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Chief Creative Nerd
Science Prof Online
Online Education Resources, LLC
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From the Virtual Cell Biology Classroom on ScienceProfOnline.com
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Creator of Science Prof Online
Chief Executive Nerd
Science Prof Online
Online Education Resources, LLC
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Image: Compound microscope objectives, T. Port
Metabolism
Diet &
Nutrition
Image: Stilleben, painting dated 1613, oil on canvas, by Floris van Dyck
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Everyday Biology
What causes smelly farts?
-
Most people pass gas at least 10 – 25x a day.
-
Farts are mostly a byproduct microbial anaerobic respiration &
fermentation in the colon (large intestine).
-
Over 99% of fart volume is non-smelly gases, including oxygen, nitrogen,
carbon dioxide, hydrogen and methane.
-
Smelly farts are caused by microbes that generate volatile sulfur
compounds and/or by feces in the rectum.
-
Diets high in healthy sulfur containing veggies (ex. broccoli, cabbage,
brussel sprouts) and protein with sulfur-containing amino acids
significantly increase the smell of farts.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Metabolism
The Transformation of Energy
• Cells either get their
energy either by
________________ or
_________ ________.
• But a cell can’t just use
sunlight or nutrients to
run cellular reactions.
• What type of fuel is
needed to run a cell?
_____
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Cells Can’t Eat
Hamburgers
Image: Hamburger, Wiki
Metabolism
Energy is obtained by
breaking chemical bonds in
foods we eat, like glucose.
Metabolism transfers
food energy into ATP
energy, the common
energy currency of cells.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Image: Leo after pouring baby food on his head , T. Port
Cellular Respiration is
Carbohydrate Catabolism
• Organisms break down carbohydrates to create ATP for
running cellular reactions.
• The monosaccharide __________ is used most
commonly.
• Glucose catabolized by:
– Aerobic cellular respiration → Results in complete breakdown of glucose
to carbon dioxide, water and a lot of
ATP
– Anaerobic respiration & Fermentation → Only partially breaks down
glucose, into pyruvic acid and organic waste products and a little .
ATP
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Basic Chemical Reactions Underlying Metabolism
1. Anabolism & Catabolism
2. Oxidation and Reduction Reactions
3. ATP Production and Energy Storage
This is stuff that you need to know before we begin
discussing cellular respiration.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Building and Breaking Down Molecules
Anabolic Reaction
(anabolism)
The phase of metabolism in
which simple substances are
synthesized into the
complex materials of living
tissue.
Catabolic Reaction
(catabolism)
The metabolic break down
of complex molecules into
simpler ones, often resulting
in release of energy.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Basic Chemical Reactions Underlying Metabolism
1. Catabolism and Anabolism
2. Oxidation Reduction (Redox) Reactions
3. ATP Production and Energy Storage
This is stuff that you need to know before we begin
discussing cellular respiration.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Oxidation-Reduction Reaction
Image: Oil Rig Platform, NASA
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Oxidation and Reduction Reactions
What do they have to do with metabolism?
• Cells use special molecules to carry electrons (often in H
atoms).
• This is potential energy.
• Two important electron carriers:
REVIEW!
Animated lesson
on Redox
Reactions and How
NAD+ Works
– Nicotinamide adenine dinucleotide (NAD+) → add electrons & hydrogen → NADH
– Flavine adenine dinucleotide (FAD) → add electrons and hydrogen → FADH2
• Think of these energy carriers as rechargeable batteries.
(When they have the electrons and hydrogens they are charged up, when they don’t,
they need charging.)
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Basic Chemical Reactions Underlying Metabolism
1. Catabolism and Anabolism
2. Oxidation and Reduction Reactions
3. ATP Production and Energy Storage
This is stuff that you need to know before we begin
discussing cellular respiration.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
ATP
ATP
Production & Energy Storage
Q: This molecule has a sugar, a base and
three phosphate groups. What kind of
monomer is it?
• Adenosine 5'-triphosphate
• Multifunctional "molecular currency" of
intracellular energy transfer.
• Metabolism releases energy from nutrients.
• That energy can be stored in high-energy
phosphate bonds of ATP.
• ATP transports chemical energy within cells.
• ATP can be used to fuel many cellular
reactions.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Image: ATP Molecule, NEUROtiker; ATP-ADP Cycle,
ATP
ATP
Production & Energy Storage
• In a working muscle cell the entire pool of ATP is
recycled once each minute.
• Over 10 million ATP per second per cell.
• A biological “rechargeable battery!
