chapter 3 2015 · · 2016-01-27chemical reactions in cells Copyright © 2009 Pearson Education, Inc. Unlinked Monomer ... the structure of the cell membrane ... specific function

Chapter Chapter 33البــاب الثالــثالبــاب الثالــث

The Molecules of Cells

الجزيئات الخلوية

Copyright © 2009 Pearson Education, Inc.

PowerPoint Lectures for

Biology: Concepts & Connections, Sixth Edition

Campbell, Reece, Taylor, Simon, and Dickey

Lecture by Richard L. MyersTranslated by Nabih Baeshen

Lactose intolerancePeople who are Lactose

Intolerance can digest foodthat contain lactose

(such as ice cream) bytaking pills that contain

the enzyme lactase

Introduction: Got Lactose?

� Most of the world’s population cannot digest milk-based foods

� They are lactose intolerant, because they lack the enzyme lactaseenzyme lactase

� This illustrates the importance of biological molecules, such as lactase, to functioning living organisms


Model of a milk digesting enzyme (Lactase)Model of a milk digesting enzyme (Lactase)Model of a milk digesting enzyme (Lactase)Model of a milk digesting enzyme (Lactase)

INTRODUCTION TO ORGANIC

COMPOUNDS (Molecules)


3.1 Life’s molecular diversity is based on the properties of carbon

� Diverse molecules found in cells are composed of carboncarboncarboncarbon bonded to other elements– Carbon-based molecules are called organic organic organic organic

compoundscompoundscompoundscompounds– By sharing electrons, carbon can bond to

four other atoms– By doing so, it can branch in up to four

directions



� Methane (CH4) is one of the simplest organic compounds– Four covalent bonds link four

hydrogen atoms to the carbon atom– Four covalent bonds link four

hydrogen atoms to the carbon atom– Each of the four lines in the formula

for methane represents a pair of shared electrons


Structuralformula

Ball-and-stickmodel

Space-fillingmodel

Three representations of methane (CH4)

Methane

The four single bonds of carbon point to the corners of a tetrahedron.


�Methane and other compounds composed of only carbon and hydrogen are called hydrocarbonshydrocarbonshydrocarbonshydrocarbonshydrocarbonshydrocarbonshydrocarbonshydrocarbons–Carbon atoms, with attached hydrogens, can bond together in chains of various lengths


Petroleum

� A chain of carbon atoms is called a carbon a carbon a carbon a carbon skeletonskeletonskeletonskeleton– Carbon skeletons can be branched or unbranched


– Therefore, different compounds with the same same same same molecular formula molecular formula molecular formula molecular formula can be produced– These structures are called isomers


Carbon skeletons vary in length.تتباين أطوال ھياكل الكربون: الطول

Branching. Skeletons may be unbranched or branched. قد تكون الھياكل متفرعة أو غير متفرعة: التفرع

Butane بيوتان Isobutane أيزوبيتان

Propane بروبانEthane إيثانLength.

Variations incarbon skeletons

Double bonds.

2-Butene بيوتان - 2

Skeletons may have double bonds,which can vary in location.

قد تحتوي الھياكل على روابط ثنائية تتنوع في مواقعھا: الروابط الثنائية

Cyclohexane ھكسان حلقي

1-Butene بيوتان - 1

Benzene بنزينSkeletons may be arranged in rings.

قد تنتظم الھياكل في حلقات: الحلقات Rings.

3.2 Characteristic chemical groups help determine the properties of organic compounds

� An organic compound has unique properties that depend upon:

– The size and shape of the molecule– The size and shape of the molecule– The groups of atoms (functional groups) attached to it

� A functional groupfunctional groupfunctional groupfunctional group affects a biological molecule’s function in a characteristic way



� Compounds containing functional groups are hydrophilichydrophilichydrophilichydrophilic (water-loving)– This means that they are soluble – This means that they are soluble

in water, which is a necessary prerequisite for their roles in water-based life.



� The functional groups are وهذه هي المجاميع الوظيفية 1.1.1.1. HydroxylHydroxylHydroxylHydroxyl groupgroupgroupgroup—consists of a hydrogenhydrogenhydrogenhydrogen bonded to an

oxygenoxygenoxygenoxygen2.2.2.2. CarbonylCarbonylCarbonylCarbonyl groupgroupgroupgroup—a carboncarboncarboncarbon linked by a double bond to

an oxygen atom3.3.3.3. CarboxylCarboxylCarboxylCarboxyl groupgroupgroupgroup—consists of a carboncarboncarboncarbon bonded to a

hydroxyl group hydroxyl group hydroxyl group hydroxyl group and double-bonded to an oxygenoxygenoxygenoxygen4.4.4.4. AminoAminoAminoAmino groupgroupgroupgroup—composed of a nitrogennitrogennitrogennitrogen bonded to two two two two

hydrogen atoms and a carbon skeletonhydrogen atoms and a carbon skeletonhydrogen atoms and a carbon skeletonhydrogen atoms and a carbon skeleton5.5.5.5. PhosphatePhosphatePhosphatePhosphate groupgroupgroupgroup—consists of a phosphorus atom

