gradient, which means from low concentration to high concentration.
Active transport requires ATP
CELL MEMBRANE
Active transport in two solutes across a membrane
Transportprotein
1
FLUIDOUTSIDECELL
Firstsolute
First solute, inside cell, binds to protein
Phosphorylated transport protein
2 ATP transfers phosphate to protein
3 Protein releases solute outside cell
4 Second solute binds to protein
Second solute
5 Phosphate detaches from protein
6 Protein releases second solute into cell
Other active transport methods: Exocytosis and endocytosis transport large molecules.Exocytosis: a vesicle from inside the
cell may fuse with the membrane and expel its contents outside of the cell.FLUID OUTSIDE CELL
CYTOPLASM
CELL MEMBRANE
VESICLE
IS ENERGY NEEDED?
Endocytosis: the membrane may fold inward, trapping material from the outside. A vesicle forms and moves into the cell. AKA: phagocytosis
CELL MEMBRANE
IS ENERGY NEEDED?
CHLOROPLASTS &
MITOCHONDRIA
Organelles that make energy available for cellular work (like active transport)
Chloroplasts carry out photosynthesis, using solar energy to produce glucose and oxygen from carbon dioxide and water
Mitochondria consume oxygen in cellular respiration, using the energy stored in glucose to make ATP
CHLOROPLASTS & MITOCHONDRIA
Nearly all the chemical energy that organisms use comes ultimately from sunlight
Energy and chemicals are recycled.
Sunlight energy
Chloroplasts,site of photosynthesis
CO2
+H2O
Glucose+O2Mitochondria
sites of cellularrespiration
(for cellular work)
Heat energy