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Images: ATP molecule, NEUROtiker; ATP-ADP Cycle, CUNY
Aerobic Cellular Respiration
Carbohydrate Catabolism
is
• Organisms catabolize (break down) carbohydrates as the
primary energy source for anabolic reactions.
• The monosaccharide glucose is used most commonly.
• Glucose catabolized by:
– Aerobic cellular respiration → Results in complete breakdown of
glucose to carbon dioxide, water and a lot of
ATP
– Anaerobic respiration & Fermentation → Only partially breaks down
glucose, into pyruvic acid and organic waste products and a little
ATP
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Aerobic Cellular Respiration →
Utilizes 1. glycolysis, 2. synthesis of acetyl
CoA, 3. Krebs cycle, and 4. electron transport
chain; results in complete breakdown of
glucose to carbon dioxide, water and
ATP
ATP
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Aerobic Cellular Respiration
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Images: Cellular Respiration, Regis Frey
Aerobic Cellular Respiration
Subpathway
1. glycolysis
2. synth acetyl-CoA
3. Krebs cycle
4. ETC
Let’s put the energy
extracted from
glucose into our energy
piggy bank.
Molecule In
Molecule Out
Energy Obtained
Glycolysis
• Occurs in
cytoplasm
of most cells.
• Involves splitting
of a six-carbon
glucose into two
three-carbon
molecules of
pyruvate.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Image: Glucose molecule, YassineMrabet
Synthesis of Acetyl-CoA
The two molecules of pyruvate
(pyruvic acid above)
result in:
– 2 molecules of __________
– 2 molecules of _____ (This is what generates carbon dioxide that you breathe out.)
– 2 molecules of ______ (electron carrier)
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Krebs Cycle
(Citric Acid Cycle)
• Great amount of energy remains
in bonds of acetyl-CoA.
• The Krebs cycle transfers much of this energy to
electron carriers NAD+ and FAD.
• Occurs in cytoplasm of prokaryotes and in matrix of
mitochondria in eukaryotes.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Image:Krebs Cycle of Cellular Respiration, Regis Frey
Electron Transport
•
Most of the ATP made in
cellular respiration comes
from the stepwise release
of energy through a series
of redox reactions between
molecules known as the
electron transport chain (ETC).
•
Must occur in a membrane. The ETC is located in cristae of mitochondria in
eukaryotes.
•
Q: Where would the ETC of prokaryotes be located?
Three main events important in the ETCs generation of ATP:
1. ______________________
2. ______________________
3. ______________________
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Image: Mitochondrion diagram M. Ruiz
Electron
Transport
1.
Oxidation Reduction
Reactions
•
The electron carriers
(NADH and FADH2) bring
electrons and protons (H+)
to the ETC.
•
Carrier molecules in the
membrane of the
mitochondria pass
electrons from one to
another and ultimately to
final electron acceptor.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Images: Mitochondrion diagram M. Ruiz
Electron transport chain, Tim Vickers
Electron
Transport
2. Creation of a Proton
Gradient
• Energy from each electron
being passed down the chain
is used to pump protons (H+)
from one side of the
membrane to the other.
• Proton gradient = type of ion
gradient (difference in ion
concentration on either side of a
membrane) … potential energy
available for work in cell.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Images: Mitochondrion diagram M. Ruiz
Electron transport chain, Tim Vickers
Electron
Transport
3. Synthesis of
ATP
H+ ions flow down
proton gradient
through protein
channels (ATP
synthase) that
phosphorylate ADP
to make ATP.
REVIEW!
Animated lesson on
Electron Transport
Chain
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Images: Mitochondrion diagram M. Ruiz
Electron transport chain, Tim Vickers
Meet the Enzyme: ATP Synthase
Important metabolic enzyme that
harnesses energy for biological cells
to use.
Involved in synthesis of adenosine
triphosphate (ATP), from:
-
adenosine diphosphate (ADP)
- a phosphate group and
- energy from H+ ion
- gradient
ATP is the most commonly used
"energy currency" of cells.
Reaction:
(ATP
synthase)
ADP + Pi ----ATP
substrate
substrate
product
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Images: ATP synthase diagram, Tim Vickers
Aerobic Cellular Respiration
REVIEW!
Animated lesson
and quizzes on
Cellular
Respiration
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Image: Cellular Respiration, Regis Frey
Aerobic cellular respiration →
Utilizes glycolysis, synthesis of acetyl-CoA, Krebs cycle,
and electron transport chain; results in complete
breakdown of _________ to carbon dioxide, water & ATP
The ultimate objective is to make
cellular work.
ATP
molecules to do
Each NADH results in 3 ATP, Each FADH2 results in 2
ATP.
A total of 38 molecules of ATP are formed from one
molecule of glucose.