bonded to four oxygen four oxygen four oxygen four oxygen atoms


المجاميع الوظيفية للمركبات العضويةأمثلة

مجموعة ھيدروكسيل

المجموعة الوظيفية

كحول

مجموعة كربونيل

الدھايد كيتون

مجموعة كاربوكسيل

حمض كربوكسيلي حمض كربوكسيليحمض كربوكسيلي مؤين حمض كربوكسيلي مؤين

مجموعة أمين

أمين أمين مؤين

مجموعة فوسفات

(ATP)فوسفات عضوي

ادينوسين

مجموعة ميثيل

مركب ميثيلي

3.3 Cells make a huge number of large molecules from a small set of small molecules

� There are four classes of biological molecules1.1.1.1. CarbohydratesCarbohydratesCarbohydratesCarbohydratesاااا2.2.2.2. ProteinsProteinsProteinsProteins3.3.3.3. LipidsLipidsLipidsLipids4.4.4.4. Nucleic acidsNucleic acidsNucleic acidsNucleic acids



� The four classes of biological molecules contain very large molecules– They are often called macromoleculesmacromoleculesmacromoleculesmacromolecules because of their large size– They are also called polymerspolymerspolymerspolymers because they are made from identical building blocks strung together– The building blocks are called monomersmonomersmonomersmonomers



� Monomers Monomers Monomers Monomers are linked together to form polymerspolymerspolymerspolymers through dehydration reactionsdehydration reactionsdehydration reactionsdehydration reactions, which remove water� Polymers are broken apart by hydrolysis,hydrolysis,hydrolysis,hydrolysis, the � Polymers are broken apart by hydrolysis,hydrolysis,hydrolysis,hydrolysis, the addition of water� All biological reactions of this sort are mediated by enzymes, which speed up chemical reactions in cells


UnlinkedMonomer

Short polymer

Dehydration

Dehydration reactions build a polymer chain

Longer polymer

DehydrationReaction

Hydrolysis breaks a polymer chain

Hydrolysis

CARBOHYDRATESCARBOHYDRATESCARBOHYDRATESCARBOHYDRATES


3.4 Monosaccharides are the simplest carbohydratesالسكريات ا2حادية ھي أبسط الكربوھيدرات

� CarbohydratesCarbohydratesCarbohydratesCarbohydrates range from small sugar molecules (monomers) to large polysaccharides– Sugar monomers are monosaccharidesmonosaccharidesmonosaccharidesmonosaccharides, such as glucose glucose glucose glucose monosaccharidesmonosaccharidesmonosaccharidesmonosaccharides, such as glucose glucose glucose glucose and fructosefructosefructosefructose– These can be hooked together to form the polysaccharidespolysaccharidespolysaccharidespolysaccharides


3.4 Monosaccharides are the simplest carbohydrates

� The carbon skeletons of monosaccharides The carbon skeletons of monosaccharides The carbon skeletons of monosaccharides The carbon skeletons of monosaccharides vary in lengthvary in lengthvary in lengthvary in length– Glucose and fructose are six carbons long– Others have three to seven carbon atoms

� Monosaccharides are the main fuels Monosaccharides are the main fuels Monosaccharides are the main fuels Monosaccharides are the main fuels (energy) (energy) (energy) (energy) for cellular for cellular for cellular for cellular workworkworkwork– Monosaccharides are also used as raw materials to manufacture other organic molecules


Structures of glucose and fructose

Glucoseا(an aldose )

Fructose(a ketose )

Three representations of the ring form of glucose

StructuralFormula

ا

AbbreviatedStructure

SimplifiedStructure

3.5 Cells link two single sugars to form disaccharides

� Two monosaccharides (monomers) can bond to form a disaccharidedisaccharidedisaccharidedisaccharide in a dehydration reaction– An example is a glucoseglucoseglucoseglucose monomer – An example is a glucoseglucoseglucoseglucose monomer

bonding to a fructosefructosefructosefructose monomer to form sucrosesucrosesucrosesucrose, a common disaccharide


Glucose Glucose

Maltose

Disaccharide formation by a dehydration reaction

3.7 Polysaccharides are long chains of sugar units

� StarchStarchStarchStarch is a storage polysaccharide composed of glucose monomers and found in plants� GlycogenGlycogenGlycogenGlycogen is a storage polysaccharide composed of glucose, which is hydrolyzed by animals when glucose is neededglucose is needed� CellulosCellulosCellulosCelluloseeee is a polymer of glucose that forms plant cell walls� ChitinChitinChitinChitin is a polysaccharide used by insects and crustaceans to build an exoskeletonCopyright © 2009 Pearson Education, Inc.

Starch granules inpotato tuber cells

Glycogen granulesin muscle tissue

GlucoseMonomer

GLYCOGEN

STARCH

Polysaccharides

Cellulose fibrils ina plant cell wall

CelluloseMolecules

CELLULOSE

Hydrogen bondsروابط ھيدروجينية

LIPIDS


SteroidsPhospholipids True Fats

3.8 Fats are lipids that are mostly energy-storage molecules

� LipidsLipidsLipidsLipids are water insoluble (hydrophobichydrophobichydrophobichydrophobic, or water fearing) compounds that are important in energy storage– They contain twice as much

energyenergyenergyenergy as a polysaccharide� FatsFatsFatsFats are lipids made from glycerol

and fatty acidsCopyright © 2009 Pearson Education, Inc.


