Transcript 919137Ch02b_EHAP-Lect

Essentials of Human Anatomy & Physiology
Seventh Edition
Elaine N. Marieb
Chapter 2
Basic Chemistry
Slides 2.21 – 2.40
Lecture Slides in PowerPoint by Jerry L. Cook
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Biochemistry: Essentials for Life
• Organic compounds
• Contain carbon
• Most are covalently bonded
• Example: C6H12O6 (glucose)
• Inorganic compounds
• Lack carbon
• Tend to be simpler compounds
• Example: H2O (water)
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Slide 2.21
Important Inorganic Compounds
• Water
• Most abundant inorganic compound in body
• Vital properties
• High heat capacity – body temp stays stable
• Polarity – water’s polarity makes it a great
solvent which allows rxns to occur easier,
allows gases/wastes to be more easily
transported or exchanged and provides
lubrication throughout the body
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Slide 2.22
Important Inorganic Compounds
• Water
• Most abundant inorganic compound in body
• Vital properties
• Chemical reactivity – to break down food,
water must be added (hydrolysis rxn)
• Cushioning – cerebrospinal fluid surrounds
the brain and cushions it from trauma;
amniotic fluid has a similar function during
pregnancy
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Slide 2.22
Important Inorganic Compounds
• Salts
• Easily dissociate into ions in the
presence of water
• Vital to many body functions: calcium
& phosphorus for bones/teeth; sodium
& potassium for nerve impulses and
iron for hemoglobin
• Include electrolytes which conduct
electrical currents
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Slide 2.23
Important Inorganic Compounds
• Acids
• Can release detectable hydrogen ions which is
really just a proton, so called proton donors
• Can act as an electrolyte in the body
• Hydrochloric acid is used in digestion
• Bases
• Proton acceptors
• Can act as an electrolyte in the body
• Bicarbonate is a base found in blood
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Slide 2.24
pH
• Living cells are really sensitive to
changes in pH
• Regulated by kidneys, lungs and
chemicals found in body fluids (buffers)
• Blood pH is extra important since it flows
to all cells all the time. It should be 7.357.45
• A small change can be life threatening
Figure 2.11
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Slide 2.25
pH
• Measures relative
concentration of
hydrogen ions
• pH 7 = neutral
• pH below 7 = acidic
• pH above 7 = basic
• Buffers
• Chemicals that can
regulate pH change
Figure 2.11
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Slide 2.25
Important Organic Compounds
• Carbohydrates
• Contain carbon, hydrogen, and oxygen
• Include sugars and starches
• Classified according to size
• Monosaccharides – simple sugars
• Disaccharides – two simple sugars joined
by dehydration synthesis
• Polysaccharides – long branching chains
of linked simple sugars
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Slide 2.26
Carbohydrates
Figure 2.12a, b
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Slide 2.27
Carbohydrates
Figure 2.12c
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Slide 2.28
Important Organic Compounds
• Lipids
• Contain carbon, hydrogen, and oxygen
• Carbon and hydrogen outnumber
oxygen
• Most are insoluble in water (not polar)
• Common foods: meat, egg yolks, dairy &
oils
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Slide 2.29
Important Organic Compounds
• 3 common types of lipids in the human
body
• Neutral fats (triglycerides)
• Phospholipids
• Steroids
• Plus lipids are part of some vitamins (fat
soluble – Vitamin a, e & k), prostaglandins
and lipoproteins (HDL & LDL in blood)
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Slide 2.30a
Important Organic Compounds
• Neutral fats (triglycerides)
• Found in fat deposits under our skin and
around our organs
• So a source of stored energy
• Also help insulate and cushion body
• A big molecule that looks like an E
• Can be saturated or unsaturated, from
plants or animals, solid or liquid
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Slide 2.30a
Important Organic Compounds
• Phospholipids
• Very similar to triglycerides – a big E but
contain one phosphate group instead
• The phosphate makes them polar on one
end, so can dissolve in water or oil
• Form cell membranes and help regulate
what can come in or out of the cell
• Steroids
• Include cholesterol, bile salts, vitamin D,
and some hormones
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Slide 2.30b
Lipids
Figure 2.14a, b
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Slide 2.31
Important Organic Compounds
• Steroids
• Very flat molecules and small compared
to the other 2 lipids – 4 interlocking rings
• Include cholesterol which helps form bile
salts, vitamin D, and some hormones
(sex hormones & cortisol)
• Too much of any steroid is hard on our
bodies, especially the kidneys
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Slide 2.30b
Cholesterol
Figure 2.14c
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Slide 2.32
Important Organic Compounds
• Proteins
• Made of amino acids – 20 different ones in
humans
• Contain carbon, oxygen, hydrogen, nitrogen,
and sometimes sulfur
• Chains of 50 to thousands of a.a. form a huge
variety of proteins for many purposes
• Order or sequence of the a.a. determines the
type of protein
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Slide 2.33a
Important Organic Compounds
• Proteins
• Account for over half of the body’s
organic matter
• Provides for construction materials for
body tissues
• Plays a vital role in cell function
• Act as enzymes, hormones, and
antibodies
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Slide 2.33b
Important Organic Compounds
• Proteins
• 2 big categories of proteins are fibrous
and globular proteins
• A special group of proteins serve as
enzymes in our bodies
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Slide 2.33b
Important Organic Compounds
• Fibrous Proteins (help anatomy)
• They are strand like and found in all of
the bodies structures: muscle, bone, cells
• Also called structural proteins
• Very stable and resistant
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Slide 2.33b
Important Organic Compounds
• Globular Proteins (help physiology)
• Have a sphere or globe shape and move
around body
• Play a crucial role in just about all body
functions, includes enzymes
• Also called functional proteins
• Very fragile structures that are easily
destroyed (denatured) by heat or change
in pH
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Slide 2.33b
Important Organic Compounds
• Enzymes
• A special group of globular proteins
• Act as catalysts to speed up reactions
• Work by holding the substance into the
correct position for the reaction to occur
• Are easily destroyed and many do destroy
after use (like the enzyme to clot blood)
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Slide 2.33b
Enzymes
Figure 2.16
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Slide 2.34
Important Organic Compounds
• Nucleic Acids
• Make up our genes, so determine who we are
• Made up of nucleotide bases
• A = Adenine
• G = Guanine
• C = Cytosine
• T = Thymine (DNA only)
• U = Uracil (RNA only)
• Make DNA and RNA
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Slide 2.35
Important Organic Compounds
• Deoxyribonucleic
acid (DNA)
• Organized by
complementary bases
to form double helix
• Provides instruction
for every protein in the
body
• RNA carries out the
instructions and is a
single strand
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Figure 2.17c
Slide 2.36
Important Organic Compounds
• Adenosine triphosphate (ATP)
• Chemical energy used by all cells
• Very similar in structure to a nucleotide
• Energy is released by breaking high energy
phosphate bond
• ATP is replenished by digesting food fuels
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Slide 2.37
Adenosine Triphosphate (ATP)
Figure 2.18a
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Slide 2.38
How ATP Drives Cellular Work
Figure 2.19
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Slide 2.39