1 BIO61-105E-Intro the Chemical Basis of Life

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General Biology BIO61-105E

-------------------------------Trimester 2/2563

Doctor of Veterinary MedicineBachelor of Science Program in

Medical Technology

Walailak University

LecturersDr. Jariya Sakayaroj (ผศ.ดร.จรยิา สากยโรจน)์*E-Mail: [email protected] Office: 116, Academic Building 1Tel: 0-7567-2040

Dr. Phitchayapak Wintachai (ดร.พชิญาภคั วนิทะชยั)E-Mail: [email protected]: 0-7567-2032

Dr. Naparat Sutthidate (ดร.นภารตัน ์ สทุธเิดช)E-Mail: [email protected]: 0-7567-2085

Department of Biology School of Science

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Life• What is life?

• Life is recognized by what living things do

The study of life reveals 6 common themes

–Organization (Order)–Information –Energy–Interactions –Regulations–Evolution

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Order of life= Levels of biological organization

• Life can be divided into different levels of biological organization – from simple to complex.

• Novel properties emerge at higher levels of organization. It is called Emergent properties

• Emergent properties result from the arrangement and interaction of parts within a system

Levels of biological organization• Biosphere

– Consists of all ecosystems on earth i.e. freshwater, ocean, forest, soil, atmosphere

• Ecosystem– consists of all the living things in a particular area,

along with all the nonliving components of the environment with which life interacts.

• Organism– Organ System Organs Tissues

• Cell– Cell Organelles Molecules Atoms

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Level of Organization in Ecosystem• Interaction

between lifeand environment

Species

PopulationsCommunities

Ecosystem

Ecosystem consists of all the living things in a particular area, along with all the nonliving components of the environment

Level of organization in Organism

Tissues

OrgansOrgan systems

Organism

Individual living things are called organisms.

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Level of organization in Cell

Atoms

MoleculesOrganelles

Cell

• The cell is an organism’s basic unit of structure and

function.

Tissues

Cells

Mole-cules

Organs

Organelles

Atoms

Continuity of life

• Gene expression is the process of converting information from DNA into RNA and protein.

Nucleus

DNA

(a) DNA double helix (b) Single strand of DNA

A

T

G

G

T

A

T

A

C

A

C

T

A

C

Nucleotide

Cell

• The processes of life involve the expression and transmission of genetic information or gene.

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Reproduction and Continuity of life

Sperm cell

Egg cell

Fertilized eggwith DNA fromboth parents Embryo’s cells

with copies ofinherited DNA

Offspring withtraits inheritedfrom both parents

Nuclei containing DNA

• DNA controls the development and maintenance of organisms.

Energy of life• Life requires energy to carry out life’s

activities.• Transformation of energy from one form to

another make life possible.ENERGY FLOW

Lightenergy

HeatChemicalenergy

Plants takeup chemicalsfrom the soil

and air.

ChemicalsDecomposersreturn chemicalsto the soil.

Chemicalspass toorganismsthat eat theplants.

• Energy flows through an ecosystem in one direction• enter as light• exit as heat

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Interaction of Life• Interactions occur between each

component at each level of biological organization from ecosystem level down to molecule level.

• Interactions occur within an organism, between organisms and between organism and its environments.

• These interactions may be beneficial or harmful.

Interaction of lifeSunlight

Leaves take incarbon dioxidefrom the air andrelease oxygen.

Animals eat leavesand fruit from the tree,returning nutrientsand minerals to thesoil in their wasteproducts.

Water andminerals inthe soil aretaken upby the treethrough itsroots.

Leaves absorb lightenergy from the sun.

Leaves fall to the ground and aredecomposed byorganisms thatreturn mineralsto the soil.

CO2

O2

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Regulation of life• All organisms must

maintain a constant internal environment to function properly.

• Feedback mechanisms allow biological processes to self-regulate

• Usually - Negative feedback

• i.e. feedback regulation of blood sugar(the end product of a process in

turn reduces the stimulus of that same process)

Insulin

Circulationthroughoutbody viablood

Insulin-producingcell in pancreas

STIMULUS: Highblood glucose level

Neg

ativ

e fe

edb

ack

Liver andmuscle cells

RESPONSE: Glucoseuptake by liver and musclecells (decrease high glucose

Levels)

Evolutionary adaptation of life• All living organisms are modified

descendants of common ancestors .– Common features – Different features

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Evolution accounts for the unity and diversity of life

• Approximately 1.8 million species have been identified and named to date (if included the unidentified species could be >10 million)– Bacteria 6,300 species– Fungi 10,000 species– Plants 290,000 species– Vertebrate 52,000 species– Insect 1 million species

• Taxonomy is the branch of biology that names and classifies species into groups.

