Chapter 13,Chemicals of life
No molecule in a living organism is a
permanent resident,Within 7 years,most of
the molecules in a human body have been
replaced by new one!
Individual? Decided completely by the
genetic code? No! An individual’s identity is
continually re-established each and every
moment.
13.1 Biomolecules are produced and utilized
in cells
? Plasma membrane,细胞
膜
? Cell wall,细胞壁
? Cell nucleus：细胞核
? Cytoplasm,细胞质
? Organelles,细胞器
? Carbohydrate,碳水化合
物
? Lipid,脂类
? Protein,蛋白质
? Nucleic acid,核酸
Plant cell
Animal cell
13.2 Carbohydrates give structure and energy
? Carbohydrates are
molecules of
carbon,hydrogen
and oxygen
produced by plant
through
photosysthesis (光
合作用 ),
? Saccharide,糖类
? Glucose,葡萄糖
? Fructose,果糖
OH
O H
O H
H
H
O H
H
O H
C H 2 O H
H
O
C H 2 O H
H O
H
O H
O H
H
H
C H 2 O H
Glucose Fructose
Honey
Sucrose,蔗糖
Lactose,乳糖
Lactase,乳糖酶
Polysaccharides (多糖 ) are complex carbohydrates
Hyaluronic acid,
透明质酸
Glucuronic acid,
葡萄醛酸
Chitin,甲壳素
The polysaccharides of the human diet are made only of
glucose,These polysaccharides include starch (淀粉 ),
glycogen （糖原） and cellulose （纤维素）,which differ
from one another in how the glucose units are chained
together.
Amylose,直链淀粉 20%
Amylopectin,支链淀粉 80%
Glycogen is found in animal tissue
Cellulose is consisted of β–glucose and has a straight
conformation.
Cellulose is by far the most abundant organic compound on earth,
But most animals,including humans,are not able to break
cellulose down to glycose.
? Fats are used for energy and insulation
? A fat is any biomolecule formed from the reaction of a glycerol
molecule,attached to three fatty acid molecules,Fatty acid can
be saturated or unsaturated,
? Fats are used to reserve energy,1 gram of fat contains about 9
calories of energy,while a gram of carbohydrate and protein
contains only 4 calories of energy.
? Fats are also used to insulate us from cold.
13.3 Lipids are insoluble in water
Saturated fat and unsaturated fat
The molecules of saturated fats
can pack together,leading to
high melting points.
The molecules of unsaturated
fats can not pack together,
leading to low melting points.
stearic acid,m.p.69℃ oleic acid,m.p.13℃
Fats from animals and plants are mixture of
different fat molecules
Table 13.1 degree of unsaturation in some common fats
Fat Percentage of total fatty acid content
Saturated Monounsaturated polyunsaturated
Coconut 93 6 1
Palm 57 36 7
Lard 44 46 10
Cottonseed 26 22 52
peanut 21 4 30
Olive 15 73 12
Corn 14 29 57
Soybean 14 24 62
Sunflower 11 49 70
Safflower 10 14 76
Canola oil 6 58 36
Steroids (类固醇 ) contain four carbon rings
? Cholesterol,胆固醇
? Testosterone,睾酮
? Estradiol,雌甾二醇
13.4 Proteins are polymers of amino acids (氨基酸 )
? 20 amino acids differ from one another by the chemical
identity of their side groups.
? Amino acids are linked through peptide bonds (肽键 ),A
group of amino acids linked together through peptide
bonds is called peptide,Peptides containing more than
ten amino acids are generally called polypeptides.
There are many kinds of proteins
Protein structure
is determined by
attractions
between
neighboring
amino acids
The proteins in hair and fingernails contain a lot of
disulfide bonds
Many proteins consist of two or more polypeptide
chains.
血红蛋白
The proteins can be denatured with the change in
conditions.
Enzymes are
biological catalysts
Figure 13.25
Upon binding to the receptor site on
the enzyme sucrase,the substrate
sucrose is split into its two monosac-
charide units,glucose and fructose.
13.5 Nucleic acids code for proteins
? Our bodies are built of proteins,Our bodies are able to assemble
amino acids in just the right order to build proteins that have highly
functional structures.
