Unit I Homework
Nutritional Analysis
Introduction
In Chapters 3 and 4 of the textbook, you learned that the body needs various macro and micronutrients in
order to function properly. You also learned about cellular metabolism and what the human body uses as
a fuel source. This all seems simple at first glance; however, it can be difficult to determine whether we
are getting what our body needs. Even when we know what our body needs, it becomes even more
difficult to make sure we are supplying our body with those needs. The car you drive probably requires
gasoline in order to function properly. When you need to go somewhere, you make sure you have enough
gasoline in the tank to reach your destination. If you do not, you probably stop at a gas station and fill
your car’s tank with gas. You do not pour cola in the tank or jelly donuts; you put gas because that is what
it needs. Why do we put cola and jelly donuts in our bodies when we do not need them? Often, it is
difficult to determine what is in the foods that we eat. Sometimes it is hard to determine if the food
contains the correct nutrients or processed foods that our body does not need. This lab exercise will help
you learn how to read nutritional labels and determine what your body needs to function properly.
Objectives
1. Analyze nutritional information based on what the body needs to function properly.
2. Calculate BMI and learn about caloric balance.
Materials
You will not need any extra materials other than your textbook and your computer (with internet access)
to complete this lab.
Directions
•
•
•
•
Type or paste all answers directly on this data sheet.
Use the following nutritional label and answer the questions that follow. You may use your
textbook as a resource when comparing the two products.
Select Save As, and save this document using your last name and student ID as the file name.
Upload the data sheet as a .doc, .docx, or .rtf file when you are finished.
Serving Size
Servings Per Container
Calories
Saturated Fat
Trans Fat
Cholesterol
Sodium
Fiber
Sugars
Protein
Vitamin A
Calcium
Vitamin C
Vitamin D
Main Ingredients
Product A
1oz
1
150
3g
0g
3mg
250mg
1g
3g
1g
35%
15%
100%
30%
Milk, potato,
vegetable oil, salt,
sugar, processed
wheat flour
Product B
1.5oz
1
165
1g
0g
1mg
225mg
3g
1g
4g
30%
25%
100%
30%
Water, nonfat milk,
whole corn, vegetable
oil, whole wheat flour,
rice flour, whole oat
flour
1
Questions 1 – 5 are short answer questions. Answer each question in the space provided. Question 6 is a
short essay. Total: 40 points
1. Which product contains the most calories per serving? (6 points)
2. Which product contains the largest serving size? (6 points)
3. Which product contains the most calories per ounce? (6 points)
4. Which product contains the most nutrients that are not as healthy for the body in large amounts?
(6 points)
5. Which product is a healthier choice? (6 points)
6. Explain why you picked the product that you did in question 5. Your answer should be in
paragraph format and should be at least 100 words in length. Type your answer directly below.
(10 points)
2
Determine your BMI
The point of this exercise is for the student to become familiar with his or her own score using a very
common biometric indicator. Conduct the exercise using your own data. However, if you do not wish to
disclose your own data, then conduct it again with reasonable fictitious data and report that.
Questions 1–4 below are short answer questions. Answer each question in the space provided. Total: 20
points
1. What is your height?
points)
ft
in What is your weight?
Lbs (5
Go to: http://www.choosemyplate.gov/ then click on ONLINE TOOLS in the menu and select BMI
CALCULATOR from the drop down menu. Follow the links to the calculator tool hosted by the CDC.gov
website. Enter the information to determine your BMI (or use the fictitious data) by clicking the link to the
Adult BMI Calculator.
Type the information from above into the appropriate spaces and then click: Calculate BMI.
2. What is your BMI? What recommendations are listed? (5 points)
On the left menu click on: Finding a Balance.
3. What is the caloric balance equation? (5 points)
4. Do you think you are in caloric balance? What are the recommended physical activity levels? (5
points)
3
Reading Nutrition Facts Labels Total: 40 points
For this portion of the assignment read the U.S. Food and Drug Administration’s food facts guide about
labels and then answer questions 1 and 2. Click here to access the guide.
Question 1. (16 points)
Write an essay at least 200 words in length that explains what are proteins, carbohydrates, and fats.
Question 2. (12 points)
Take any can of vegetables from your pantry. Report the levels of proteins, carbohydrates, and fats for a
serving size of your vegetable.
