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Intensive Lecture
2. 习题训练
Exercise
3. 课堂总结
Review
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Biochemistry
1. 知识精讲
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目 录
Contents
1
Biochemistry
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Elements, Atoms and Compounds
Basics of Biochemistry
-
•
Ø Elementary Organic Chemistry
•
Compounds: a substance consisting of two or more different elements combinedin a fixed ratio
Enzymes
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Large Biological Molecules
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Ø Elements, Compounds and Water
Element: a substance that cannot be broken down to other substances by chemical reactions
I
an
means
Atom: the smallest unit of matter that retains the properties of an element
•
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Part 1
Elements and Compounds
Sodium
Chlorine
Sodium
chloride
1
Elements and Compounds
Chemical Bonds: Covalent Bonds and Ionic Bonds
•
Essential elements: an organism needs to live a healthy
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Ø Nonpolar covalent bonds: electrons are shared equally as the two atoms have the same
life and reproduce. For example, 25 elements for humans
Trace elements: essential elements but in only minute
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electronegativity
Ø Polar covalent bonds: the electrons of the bond are not shared equally
•
quantities. For example, iron (Fe) for all forms of life, and
Ionic bonds: the attraction between the cation (+) and anion (-)
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iodine (I) for vertebrates to produce thyroxin
•
There are elements toxic to organisms, for example,
arsenic
2
Weak Chemical Interactions
Cl–
Chloride ion
(an anion)
Properties of Water for Life
The polarity of water molecules results in hydrogen bonding.
There are also weak chemical interactions between and within molecules.
Hydrogen bonds: the attraction between a hydrogen and an electronegative atom nearby
•
Van der Waals interaction: attraction by charge differences between molecules or atoms in
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close proximity
Na+
Sodium ion
(a cation)
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Elements and Compounds
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Water (H2O)
Polar
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Oxygen (O2)
Nonpolar
Cl
Na
•
The water molecule is a polar molecule: The opposite ends
have opposite charges
•
Polarity allows water molecules to form hydrogen bonds
with each other
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and 17 for plants
Covalent bonds: the sharing of a pair of valence electrons by two atoms
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1
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The Elements of Life
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Elements and Compounds
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1
Hydrogen bonds
Forming of
Hydrogen bonds
2
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2
Properties of water contribute to Earth’s fitness for life.
Properties of Water for Life
Cohesive behavior of water
•
•
Ability to moderate temperature
•
Expansion upon freezing
•
Versatility as a solvent
Cohesion: a phenomenon that hydrogen bonds hold
water molecules together
•
Adhesion: the attraction between different substances,
e.g. water and plant cell walls
•
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Cohesive behavior
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Four of water’s properties that facilitate an environment for life are:
Surface tension: a phenomenon at the surface of a
liquid caused by intermolecular forces
•
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Properties of Water for Life
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Cohesion helps the transport of water against gravity
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Properties of Water for Life
2
Insulation of Bodies of Water by Floating Ice
Specific heat: the amount of heat that be absorbed or lost for 1 g of that substance to change
•
dense
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its temperature by 1ºC
•
Evaporative cooling: a process that remains surface cools while a liquid evaporates
•
Water has a high specific heat because of the hydrogen bonding, which minimizes
temperature fluctuations to within limits that permit life
•
Ice floats in liquid water because hydrogen bonds in ice are more “ordered,” making ice less
•
When a deep body of water cools, the floating ice insulates the liquid water below, preventing
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Properties of Water for Life
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Moderation of Temperature
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2
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in plants, and surface tension is related to cohesion.
it from freezing and allowing life to exist under the frozen surface
Evaporative cooling of water helps stabilize temperatures in organisms and bodies of water
3
The Solvent of Life
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Properties of Water for Life
Water is a versatile solvent due to its polarity, which allows it to form hydrogen bonds easily
•
pH: Acids and Bases
The pH scale measures the H+ concentration of a solution.