The study of the evolution of life• The changes within a species from one generation to next

generation lead to evolution.• Charles Darwin – the Naturalist• Individuals that are best suited to their environment are more likely

to survive and reproduce• Over time, more individuals in a population will have the

advantageous traits

• Evolution occurs as the unequal reproductive success of individuals

• In other words, the environment “selects” for the propagation of beneficial traits

• Darwin called this process natural selection

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Outline & Learning Objectives

II: Chemical basis of life- Basic properties of cells - The life-supporting properties of

water - Molecules of life: carbohydrates, lipids, proteins and nucleic acids

ELEMENTS & COMPOUNDS

“Organisms are composed of matter”Matter consist of chemical elements in pure form and in compoundsAn element is a substance that cannot be broken down into simpler chemical substancesA compound is a substance consisting of two or more different elements combined in a fix ratio.

Sodium(Metal)

Chlorine(Poisonous gas)

Sodium Chloride(Edible compound)

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The main components of a living cell are carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur.

Carbon, hydrogen, oxygen, and nitrogen make up the bulk of living matter.

P Phosphorus

AtomicNumber=15 Atomic mass= 30


Sulfur


Carbon


Hydrogen


Nitrogen


Oxygen



Essential elements of life

About 25 of the 92 natural elements are known to be essential to life.

Just four of these, C H O N make up 96% living matter.

Trace elements are those required by organism in only minute quantities.(less than 0.01%)

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ATOM : AN ELEMENT’S PROPERTIES

-Each element consist of atom that is different from the atom of other element.

-An atom is the smallest particle of an element that has the characteristics of that element.

-Structure of atom: Nucleus: composed of

protons (+) , neutrons (0), electrons (-)

Atomic Number and Atomic Mass

Example:Carbon has atomic number 6, so it has 6 protons and 6 electrons.It has a mass number of 12 (round to the nearest whole number) so it has 12 – 6 = 6 neutrons.


The certain atom has the same number of protonparticles and electron particles.

The number of protons in their nucleus, is called the Atomic number.

The number of the sum protons plus neutrons iscalled the Atomic mass = Mass number.

Carbon

Atomic Number = 6 Atomic mass = 12

protons (+) , neutrons (0),electrons (-)

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Example: Carbon atom


We can write atomic number as subscriptto the left of element’s symbol.

The atomic mass or mass number is writtenas superscript to the left of element’s symbol.

Protons = 6Electrons = 6Neutrons = 6Atomic number = 6Mass number = 12Atomic mass = 12 daltons Na23

11Mg24

12

Carbon

Atomic Number = 6 Atomic mass = 12

C12

6

C6Atomic number

C12Atomic mass

© 2014 Pearson Education, Inc.

Electron Distribution and Chemical Properties

The chemical behavior of an atom is determined by the distribution of electrons in electron shells

The periodic table of the elements shows the electron distribution for each element

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Atoms whose shells are not full tend to interact with other atoms and gain, lose, or share electrons.

These interactions are form chemical bonds.- Ionic bonds are attractions between charged

atoms or ions of opposite charge, when atoms gain or lose electrons

BOND : INTERACTION OF ELECTRONS

Transfer of electron

NaSodium atom

ClChlorine atom

Na+

Sodium ionCl–

Chloride ion

Sodium chloride (NaCl)

Na Cl ClNa

+ ––

–

+ -

Cation Anion

Sodium and chloride ions bond toform sodium chloride, common table salt.

Na+

Cl–

IONIC BONDS AND IONIC COMPOUNDS

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COVALENT BONDS AND COMPOUNDS

The information and function of molecules depend on chemical bonding between atoms

Covalent bond is the sharing of one or more pairs valence electrons by two atoms into molecules, H-H, C-H4, H2-O


** The strongest chemical bonds are covalence bonds, which link atoms to form cell’s molecules.

H2: 2H atoms share one pair of E, forming a single bondO2: 2O atoms share 2 pairs of E, forming a double bond.CH4: 4H atoms and 1O, forming methaneH2O: 2H atoms and 1O joined by single bond, forming water molecule.

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Unequal electron sharing creates polar molecules.

A molecule is nonpolar when its covalently bonded atoms share electrons equally.


(–)

(+) (+)

O

HH

Hydrogen bonds are weak bonds important in the chemistry of life The charged regions on water molecules

are attracted to the oppositely charged regions on nearby molecules

HYDROGEN BONDS

Hydrogen

bond (+)

(+)

H

H(+)

(+)

(–)

(–)

(–)(–)

O

Hydrogen bonds make liquid water cohesive tension (H holds substance together)

Cohesion due to H-bonding contributes to the transport of water and dissolved nutrients against gravity in plants.

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WATER AND LIFE

Water makes up 70 to 95% of most organisms, therefore it is the most common compound found in most cells.

-Water molecules are cohesive (stick together) and adhesive (stick to other substances) due to the hydrogen bonding.

-Water is able to absorb large amounts of heat. As a result, lakes and oceans stabilize air and land temperatures.

-Water absorbs heat when it evaporates, allowing organisms to release excess heat.

WATER AND LIFE

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The water in form of Ice is less dense than liquid water Hydrogen bonds hold molecules in ice farther

apart than in liquid water

Liquid waterHydrogen bonds

constantly break and re-form

IceHydrogen bonds are stable

Hydrogen bond

WATER AND LIFE

Ice:H bonds are stable

Liquid water:H bonds breaks & reform

Carbohydrates

Proteins

Lipids Nucleic acids

ORGANIC COMPOUNDS AND LIFE

Organic compounds or macromolecules of cell have four compounds.