Review the label for hamburger and answer question 3. Click here to read the label.
Question 3. (12 points)
Discuss what stands out to you as a difference between your veggie and the hamburger. Your answer
should be at least 100 words in length.
4
Chapter 1
Can Science Cure the Common Cold?
Introduction to the Scientific Method
Fourth Edition
BIOLOGY
Science for Life | with Physiology
Colleen Belk • Virginia Borden Maier
© 2013 Pearson Education, Inc.
Copyright © 2009 Pearson Education, Inc.
PowerPoint Lecture prepared by
Jill Feinstein
Richland Community College
1.1 The Process of Science
Science refers to a body of knowledge.
Science is not a giant collection of facts to be
memorized.
It important to learn about the process of science
called the scientific method.
The scientific method allows the solving of
problems and answering of questions.
Observations
Proposing ideas
Testing the ideas
Discarding or modifying ideas based on results
© 2013 Pearson Education, Inc.
1.1 The Process of Science
The Nature of Hypotheses
Hypothesis: proposed explanation for a set of
observations
Hypotheses needs to be:
Testable – It must be possible to examine the
hypothesis through observations.
Falsifiable – It must be able to potentially be
proven false.
© 2013 Pearson Education, Inc.
1.1 The Process of Science
Where do hypotheses come from?
Both logical and creative influences are used to
develop a hypothesis.
© 2013 Pearson Education, Inc.
1.1 The Process of Science
Scientific Theory
Powerful, broad explanation of a large set of
observations
Based on well supported hypotheses
Supported by research from several different
independent sources
© 2013 Pearson Education, Inc.
1.1 The Process of Science
The Logic of Hypothesis Tests
Inductive reasoning: combining a series of
specific observations into a generalization to
create a hypothesis
© 2013 Pearson Education, Inc.
1.1 The Process of Science
The Logic of Hypothesis Tests
To test the hypothesis use deductive reasoning:
This involves using a general principle to predict
an expected observation using if/then statements.
For example, If vitamin C decreases the risk of
catching a cold, then people who take in additional
Vitamin C will get less colds.
© 2013 Pearson Education, Inc.
1.1 The Process of Science
The Logic of
Hypothesis Tests
The process looks
something like this:
© 2013 Pearson Education, Inc.
1.1 The Process of Science
© 2013 Pearson Education, Inc.
1.1 The Process of Science
The Logic of Hypothesis Tests
A hypothesis that fails our test is rejected and
considered disproven.
A hypothesis that passes is supported, but not
proven.
Why not? An alternative hypothesis might be
the real explanation.
© 2013 Pearson Education, Inc.
1.2 Hypothesis Testing
The most powerful way to test hypotheses: do
experiments.
Experiments support the hypothesis that the
common cold is caused by a virus.
© 2013 Pearson Education, Inc.
1.2 Hypothesis Testing
The Experimental Method
Experiments are designed to collect data or
information to test specific hypotheses.
Variables are factors that can change in value
under different conditions.
Independent variables can be manipulated by
the scientist.
Dependent variables cannot be changed by
the researcher.
© 2013 Pearson Education, Inc.
1.2 Hypothesis Testing
Controlled Experiments
Controlled experiment: tests the effect of a
single variable
Control: a subject who is not exposed to the
experimental treatment but has all other variables
the same
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1.2 Hypothesis Testing
Controlled Experiments
Differences seen between the experimental
group and control group can be attributed to
the experimental treatment.
Random Assignment
An effective way of assigning individuals to
groups for testing
© 2013 Pearson Education, Inc.
1.2 Hypothesis Testing
Controlled Experiments
Example: Echinacea tea experiment:
Hypothesis: Drinking Echinacea tea relieves
cold symptoms.
Experimental group drinks Echinacea tea 5-6
times daily.
Control group drinks “sham” Echinacea tea 5-6
times daily (placebo).
Both groups rated the effectiveness of their
treatment on relieving cold symptoms.
© 2013 Pearson Education, Inc.
1.2 Hypothesis Testing
Controlled Experiments
People who received
echinacea tea felt that
it was 33% more effective
at reducing symptoms.
© 2013 Pearson Education, Inc.
1.2 Hypothesis Testing
Minimizing Bias in Experimental Design
If human subjects know whether they have received
the real treatment or a placebo, they may be biased.