� Fatty acids link to glycerol by a Fatty acids link to glycerol by a Fatty acids link to glycerol by a Fatty acids link to glycerol by a dehydration reactiondehydration reactiondehydration reactiondehydration reaction– A fat contains one glycerol linked

to three fatty acids– A fat contains one glycerol linked

to three fatty acids– Fats are often called triglycerides

because of their structure


Fatty acid

Glycerol

Fatty acid

A dehydration reaction linkinga fatty acid to glycerol

A fat molecule made fromglycerol and three fatty acids


� Some fatty acids contain double bondsSome fatty acids contain double bondsSome fatty acids contain double bondsSome fatty acids contain double bonds– This causes links or bends in the carbon chain because the maximum number of hydrogen atoms cannot bond to the carbons at the double bondbond– These compounds are called unsaturatedunsaturatedunsaturatedunsaturated fats fats fats fats because they have fewer than the maximum number of hydrogens– Fats with the maximum number of hydrogensare called saturated fatssaturated fatssaturated fatssaturated fats


3.9 Phospholipids and steroids are important lipids with a variety of functions

� PhospholipidsPhospholipidsPhospholipidsPhospholipids are structurally similar to fats and are an are structurally similar to fats and are an are structurally similar to fats and are an are structurally similar to fats and are an important component of all cellsimportant component of all cellsimportant component of all cellsimportant component of all cells1. For example, they are a major part of cell membranes, in which they cluster into a bilayerof phospholipids2. The hydrophilichydrophilichydrophilichydrophilic heads are in contact with the water of the environment and the internal part of the cell3. The hydrophobichydrophobichydrophobichydrophobic tails band in the center of the bilayer


Water

Hydrophobic

Hydrophilicheads

رؤس محبة للماء

Section of a phospholipid membrane

Cell external surface

Hydrophobictails

ذيول كارھة للماء

Waterالسطح الداخلي

للخليةCell internal

surface

3.9 Phospholipids and steroids are important lipids with a variety of functions

� Steroids Steroids Steroids Steroids are lipids composed of fused ring are lipids composed of fused ring are lipids composed of fused ring are lipids composed of fused ring structuresstructuresstructuresstructures– CholesterolCholesterolCholesterolCholesterol is an example of a

steroid that plays a significant role in steroid that plays a significant role in the structure of the cell membrane

– In addition, cholesterol is the compound from which we synthesize sex hormones


PROTEINS


3.11 Proteins are essential to the structures and functions of life

� A proteinproteinproteinprotein is a polymer built from various combinations of 20 amino acid monomers– Proteins have unique structures that are directly related to their functionsare directly related to their functions– EnzymesEnzymesEnzymesEnzymes, proteins that serve as metabolic catalysts, regulate the chemical reactions within cells


3.11 Proteins are essential to the structures and functions of life

ا

� Structural Structural Structural Structural proteins provide associations between body parts and contractilecontractilecontractilecontractile proteins are found within muscle

� DefensiveDefensiveDefensiveDefensive proteins include antibodies of the � DefensiveDefensiveDefensiveDefensive proteins include antibodies of the immune system, and signalsignalsignalsignal proteins are best exemplified by the hormones

� ReceptorReceptorReceptorReceptor proteins serve as antenna for outside signals, and transporttransporttransporttransport proteins carry oxygen


3.12 Proteins are made from amino acids linked by peptide bonds

� Amino acidsAmino acidsAmino acidsAmino acids, the building blocks of proteins, have an amino group and a carboxyl group– Both of these are covalently bonded covalently bonded covalently bonded covalently bonded to a – Both of these are covalently bonded covalently bonded covalently bonded covalently bonded to a central carbon atom– Also bonded to the central carbon is a hydrogen atom hydrogen atom hydrogen atom hydrogen atom and some other chemical chemical chemical chemical group symbolized by Rgroup symbolized by Rgroup symbolized by Rgroup symbolized by R


General structure of an amino acid

Carboxylgroup

AminoGroup

م


� Amino acids are classified as hydrophobic hydrophobic hydrophobic hydrophobic or hydrophilichydrophilichydrophilichydrophilic– Some amino acids have a nonpolar R group – Some amino acids have a nonpolar R group

and are hydrophobichydrophobichydrophobichydrophobic– Others have a polar R a polar R a polar R a polar R group and are

hydrophilichydrophilichydrophilichydrophilic, which means they easily dissolve in aqueous solutions


Examples of amino acids with hydrophobic and hydrophilic R groups

Leucine (Leu)

Hydrophobic

Serine (Ser)ا

Hydrophilic

Aspartic acid (Asp)


� Amino acid monomersmonomersmonomersmonomers are linked together to form polymericpolymericpolymericpolymeric proteins– This is accomplished by an enzymeenzymeenzymeenzyme----mediated dehydration reactionmediated dehydration reactionmediated dehydration reactionmediated dehydration reactionmediated dehydration reactionmediated dehydration reactionmediated dehydration reactionmediated dehydration reaction– This links the carboxyl group carboxyl group carboxyl group carboxyl group of one amino acid to the amino group amino group amino group amino group of the next amino acid

– The covalentcovalentcovalentcovalent linkage resulting is called a peptide bonda peptide bonda peptide bonda peptide bondCopyright © 2009 Pearson Education, Inc.