This is the study of organic compounds, those compounds containing carbon and made by living organisms.

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CARBON (C) Has 4 electrons to share in its

outer shell Can bond with up to 4 other

atoms or compounds Can bond to other carbon

atoms in chains and rings to form large complex molecules

Can form single, double, or triple bonds (single bond –shares 1 electron, double –shares 2 electrons, etc.)


Polymer – a large molecule formed when many smaller molecules bond together. The smaller molecules are called monomers.

Polymerization – process of building polymersCondensation reaction – reaction by which

polymers are formed; also called dehydration synthesis

Hydrolysis – reaction by which polymers are broken apart


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Carbohydrates -Monosaccharides -Disaccharides -Polysaccharide

Lipids -Fatty acids -Triacylglycerols -Phospholipids -Steroids -Terpenes

-Wax

Proteins -Amino acid

-Polypeptides

Nucleic acids -Nucleotides -DNA and RNA


CARBOHYDRATES: FUEL & BUILDING MATERIALS

Used by cells to store and release energy Composed of C, H, and O with a ratio of 2H:1O Monosaccharide (building block) is a monomer or

simple sugar. Examples: Glucose, Fructose, and Galactose

Disaccharide is formed when two monosaccharides bond together; Example: Sucrose = fructose + glucose

ORGANIC COMPOUNDS AND LIVE

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From monosaccharide to disaccharide by dehydration synthesis



From monosaccharide to disaccharide by dehydration synthesis

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Polysaccharides are the largest carbohydrates (macromolecules).Example: Starch, Glycogen, Cellulose, and Chitin

– Starch – how plants store food they make

– Glycogen – how animals store food reserves in the liver

– Cellulose – structural material in plant cell walls; the fiber in the food you eat

– Chitin – structural material in fungal cell walls; in the exoskeletons of arthropods



Polysaccharides : Starch (storage polysaccharides)

Amylose starch has a linear chain structure made up of hundreds of glucose molecules that is linked by a

Amylopectin starch is branched containing an about every 30 glucose

units. Like amylose it is a homopolymer composed of many glucose units

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Polysaccharides : Cellulose

Cellulose is the major polysaccharide found in plants responsible for structural role.

Cellulose is an unbranched polymer of glucose residues put together via , which allow the molecule to form long and straight chains.

This straight chain conformation is ideal of strong fibers.


Glycogen is found in animals, and it is branched like amylopectin. It is formed by mostly but branching occurs more frequently than in amylopectin as occur about every ten units.

Polysaccharides : Glycogen

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LIPIDS -Commonly called fats and oils -Are insoluble in water because

the molecules are nonpolar -Used for energy storage,

insulation, and protective coverings; they are a major component in cell membranes

-Contain numerous C-H chains called fatty acids


LIPIDS

3 types of lipids which are important to cells:1. Triglycerides 2. Phospholipids 3. Steroids


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LIPIDS 1. Triglycerides (Triacylglycerol)

-The most common type of lipid-A glycerol molecule and 3 molecules of fatty acids are linked by an ester bond formed during dehydration synthesis.


FATTY ACIDS:• Saturated fats contain only single bonds in the C-H

chains; are solid at room temperature• Unsaturated fats contain some double bonds in the

C-H chains; are liquid at room temperature


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LIPIDS 2. Phospholipids

-Same as triglycerides except one of the fatty acid molecules is replaced by a phosphate group (PO4)

-3

-The phosphate group is polar and so is attracted to water, therefore the phospholipid has two district ‘ends’.

-A hydrophilic end (water loving) that dissolves in water and a hydrophobic end (water hating) is repelled by water.


-Hydrophilic part

-Hydrophobic part

LIPIDS 3. Steroids

-Very different structure: 4 carbonrings with variety of different sidechains

- -Cholesterol: animal cell membrane,- Sex hormones-


ultraviolet

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PROTEINS Monomers are amino acids There are 20 amino acids composed of C, H, O, N, and S Proteins are formed by the bonding of amino acids; the

bond is called a peptide bond


-Proteins are large, complex molecules that play

many critical roles in the body.

-They do most of the work in cells and are required for the structure, function, and regulation of the body’s

tissues and organs.

-Proteins are made up of hundreds or thousands of smaller units called amino acids, which are attached

to one another in long chains.

PROTEINS


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FUNCTIONS OF PROTEINS:

Structural – hair, nails Transport – hemoglobinMovement – muscle

fibers and cytoskeletal elements

Defense – antibodiesRegulation of cell

functions – hormones and enzymes


NUCLEIC ACIDS: STORE, TRANSMIT, EXPRESS HEREDITARY INFORMATION

DNA and RNA Function – control cell activities by directing protein

synthesis Monomers are nucleotides which are made up of a

nitrogenous base, a sugar, and a phosphate group DNA – deoxyribonucleic acid is the master genetic

code RNA – ribonucleic acid functions to make copies of

DNA


Documents

1 BIO61-105E-Intro the Chemical Basis of Life