Blind experiment: subjects don’t know what kind of
treatment they have received
Double blind experiment: the person
administering the treatments and the subjects do
not know who is in each group until after the
experiment is over
© 2013 Pearson Education, Inc.
1.2 Hypothesis Testing
Minimizing Bias in Experimental Design
© 2013 Pearson Education, Inc.
1.2 Hypothesis Testing
Using Correlation to Test Hypotheses
The “gold standard” for experimentation
Double-blind, placebo controlled, and randomized
experiments
Model systems can be used in experiments
when it appears to dangerous or unethical to test
on humans.
examples: mice, rats, dogs and pigs
A correlation can be used to test hypotheses
when controlled experiments on humans is
impossible to perform.
© 2013 Pearson Education, Inc.
1.2 Hypothesis Testing
Using Correlation to Test Hypotheses
Using existing data, is there a correlation
between variables?
Hypothesis: Stress makes people more susceptible
to catching a cold.
Is there a correlation between stress and the
number of colds people have caught?
© 2013 Pearson Education, Inc.
1.2 Hypothesis Testing
Using Correlation to Test Hypotheses
Results of such a study: The number of colds
increases as stress levels increase.
Caution! Correlation does not imply causation.
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1.2 Hypothesis Testing
Using Correlation to Test Hypotheses
The correlation might be due to other reasons.
© 2013 Pearson Education, Inc.
1.2 Hypothesis Testing
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1.3 Understanding Statistics
Overview: What Statistical Tests Can Tell Us
Statistics in science is used to evaluate and
compare data.
We can extend the results from small samples to an
entire population using statistical tests.
Statistically significant: results are very unlikely to
be due to chance differences and represents a true
difference between groups.
© 2013 Pearson Education, Inc.
1.3 Understanding Statistics
The Problem of Sampling Error
Sampling error: the effect of chance on
experimental data
We can calculate the probability that a result is
simply due to sampling error.
Confidence interval: the range of values from a
sample that has a 95% probability of containing the
true population mean (average)
© 2013 Pearson Education, Inc.
1.3 Understanding Statistics
Factors that Influence Statistical Significance
Sample size
The true difference between populations
Bigger is better: more likely to detect differences
© 2013 Pearson Education, Inc.
1.3 Understanding Statistics
Factors that Influence Statistical Significance
© 2013 Pearson Education, Inc.
1.3 Understanding Statistics
What Statistical Tests Cannot Tell Us
If an experiment was designed and carried out
properly
If observer error occurred, only can evaluate the
probability of sampling error
May not be of any biological significance
© 2013 Pearson Education, Inc.
1.4 Evaluating Scientific Information
Primary Sources
Researchers can submit a paper about their results
to a professional journal (primary source).
Primary Sources undergo peer review: evaluation
of submitted papers by other experts.
Secondary sources: books, news reports, the
internet, and advertisements
© 2013 Pearson Education, Inc.
1.4 Evaluating Scientific Information
Information from Anecdotes
Anecdotal evidence is based on one person’s
experience, not on experimental data.
Example: a testimonial from a celebrity
© 2013 Pearson Education, Inc.
1.4 Evaluating Scientific Information
Science in the News
© 2013 Pearson Education, Inc.
1.4 Evaluating Scientific Information
Science in the News
Secondary sources may be missing critical
information or report the information incorrectly.
Consider the source of media reports.
Be careful with the internet since anyone can
post information.
Be very cautious about claims made in paid
advertisements.
© 2013 Pearson Education, Inc.
1.4 Evaluating Scientific Information
Understanding Science from Secondary Sources
Use your understanding of the process of science to
evaluate science stories.
News media generally highlight only those science
stories that seem newsworthy.
They are more likely to report a positive result than
a negative one.
© 2013 Pearson Education, Inc.
1.5 Is There a Cure for the Common Cold?
No, but prevention methods are known.
Wash your hands!
No effect on cold susceptibility:
Vitamin C
Exposure to cold temperatures
Exercise
No vaccine for the common cold
© 2013 Pearson Education, Inc.
Chapter 2
Are We Alone in the Universe?
Water, Biochemistry, and Cells
Fourth Edition
BIOLOGY
Science for Life | with Physiology
Colleen Belk • Virginia Borden Maier
© 2013 Pearson Education, Inc.
Copyright © 2009 Pearson Education, Inc.