Lets figure out how we got 38 ATP by the end of aerobic
respiration.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Where does the energy
come from?
In other words, how do we get
glucose to begin with?
Autotroph - organism that makes organic
compounds from inorganic sources.
Plants, some bacteria, and some protista
make their own food using light energy.
Heterotroph - organism that cannot make
organic compounds from inorganic sources.
They obtain their organic compounds by
consuming other organisms. Almost all
animals, fungi and some Protista and bacteria.
Sun
→ Autotroph → Heterotroph
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Conversion of Energy
• Every food chain begins with
anabolic pathways in
organisms that synthesize
their own organic molecules
from inorganic carbon dioxide.
• Most of these organisms
capture light energy from the
sun and use it to drive the
synthesis of glucose from
CO2 and H2O by a process
called photosynthesis.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Cells that Run on
Solar Power
• Organisms capture light energy
with pigment molecules;
primarily chlorophyll.
Cyanobacteria are
photosynthetic bacteria.
Elodea plant cells with
chloroplasts visible.
• Prokaryotic autotrophs have
chlorophyll in their cytoplasm.
• Eukaryotic autotrophs have
chlorophyll organized in special
photosystems within
chloroplast organelles.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Images: Cyanobacteria, Bob Baylock; Elodea plant
cells, T. Port Chloroplast diagram, Wiki
Using oxygen (1/2 O2) in metabolism
creates toxic waste.
Cells that are able to use aerobic respiration produce
special molecules that detoxify oxygen:
(catalase)
Catalase: H2O2 ------- H20 and 02
(SOD)
Superoxide dismutase (SOD): oxygen radical ------- H20 and
O2
Q: What kind of molecules are catalase and SOD?
Cells that don’t make one or both of these cannot
exist in the presence of oxygen.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Bacterial Genus: Clostridium
GRAM-POSITIVE
Obligate anaerobe, bacillus-shaped
All species form endospores.
Clostridium
botulinum
All have a strictly fermentative
mode of metabolism (Don’t’ use oxygen).
Vegetative cells are killed by exposure to
O2, but their endospores are able to
survive long periods of exposure to air.
Known to produce a variety of toxins, some
of which are fatal.
Clostridium tetani = agent of tetanus
C. botulinum = agent of botulism
C. perfringens = one of the agents of gas gangrene
C. difficile = part of natural intestinal flora, but
resistant strains can overpopulate and cause
pseudomembranous colitis.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Images:Clostridium botulinum: stained with Gentian violet. CDC
Public Health Image Library. (PHIL #2107), 1979; Charles Bell
If oxygen is
required for
aerobic cellular
respiration…
how do cells
get energy if
there is no
O2,
or if they
can’t use oxygen?
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Images: Clostridium botulinum,
CDC; Calvin holding breath, Bill
Anaerobic Cellular Respiration
• Many anaerobic
bacteria, and muscle
cells that run out of
O2, can make ATP by
using something
other than oxygen as
an electron acceptor
(nitrate, sulfate & carbon dioxide).
• In anaerobic
respiration, not all
the ETC is used, so
less ATP is
produced.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Image: Electron transport chain, Tim Vickers
More Fun With
Farts
•
When CO2 is used as an electron
acceptor in anaerobic respiration, the
product is either methane or acetic
acid (depending on the organism).
•
Methane produced in our gut (and released as farts) results from this
process.
•
New study of people with GI symptoms, found that those with high
levels of hydrogen (H) and methane (CH4) gases in their breath also
had higher body mass index (BMI) and % body fat.
•
Having both CH4 and H in breath indicates presence of
Methanobrevibacter smithii, a key methane-producing microbe
(Archaea) in the human gut.
•
In addition to making methane, M. smithii scavenges hydrogen from
other microbes, and these 2 actions appear to increase nutrient
absorption and promote weight gain.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Image: Methane 3D, Ben MillsMethane=producing Gut Organisms
May Promote Weight Gain” Medscape.
Fermentation
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
How do we metabolize proteins & fats?
.
Excess
amino acids can be used to synthesize ________, ________, and alpha
ketogluterate, which enters the Krebs cycle.
The glycerol & fatty acids of fats can also be converted to pyruvate and Acetyl CoA and
then enter cellular respiration.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Aerobic
vs
Anaerobic Respiration
• Q: What is the
key difference
between aerobic
and anaerobic
respiration?
• Q: How does this
difference
impact the
amount of energy
that anaerobes
can harvest from
their food?
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
REVIEW!
Interactive
animated lesson
and comparing
Anaerobic vs
Aerobic
Respiration
Image: Electron transport chain, Tim Vickers
Fermentation
•
When there is no final electron acceptor for the ETC, then electron
transport can’t happen.
