Transcript Biochemistry_Short_Course

Essentials of Human Anatomy & Physiology
Elaine N. Marieb
Chapter 2
Seventh Edition
Biochemistry short
course
Modified by S. Mendoza 9/2013
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Isotopes
Versions of elements
Same # protons & electrons so chemical
properties are exactly the same but;
Different # of neutrons so may be radioactive
Radioisotopes
Used in diagnostics & treatments due to
radioactive properties
Chosen based on
• Target tissue
• Shortest half life
• Read about its importance in your notes
Compounds – Read &
understand this info
When atoms combine, they form
Molecules/Compounds
Type of bond formed is determined by
• Atoms involved in bond
• # of bonding electrons
Polarity of bond formed is determined by
• Atoms involved in bond
• How atoms share/transfer electrons
Polarity of Molecules
Nonpolar molecules
Share electrons
equally
Electrically balanced
Symmetrical geometry
Polar molecules
Share electrons
unequally
Asymmetrical
Has + and –
charged poles
Sketch this
Hydrogen bonds
Strongest intermolecular bond between
polar molecules
Hydrogen has partial positive charge & is
attracted to an electronegative atom on
another molecule
Responsible for 3-D shape of molecules by
“sticking” molecules together thus being
Extremely important in determining
the properties of water and biological
molecules such as proteins
• Allows blood (mostly H2O) to
absorb and transport a large
amount of nutrients
• DNA’s alpha helix shape is due to
hydrogen bonds between strands
Inorganic Compounds
Important to Know:
Do NOT contain carbon with hydrogen
Tend to be simpler compounds
Example: H2O (water)
Water = 60-80% of your body
(so pretty important to understand about it!)
High heat capacity
Absorbs large amounts of heat energy
BEFORE changing temperature
Assures body temperature homeostasis
High heat of vaporization
Absorbs large amount of heat energy BEFORE
changing phase and carrying the heat away
Efficient cooling mechanism
Water
Polarity gives
excellent solvent
properties
Hydration layers
Transport medium
Lubricant
Polarity allow water
to surround and
separate polar
compounds & small
molecules
Water
Water is an important part of many
chemical reactions
Dehydration synthesis
Hydrolysis
Water
The presence of water in fluids & tissues
also plays an important role in protection
through cushioning
Cerebrospinal fluid
Tissue fluid
Salts
Consists of metal cation with nonmetal
anion to form an ionic compound - pH can
be anything
Easily dissociate/separate into ions in the
presence of water
Vital to many body functions - Function as
electrolytes to carry current in the body in
processes such as:
Nerve transmission
Muscle contraction
Electrolytes - Table 2.1, page 24
Acids & Bases
Acids are compounds that increase the
presence of hydronium ions (H+)
HCl, H2SO4, etc
pH is below 7
Bases are compounds that increase the
presence of hydroxide ions (OH-)
NaOH, NH3, etc
pH is above 7
pH – a logarithmic scale
• Measures relative
concentration of hydronium
ions
• Scale runs from 0-14 with
each unit representing a
tenfold change in H+ conc.
• pH 7 = neutral
• pH below 7 = acidic
• pH above 7 = basic
Figure 2.11
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 2.25
Buffers
Combinations of acids & bases that allow
your body to resist large, abrupt (sudden)
changes in pH
This allows your body to maintain pH
homeostasis
If this buffer is overloaded, a disease
process will be initiated
Organic Macromolecules
Important to Know:
Contain carbon and hydrogen
Most are covalently bonded & complex
Example: C6H12O6 (glucose)
4 Types of Macromolecules
Important Organic Compounds
• Basic Info: Carbohydrates (contain CHO)
• 1-2% of body mass
• Classified according to size & solubility
• Solubility is important for transport
& reactivity
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 2.26
Monosaccharides
• Monosaccharides & disaccharides – simple
sugars
• Small size = greater solubility
• Simple sugars that body uses for immediate
energy
• Examples: Glucose, fructose, and
galactose/Sucrose, maltose, and lactose
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 2.26
Polysaccharides
Storage forms of sugars (cellular fuel & some
structural components) = larger size so lower
solubility (doesn’t break down as easily)
Starch
• Type of polysaccharide found in Plants
• Cellulose & lignin indigestible by humans
• Used for FIBER (drink lots of water!!)
Glycogen
• Skeletal muscle and liver cells in animals
• Glycogen use: stored energy that is quickly
available
Polysaccharides
Made by using dehydration synthesis
reactions that join monosaccharides
• All complex sugars (disaccharides &
polysaccharides) MUST be broken down
into MONOSACCHARIDES for the body to
utilize in glycolysis and cellular respiration
Dehydration Synthesis
An anabolic process by which
two molecules are chemically
joined through the use of
enzymes and a loss of water
Hydrolysis
A catabolic process by which
the bonds between monomers
are broken by the enzyme
and the addition of water.
Sucrose = Glucose + Fructose
FYI: Using Glycogen
If your blood sugar (glucose) gets too high:
Your body stores it in your liver and skeletal
muscles as glycogen
If your blood sugar gets too low:
Your body breaks down the glycogen and
releases glucose to your blood
Just another example of negative
feedback systems!