PowerPoint Lecture prepared by
Jill Feinstein
Richland Community College
What is Life
List 10 things that are alive.
What are some characteristics that they all
share?
Compare living organisms.
http://www.youtube.com/watch?
v=Jcu81UgTBFs
© 2013 Pearson Education, Inc.
2.1 What Does Life Require?
A Definition of Life
There is no simple definition of life. Instead there is
a list of characteristics.
growth
movement
reproduction
response to external environmental stimuli
metabolism
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2.1 What Does Life Require?
A Definition of Life
But, all Earth organisms…
have a common set of biological molecules
are composed of cells
can maintain homeostasis
can evolve
require liquid water
© 2013 Pearson Education, Inc.
2.1 What Does Life Require?
The Properties of Water
Elements: fundamental forms of matter
Atoms: the smallest units of an element
Atoms are composed of
Protons (positive charge) and neutrons in the
nucleus of the atom
Electrons (negative charge) are found in an
“electron cloud”
Ions are atoms with an electrical charge.
© 2013 Pearson Education, Inc.
2.1 What Does Life Require?
The Properties of Water
Atomic number is determined by the
number of protons in the nucleus.
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2.1 What Does Life Require?
The Properties of Water
Molecule: two or more atoms held together by
chemical bonds
Water molecule: two hydrogen atoms bonded to one
oxygen atom
Water is a good solvent (helps chemical reactions).
Solute: what is being dissolved in the solvent
Solution: solutes added to a solvent
© 2013 Pearson Education, Inc.
2.1 What Does Life Require?
The Properties of Water
Hydrogen bond: the weak attraction between the
hydrogen atom of one water molecule and the
oxygen atom of another
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2.1 What Does Life Require?
The Properties of Water
Water facilitates chemical reactions.
Solutes in the mixture are called reactants.
End result of the chemical reaction are called
products.
Water molecules tend to stick together:
cohesion.
Water moderates temperature.
© 2013 Pearson Education, Inc.
2.1 What Does Life Require?
The Properties of Water
Water can dissolve acids
and bases.
The pH scale is a measure of
the relative amounts of acids
and bases in a solution.
pH greater than 7 = basic
pH lower than 7 = acidic
Pure water = 7 – neutral
© 2013 Pearson Education, Inc.
2.1 What Does Life Require?
Organic Chemistry
All life on Earth is based on organic chemistry: the
chemistry of the complex carbon containing
molecules.
Carbon makes up most of the mass of living
organisms.
Carbon: a molecular TinkerToy
Can bond to 4 different atoms at once
Carbon can make hydrocarbons.
Simple organic molecules
Carbon can make macromolecules.
© 2013 Pearson Education, Inc.
2.1 What Does Life Require?
Organic Chemistry
Chemical bonds are dependent on the atom’s
electron configuration.
Electrons are arranged in energy levels or
electron shells.
1st electron shell holds up to 2 electrons.
2nd and 3rd electron shells holds up to 8 electrons
each.
The outer shell that holds electrons is called the
valence shell.
© 2013 Pearson Education, Inc.
2.1 What Does Life Require?
Organic Chemistry
Covalent bonds: strong bonds from sharing electrons
Single bonds indicate sharing of one pair of electrons.
Double bonds share two pairs of electrons.
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2.1 What Does Life Require?
Organic Chemistry
Ionic bonds: occurs when there is a transfer of
electrons between atoms
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2.1 What Does Life Require?
Structure and Function of Macromolecules
Carbohydrates: molecules of carbon, oxygen,
and hydrogen
Major source of energy for cells
Monosaccharides or simple sugars are building
blocks for carbohydrates.
Disaccharides are composed of two
monosaccharides.
Polysaccharides are composed of many
monosaccharides.
© 2013 Pearson Education, Inc.
2.1 What Does Life Require?
Structure and Function of Macromolecules
Carbohydrates
© 2013 Pearson Education, Inc.
2.1 What Does Life Require?
Structure and Function of Macromolecules
Proteins: polymers of amino acids; joined by
peptide bonds
Proteins are made up of carbon, oxygen, hydrogen,
and nitrogen.
There are 20 different amino acids, with different
chemical properties.
Different combinations of amino acids give proteins
different properties.
© 2013 Pearson Education, Inc.