•
Fermentation is an alternative system that allows glycolysis to
continue without the other steps of cellular respiration.
•
Not as energetically efficient as respiration.
•
Produces only 2 ATP.
ATP
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
ATP
Fermentation
Two different fermentation pathways:
• Yeasts and some bacteria are able
to get their ATP from glycolysis
by using alcoholic fermentation.
Converts pyruvate into ethanol and
carbon dioxide.
The formation of carbon dioxide, a byproduct of
ethanol fermentation, causes bread to rise.
• Animal cells and some bacteria
through the process of lactic acid
fermentation. Here pyruvate
results in end product of lactic
acid.
When muscles need energy produced faster than
the body can deliver oxygen, such as when lifting
heavy weights, the working muscles generate
energy anaerobically, through lactic acid
fermentation.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Images: Bread Rolls, Bangin; Dexter Jackson, Local
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Image: Glycolysis, Regis Frey
Fermentation
REVIEW!
Interactive
animated lesson
comparing
Alcoholic
vs
Lactic Acid
Fermentation
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Why does fermentation require extra
steps after glycolysis?
•
In fermentation, after glycolysis,
there are additional steps to oxidize
NADH (into NAD+).
•
Electrons and hydrogen ions from
the NADH that was produced by
glycolysis are donated to another
organic molecule.
•
No more ATP is created through
these additional steps.
•
So essentially…
FERMENTATION =
glycolysis + recycling of NAD+
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Image: Glycolysis, Regis Frey
Fermentation
•
Most of the potential energy remains in the bonds of fermentation products.
•
Fermentation products are wastes to cells that make them, many are useful to
humans (ethanol, acetic acid, and lactic acid).
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Alcohol Fermentation in Wine
Louis Pasteur & Industrial Microbiology
- Q: What is fermentation?
1. Blobs were alive because
they divide and make more of
themselves.
- What causes fermentation?
Some scientists thought that air caused fermentation
Others thought that microbes caused fermentation.
- Q: What is pasteurization?
Are these nonliving blobs or
living microbes?
Pasteur’s
Observations:
2. Put grape juice + yeast in open and
in air-tight containers. Fermentation
occurred in both. This means that
yeast are facultative anaerobes.
3. Took two flasks of sterile grape juice
and introduced bacteria into one and
yeast into another.
< yeast + grapes = yummy wine  (ethanol)
bacteria + grapes = spoiled wine  (lactic
acid) >
Image: Louis Pasteur, Pierre Lamy Petit, circa 1866; Grapes
fermenting; Sachromyces yeast; Lactobacillus, Public health Image
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Metabolism:
Diet &
Nutrition
Stuff We Need
______nutrients:
• Carbohydrates
• Proteins
• Lipids
______nutrients:
• Vitamins
• Minerals
…and, of course, Water
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Image: Stilleben, painting dated 1613, oil on canvas, by Floris van Dyck
3 of the 4 macromolecules commonly occur on Nutrition
Labels, and are the major components in our diet.
Q: Which organic macromolecule is not a common part of our diet?
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Images: Nutrition Label, Wiki
Organic Molecules - Carbohydrates
• “carbon” - hydrates”
Boogers
• One carbon molecule to one water
molecule (CH20)n.
• saccharide is a synonym for
carbohydrate.
• The prefixes on the word
“saccharide” relates to the size of
the molecule (mono-, di-, tri- poly-).
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Chocolate
Cake
You probably know that
chocolate cake is full of
refined sugars…carbs. You
may not know that boogers
contain carbs as well.
Boogers are dried-up mucus
and dirty nose debris. Mucus
is made mostly out of sugars
and protein. Looks like this
little punkin is double
dipping. Bon appetite!
Image: Sucrose, Wiki
Organic Molecules - Carbohydrates
Monosaccharides
•
•
•
single sugars (one molecule)
simplest
*glucose, fructose
Disaccharides
•
•
•
•
double sugars
combination of two monosaccharides
* sucrose = glucose + fructose
* lactose = glucose + galactose
Polysaccharides
•
•
•
•
macromolecules; polymers composed of several sugars
can be same monomer (many of same monosaccharide) or
mixture of monomers
food storage carbohydrates: glycogen (animals) starch (plants)
structural carbs: chitin (animals), cellulose (plants)
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Carbohydrates -
Nutrition
•
Present in fruits, vegetables and grains…
essentially in plant matter, and low amounts in
dairy.
•
_______ carbs are not bad for you. They should
be the type of food you eat the most of (45 – 65%
of your daily food intake).