•
The pH of a solution is defined by the negative logarithm of H+ concentration: pH = –log [H+]
Large polar molecules such as proteins can dissolve in water if they have ionic and polar regions
•
In any aqueous solution at 25°C, the product of H+ and OH– is constant: [H+][OH–] = 10–14
•
A substance that has an/no affinity for water is hydrophilic/hydrophobic
•
pH values less than 7 in acidic solutions, greater than 7 in basic solutions
•
Most biochemical reactions occur in an aqueous solution which facilitates the collisions of
•
Buffers: substances that minimize changes in concentrations of H+ and OH– in a solution
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molecules
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•
3
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2
Quizzes
Quizzes
Clothes washing detergent must be able to remove grease and oil stains from clothing while
10-6 molar? (Hint: You don’t need a calculator!) (
also dissolving and washing away in the rinse water. Which of the following is the correct
C. 5.7
D. 6
E. 6.4
structure of the detergent molecules and the correct reason for it? ( )
A. Detergent molecules are polar and are therefore able to dissolve both grease and water.
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B.
2-6
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A. 2
)
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(2010 USABO) What is the pH of a solution where the concentration of hydrogen ions is 2 ×
B. Detergent molecules are nonpolar and are therefore able to dissolve in both grease and
water.
C. One end of a detergent molecule is nonpolar in order to dissolve oily stains, while the
other end is polar to dissolve in the rinse water.
D. One end of a detergent molecule is polar in order to dissolve oily stains, while the other
end is nonpolar to dissolve in the rinse water.
4
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Biochemistry
1
Isomers
Isomers: same molecular formula, different structures and properties.
Basics of Biochemistry
Structural isomers have different covalent arrangements of their atoms
Ø Elements, Compounds and Water
•
cis-trans isomers have the same covalent arrangements but differ in spatial arrangements
Ø Elementary Organic Chemistry
•
Enantiomers are isomers that are mirror images of each other
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Part 1
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•
Large Biological Molecules
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Functional Groups
2
Functional Groups
Functional groups are the components of organic molecules that are most commonly involved
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in chemical reactions
•
The number and arrangement of functional groups give each molecule its unique properties
•
Seven functional groups, such as hydroxyl, carbonyl and carboxyl group, are most important in
the chemistry of life
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Functional groups are important in the processes of life.
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Enzymes
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Macromolecules Built from Monomers
Polymers are built from monomers.
A polymer is a long molecule consisting of many similar building blocks called monomers
•
A condensation or dehydration reaction occurs when two monomers bond together through
The Condensation Reaction and Hydrolysis
Three classes of life’s organic molecules are both macromolecules and polymers:
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Hydrolysis disassembles polymers to monomers
•
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Ø Proteins
Ø Nucleic acids
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Condensation
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the loss of a water molecule
Ø Carbohydrates
Macromolecules Built from Monomers
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3
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1
Biochemistry
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Basics of Biochemistry
•
Monosaccharides: the simplest carbohydrates such as glucose and galactose
Large Biological Molecules
•
Disaccharide: two monosaccharides joins by a dehydration reaction, such as sucrose formed
Ø Lipids
Ø Proteins
Ø Nucleic acids
by glucose and fructose, lactose formed by glucose and galactose
•
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Ø Carbohydrates
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Part 1
Monosaccharides and Disaccharide
Carbohydrates serve as fuel and building material.
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Polysaccharides: polymers composed of many sugar building blocks
Enzymes
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Monosaccharides and Disaccharide
Monosaccharides are usually multiples of CH2O.
Monosaccharides and Disaccharide
Disaccharide consists of two monosaccharides.
Monosaccharides are classified by：
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•
1
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Ø The location of the carbonyl group (as aldose or ketose)
•
A disaccharide is formed when a dehydration reaction joins two monosaccharides
•
This covalent bond is called a glycosidic linkage
Ø The number of carbons in the carbon skeleton
raw material for building molecules
Many sugars form rings in aqueous solutions
Glucose
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Polysaccharides, the polymers of sugars, have storage and structural roles.