2.1 What Does Life Require?
Structure and Function of Macromolecules
© 2013 Pearson Education, Inc.
2.1 What Does Life Require?
Structure and Function of Macromolecules
Lipids: hydrophobic; composed mostly of carbon
and hydrogen
Three types:
Fat is composed of a glycerol molecule joined with
3 fatty acid tails.
Steroids are a four carbon ring structure such as
cholesterol, estrogen, and testosterone.
Phospholipids are composed of a glycerol
molecule, 2 fatty acid tails, and a phosphate group.
© 2013 Pearson Education, Inc.
2.1 What Does Life Require?
Structure and Function of Macromolecules
Lipids:
© 2013 Pearson Education, Inc.
2.1 What Does Life Require?
Structure and Function of Macromolecules
Nucleic acids: polymers of nucleotides
Nucleotide: sugar + a phosphate + a nitrogenous
base
© 2013 Pearson Education, Inc.
Figure 2.15c
2.1 What Does Life Require?
Structure and Function
of Macromolecules
Nucleotides are of two types:
RNA and DNA, depending
on the sugar.
DNA is the hereditary material
in nearly all organisms.
The structure of a DNA
molecule is a double helix.
© 2013 Pearson Education, Inc.
2.1 What Does Life Require?
Structure and Function of Macromolecules
Bonding between
bases on opposite
strands follows
strict base-pairing rules:
A with T
G with C
Each strand consists
of a sugar-phosphate backbone.
© 2013 Pearson Education, Inc.
2.2 Life on Earth
Prokaryotic and Eukaryotic Cells
A cell is the fundamental structural unit of life.
All cells on Earth are either prokaryotic or
eukaryotic.
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2.2 Life on Earth
Prokaryotic and Eukaryotic Cells
Prokaryotic cells are smaller and simpler in
structure.
Prokaryotic cells probably resemble the
earliest cells to arise on Earth.
Some structures in the Martian meteorite
resemble Prokaryotic cells .
Prokaryotes do not have a true nucleus.
Prokaryotes do have a cell wall.
© 2013 Pearson Education, Inc.
2.2 Life on Earth
Prokaryotic and Eukaryotic Cells
Eukaryotic cells are much more complex.
Have a true nucleus surrounded by a membrane
Also have membrane-bound organelles with
specialized jobs
© 2013 Pearson Education, Inc.
2.2 Life on Earth
Cell Structure
All cells are surrounded by a plasma membrane.
Made of a phospholipids bilayer: hydrophobic
tails orient inside the membrane, away from water
Fluid mosaic: lipids and proteins can move about
within the membrane
Semipermeable: some molecules can cross and
some can’t
© 2013 Pearson Education, Inc.
2.2 Life on Earth
Cell Structure
Nucleus: surrounded by a double nuclear
membrane which houses DNA
Ribosomes: assembly proteins can be attached to
membranes or free floating
Cytosol: watery substances that surrounds the
nucleus and organelles
Mitochondria: provide energy for the cell, using
oxygen
Chloroplasts: sites of photosynthesis in plant cells
Lysosomes: contain digestive enzymes to break
down substances
© 2013 Pearson Education, Inc.
2.2 Life on Earth
Cell Structure
Rough Endoplasmic reticulum: involved in protein
synthesis and has ribosomes attached to its
membrane
Smooth Endoplasmic reticulum: involved in lipid
synthesis and lacks ribosomes
Golgi apparatus: modifies and sorts proteins and
packages them into vesicles
Centrioles: moves genetic material during cell division
Cytoskeleton: maintains cell shape
Central vacuole: found in plant cells and stores
water, starch and pigments
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2.2 Life on Earth
Cell Structure
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2.2 Life on Earth
The Tree of Life and Evolutionary Theory
All Earth organisms share many similarities:
Same basic biochemistry, with same types of
macromolecules
All organisms consist of cells
Cells always have phospholipids bilayer plasma
membrane
Eukaryotes share most of the same organelles
These ideas are known as the theory of evolution
Natural selection is based on the variations in
organisms that may increase or decrease survival
© 2013 Pearson Education, Inc.
2.2 Life on Earth
The Tree of Life
and Evolutionary
Theory
This unity of life
is best explained
by a tree of life,
with modern
species having
evolved from
common ancestors.
© 2013 Pearson Education, Inc.