? A nucleotide (核苷 ) consists of a phosphate (磷酯 ),a ribose sugar (核
糖 ),and a nitrogenous base (碱基 ).
? A nucleic acid is a polymer made up to nucleotide monomers.
? Two types of nucleic
acids,deoxyribonucleic
acid (脱氧核糖核酸 ) and
ribonucleic acid (核糖核
酸 ).
? Deoxyribonucleic acids
are the primary source of
genetic information and
are found in the cell
nucleus.
? Ribonucleic acids occur
mostly outside the cell
nucleus in the cytoplasm,
where they piece
together amino acids to
make proteins,
DNA is the template of life
? Gregor Mendel’s work
rose the idea of heredity,
The unit containing the
heritable information is
called genes,In 1900s,
genes have been related
to chromosomes (染色
体 ),which consist of
DNA and proteins,
? In 1953,James Watson and Francis Crick
proposed the double helix structure of DNA,The
most critical point of double helix model is the
hydrogen bonding between guanine and cytosine,
and also between adenine and thymine.
Replication of
DNA
? One gene codes for one polypeptide
? Gene controls the protein’s amino acid
sequence,Each gene codes for the synthesis of
a particular protein.
? The number of human gene is 30000-100000.
? Each chromosome contains 1000-2000 genes.
? Each DNA molecule contains about 3.1 billion
base pairs.
? Genes make up only about 20% of a DNA
molecule.
? RNA is largely responsible for protein synthesis
? The manufacturing of proteins involves two
processes,transcription (转录 ) and translation
(转译 ).
? These steps are mediated by the three forms of
RNA,messenger RNA (信使 RNA,mRNA),
ribosomal RNA (核糖体 RNA,rRNA) and
transfer RNA (转移 RNA,tRNA).
Codon （密码子、三联体）
Translation
Ribosome
Ribosome
? Genetic engineering
? Restriction enzyme (限制酶 ) ban cleave long strands of
DNA into small fragments.
? Gel electrophoresis is used to separate fragmented DNA.
Gel electrophoresis
Recombinant
（重组） DNA
Gene
cloning
(基因克隆 )
13.6 Vitamins are organic,minerals are inorganic
? Lipid-soluble vitamins and water-soluble
vitamins
? Lipid-soluble vitamins can be stored in
body for long time,but not for children.
? Over-dose of vitamins A and D are harmful.
? Vitamins B and C are washed away by
water.
Table 13.2 Some Vitamins Needed by the Human Body
Vitamin Function Deficiency syndrome
Lipid-soluble
Vitamin A (retinol) Precursor to rhodopsin,a
chemical used for
vision; assists in
inhibiting bacterial and
viral infections
Night blindness
Vitamin D (calciferol) Helps incorporate calcium
into body
Weak bones
Vitamin E (tocopherol) Inhibits oxidation of
polyunsaturated fats;
free radical scavenger;
Diminished hemoglobin
Vitamin K ( phylloquinone) helps maintain ability to
form blood clots
Abnormal bleeding
Water-soluble
B vitamins Coenzymes in biochemical
reactions for growth
and energy production
Various nerve and skin
disorders,anemia
Vitamin C (ascorbic acid) Antioxidant; asisits in
inhibiting bacterial and
viral infections
scurvy
Minerals
Macromineral (ionic form) Some functions Deficiency syndrome
Sodium (Na+) Transportation of molecules
across cell membrane,
nerve function
Muscle cramps,reduced
appetite
Potassium(K+) Transportation of molecules
across cell membrane,
nerve function
Muscular weakness,paralysis,
nausea,heart failure
Calcium(Ca2+) Bone and tooth formation,
nerve and muscle function
Retarded growth,possibly
loss of bone mass
Magnesium(Mg2+) Enzyme function Nervous system disturbances
Chlorine(Cl-) Transportation of molecules
across cell membrane,
digestive fluid,nerve
function
Muscle cramps,reduced
appetite
Phosphorus(H2PO4-) Bone and tooth formation,
nerve and muscle function