Peptide bond

DehydrationReaction

Peptide bond formation

Carboxylgroup

Aminogroup

Dipeptideثنائي الببتيد

Amino acid Amino acid

3.13 A protein’s specific shape determines its function

� A polypeptide chain contains hundreds or thousands of amino acids linked by peptide bonds– The amino acid sequence causes the – The amino acid sequence causes the polypeptide to assume a particular shape– The shape of a protein determines its specific function


Groove

Space-filling model of lysozyme

3.14 A protein’s shape depends on four levels of structure

� A protein can have four levels of structure– Primary structurePrimary structurePrimary structurePrimary structure – Secondary structureSecondary structureSecondary structureSecondary structure – Secondary structureSecondary structureSecondary structureSecondary structure – Tertiary structureTertiary structureTertiary structureTertiary structure – Quaternary structureQuaternary structureQuaternary structureQuaternary structure



� The primary structureprimary structureprimary structureprimary structure of a protein is its unique amino acid sequence– The correct amino acid sequence is

determined by the cell’s genetic determined by the cell’s genetic information

– The slightest change in this sequence affects the protein’s ability to function


Amino acidsPrimary structureأحماض أمينية

التركيب ا7ولي


� Protein secondary structuresecondary structuresecondary structuresecondary structure results from coiling or folding of the polypeptide– Coiling results in a helical structure called an alpha helixalpha helixalpha helixalpha helix

– Folding may lead to a structure called a pleated sheetpleated sheetpleated sheetpleated sheet

– Coiling and folding result from hydrogen bonding hydrogen bonding hydrogen bonding hydrogen bonding between certain areas of the polypeptide chain


Amino acids

Hydrogen bond

Alpha helix

Secondary structure

Pleated sheet


� The overall three-dimensional shape of a protein is called its tertiary structuretertiary structuretertiary structuretertiary structure– Tertiary structure generally results from interactions between the R groups of the interactions between the R groups of the various amino acids– Disulfide bridges Disulfide bridges Disulfide bridges Disulfide bridges are covalentcovalentcovalentcovalent bonds that further strengthen the protein’s shape


Globular Polypeptide(single subunit(single subunitof transthyretin)

Tertiary structure


� Two or more polypeptide chains Two or more polypeptide chains Two or more polypeptide chains Two or more polypeptide chains (subunits) associate providing (subunits) associate providing (subunits) associate providing (subunits) associate providing quaternary quaternary quaternary quaternary structurestructurestructurestructure– Collagen is an example of a protein with quaternary structurewith quaternary structure– Its triple helix gives great strength to connective tissue, bone, tendons, and ligaments


PolypeptidePolypeptidePolypeptidePolypeptide chain (alpha helix)chain (alpha helix)chain (alpha helix)chain (alpha helix)

Collagen is a fibrous protein

with helical subunits Interwind into a larger triple

helix, this

Collagen fiberCollagen fiberCollagen fiberCollagen fiber

helix, this arrangement gives

the long fibers great strength

Triple helix

Transthyretin, withfour identical globularpolypeptide subunits

Quaternary structure

Transthyretin:A plasma protein consisting of 127 amino acids that binds retinol and thyroxine

Four Levels of Protein Structureأربع مستويات من تركيب البروتين

Primary structurePrimary structurePrimary structurePrimary structure

Amino acids أحماض أمينية

Hydrogen bondروابط ھيدروجينية

Secondary structureSecondary structureSecondary structureSecondary structure

Pleated sheetصحيفة مطوية

Alpha helixحلزون ألفا

Transthyretin, withfour identical globularpolypeptide subunitsالترانسثيريتين بأربع من الوحدات

الفرعية الكروية المتماثلة من متعدد البيبتيدات

Quaternary structureQuaternary structureQuaternary structureQuaternary structure

حلزون ألفاصحيفة مطوية

Tertiary structureTertiary structureTertiary structureTertiary structureGlobular Polypeptide

(single subunitof transthyretin)

3.13 A protein’s specific shape determines its function

� If for some reason a protein’s shape is altered, it can no longer function– DenaturationDenaturationDenaturationDenaturation will cause polypeptide chains to unravel and lose their shape and, thus, their functionfunction– Proteins can be denatured by changes in salt salt salt salt

concentration and pHconcentration and pHconcentration and pHconcentration and pH


NUCLEIC ACIDS


3.16 Nucleic acids are information-rich polymers of nucleotides

� DNADNADNADNA (deoxyribonucleic aciddeoxyribonucleic aciddeoxyribonucleic aciddeoxyribonucleic acid) and RNARNARNARNA (ribonucleic ribonucleic ribonucleic ribonucleic acidacidacidacid) are composed of monomers called nucleotidesnucleotidesnucleotidesnucleotides– Nucleotides have three parts

– A fiveA fiveA fiveA five----carbon sugar carbon sugar carbon sugar carbon sugar called ribose in RNA and deoxyribose in DNA– A phosphate groupA phosphate groupA phosphate groupA phosphate group – A nitrogenous base


Nitrogenous

nucleotide, consisting of a phosphate group, sugar, and a nitrogenous base

PhosphateGroup

Nitrogenousbase

(adenine)