Chapter 3
Is it Possible to Supplement Your
Way to Better Health?
Nutrients and Membrane Transport
Fourth Edition
BIOLOGY
Science for Life | with Physiology
Colleen Belk • Virginia Borden Maier
© 2013 Pearson Education, Inc.
Copyright © 2009 Pearson Education, Inc.
PowerPoint Lecture prepared by
Jill Feinstein
Richland Community College
3.1 Nutrients - Macronutrients
Nutrients: substances in foods that provide
structural materials or energy
Macronutrients: nutrients that are required in large
amounts
Water
Adults need about 3 liters per day.
Too little leads to dehydration
Maintains blood pressure
Involved in all cellular activities
© 2013 Pearson Education, Inc.
3.1 Nutrients - Macronutrients
Carbohydrates: main energy source
Simple sugars (glucose) enter our system
quickly.
Complex carbohydrates (branching chains of
simple sugars) are digested more slowly.
Starch: complex carbohydrate from plants
Glycogen: complex carbohydrate from animals
© 2013 Pearson Education, Inc.
3.1 Nutrients - Macronutrients
Processed food
Food that has undergone processing that has
been stripped it of its nutritional value
Whole foods
Foods that have not been stripped of their
nutrition
Fiber: indigestible complex carbohydrates
Essential for large intestine function
Lowers cholesterol and reduces cancer risk
© 2013 Pearson Education, Inc.
3.1 Nutrients - Macronutrients
Proteins
Polymers of amino acids
Essential amino acids: we cannot make these
ourselves; must obtain them from food
Complete proteins: contain all the essential
amino acids we need
Plant proteins can be combined to make them
complete.
© 2013 Pearson Education, Inc.
3.1 Nutrients - Macronutrients
Fats
Energy storage molecules
Acts as a cushion and insulator
Consist of a glycerol attached to fatty acid tails
Essential fatty acids: we cannot make these
ourselves (e.g., omega-3 and omega-6)
© 2013 Pearson Education, Inc.
3.1 Nutrients - Macronutrients
Fats
Saturated fats: fatty acid carbons are bound
to as much hydrogen as possible
Lack double bonds
Solid at room temperature
Most animal fats are saturated.
© 2013 Pearson Education, Inc.
3.1 Nutrients - Macronutrients
Fats
Unsaturated fats are not bound to as much
hydrogen as possible.
Contain double bonds which give kinks in the tails
Liquid at room temperature
Most plant fats (oils) are unsaturated or
polyunsaturated.
© 2013 Pearson Education, Inc.
3.1 Nutrients - Macronutrients
Fats
Polyunsaturated fats
Have many double bonds preventing it from
tightly packing
Hydrogenation
Process that adds hydrogen atoms to
unsaturated fats to make it a solid
Trans fats are produced by incomplete
hydrogenation and not beneficial
May be linked to an increased risk of heart
disease and diabetes
© 2013 Pearson Education, Inc.
3.1 Nutrients - Micronutrients
Micronutrients: nutrients that are needed in
small quantities
Vitamins: Table 3.1 lists the various vitamins
organic substances which usually function as
coenzymes
Vitamin D the only one we can synthesize
Water-soluble vitamins
Not stored in the body and typically the cause of
deficiencies
Fat-soluble vitamins
Stored in fat and can cause problems in excess
© 2013 Pearson Education, Inc.
3.1 Nutrients - Micronutrients
Minerals: inorganic substances
Do not contain carbon but essential for cell functions
Must be supplied through diet and are water soluble
Calcium is a very important mineral that plays a role
in bones, clotting, muscle contraction, and nerve
impulses
Table 3.2 lists the various minerals and their
functions
© 2013 Pearson Education, Inc.
3.1 Nutrients - Micronutrients
Antioxidants
Found in whole foods
Protect cells from damage by free radicals
Free radicals can damage DNA and cell membranes.
Table 3.3 describes food sources of antioxidants.
© 2013 Pearson Education, Inc.
3.2 Transport Across Membranes
Nutrients have to
move across the
cell membrane
in order to be used
by the cell.
Plasma membrane
is composed of a
phospholipid bilayer
& is differentially
permeable.
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3.2 Transport Across Membranes
Diffusion: movement of molecules from area of
high concentration to low concentration
Passive transport: diffusion of small hydrophobic
molecules without energy
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3.2 Transport Across Membranes
Facilitated diffusion: transport of hydrophilic and
charged molecules across the membrane.