The difference is based on two ring forms for glucose: alpha (α) and beta (β)
structure and function of a polysaccharide
•
Starch is helical and cellulose is straight because of the different linkage
•
Many herbivores have symbiotic relationships with some microbes that have enzymes to digest
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Storage polysaccharides: starch (a storage polysaccharide in plants), glycogen
(a storage polysaccharide in animals)
•
Both starch and cellulose are polymers of glucose.
Sugar monomers and the positions of glycosidic linkages determines the
Structural polysaccharides: cellulose (a major component of the cell wall of
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Structure of Starch and Cellulose
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Polysaccharides
•
Sucrose
Dehydration reaction in the synthesis of sucrose
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2
Fructose
1–2
glycosidic
linkage
cellulose
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•
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Monosaccharides serve as a major fuel for cells and as
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plant), chitin (found in the exoskeleton of arthropods and cell walls of many
fungi)
Chitin monomer
7
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The Benedict‘s Test
Ø Amylopectin (branched,
支链), with α-1,6 linkage
at the branch points
•
Reducing sugar: all monosaccharides and most disaccharides (except sucrose)
•
Benedict‘s reagent: an aqueous solution of CuSO4, Na2CO3 and sodium citrate, and blue CuSO4 are
reduced to red Cu2O in Benedict’s test
•
Sucrose (non-reducing) is hydrolyzed with dilute HCl first, neutralized with NaHCO3 and then can
be tested positive with Benedict’s reagent
•
A blue-black colour indicates the presence of starch when treated with
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直链), with α-1,4 linkage
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Two kinds of starch:
Ø Amylose (unbranched,
•
Tests for Carbohydrates
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Both starch and cellulose are polymers of glucose.
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Structure of Starch and Cellulose
Glycogen is like amylopectin
drops of iodine/KI solution
but more extensively
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branched
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Quizzes
Quizzes
( )
only by 1,4 glycosidic bonds? ( )
B. glycogen
C. glycerol
D. glucagon
B. Amylose
C. Cellulose
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A. glycine
A. Amylopectin
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(2020 BBO, 1) In which of the following polymers would you find alpha glucose joined
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Which of the following is stored in the human liver to be used later as a source of energy?
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D. Glycogen
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Biochemistry
1
Lipids
Lipids do not form polymers and have little or no affinity for water.
Basics of Biochemistry
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covalent bonds
Large Biological Molecules
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The most biologically important lipids are fats, phospholipids, and steroids
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Ø Carbohydrates
Part 1
Lipids are hydrophobic because they consist mostly of hydrocarbons, which form nonpolar
Ø Lipids
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Ø Proteins
Ø Nucleic acids
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Enzymes
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Fats
2
Fats
Saturated fatty acids and unsaturated fatty acids
Glycerol is a three-carbon alcohol with a hydroxyl group attached to each carbon
•
A fatty acid consists of a carboxyl group attached to a long carbon skeleton
•
Three fatty acids are joined to glycerol, creating a triacylglycerol or triglycerides
•
Saturated fats: fats made from saturated fatty acids, solid at room temperature
•
The major function of fats is energy storage
•
Unsaturated fats (also called oils): fats made from unsaturated fatty acids, liquid at room
Glycerol
Saturated fatty acids have no double bonds, and unsaturated fatty acids have one or more
double bonds
temperature
•
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Ester bond
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Fats are constructed from glycerol and fatty acids.
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2
Cholesterol, a steroid
Phospholipid symbol
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Fat molecule (triacylglycerol)
Plant fats and fish fats are usually unsaturated
Fat molecule (triacylglycerol)
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In phospholipid, 2 fatty acids and 1 phosphate group are attached to glycerol
•
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Phospholipids are the major component of nearly all cell membranes, forming a bilayer
Some hormones are made from steroids, such as sex hormones
Cholesterol
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arrangement
Cholesterol is a component in animal cell membranes, and high level of cholesterol in blood
may contribute to cardiovascular disease
•
When phospholipids are added to water, they self-assemble into a bilayer, with the hydrophobic
tails pointing toward the interior
•
Steroids are characterized by a carbon skeleton consisting of four fused rings.