Sugar

Dehydration

Short polymer MonomerHydrolysis

Longer polymer

Nucleotide

Sugar-phosphate backbone Part of a polynucleotide

Base pair

DNA double helix

� DNA nitrogenous bases are adenine (A), thymine (T), cytosine (C), and guanine (G)– RNA also has A, C, and G, but


– RNA also has A, C, and G, but instead of T, it has uracil (U)



� Two polynucleotide strands wrap around each other to form a DNA double helixdouble helixdouble helixdouble helix– The two strands are associated because

particular bases always hydrogen bond to one anotherone another

– A pairs with T, and C pairs with G,producing base pairsbase pairsbase pairsbase pairs

� RNA is usually a single polynucleotide strand



� A particular nucleotide sequence that can instruct the formation of a polypeptide is called a genegenegenegene– Most DNA molecules consist of millions of

base pairs and, consequently, many base pairs and, consequently, many genes

– These genes, many of which are unique to the species, determine the structure of proteins and, thus, life’s structures and functions


3.17 EVOLUTION CONNECTION: Lactose tolerance is a recent event in human evolution

� Mutations Mutations Mutations Mutations are alterations in bases or the sequence of are alterations in bases or the sequence of are alterations in bases or the sequence of are alterations in bases or the sequence of bases in DNAbases in DNAbases in DNAbases in DNA

� Lactose tolerance is the result of mutationsLactose tolerance is the result of mutationsLactose tolerance is the result of mutationsLactose tolerance is the result of mutations– In many people, the gene that dictates lactose utilization In many people, the gene that dictates lactose utilization In many people, the gene that dictates lactose utilization In many people, the gene that dictates lactose utilization

is turned off in adulthoodis turned off in adulthoodis turned off in adulthoodis turned off in adulthood– In many people, the gene that dictates lactose utilization In many people, the gene that dictates lactose utilization In many people, the gene that dictates lactose utilization In many people, the gene that dictates lactose utilization

is turned off in adulthoodis turned off in adulthoodis turned off in adulthoodis turned off in adulthood– Apparently, mutations occurred over time that prevented Apparently, mutations occurred over time that prevented Apparently, mutations occurred over time that prevented Apparently, mutations occurred over time that prevented

the gene from turning offthe gene from turning offthe gene from turning offthe gene from turning off– This is an excellent example of human evolutionThis is an excellent example of human evolutionThis is an excellent example of human evolutionThis is an excellent example of human evolution


You should now be able to ينبغي أن تكون قادراً ا;ن على فعل ما يلي1. Discuss the importance of carbon to life’s molecular diversity

ناقش أهمية الكربون في تنوع الجزيئات الحيوية. 12. Describe the chemical groups that are important to life

صف المجاميع الكيميائية الهامة للحياة. 23. Explain how a cell can make a variety of large molecules from a small set of molecules

اشرح كيفية تصنيع الخلية للعديد من الجزيئات الكبيرة من مجموعة صغيرة من . 3 الجزيئاتاشرح كيفية تصنيع الخلية للعديد من الجزيئات الكبيرة من مجموعة صغيرة من . 34. Define monosaccharides, disaccharides, and polysaccharides and explain their functions

عرف السكاكر األحادية والثنائية والعديدة مع شرح وظائفها. 45. Define lipids, phospholipids, and steroids and explain their functions

عرف اللبيدات والدهون الفسفورية واالسترويدات مع شرح وظائفها. 5Copyright © 2009 Pearson Education, Inc.

You should now be able to ينبغي أن تكون قادراً ا;ن على فعل ما يلي

6. Describe the chemical structure of proteins and their importance to cellsصف التركيب الكيميائي للبروتينات وأهميتها للخاليا. 6

7. Describe the chemical structure of nucleic acids and how they relate to inheritanceand how they relate to inheritanceصف التركيب الكيميائي لألحماض النووية وعالقتها بالوراثة. 7


Chapt. 3: The Molecules Of Cellsالجزيئات الخلوية

تعريف المصطلـــــح المصطلــــــــــــــح

Organic Compounds (Molecules) العضوية) الجزيئات(مدخل للمركبات

Organic Compounds بالمركبات العضويةتسمى الجزيئات التي أساسھا ذرة الكربون

Hydrocarbons يسمى كل من الميثان والمركبات المؤلفة من كربون وھيدروجين فقط

بالھايدروكربونات

Carbon Skeleton تسمسى سلسلة ذرات الكربون بالھيكل الكربوني

Carbon Skeletons Can Be Branched Or Unbranched

قد يتفرع الھيكل الكربوني أو 9 يتفرع

Therefore, Different Compounds With The لذلك يمكن إنتاج مركبات مختلفة بنفس الصيغة الجزيئية

Same Molecular Formula Can Be Produced لذلك يمكن إنتاج مركبات مختلفة بنفس الصيغة الجزيئية

These Structures Are Called Isomers تعرف ھذه التراكيب بالنظائر

Functional Group Affects A Biological Molecule’s Function In A Characteristic Way

تؤثر المجموعة الوظيفية في وظيفة الجزيئ الحيوي بطريقة مميزة

Hydrophilic (Water-Loving) المركبات المحتوية على مجاميع وظيفية تكون محبة للماء

This Means That They Are Soluble In Water, Which Is A Necessary Prerequisite For Their Roles In Water-Based Life