Uses proteins embedded in the membrane
No input of energy required
© 2013 Pearson Education, Inc.
3.2 Transport Across Membranes
Osmosis: movement of water across a
membrane, from high to low concentration.
When an animal cell is placed in salt water it will
shrivel.
When an animal cell is placed in distilled water it
will swell and burst.
© 2013 Pearson Education, Inc.
Solutions
Isotonic – same
Hypotonic – less
Hypertonic – more
When the solute cannot move – the water moves!
Which way does water move?
http://www.youtube.com/watch?v=SrON0nEEWmo
© 2013 Pearson Education, Inc.
3.2 Transport Across Membranes
Active transport
Uses proteins to move molecules from low to high
concentration
Powered by energy from ATP
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3.2 Transport Across Membranes
Exocytosis: a membrane-bound vesicle fuses with
the membrane and expels the large molecule
Endocytosis: a vesicle forms around a large
molecule and brings it into the cell
© 2013 Pearson Education, Inc.
3.2 You are what you eat
Food is digested into building blocks used by cells
for various functions and structures.
© 2013 Pearson Education, Inc.
Chapter 4
Fat: How Much Is Right for You?
Enzymes, Metabolism, and
Cellular Respiration
Fourth Edition
BIOLOGY
Science for Life | with Physiology
Colleen Belk • Virginia Borden Maier
© 2013 Pearson Education, Inc.
Copyright © 2009 Pearson Education, Inc.
PowerPoint Lecture prepared by
Jill Feinstein
Richland Community College
4.1 Enzymes and Metabolism
Enzymes
Proteins that catalyze
(speed up) chemical
reactions in a cell
Metabolism: all chemical
reactions occurring in
the body
Enzymes work by lowering
the activation energy
needed for a reaction.
© 2013 Pearson Education, Inc.
4.1 Enzymes and Metabolism
Substrate are substances being catalyzed.
Active site is where the substrate binds to the enzyme.
The binding of the substrate and enzyme causes a
shape change and called induced fit.
Specificity of the enzyme to the substrate is based on
enzyme shape and active site.
© 2013 Pearson Education, Inc.
4.1 Enzymes and Metabolism
A calorie is the amount of energy required to raise
the temperature of 1 gram of water by 1C.
1000 calories 1 kilocalorie or Calorie
Calorie:
Unit of energy represented on food labels
Calories are consumed by cells to do work.
Extra calories can be stored as fat.
Metabolic rate: the rate at which the body uses
energy
© 2013 Pearson Education, Inc.
4.1 Enzymes and Metabolism
Basal Metabolic Rate or BMR represents the
resting energy of an awake, resting, but alert
person.
70 Calories/hour or 1680 Calories/day
Metabolic rate is influenced by many factors:
Body weight, sex, exercise, genetic makeup, age,
and nutritional status
http://www.bmrcalculator.org/
© 2013 Pearson Education, Inc.
4.2 Cellular Respiration
Cellular respiration is a series of enzymatic
reaction that converts energy from food into energy
stored in ATP.
ATP consists of adenine, a sugar, and 3 phosphate
groups.
© 2013 Pearson Education, Inc.
4.2 Cellular Respiration
When a phosphate group is transferred from ATP
to another molecule (phosphorylation), energy
is transferred and ADP is produced.
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4.2 Cellular Respiration
The energy from ATP can power different kinds of
work in the cell.
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4.2 Cellular Respiration
As ATP is used in the cell it must be replenished by
cellular respiration.
Aerobic cellular respiration occurs in the
mitochondria and requires the presence of oxygen.
C6H12O6 + 6O2 6CO2 + 6H2O
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4.2 Cellular Respiration
Aerobic cellular respiration takes the energy from
glucose and uses it to make ATP.
This process occurs in three complex steps starting
in the cytosol of the cell and completing in the
mitochondria.
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4.2 Cellular Respiration - Step 1: Glycolysis
6-carbon glucose molecule is broken down into two
3-carbon pyruvic acid molecules.
Takes place in the cytosol and doesn’t require
oxygen and produces 2 ATP.
NAD+ is used as a chemical taxi cab.
These pick up the electrons and hydrogen ions
released during glycolysis and become NADH.