The two fatty acid tails are hydrophobic, but the phosphate group and its attachments form a
hydrophilic head
•
Steroids
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Phospholipids
Phospholipid
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Biochemistry
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Phospholipids and triglycerides both ________. ( )
B) have three fatty acids
Large Biological Molecules
C) have a glycerol backbone
D) have a phosphate
Part 1
Ø Carbohydrates
Ø Lipids
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Basics of Biochemistry
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A) contain serine or some other organic compound
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3
Ø Proteins
Ø Nucleic acids
Enzymes
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2
Proteins have many structures, resulting in a wide range of functions.
Polypeptides are polymers built from the same set of 20 amino acids.
•
Protein functions include structural support, storage, transport, cellular communications,
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Polypeptides
movement, and defense against foreign substances
•
properties due to differing side chains, called R groups
•
Enzymes are a type of protein that acts as a catalyst to speed up chemical reactions, and they
Two amino acids are joined together through a dehydration reaction, forming a peptide bond.
Repeating the process over and over creates a polypeptide chain
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can perform their functions repeatedly
Amino acids are organic molecules with carboxyl and amino groups, differ in their
•
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Functions of Proteins
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Each polypeptide has a unique linear sequence of amino acids, and a protein consists of one or
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more polypeptides
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Polypeptides
2
Amino Acids
Ø Nonpolar amino acids: have nonpolar R groups and are
Ø Nonpolar amino acids: have nonpolar R groups and are
that are charged (ionized) at cellular pH and are
hydrophilic
Ø Polar amino acids: have polar R groups and are hydrophilic
Ø Electrically charged amino acids: have functional groups
that are charged (ionized) at cellular pH and are
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Ø Electrically charged amino acids: have functional groups
hydrophobic
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hydrophobic
Ø Polar amino acids: have polar R groups and are hydrophilic
Polypeptides
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Amino Acids
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Peptide bond
Carboxyl
group
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Amino
group
hydrophilic
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A protein consists of one or more polypeptides twisted, folded, and coiled into a unique shape
•
Four levels of protein structure: the primary, the secondary, the tertiary and the quaternary
•
The primary structure of a protein is its unique sequence of amino acids, which determines
Secondary Structure
•
Secondary structure consists of coils and folds in the polypeptide chain resulted from
hydrogen bonds between repeating constituents of the polypeptide backbone
•
Typical secondary structures are a coil called an α helix and a folded structure called a β
pleated sheet
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the three-dimensional structure of the protein
The Three-Dimensional Structure of Proteins
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A protein’s structure determines its function.
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Protein Structure and Function
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•
Quaternary structure results when two or more polypeptide chains form one macromolecule
various side chains (R groups), which include hydrogen
•
Collagen is a fibrous protein consisting of three polypeptides coiled like a rope
•
Hemoglobin is a globular protein consisting of two α and two β subunits, both consist
Waals interactions
Strong covalent bonds called disulfide bridges may
reinforce the protein’s structure
primarily of α-helical secondary structure
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Tertiary structure is determined by interactions among
bonds, ionic bonds, hydrophobic interactions, and van der
•
The Three-Dimensional Structure of Proteins
Quaternary Structure
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Tertiary Structure
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The Three-Dimensional Structure of Proteins
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β pleated sheet
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α helix
12
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Physical and chemical conditions can affect protein structure
•
Alterations in pH, salt concentration, temperature, or other environmental factors can cause a
protein to unravel
Fat Emulsion Test and Biuret Test
•
This loss of a protein’s native structure is called denaturation, and a denatured protein is
Biuret reagent is initially blue, but forms a violet colour when added to a solution containing
proteins
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biologically inactive
Dissolve the substance with absolute ethanol, then decant the mixture into water, a cloudy white
suspension is formed with the presence of lipids (fat emulsion test)
•
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Tests for Lipids and Proteins
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Various factors affect protein structure.