Weakness,calcium loss
Sulfur(SO42-) Amino acid component Protein deficiency
Table 13.3 Some Macrominerals Needed by the Human Body
ATP&ADP
13.7 Metabolism (代谢 ) is the cycling of biomolecules
through the body catabolism and metabolism
13.8 The food pyramid summarizes a healthful diet
Carbohydrates
Glycemic Index （血糖指数）
Glucose 100 Honey 58
Baked potato 85 Sweet corn 55
Cornflakes 83 Brown rice 55
Microwaved potato 82 Popcorn 55
Jelly beans 80 Oatmeal cookies 55
Vanilla wafer 77 Sweet potato 54
French fries 75 Banana 54
Cheerios 74 Milk chocolate 49
White bread 71 Orange 44
Mashed potato 70 Snickers candy bar 40
Life-savers candy 70 Pinto beans 39
Shredded wheat 69 Apple 38
Wheat bread 68 Spaghetti,boiled 5minutes 36
Sucrose 64 Skim milk 32
Raisins 64 Whole milk 27
Mars candy bar 64 Grapefruit 25
High-fructose corn syrup 62 soybean 18
White rice 58 peanuts 15
Table 13.4 Glycemic Index for Select Foods
source,Jennie Brand Miller et al.,the Glucose Revolution,the authoritative guide to the Glycemic index.
Sydney,Marlowe & company,1999
? Unsaturated fats are generally more healthful than
saturated fats
Saturated fats are used to synthesize cholesterol.
Fats are also packaged with water soluble proteins
(Lipoproteins) to move through bloodstream.
? Hydrogenation of unsaturated fats can be used to
prepare margarine and also in the process of making
chocolates.
Lipoprotein Percent
protein
Density(g/ml) Primary function
Very-low-density(VLDL) 5 1.006-1.019 Fat transport
Low-density(LDL) 25 1.019-1.063 Cholesterol transport(to cells to
build cell walls)
High-density(HDL) 50 1.063-1.210 Cholesterol transport(to liver for
processing)
Table 13.5 The Classification of Lipoproteins
Essential for
adults
Essential for
children
No molecule in a living organism is a
permanent resident,Within 7 years,most of
the molecules in a human body have been
replaced by new one!
Individual? Decided completely by the
genetic code? No! An individual’s identity is
continually re-established each and every
moment.
13.1 Biomolecules are produced and utilized
in cells
? Plasma membrane,细胞
膜
? Cell wall,细胞壁
? Cell nucleus：细胞核
? Cytoplasm,细胞质
? Organelles,细胞器
? Carbohydrate,碳水化合
物
? Lipid,脂类
? Protein,蛋白质
? Nucleic acid,核酸
Plant cell
Animal cell
13.2 Carbohydrates give structure and energy
? Carbohydrates are
molecules of
carbon,hydrogen
and oxygen
produced by plant
through
photosysthesis (光
合作用 ),
? Saccharide,糖类
? Glucose,葡萄糖
? Fructose,果糖
OH
O H
O H
H
H
O H
H
O H
C H 2 O H
H
O
C H 2 O H
H O
H
O H
O H
H
H
C H 2 O H
Glucose Fructose
Honey
Sucrose,蔗糖
Lactose,乳糖
Lactase,乳糖酶
Polysaccharides (多糖 ) are complex carbohydrates
Hyaluronic acid,
透明质酸
Glucuronic acid,
葡萄醛酸
Chitin,甲壳素
The polysaccharides of the human diet are made only of
glucose,These polysaccharides include starch (淀粉 ),
glycogen （糖原） and cellulose （纤维素）,which differ
from one another in how the glucose units are chained
together.
Amylose,直链淀粉 20%
Amylopectin,支链淀粉 80%
Glycogen is found in animal tissue
Cellulose is consisted of β–glucose and has a straight
conformation.
Cellulose is by far the most abundant organic compound on earth,
But most animals,including humans,are not able to break
cellulose down to glycose.
? Fats are used for energy and insulation
? A fat is any biomolecule formed from the reaction of a glycerol
molecule,attached to three fatty acid molecules,Fatty acid can
be saturated or unsaturated,
? Fats are used to reserve energy,1 gram of fat contains about 9
calories of energy,while a gram of carbohydrate and protein
contains only 4 calories of energy.