•
Complex carbs more nutrient-rich and harder for
your body to break down. They enter blood
stream more slowly, and include fiber.
•
Highly processed, refined carbs (such as sucrose) are
like “pre-chewed” food, so are very easily
digested. They quickly enter blood stream, and
can cause levels of the hormone _______ to
spike.
•
Consuming too many refined carbs can increase
your risk of Type 2 diabetes.
•
Q: Lets list some complex carb and simple carb
food sources on the board.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Image: Vegetables, Gpics, Wiki; Grains, USDA; Fruits, Bill Ebbesen
Organic Molecules - Proteins
Proteins are macromolecules, polymers
composed of monomers called…
Amino acids
contain a:
1. base amino group ( -NH2)
2. acidic carboxyl group ( -COOH)
3. hydrogen atom
…all attached to same carbon atom (the α –
carbon…alpha carbon).
4. Fourth bond attaches α-carbon to a side
group (--R) that varies among different
amino acids.
Side groups important … affects the way a
proteins amino acids interact with one
another, and how a protein interacts with
other molecules.
Essential amino acids:
Cannot be synthesized by the
body. They must be ingested
in the diet.
Arginine * Histidine * Methionine* Threonine *
Valine * Isoleucine * Lysine * Phenylalanine *
Tryptophan * Leucine
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Organic Molecules – Proteins
Peptide Bonds
Link amino acids together in
chains, like the beads on a
necklace.
A dipeptide is 2 amino acids
linked together.
A polypeptide, more than two.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Image: Protein Primary Structure, Wiki
Levels of
Protein
Structure
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Image: Levels of protein structure, M Ruiz
Organic Molecules - Proteins
Complex organic macromolecules fundamental to living cells.
Composed of one or more chains of amino acids.
Proteins perform many functions in cells, including:
1. Structural
• Components in cell walls, membranes,
and within cells themselves.
2. Enzymes
• Chemicals that speed up a chemical reaction.
• The catalysts in cells are called enzymes.
3. Regulation
• Some regulate cell function by stimulating or hindering either the
action of other proteins or the expression of genes.
4. Transportation
• Some act as channels and “pumps” that move substances into or out of
cells.
5. Defense
• Antibodies = proteins that defend your body against microorganisms
• Some bacteria produce proteins (bacteriocins) that kill other
bacteria.
Images : Cell Membrane, Wiki; Channel Protein, Wiki; Antibody,
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Q: How do you sabotage
a protein?
• Alteration of a protein shape
through some form of external
stress
Irreversible egg
protein
denaturation
caused by high
temperature (while
cooking it).
Example, by applying heat, acidic
or alkaline environment
•
Denatured protein can’t carry out
its cellular function .
•
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Organic Molecules – Nucleic Acids
Nucleic acids
(both RNA and DNA)
nucleotides.
are macromolecules; polymers made up of monomers called
Nucleic acids deoxyribonucleic acid
(DNA) and
ribonucleic acid
(RNA) =
genetic material of cells.
Names derived from type of sugar contained within molecules = ribose
Nucleotides
Each monomer of nucleic acid is a nucleotide and consists of 3 portions:
- a sugar
- one or more phosphate
- one of five cyclic
nitrogenous bases
+adenine, guanine (double-ringed purines)
+ cytosine, thiamine or uracil (single-ringed pyrimidines)
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Image: Nucleotide Structure, Wikipedia
Organic Molecules – Nucleic Acids
Nucleic Acid Structure
Nucleotides linked by covalent
bonds between sugar of one
nucleotide and phosphate of
next (sugar-phosphate backbone).
Nitrogenous bases extend
from it like teeth of a comb.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Nucleic Acids - DNA
DNA is a double stranded molecule, analogous to a
ladder.
The “ladder” =
• two deoxyribose-phosphate chains form the “side
rails”
• base pairs, linked by hydrogen bonds, form the
“rungs”.
Purine Bases
(double ring)
Adenine & Guanine
Pyrimidine Bases
Cytosine & Thymine
(single ring)
Base Pairs (purine always pairs with pyrimidine):
Adenine + Thymine
Cytosine + Guanine
Q: How do I remember this?
Hydrogen bonds attract the bases from one strand
to the bases on the other strand and also twist the
phosphate-sugar backbones into a helix.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Images: Model of DNA Molecule, Field Museum,
Chicago, T. Port DNA, Biology Corner Website
ATP
Production and Energy Storage
• Q: This molecule has a sugar, a base and three
phosphate groups. What kind of monomer is it?
• Adenosine 5'-triphosphate
• Multifunctional "molecular currency" of
intracellular energy transfer.