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Factors that Affect Protein Structure
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Quizzes
Quizzes
following EXCEPT a: ( )
A. Iron
B. Change in the secondary structure of the protein
C. Loss of catalytic activity of the protein
D. Loss of a negatively charged side chain
C. Nitrogen
D. Phosphorus
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A. Change in the quaternary structure of the protein
B. Oxygen
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(2019 BBO, 9) Which of the following elements is NOT present in haemoglobin? ( )
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(2011 USABO) Replacement of a lysine with a glycine in a protein could result in all of the
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E. Hydrogen
E. Loss of the protein’s ability to interact with other proteins
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Biochemistry
1
The Roles of Nucleic Acids
Nucleic acids store and transmit hereditary information.
Basics of Biochemistry
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acid (DNA) and ribonucleic acid (RNA)
Large Biological Molecules
•
Ø Carbohydrates
Gene expression: DNA directs synthesis of messenger
Ø Lipids
synthesis in ribosomes
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Ø Proteins
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RNA (mRNA) and, through mRNA, controls protein
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Part 1
There are two types of nucleic acids: deoxyribonucleic
Ø Nucleic acids
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The Structure of Nucleic Acids
2
Nucleotide Monomers
•
Each nucleotide consists of a nitrogenous base, a pentose sugar, and a
•
phosphate group
Ø Pyrimidines (Cytosine, Thymine, and Uracil) have a single
•
The portion of a nucleotide without the phosphate group is called a nucleoside
•
In DNA, the sugar is deoxyribose, and in RNA the sugar is ribose
Nitrogenous
base
Sugar
(pentose)
Deoxyribose (in DNA)
Ribose (in RNA)
There are two families of nitrogenous bases:
six-membered ring
Ø Purines (Adenine and Guanine) have a six-membered ring
fused to a five-membered ring
•
NDA strand
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Nucleic acids are polynucleotides made of monomers called nucleotides
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•
Phosphate
group
The Structure of Nucleic Acids
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Nucleic acids are polymers call polynucleotides.
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Enzymes
Base pairing: A=T and C≡G in DNA, A=U instead in RNA
Nitrogenous bases
Nucleoside
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The Structure of Nucleic Acids
Energy Currency: ATP
•
Adjacent nucleotides are joined by phosphodiester linkage
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•
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that form between the –OH group on the 3’ carbon of one
nitrogenous base adenine, and a chain of three phosphate groups.
•
nucleotide and the phosphate on the 5’ carbon on the next
These links create a backbone of sugar-phosphate units with
The terminal phosphate bond breaks, releasing a molecule of inorganic phosphate (HOPO32-, Pi)
and a ADP (adenosine diphosphate)
•
ATP can be regenerated by addition of a phosphate group to ADP
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nitrogenous bases as appendages
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ATP (adenosine triphosphate) is a nucleotide triphosphate consisting of the sugar ribose, the
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Nucleotide Polymers
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The Structure of Nucleic Acids
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The DNA Double Helix
5
•
Chromatin: a complex of DNA and protein, found in the nucleus of eukaryotic cells
spiraling around an imaginary axis, forming a
•
Histones: proteins that are responsible for the first level of DNA packing in chromatin
•
Nucleosome: “beads” resembled from unfolded chromatin (10 nm in diameter); the “string”
The two backbones run in opposite 5’ → 3’
directions from each other, which is referred to as
antiparallel
•
The nitrogenous bases in DNA pair up and form
between beads is linker DNA
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A DNA molecule has two polynucleotides
double helix
•
Chromatin is composed of DNA and histones.
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Components of Chromosomes
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DNA is a double helix that stores genetic information.