يعني ھذا أنھا تذوب في الماء وھذا متطلب ضروري للقيام بوظائفھا

الحيوية المعتمدة على الماء

Hydroxyl Group—Consists Of A Hydrogen Bonded To An Oxygen

تتكون من ھيدروجين مرتبط بأوكسجين–الھيدروكسيلمجموعة

Carbonyl Group—A Carbon Linked By A Double Bond To An Oxygen Atom

كربون متصل بذرة أوكسجين برابطة ثنائية–الكربونيلمجموعة

Carboxyl Group—Consists Of A Carbon Bonded To A Hydroxyl Group And Double-Bonded To An Oxygen

تتألف من كربون مرتبط بمجموعة –كربوكسيلمجموعة

كما وترتبط برابطة ثنائية باRوكسجين الھيدروكسيل

Amino Group—Composed Of A Nitrogen Bonded To Two Hydrogen Atoms And A Carbon Skeleton

مكونة من نيتروجين مرتبط بذرتي ھيدروجين –مجموعة أمين

وھيكل كربوني

Phosphate Group—Consists Of A Phosphorus تتكون من ذرة فوسفور مرتبطة بأربعة ذرات –مجموعة فوسفات



Phosphate Group—Consists Of A Phosphorus Atom Bonded To Four Oxygen Atoms

تتكون من ذرة فوسفور مرتبطة بأربعة ذرات –مجموعة فوسفات

أوكسجين

Biological Molecules ھناك أربعة أصناف من الجزيئات الحيوية

Carbohydrates الكربوھيدرات

Proteins البروتينات

Lipids الدھون(اللبيدات(Nucleic Acids حماض النوويةRا

Macromolecules Because Of Their Large Size تسمى عادة بالجزيئات الكبيرة لحجمھا الكبير

They Are Made From Identical Building Blocks Strung Together

Rنھا مكونة من وحدات بنائية متماثلة بالبوليميراتتسمى أيضاً

متماسكة بقوة

The Building Blocks Are Called Monomers بالمونيميراتتسمى وحدات البناء

Dehydration Reactions, Which Remove Water

بتفاعYت نزع الماء بوليميراتلتكون ببعضھا المونيميراتترتبط

Polymers Are Broken Apart By Hydrolysis, The Addition Of Water

)بإضافة الماء( الحلمأةأو بالتميؤ البوليميراتتنحل

All Biological Reactions Of This Sort Are Mediated By Enzymes, Which Speed Up Chemical Reactions In Cells

كل ھذه العمليات الحيوية من ھذا النوع تتوسط فيھا ا]نزيمات التي

تسرع من التفاعYت الكيميائية في الخYيا

Dehydration Reaction تفاعل نزع الماء




Hydrolysis الحلمأةأو التميؤ

Monosaccharides, Such As Glucose And Fructose

سكر مثل الجلوكوز مونيميراتالسكريات اRحادية عبارة عن

والفركتوز

Disaccharide In A Dehydration Reaction البعض ليكونا ببعضھما) مونيمران(يمكن أن يرتبط سكران أحاديان

سكراً ثنائياً بتفاعل نزع الماء

An Example Is A Glucose Monomer Bonding To A Fructose Monomer To Form Sucrose, A Common Disaccharide

لتكوين الفركتوز بمونيمرالجلوكوز مونيمر إرتباطمثال ذلك ھو

)سكر ثنائي شائع( السكروز

Starch Is A Storage Polysaccharide Composed Of Glucose Monomers And Found In Plants

جلوكوز مونيميراتتخزيني ويتكون من سكرمتعددالنشا عبارة عن

ويوجد في النبات

Glycogen Is A Storage Polysaccharide Composed Of Glucose, Which Is Hydrolyzed By Animals When Glucose Is Needed

تخزيني ويتكون من سكرمتعددعن الحيوانيعبارةأو النشا الجYيكوجين

عند الحاجة إلى الجلوكوز الجYيكوجينالجلوكوز ، وتحلل الحيوانات

Cellulose Is A Polymer Of Glucose That Forms Plant Cell Walls

جلوكوزي يكون جدر الخYيا في النباتات بوليميرعبارة عن السيليلوز



Forms Plant Cell Walls Chitin Is A Polysaccharide Used By Insects And Crustaceans To Build An Exoskeleton

عبارة عن سكر متعدد تستخدمه الحشرات والقشريات لبناء الكايتين

ھياكلھا الخارجية

Lipids Are Water Insoluble (Hydrophobic, Or Water Fearing) Compounds That Are Important In Energy Storage

، وھي ھامة في ) كارھة للماء(ھي مركبات 9 تذوب في الماء اللبيدات

تخزين الطاقة

They Contain Twice As Much Energy As A Polysaccharide

المتعددة السكاكرتحتوي على ضعف الطاقة الموجودة في

Fats Are Lipids Made From Glycerol And Fatty Acids

نوع من اللبيدات مكونة من ) السمن والزبدة والزيت(الدھون

جليسيرول وأحماض دھنية

Unsaturated Fats Because They Have Fewer Than The Maximum Number Of Hydrogens

تسمى ھذه المركبات بالدھون غير المشبعة Rنھا تحتوى على عدد أقل

من العدد الكلي للھيدروجين

Fats With The Maximum Number Of Hydrogens Are Called Saturated Fats

تسمى الدھون المحتوية على العدد الكلي للھيدروجين بالدھون المشبعة

)الكربون ذراتروابط ثنائية بين بھا9 يوجد (Phospholipids Are Structurally Similar To Fats And Are An Important Component Of All Cells