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4.2 Cellular Respiration - Step 2: Citric Acid Cycle
Citric acid cycle: series of chemical reactions
catalyzed by 8 different enzymes in the
mitochondrial matrix
The result is the generation of 2 ATP, release of
carbon dioxide and NADH.
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4.2 Cellular Respiration - Step 3: Electron Transport
and ATP Synthesis
Electron transport chain acts like a conveyor belt,
moving electrons through a series of proteins.
NADH drops off its electrons and hydrogen ions.
The protein carriers move the electrons through the
chain and move the hydrogen into the
intermembrane space.
The concentration of H+ ions increases within the
intermembrane space.
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4.2 Cellular Respiration - Step 3: Electron Transport
and ATP Synthesis
H+ ions are charged, and can’t simply diffuse back
across the membrane.
They pass through protein channels called ATP
synthase, generating 32 or 34 ATP molecules as
they do.
At the end of the chain, the electrons combine with
oxygen to produce water.
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4.2 Cellular Respiration - Metabolism of Other
Nutrients
Proteins and fats can also provide energy when
carbohydrates are unavailable.
They are broken down and their subunits feed into
aerobic cellular respiration.
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4.2 Cellular Respiration - Metabolism Without
Oxygen: Anaerobic Respiration and
Fermentation
Cells can generate
energy without oxygen
through anaerobic
respiration.
Muscle cells can
produce lactic acid to
regenerate NAD+
through fermentation.
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4.2 Cellular Respiration - Metabolism Without
Oxygen: Anaerobic Respiration and
Fermentation
Bacteria in yogurt also
use fermentation to
make lactic acid.
Yeast cells use
fermentation to convert
glucose to ethanol.
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4.3 Body Fat and Health
Difficult to define “overweight” precisely
Women need more body fat to maintain fertility than men.
Average healthy body fat percentages:
Women: 22% and Men: 14%
Body Mass Index (BMI): correlates amount of body
fat with risk of illness and death, using both height and
weight
Healthy range of BMI = 20-25
Obesity: BMI of 30 or higher
http://www.cdc.gov/healthyweight/assessing/bmi/
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Extra Calories
It takes 3500 calories to make a pound of fat.
If you ate 300 less calories per day and exercised
an additional 200 calories, how long would it take
you to lose 1 pound of fat?
How much weight loss is healthy per week?
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4.3 Body Fat and Health
Risk of obesity is influenced by both lifestyle
(diet, exercise) and genetics.
Obesity increases risks of:
Diabetes
Hypertension
Heart disease
Stroke
Joint problems
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4.3 Body Fat and Health
Diabetes: disorder of carbohydrate metabolism
Insulin: hormone that triggers cells to take up
glucose; produced by beta cells of the pancreas
Type 1 Diabetes (not associated with obesity)
Usually arises in childhood
Cannot produce insulin (no beta cells)
Treated with daily insulin injections
Type 2 Diabetes (associated with obesity)
Usually arises in adults
May be controlled by diet and exercise
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4.3 Body Fat and Health
Hypertension: high blood pressure (the force
exerted on blood vessels by the blood)
Systolic: blood pressure as the heart contracts
Diastolic: blood pressure while heart is relaxing
Normal blood pressure is about 120 systolic and
80 diastolic (120/80)
Hypertension: persistently over 140/90
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4.3 Body Fat and Health
Heart attack: a sudden loss of blood to the heart
because of blocked arteries
Stroke: a sudden loss of blood to the brain
because of blocked arteries
Cholesterol: a lipid that can build up in arteries
Low-density lipoproteins (LDLs): distribute
cholesterol throughout the body and dumps excess
in the arteries
High-density lipoproteins (HDLs): carry excess
cholesterol to the liver for excretion as bile
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Cholesterol
Total: Less than 200 mg/dL
LDL: Less than 100 mg/dL
HDL: Above 60 mg/dL
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4.3 Body Fat and Health
Anorexia: self-starvation
Can starve heart muscles, producing altered rhythms
Amenorrhea: cessation of menstruation; can be
permanent and result in sterility
Increases risk of osteoporosis
Bulimia: binge-eating followed by purging
Many of the same health effects as anorexia
May lead to stomach rupture
Dental and gum problems from stomach acid
Dehydration (sometimes fatal)
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