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Phosphodiester linkage in
the covalent backbone of DNA and RNA
hydrogen bonds (A — T, G—C), thus the two
strands are complementary
15
Heterochromatin: tightly packed form of DNA or condensed DNA
•
Euchromatin: loosely packed form of chromatin
•
Dense packing of the heterochromatin makes it difficult for the cell to express genetic
There are two chromosomes of each of 23 types in human somatic cells.
•
Karyotype (核型): an ordered display of the pairs of chromosomes from a cell
•
Homologous chromosomes: the two chromosomes of a pair with the same length, centromere
position, and staining pattern
•
X and Y are called sex chromosomes, the others are called autosomes
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information coded in these regions
Sets of Chromosomes in Human Cells
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7
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There are different packed stations of chromatins.
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Euchromatin and Heterochromatin
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Quizzes
Quizzes
G/C pairs form with 3 hydrogen bonds, whilst A/T pairs form with 2 hydrogen bonds.
A. There are always equal amounts of guanine and cytosine nucleotides
Which of the following helices will denature at the highest temperature? ( )
D. Phosphodiester bonds link adjacent nucleotides
E. Hydrogen bonds are the major forces that maintain a double helix structure
A. Short strand with a high proportion of A/T base pairs.
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C. Uracil pairs with adenine
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B. Purine bases pair with pyrimidine bases
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(2019 BBO, 7) Heat causes the two strands of DNA helices to separate (melt / denature).
one ? ( )
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(2015 BBO, 11) The following statements about the structure of DNA are all true except which
B. Long strand with a high proportion of A/T base pairs.
C. Short strand with a high proportion of G/C base pairs.
D. Long strand with a high proportion of G/C base pairs.
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1
Enzymes as Catalysts
Enzymes speed up metabolic reactions by lowering energy barriers.
Biochemistry
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reaction without being consumed by the reaction
1. Elements and Compounds
•
2. Water and Life
Enzymes catalyze reactions by lowering the barrier of free energy of activation (or activation
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energy, EA), the initial energy needed to start a chemical reaction
•
3. Elementary Organic Chemistry
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Part 1
An enzyme is a macromolecule that acts as a catalyst, a chemical agent that speeds up a
Enzymes do not affect the change in free energy (∆G), only hasten
reactions that would occur eventually
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4. Large Biological Molecules
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Enzymes as Catalysts
1
The substrate binds to the active site of the enzyme.
•
The enzyme binds to its substrate with active site, forming an enzyme-
•
Enzyme models:
Ø The lock and key model
Ø The induced fit (诱导契合) model
•
The active site can lower an EA barrier by:
Ø Orienting substrates correctly
Ø Straining substrate bonds
Ø Providing a favorable microenvironment
Ø Covalently bonding to the substrate
•
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Substrate: the reactant that an enzyme acts on
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substrate complex
Enzymes as Catalysts
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An enzyme can recognize its specific substrate.
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5. Enzymes
The enzyme reaches the saturated state, the concentration of substrate will be high enough that
all enzyme molecules will have their active sites engaged
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Competitive and Noncompetitive inhibitors
2
Effects of Local Conditions
Temperature, pH and Cofactors
•
Enzyme inhibitors: chemicals that selectively inhibit the action of specific enzymes
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Effects of Local Conditions
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Ø Competitive inhibitors bind to the active site of an enzyme, competing with the substrate
Temperature and pH: each enzyme has an optimal temperature and pH to function, for example,
70℃ for thermophilic bacteria and low pH for pepsin
Ø Noncompetitive inhibitors bind to another part of an enzyme, causing the enzyme to change shape and
•
making the active site less effective, such as toxins, poisons, pesticides and antibiotics
Cofactors: nonprotein enzyme helpers, often for chemical processes like electron transfers
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Ø Examples of inorganic cofactor: Zn2+, Fe3+, Cu2+
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Effects of Local Conditions
3
•
Michaelis–Menten constant, Km, is the substrate concentration at which an enzyme works at half
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Turnover rate: the number of substrate molecules converted by one enzyme molecule per second
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Allosteric regulation (变构调节) occurs when a regulatory molecule binds to a protein at one
site and affects the protein’s function at another site
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Each enzyme has active and inactive forms
Ø The binding of an activator stabilizes the active form of the enzyme
Vmax gives information about the maximum rate of reaction that is possible and Km measures the
affinity of the enzyme for the substrate
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Allosteric regulation may either inhibit or stimulate an enzyme’s activity.