? Fats are also used to insulate us from cold.
13.3 Lipids are insoluble in water
Saturated fat and unsaturated fat
The molecules of saturated fats
can pack together,leading to
high melting points.
The molecules of unsaturated
fats can not pack together,
leading to low melting points.
stearic acid,m.p.69℃ oleic acid,m.p.13℃
Fats from animals and plants are mixture of
different fat molecules
Table 13.1 degree of unsaturation in some common fats
Fat Percentage of total fatty acid content
Saturated Monounsaturated polyunsaturated
Coconut 93 6 1
Palm 57 36 7
Lard 44 46 10
Cottonseed 26 22 52
peanut 21 4 30
Olive 15 73 12
Corn 14 29 57
Soybean 14 24 62
Sunflower 11 49 70
Safflower 10 14 76
Canola oil 6 58 36
Steroids (类固醇 ) contain four carbon rings
? Cholesterol,胆固醇
? Testosterone,睾酮
? Estradiol,雌甾二醇
13.4 Proteins are polymers of amino acids (氨基酸 )
? 20 amino acids differ from one another by the chemical
identity of their side groups.
? Amino acids are linked through peptide bonds (肽键 ),A
group of amino acids linked together through peptide
bonds is called peptide,Peptides containing more than
ten amino acids are generally called polypeptides.
There are many kinds of proteins
Protein structure
is determined by
attractions
between
neighboring
amino acids
The proteins in hair and fingernails contain a lot of
disulfide bonds
Many proteins consist of two or more polypeptide
chains.
血红蛋白
The proteins can be denatured with the change in
conditions.
Enzymes are
biological catalysts
Figure 13.25
Upon binding to the receptor site on
the enzyme sucrase,the substrate
sucrose is split into its two monosac-
charide units,glucose and fructose.
13.5 Nucleic acids code for proteins
? Our bodies are built of proteins,Our bodies are able to assemble
amino acids in just the right order to build proteins that have highly
functional structures.
? A nucleotide (核苷 ) consists of a phosphate (磷酯 ),a ribose sugar (核
糖 ),and a nitrogenous base (碱基 ).
? A nucleic acid is a polymer made up to nucleotide monomers.
? Two types of nucleic
acids,deoxyribonucleic
acid (脱氧核糖核酸 ) and
ribonucleic acid (核糖核
酸 ).
? Deoxyribonucleic acids
are the primary source of
genetic information and
are found in the cell
nucleus.
? Ribonucleic acids occur
mostly outside the cell
nucleus in the cytoplasm,
where they piece
together amino acids to
make proteins,
DNA is the template of life
? Gregor Mendel’s work
rose the idea of heredity,
The unit containing the
heritable information is
called genes,In 1900s,
genes have been related
to chromosomes (染色
体 ),which consist of
DNA and proteins,
? In 1953,James Watson and Francis Crick
proposed the double helix structure of DNA,The
most critical point of double helix model is the
hydrogen bonding between guanine and cytosine,
and also between adenine and thymine.
Replication of
DNA
? One gene codes for one polypeptide
? Gene controls the protein’s amino acid
sequence,Each gene codes for the synthesis of
a particular protein.
? The number of human gene is 30000-100000.
? Each chromosome contains 1000-2000 genes.
? Each DNA molecule contains about 3.1 billion
base pairs.
? Genes make up only about 20% of a DNA
molecule.
? RNA is largely responsible for protein synthesis
? The manufacturing of proteins involves two
processes,transcription (转录 ) and translation
(转译 ).
? These steps are mediated by the three forms of
RNA,messenger RNA (信使 RNA,mRNA),
ribosomal RNA (核糖体 RNA,rRNA) and
transfer RNA (转移 RNA,tRNA).
Codon （密码子、三联体）
Translation
Ribosome
Ribosome
? Genetic engineering
? Restriction enzyme (限制酶 ) ban cleave long strands of
DNA into small fragments.
? Gel electrophoresis is used to separate fragmented DNA.