الفسفورية الدھون في تركيبھا وھي من المكونات اللبيداتتشابه

اRساسية للخلية

For Example, They Are A Major Part Of Cell Membranes, In Which They Cluster Into A Bilayer Of Phospholipids

على سبيل المثال ھي مكون ھام لhغشية الخلوية حيث تتجمع على

ھيئة طبقتين من الدھون الفسفورية

Steroids Are Lipids Composed Of Fused



Steroids Are Lipids Composed Of Fused Ring Structures

عبارة عن دھون مكونة من حلقات تركيبية متداخلة اRسترويدات

Cholesterol Is An Example Of A Steroid That Plays A Significant Role In The Structure Of The Cell Membrane

التي تلعب دوراً ھاماً في تركيب لYسترويداتھو مثال الكوليسترول

غشاء الخلية

In Addition, Cholesterol Is The Compound From Which We Synthesize Sex Hormones

ھرموناتنا بهھو المركب الذي نبني الكوليسترولبا]ضافة لذلك فإن الجنسية

Anabolic Steroids Are Synthetic Variants Of Testosterone That Can Cause A Buildup Of Muscle And Bone Mass

البنائي عبارة عن توليفة صناعية من اRيض سترويدات

والتي تؤدي لبناء الكتلة العضلية ) الذكورة ھرمونات( التيستيسترونات

والعظمية

Protein Is A Polymer Built From Various Combinations Of 20 Amino Acid Monomers

مونيمراتمن 20يبنى من توافيق بين بوليمرالبروتين عبارة عن اRمينيةاRحماض



Organic Compounds (Molecules) العضوية) الجزيئات(مدخل للمركبات

Organic Compounds بالمركبات العضويةتسمى الجزيئات التي أساسھا ذرة الكربون

Hydrocarbons يسمى كل من الميثان والمركبات المؤلفة من كربون وھيدروجين فقط

بالھايدروكربونات

Carbon Skeleton تسمسى سلسلة ذرات الكربون بالھيكل الكربوني

Carbon Skeletons Can Be Branched Or Unbranched

قد يتفرع الھيكل الكربوني أو 9 يتفرع

Therefore, Different Compounds With The لذلك يمكن إنتاج مركبات مختلفة بنفس الصيغة الجزيئية

Same Molecular Formula Can Be Produced لذلك يمكن إنتاج مركبات مختلفة بنفس الصيغة الجزيئية

These Structures Are Called Isomers تعرف ھذه التراكيب بالنظائر

Functional Group Affects A Biological Molecule’s Function In A Characteristic Way

تؤثر المجموعة الوظيفية في وظيفة الجزيئ الحيوي بطريقة مميزة

Hydrophilic (Water-Loving) المركبات المحتوية على مجاميع وظيفية تكون محبة للماء

This Means That They Are Soluble In Water, Which Is A Necessary Prerequisite For Their Roles In Water-Based Life

يعني ھذا أنھا تذوب في الماء وھذا متطلب ضروري للقيام بوظائفھا

الحيوية المعتمدة على الماء

Hydroxyl Group—Consists Of A Hydrogen Bonded To An Oxygen

تتكون من ھيدروجين مرتبط بأوكسجين–الھيدروكسيلمجموعة

Carbonyl Group—A Carbon Linked By A Double Bond To An Oxygen Atom

كربون متصل بذرة أوكسجين برابطة ثنائية–الكربونيلمجموعة

Carboxyl Group—Consists Of A Carbon Bonded To A Hydroxyl Group And Double-Bonded To An Oxygen

تتألف من كربون مرتبط بمجموعة –كربوكسيلمجموعة

كما وترتبط برابطة ثنائية باRوكسجين الھيدروكسيل

Amino Group—Composed Of A Nitrogen Bonded To Two Hydrogen Atoms And A Carbon Skeleton

مكونة من نيتروجين مرتبط بذرتي ھيدروجين –مجموعة أمين

وھيكل كربوني

Phosphate Group—Consists Of A Phosphorus تتكون من ذرة فوسفور مرتبطة بأربعة ذرات –مجموعة فوسفات



Phosphate Group—Consists Of A Phosphorus Atom Bonded To Four Oxygen Atoms

تتكون من ذرة فوسفور مرتبطة بأربعة ذرات –مجموعة فوسفات

أوكسجين

Biological Molecules ھناك أربعة أصناف من الجزيئات الحيوية

Carbohydrates الكربوھيدرات

Proteins البروتينات

Lipids الدھون(اللبيدات(Nucleic Acids حماض النوويةRا

Macromolecules Because Of Their Large Size تسمى عادة بالجزيئات الكبيرة لحجمھا الكبير