• Organisms release energy from nutrients; can be
concentrated and stored in high-energy phosphate
bonds of ATP.
•
Transports chemical energy within cells for
metabolism.
• Produced as energy source during
photosynthesis and cellular respiration.
• Consumed by many enzymes and a multitude of
cellular processes
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Image: ATP Molecule, NEUROtiker; ATP-ADP Cycle,
Organic Molecules – Lipids
(Fats, Phospholipids, Waxes & Steroids)
Hydrophobic macromolecules…insoluble in water.
Not attracted to water because …
non-polar covalent bonds linking carbon & hydrogen aren’t attracted to the polar
bonds of water.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Images: Cholesterol, Wiki; Phospholipid Structure, Bryan
Derksen. Wiki Honeycomb, Wikii; Oil & Water, Kidipede
Organic Molecules – Lipids
(Fats, Phospholipids, Waxes & Steroids)
Fats
Fats and oils are made
from two kinds of
molecules:
•
glycerol
(a type of alcohol)
•
fatty acids
(triglycerides)
Images: Oil & Water, Kidipede
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Organic Molecules – Lipids
(Fats, Phospholipids, Waxes & Steroids)
Phospholipids
•
Phospholipids are a major
component of all cell membranes.
•
Most phospholipids contain a
diglyceride as the tail, and a
phosphate group for head.
•
Hydrocarbon tails are
hydrophobic, but phosphate
heads are hydrophilic.
•
So phospholipids are soluble in
both water and oil.
•
Tails from both layers facing
inward and the heads facing
outward = phospholipid
bilayer.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Image: Cell Membrane, Wiki;
Organic Molecules – Lipids
(Fats, Phospholipids, Waxes & Steroids)
Waxes
•
Do not have a hydrophilic head: so
completely water insoluble.
Steroids
•
The central core of a cholesterol
molecule (4 fused rings) is shared
by all steroids.
•
Cholesterol is precursor to our
sex hormones and Vitamin D.
•
Our cell membranes contain
cholesterol (in between the
phospholipids) to help keep
membrane “fluid” even when
exposed to cooler temperatures.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Image: Lava Lamp, Wiki; Cholesterol molecule, Wiki;
Phospholipids & Cholesterol, Cytochemistry.net
REVIEW!
Animated lessons on
Organic Macromolecules
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Images: Cholesterol, Wiki; Chilesterol; Amino Acids &
Peptide Bonds; DNA Molecule, National Science
Carbohydrates -
Fiber
•
Also called “bulk” or “roughage”.
•
Most are indigestible ___________________.
•
There are two main types of fiber with different
effects: insoluble fiber and soluble fiber.
•
______________________ improves elimination by
increasing stool bulk, preventing constipation and
decreasing risk of colon cancer.
•
Foods high in insoluble fiber: legumes, whole grains,
vegetables, fruits, nuts and seeds.
•
___________________ delays gastric emptying,
slows absorption of glucose into the bloodstream and
inhibits cholesterol absorption.
•
Good sources of soluble fiber : Fruits, vegetables, oat
bran, legumes, barley, nuts and seeds.
•
The American Dietetic Association recommend 20 to
35 grams of total fiber each day. Most people get
FAR LESS than this.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Image: Vegetables, Gpics,USDA; Fruits, Bill Ebbesen
Proteins - Organic Macromolecules
Proteins are macromolecules, polymers composed of
____________ called _______________.
Amino acids contain a
1. base amino group ( -NH2)
2. acidic carboxyl group ( -COOH)
3. hydrogen atom
…all attached to same carbon atom (the α –
carbon…alpha carbon).
Fourth bond attaches α-carbon to a side group (--R)
that varies among different amino acids.
There are hundreds, but most organisms use only 21
amino acids to build proteins.
Side groups important … affects the way a protein’s
amino acids interact with one another, and how a
protein interacts with other molecules.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Proteins -
Organic Macromolecules
Q:What kind of bonds link
amino acids together?
Q: Do you think these
bonds are … ionic?
covalent?
A dipeptide is 2 amino
acids linked together.
A polypeptide, more than
two.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Image: Protein Primary Structure, Wiki
Protein
Structure
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Image: Levels of protein structure, M Ruiz
Proteins -
Dietary
•
__________ Proteins = contain all
essential amino acids necessary for
good health
•
__________ Proteins = are missing
some of the essential amino acids
necessary for good health
•
Essential Amino Acids = can’t be
synthesized by the human body
•
Percentage of daily food intake that
should be protein: 10 – 35%.