Gel electrophoresis
Recombinant
（重组） DNA
Gene
cloning
(基因克隆 )
13.6 Vitamins are organic,minerals are inorganic
? Lipid-soluble vitamins and water-soluble
vitamins
? Lipid-soluble vitamins can be stored in
body for long time,but not for children.
? Over-dose of vitamins A and D are harmful.
? Vitamins B and C are washed away by
water.
Table 13.2 Some Vitamins Needed by the Human Body
Vitamin Function Deficiency syndrome
Lipid-soluble
Vitamin A (retinol) Precursor to rhodopsin,a
chemical used for
vision; assists in
inhibiting bacterial and
viral infections
Night blindness
Vitamin D (calciferol) Helps incorporate calcium
into body
Weak bones
Vitamin E (tocopherol) Inhibits oxidation of
polyunsaturated fats;
free radical scavenger;
Diminished hemoglobin
Vitamin K ( phylloquinone) helps maintain ability to
form blood clots
Abnormal bleeding
Water-soluble
B vitamins Coenzymes in biochemical
reactions for growth
and energy production
Various nerve and skin
disorders,anemia
Vitamin C (ascorbic acid) Antioxidant; asisits in
inhibiting bacterial and
viral infections
scurvy
Minerals
Macromineral (ionic form) Some functions Deficiency syndrome
Sodium (Na+) Transportation of molecules
across cell membrane,
nerve function
Muscle cramps,reduced
appetite
Potassium(K+) Transportation of molecules
across cell membrane,
nerve function
Muscular weakness,paralysis,
nausea,heart failure
Calcium(Ca2+) Bone and tooth formation,
nerve and muscle function
Retarded growth,possibly
loss of bone mass
Magnesium(Mg2+) Enzyme function Nervous system disturbances
Chlorine(Cl-) Transportation of molecules
across cell membrane,
digestive fluid,nerve
function
Muscle cramps,reduced
appetite
Phosphorus(H2PO4-) Bone and tooth formation,
nerve and muscle function
Weakness,calcium loss
Sulfur(SO42-) Amino acid component Protein deficiency
Table 13.3 Some Macrominerals Needed by the Human Body
ATP&ADP
13.7 Metabolism (代谢 ) is the cycling of biomolecules
through the body catabolism and metabolism
13.8 The food pyramid summarizes a healthful diet
Carbohydrates
Glycemic Index （血糖指数）
Glucose 100 Honey 58
Baked potato 85 Sweet corn 55
Cornflakes 83 Brown rice 55
Microwaved potato 82 Popcorn 55
Jelly beans 80 Oatmeal cookies 55
Vanilla wafer 77 Sweet potato 54
French fries 75 Banana 54
Cheerios 74 Milk chocolate 49
White bread 71 Orange 44
Mashed potato 70 Snickers candy bar 40
Life-savers candy 70 Pinto beans 39
Shredded wheat 69 Apple 38
Wheat bread 68 Spaghetti,boiled 5minutes 36
Sucrose 64 Skim milk 32
Raisins 64 Whole milk 27
Mars candy bar 64 Grapefruit 25
High-fructose corn syrup 62 soybean 18
White rice 58 peanuts 15
Table 13.4 Glycemic Index for Select Foods
source,Jennie Brand Miller et al.,the Glucose Revolution,the authoritative guide to the Glycemic index.
Sydney,Marlowe & company,1999
? Unsaturated fats are generally more healthful than
saturated fats
Saturated fats are used to synthesize cholesterol.
Fats are also packaged with water soluble proteins
(Lipoproteins) to move through bloodstream.
? Hydrogenation of unsaturated fats can be used to
prepare margarine and also in the process of making
chocolates.
Lipoprotein Percent
protein
Density(g/ml) Primary function
Very-low-density(VLDL) 5 1.006-1.019 Fat transport
Low-density(LDL) 25 1.019-1.063 Cholesterol transport(to cells to
build cell walls)
High-density(HDL) 50 1.063-1.210 Cholesterol transport(to liver for
processing)
Table 13.5 The Classification of Lipoproteins
Essential for
adults
Essential for
children