LIPIDS
Or fat fat fat fat fat
Important Organic Compounds
• Intro to Lipids
• Non Polar organic compound
• Similar to carbs in that they contain
carbon, hydrogen, and oxygen BUT
• There is a greater C to H ratio – that is
what makes them more energy rich than
carbs
• There are 3 main types of fats
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 2.29
Lipids
KNOW THIS FACT:
Lipids are not soluble in water. This is because
water is polar and most lipids are nonpolar.
Why are nonpolar substances unable to
dissolve in a polar substance such as water?
(can’t form hydrogen bonds so can’t be
surrounded or dissolved to become soluble)
Neutral Fats - Aka. – Triglycerides
(be able to recognize diagrams)
Functions of Neutral Fats
1. INSULATION (subcutaneous fat)
2. ENERGY STORAGE - Most concentrated source
of usable energy/fuel
3. CUSHIONING FOR INTERNAL ORGANS
4. ABSORPTION OF FAT SOLUBLE VITAMINS:
1. Vitamins ADEK
2. THESE VITAMINS CANNOT BE ABSORBED UNLESS
THEY ARE DISSOLVED IN FAT (more about this
later)
Pay attention to the
next few slides – you
don’t need to memorize
this info
You will need to understand it to
help you later in the course!
Saturated Fats vs.
Unsaturated
Saturated Fats –
SINGLE C-C BONDS, straight, pack
closely together
SOLID at room temp.
ANIMAL FATS
Saturated Fats vs.
Unsaturated
Unsaturated Fats –
DOUBLE C=C BONDS, Bent, can’t pack closely
together
LIQUID at room temp
PLANT FATS
Saturated vs. Unsaturated Fats
Unsaturated fats are better than
saturated because the body can break
them down easier at the double bond
and so they are used more quickly in
the body’s metabolism.
FYI: CIS vs. TRANS ISOMERS
FYI: Trans Fats
Produced when cis vegetable oils are
heated.
Multiple heatings, such as a fast food fryer,
converts large quantities of cis to trans
bonds
Concern: trans fatty acids are carcinogenic
Back to notes now!
Phospholipids
Complex
lipids
Phospho
portion is
polar
Lipid
portion is
non polar
Use of Phospholipids
Important for
cell
membrane
repair and
construction
Also a
component
of nervous
tissue
Myelin Sheath: Insulates
Nerve
Steroids
Hydrocarbon ring structures
Vital to homeostasis
Steroids: Example
Cholesterol is found in all ANIMAL tissue.
Plants do NOT contain cholesterol
Cholesterol is the MOST IMPORTANT steroid since
it is essential for the manufacture of ALL other
steroids
It also helps to STABILIZE your cell membranes.
Pay attention to the
next slide – you don’t
need to memorize this
info
You will need to understand it to
help you later in the course!
FYI: HDL vs. LDL
LIPOPROTEINS are molecules that help transport
lipids in the blood (since lipids are NOT water
soluble, they cannot circulate by themselves)
HIGH DENSITY LIPOPROTEINS
Transport excess cholesterol to liver for breakdown
LOW DENSITY LIPOPROTEINS
Transport excess cholesterol to cells for storage (can clog
artery walls, etc.)
YOU WANT YOUR HDL LEVEL TO BE HIGHER
THAN YOUR LDL LEVEL
HDL & LDL
Fat Soluble Vitamins
ADEK
Page 41 & 457
Toxicity: easier to OD on these than on
water soluble vitamins
ADEK excesses are stored in your fat cells
Other vitamins are excreted in the water
based urine
PROTEINS
In charge of all your body functions
Proteins
10-30% of body mass
Consists of amino acids
connected by peptide
bonds
Unique properties of
each protein are
determined by
Type of amino acid
Sequence of amino acid
Functions of Proteins
Proteins have a wide variety of functions.
These functions can be divided into 2
categories:
STRUCTURAL: General Use is to support and
strengthen - Linear building proteins
FUNCTIONAL: General use is to play crucial
roles in biological processes - Globular action
proteins
Proteins
Structural
Insoluble in
water
Not chemically
active
Collagen,
keratin, elastin
Functional
Soluble in water
Chemically active
Antibodies,
hormones, most
enzymes (anything
ending in -ase),
hemoglobin
Enzymes
Function of proteins depend on their
structure
Structure depends on H bonds
Active site and substrate
relationship crucial to the function Shape of active site determines
enzyme specificity
IMPORTANT: Enzyme
Specificity – add to diagram
Enzyme: regulatory protein acting as a catalyst
for a reaction (The enzyme is not changed at
all by the chemical reaction so can be reused
over and over
Substrate: the molecule that is affected
by the enzyme
Active site: place on the enzyme where
the reaction occurs
Enzyme - specificity
ONE ENZYME ACTS ON ONLY ONE
SUBSTRATE: VERY SPECIFIC !
Amylase breaks down amylose
Lactase breaks down lactose
Enzyme action
Enzymes can act as a catalyst
A molecule that lowers ACTIVATION
ENERGY
Protein denaturation
2 causes: Extremes in
temperature & pH
3 results(know this!)
Disrupts H bonds
Structure/active site is lost
Function is lost
ATP
Chemical energy universally usable by all
cells
Contain just the right amount of energy for
most biochemical reactions
Reversible reaction - ATP is replenished by
oxidation of food fuels
Oxygen is required!!
Important Organic Compounds
• Deoxyribonucleic
acid (DNA) &
Ribonucleic Acid
(RNA)
• Collectively
provides
instructions to
make every
protein in the body
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 2.17c
Slide 2.36