•
The amount of protein that a person
actually requires on a daily basis is
quite small, approximately 0.8 gram per
pound of body weight, depending on level
of physical activity. (That means, for example,
that 150# person needs about 120 grams or 4.25 oz of
protein daily.) – USDA
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Lentils, a vegetable protein, Paul
Goyette; Roasted chicken, Viperx, Wiki
Lipids
- Organic Macromolecules
Fats, Phospholipids, Waxes & Steroids
Hydrophobic macromolecules…insoluble in water.
Not attracted to water because …
non-polar covalent bonds linking carbon & hydrogen aren’t attracted to the
polar bonds of water.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Images: Cholesterol, Wiki; Phospholipid Structure, Bryan
Derksen. Wiki Honeycomb, Wikii; Oil & Water, Kidipede
Lipids
- Organic Macromolecules
Fats
Fats and oils are made
from two kinds of
molecules:
• ____________
(a type of alcohol)
• _____________
(triglycerides)
Images: Oil & Water, Kidipede
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Lipids - Dietary Fats
Saturated fats
•
•
Mostly from animal sources.
•
Single bonds between the carbons in
their fatty acid tails (all carbons are
bonded to max number of hydrogens
possible).
Hydrocarbon chains fairly straight and
packed closely together … so
______at room temperature.
Unsaturated fats (oils)
•
Mostly from plant sources.
•
Have double bonds between some
carbons in the hydrocarbon tail,
causing bends or “kinks” in shape.
•
Kinks in hydrocarbon tails, so
unsaturated fats can’t pack closely
together … ________ at room temp.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Lipids – Dietary Fats
•
We typically refer to them all as “Fats”, but remember, fats
are only one of several molecules known as lipids.
•
Phospholipids, steroids and true fats play an important role in
human nutrition, should get no more than 30% of calories from
fats., and the type of fat consumed is very important!
•
_____________ fatty acids (EFAs) are fats that the body
can’t make, but needs to take in from outside sources.
•
There are two families of EFAs: omega-3 and omega-6. Fats
from each of these families are essential, as the body can
convert one omega-3 to another omega-3, for example, but
cannot create an omega-3 from scratch.
•
When the EFAs were discovered in 1923, they were designated
Vitamin F. In 1930, further research showed that the two EFAs
are better classified with the fats than with the vitamins.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Olive oil
has both
omega 3
and
omega 6
EFAs
Lipids
•
Phospholipids are a major
component of all cell
membranes.
•
Most phospholipids contain a
diglyceride, a phosphate group,
and a simple organic molecule
such as choline.
•
The diglyceride tails are
___________, but phosphate
group end is _____________.
•
So phospholipids are soluble in
both water and oil.
•
– Phospholipids
Tails from both layers facing
inward and the heads facing
outward = phospholipid
_______.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Image: Cell Membrane, Wiki;
Phospholipids - Dietary
•
Because they are polar (hyprophobic
and hydrophilic parts) phospholipids
can act as an emulsifier in foods,
enabling oils to dissolve in water.
•
_______, which is made of
phospoholipid, is used in cooking
sprays and as a food emulsifier.
For example, lecithin keeps the
cocoa and cocoa butter in a candy
bar from separating.
Originally discovered in egg yolk,
and today commercially extracted
from soybeans, but widely present
in animal and plant tissues.
•
Remember, if we are eating cells,
we are eating phospholipids.
Steamed and salted, edamame (soybeans) is yummilicious;
as addictive as potato chips, but much healthier! Protein,
carbs and healthy fats all in one food item.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Image: Edamame, Tammy Green
Lipids -
Waxes & Steroids
Waxes
•
Do not have a hydrophilic head: so
completely water insoluble.
•
Many plants, especially those found in
warm climates, produce waxes to reduce
dehydration.
Steroids
•
The central core of a cholesterol
molecule (4 fused rings) is shared by all
steroids,
•
Cholesterol is precursor to our sex
hormones and Vitamin D.
•
Our cell membranes contain __________
(in between the phospholipids) to help
keep membrane “fluid” even when
exposed to cooler temperatures.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Image: Lava Lamp, Wiki; Cholesterol molecule, Wiki;
Phospholipids & Cholesterol, Cytochemistry.net
Calories
(really Kilocalories)
Q: What is a calorie?
Carbohydrates have ____ calories
per gram.
Fiber, a type of less-digestible
carb has ____ calories per
gram.
Proteins have _____ calories per
gram.
Fats have ___ calories per gram.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
How many calories
are in alcohol?
______ calories per gram.
But different drinks have
different strengths of alcohol.
So you can calculate the calories in
any alcoholic drink that you
consume with the following
calculation:
1.6 x alcohol % x oz in a glass
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
To learn more about alcohol and your
health, see the “Rethinking Drinking”
website by the NIAAA (National Institute
on Alcohol Abuse and Alcoholism).