They Are Made From Identical Building Blocks Strung Together

Rنھا مكونة من وحدات بنائية متماثلة بالبوليميراتتسمى أيضاً

متماسكة بقوة

The Building Blocks Are Called Monomers بالمونيميراتتسمى وحدات البناء

Dehydration Reactions, Which Remove Water

بتفاعYت نزع الماء بوليميراتلتكون ببعضھا المونيميراتترتبط

Polymers Are Broken Apart By Hydrolysis, The Addition Of Water

)بإضافة الماء( الحلمأةأو بالتميؤ البوليميراتتنحل

All Biological Reactions Of This Sort Are Mediated By Enzymes, Which Speed Up Chemical Reactions In Cells

كل ھذه العمليات الحيوية من ھذا النوع تتوسط فيھا ا]نزيمات التي

تسرع من التفاعYت الكيميائية في الخYيا





Hydrolysis الحلمأةأو التميؤ

Monosaccharides, Such As Glucose And Fructose

سكر مثل الجلوكوز مونيميراتالسكريات اRحادية عبارة عن

والفركتوز

Disaccharide In A Dehydration Reaction البعض ليكونا ببعضھما) مونيمران(يمكن أن يرتبط سكران أحاديان

سكراً ثنائياً بتفاعل نزع الماء

An Example Is A Glucose Monomer Bonding To A Fructose Monomer To Form Sucrose, A Common Disaccharide

لتكوين الفركتوز بمونيمرالجلوكوز مونيمر إرتباطمثال ذلك ھو

)سكر ثنائي شائع( السكروز

Starch Is A Storage Polysaccharide Composed Of Glucose Monomers And Found In Plants

جلوكوز مونيميراتتخزيني ويتكون من سكرمتعددالنشا عبارة عن

ويوجد في النبات

Glycogen Is A Storage Polysaccharide Composed Of Glucose, Which Is Hydrolyzed By Animals When Glucose Is Needed

تخزيني ويتكون من سكرمتعددعن الحيوانيعبارةأو النشا الجYيكوجين

عند الحاجة إلى الجلوكوز الجYيكوجينالجلوكوز ، وتحلل الحيوانات

Cellulose Is A Polymer Of Glucose That Forms Plant Cell Walls

جلوكوزي يكون جدر الخYيا في النباتات بوليميرعبارة عن السيليلوز



Forms Plant Cell Walls Chitin Is A Polysaccharide Used By Insects And Crustaceans To Build An Exoskeleton

عبارة عن سكر متعدد تستخدمه الحشرات والقشريات لبناء الكايتين

ھياكلھا الخارجية

Lipids Are Water Insoluble (Hydrophobic, Or Water Fearing) Compounds That Are Important In Energy Storage

، وھي ھامة في ) كارھة للماء(ھي مركبات 9 تذوب في الماء اللبيدات

تخزين الطاقة

They Contain Twice As Much Energy As A Polysaccharide

المتعددة السكاكرتحتوي على ضعف الطاقة الموجودة في

Fats Are Lipids Made From Glycerol And Fatty Acids

نوع من اللبيدات مكونة من ) السمن والزبدة والزيت(الدھون

جليسيرول وأحماض دھنية

Unsaturated Fats Because They Have Fewer Than The Maximum Number Of Hydrogens

تسمى ھذه المركبات بالدھون غير المشبعة Rنھا تحتوى على عدد أقل

من العدد الكلي للھيدروجين

Fats With The Maximum Number Of Hydrogens Are Called Saturated Fats

تسمى الدھون المحتوية على العدد الكلي للھيدروجين بالدھون المشبعة

)الكربون ذراتروابط ثنائية بين بھا9 يوجد (Phospholipids Are Structurally Similar To Fats And Are An Important Component Of All Cells

الفسفورية الدھون في تركيبھا وھي من المكونات اللبيداتتشابه

اRساسية للخلية

For Example, They Are A Major Part Of Cell Membranes, In Which They Cluster Into A Bilayer Of Phospholipids

على سبيل المثال ھي مكون ھام لhغشية الخلوية حيث تتجمع على

ھيئة طبقتين من الدھون الفسفورية

Steroids Are Lipids Composed Of Fused



Steroids Are Lipids Composed Of Fused Ring Structures

عبارة عن دھون مكونة من حلقات تركيبية متداخلة اRسترويدات

Cholesterol Is An Example Of A Steroid That Plays A Significant Role In The Structure Of The Cell Membrane

التي تلعب دوراً ھاماً في تركيب لYسترويداتھو مثال الكوليسترول

غشاء الخلية

In Addition, Cholesterol Is The Compound From Which We Synthesize Sex Hormones

ھرموناتنا بهھو المركب الذي نبني الكوليسترولبا]ضافة لذلك فإن الجنسية

Anabolic Steroids Are Synthetic Variants Of Testosterone That Can Cause A Buildup Of Muscle And Bone Mass

البنائي عبارة عن توليفة صناعية من اRيض سترويدات

والتي تؤدي لبناء الكتلة العضلية ) الذكورة ھرمونات( التيستيسترونات

والعظمية

Protein Is A Polymer Built From Various Combinations Of 20 Amino Acid Monomers

مونيمراتمن 20يبنى من توافيق بين بوليمرالبروتين عبارة عن اRمينيةاRحماض

chapter 3 2015 · · 2016-01-27chemical reactions in cells Copyright © 2009 Pearson Education, Inc. Unlinked Monomer ... the structure of the cell membrane ... specific function

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