•
its maximum rate
Allosteric Regulation and Feedback Inhibition
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Michaelis–Menten Constant
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2
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Ø Examples of organic cofactor (coenzyme): most vitamins
Ø The binding of an inhibitor stabilizes the inactive form of the enzyme
•
Cooperativity (协同效应): binding by a substrate to one active site stabilizes favorable
conformational changes at all other subunits, thus amplify enzyme activity
Ø The binding of oxygen to hemoglobin (though not an enzyme)
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Allosteric Regulation and Feedback Inhibition
4
Allosteric Regulation and Feedback Inhibition
Feedback Inhibition
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Feedback inhibition: a metabolic pathway is halted by the
inhibitory binding of its end product to an enzyme that acts
early in the pathway
Feedback inhibition prevents a cell from wasting chemical
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resources by synthesizing more product than is needed
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Cooperativity: another type of allosteric activation
Feedback inhibition in isoleucine synthesis
Allosteric activators and inhibitors
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Quizzes
Quizzes
(2011 USABO) In the example, assume that D is an allosteric inhibitor of the enzyme E2. D
following pathway, where E represents different enzymes, and A, B, C, D and F represent
would (
)
A. Compete with B for binding to the E2 active site
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substrates and products of the pathway. Feedback inhibition of this pathway may involve (
)
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(2011 USABO) Many metabolic pathways involve multi-step reactions. Consider the
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A. The product of the final reaction, F, interacting with and inhibiting E1
B. Compete with F for binding with E2
B. F interacting with and inhibiting product B
C. Bind directly to the substrate B and prevent it from entering the E2 active site
C. Product B interacting with and inhibiting E4
D. Product C interacting with and inhibiting E4
E. E3 interacting with and inhibiting E2
D. Bind E2 at a site different from the active site but change the shape of the active site so B
can no longer bind
E. Bind E2 at the active site, change its shape and prevent B from binding the active site
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All the following are carbohydrates except ( )
A. starch.
B. glycogen.
Exercise
C. chitin.
D. glycerol.
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习题训练 Exercise
3
习题训练 Exercise
(2006 USABO) The molecular weight of fumarate is 160.0. How many grams of fumarate
using Benedict's solution. The same volume of glucose and Benedict's solution was
are there in 200 mL of a 0.1M fumarate solution? ( )
B. Sample 2: yellow
C. Sample 3: green
D. Sample 4: brick-red
Place the samples in decreasing order of concentration.
A. 0.32 grams
B. 3.20 grams
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A. Sample 1: orange
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used in each case. After 5 minutes the colour of the precipitate was noted:
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(2020 BBO, 2) Four different concentrations of glucose solution were each tested
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E. cellulose.
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习题训练
习题训练 Exercise
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Part 2
1
C. 8.00 grams
D. 80.00 grams
E. 3.20 kg
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习题训练 Exercise
5
习题训练 Exercise
Maltotriose is a trisaccharide composed of three glucose molecules linked through α-1,4
membrane?( )
glycosidic linkages formed via dehydration synthesis. What would the formula be for
B. C18H10O15
C.
C. C18H32O16
D. C3H6O3
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E.
B.
)
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A. C18H36O18
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A.
maltotriose? (
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(2014 USABO) Which of the following is NOT a component of the cell wall or cell
D.
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课堂总结
Review
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课堂总结 Review
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Part 3
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谢谢聆听，下次课再见~
Exercise 1D 2DABC 3~5BDC
22
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