VITAMINS -
Micronurteints
•
________________ usually not produced by the
body, but essential in minute amounts for
metabolism.
•
Do not serve as a source of energy, but some help
facilitate many metabolic reactions as
_____________.
•
Example: B vitamins
- Eight water-soluble vitamins that play important roles in cell
metabolism.
-Once thought to be a single vitamin, referred to as Vitamin B
(much like how people refer to Vitamin C or Vitamin D).
- Later research showed that they are chemically distinct
vitamins that often coexist in the same foods.
- Supplements containing all eight B vitamins are generally
referred to as a vitamin B complex. Individual B vitamin
supplements are referred to by the specific name of each vitamin
(e.g. B1, B2, B3).
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Images: B vitamin caplets, Ragesoss
VITAMIN - B12
•
Largest and most complex of all the vitamins.
•
Sources of B12: Only bacteria can synthesize. Present in
animal products such as meat, poultry, fish (including
shellfish), and to a lesser extent, dairy. Vegans need to take
supplements.
•
Involved in many aspects of our health. Required for proper
red blood cell formation, neurological function, and DNA
synthesis.
•
10-15% of people are believed to be deficient in this vitamin.
•
B12 and Depression
Observational studies have found as many as 30% of patients
hospitalized for depression to be deficient in vitamin B12.
A recent cross-sectional study of 700 community-living, physically
disabled women over the age of 65 found that vitamin B12 deficient
women were twice as likely to be severely depressed as non-deficient
women.
The reasons for the relationship between vitamin B12 deficiency and
depression are not clear.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Learn more about Vitamin
B12 from the website of the
Office of Dietary
Supplements, National
Institutes of Health.
Image:
PeriodicofTable
of B12,
Elements
Image: Molecular
structure
Vitamin
Wiki
MINERALS - Magnesium
•
Magnesium plays an important role in the production and
transport of _________.
•
It is also important for the contraction and relaxation
of muscles.
•
Magnesium is involved in the synthesis of protein, and it
assists certain enzymes in the body.
•
Over 300 enzymes require magnesium ions for their
catalytic action, including all enzymes using or
synthesizing ATP, or those that use other nucleotides to
synthesize DNA and RNA.
•
Human magnesium deficiency is common, with only
approximately 32% of the United States meeting the
RDA.
•
Low levels of magnesium in the body have been
associated with development of illnesses such as asthma,
diabetes, and osteoporosis.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
12
Mg
24.305
Magnesium
Images: Magnesium crystals, Warut Roonguthai;
Food sources of Magnesium, Peggy Greb
WATER
•
All chemical reactions of living things take place in water.
•
Many types of metabolic wastes can only be eliminated from body when dissolved in water.
•
The catalysis of materials requires water.
•
You may be able to survive weeks without
food, but wouldn’t last more than a few days
without water.
•
Human body ~ 65% water (even dense tissue
like bone is 33% water).
•
Food provides ~ 20% of total water intake.
Remaining 80% from water and other beverages.
•
Institute of Medicine advises men consume
roughly 3.0 liters (~ 13 cups) total beverages
daily & women consume 2.2 liters (~ 9 cups).
•
Q: What are some reactions that we have
discussed in class that involve water?
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Confused about what to eat?
• Eat more fresh food!
• Eat local food when you can!
• Complex carbs, balanced
wit protein and healthy fats.
• Reduce animal fats and refined sugar.
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Image: Edamame, Tammy Green
Confused?
Here are links to fun resources that further explain
nutrition:
•
Metabolism: Diet & Nutrition Main Page on the Virtual Cell
•
Cellular Respiration
•
“The Body Machine”
•
“Sugar, Sugar”
a song by The Archies.
•
Food Molecules
video from HowStuffWorks, a Discovery company.
•
“Do You Want Fries With That?” song by Tim McGraw.
Biology Classroom of Science Prof Online.
animation by Jay Phelan, “What is Life? A
Guide to Biology”, W. H. Freeman & Co.
music video by School House Rock.
(You must be in PPT slideshow view to click on links.)
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Are you feeling blinded by science?
Do yourself a favor. Use the…
Virtual Cell Biology
Classroom (VCBC) !
The VCBC is full of resources to help you succeed,
including:
•
practice test questions
•
•
•
review questions
study guides and learning objectives
PowerPoints on other topics
You can access the VCBC by going to the Science Prof Online website
www.ScienceProfOnline.com
Images: Blinded With Science album, Thomas Dolby; Endomembrane system, Mariana Ruiz, Wiki