1 chemical constituents of cells organic v. inorganic molecules organic molecules contain c and h...

1

Chemical Constituents of Cells

Organic v. Inorganic Molecules

Organic molecules • Contain C and H• Usually larger than inorganic molecules• Dissolve in water and organic liquids• Carbohydrates, proteins, lipids, and nucleic acids

Inorganic molecules • Generally do not contain C• Usually smaller than organic molecules• Usually dissociate in water, forming ions • Water, oxygen, carbon dioxide, and inorganic salts

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Chemical Constituents of Cells

Organic v. Inorganic Molecules

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Inorganic SubstancesWater

• Most abundant compound in living material• Universal Solvent

• Many solutes are dissolved in our body’s water• Many ionic compounds (NaCl) dissociate or break apart in water

• Participates in many chemical reactions (cells and fluid)• Dehydration (synthesis) – water is removed from adjacent atoms to

form a bond between them.• Hydrolysis (degradation) – water is used to break bonds between

molecules.•Water is an excellent temperature buffer

• Absorbs and releases heat very slowly •Water provides an excellent cooling mechanism

• It requires a lot of heat to change water from a liquid to a gas. If water does change form and evaporates, it leaves a cool surface behind.

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Inorganic Substances

Water (Cont)•Water serves as a lubricant

• Mucus, joints and internal organs. •Two-thirds of the weight of an adult human• Major component of all body fluids (about 70%)• Medium for most metabolic reactions• Important role in transporting chemicals in the body

Oxygen (O2) • Used by organelles to release energy from nutrients in order to drive cell’s metabolic activities• Necessary for survival•Gas that is transported in the blood.

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Inorganic Substances

Carbon dioxide (CO2)• Waste product released during metabolic reactions• Must be removed from the body

Inorganic salts• Abundant in body fluids• Sources of necessary ions (Na+, Cl-, K+, Ca2+, etc.)• Play important roles in metabolism

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Organic Substances• Contains the atoms carbon (and hydrogen)

• Small molecules (monomers or building blocks) are covalently bonded•Together to form large polymers or macromolecules•Water is usually involved in the formation and breakage of bonds between monomers.•Dehydration synthesis – removal of water to form a covalent bond between monomers;•Hydrolysis – using water to break bonds between monomers.

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+

Glucose Fructose

Water isreleased

Monomers linked by covalent bond

Monomers linked by covalent bond

Water isconsumed

Sucrose

(a) Dehydration synthesis

Monomers are joined by removal of OH from one monomerand removal of H from the other at the site of bond formation.

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(b) Hydrolysis

Monomers are released by the addition of a water molecule, adding OH to one monomer and H to the other.

(c) Example reactions

Dehydration synthesis of sucrose and its breakdown by hydrolysis

Monomer 1 Monomer 2

Monomer 1 Monomer 2

+

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Organic Substances

• Four major classes found in the cells include;• Carbohydrates• Lipids• Proteins• Nucleic acids

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Organic SubstancesCarbohydrates (Sugars)

• Provide energy to cells• Supply materials to build cell structures• Water-soluble• Contain C, H, and O• Ratio of H to O close to 2:1 (C6H12O6)

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Organic SubstancesCarbohydrates (Sugars)

•Function = energy storage/energy source• How is the energy that is stored in carbohydrates release?

• CELLULAR RESPIRATION OVERVIEW oxygen ↓glucose → H2O + CO2

↓ energy (ATP)

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Organic SubstancesCarbohydrates

(a) Some glucose molecules (C6H12O6) have a straight chain of carbon atoms.

C

C

C

C

C

C

H

O

H

O

O

O

HH

OH

H

H

H

H O

H

H

H

H

C

H

O

O H

H

OH

O H

H

H H

C

O

H

C

C C

OC

H

(b) More commonly, glucose molecules form a ring structure.

O

(c) This shape symbolizes the ring structure of a glucose molecule.

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Organic SubstancesCarbohydrates

O

(a) Monosaccharide

O O

O

(b) Disaccharide

O

O

O

(c) Polysaccharide

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Organic SubstancesLipids

• Soluble in organic solvents; insoluble in water•Types

• Fats (triglycerides) •Used primarily for energy; most common lipid in the body• Contain C, H, and O but less O than carbohydrates (C57H110O6)• Building blocks are 1 glycerol and 3 fatty acids per molecule• Saturated

• Have only single bonds between carbons in their fatty acid chains• Are solid at room temperature• Are animal fats• Are nutritionally “BAD” fat

•Unsaturated• Have one or more double bond between the carbons in their fatty acid

chains• Are liquid at room temperature - oils• Are plant fats• Are nutritionally “GOOD” fat

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• Fats (triglycerides)•Trans fats

• Unsaturated fats that have been solidified by artificial means• Not produced nor maintained in the body• Include margarine• The WORST type of fat

•Function = energy storage/energy source

Glycerolportion

Fatty acidportions

C

O

OH C C

H

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

H

C

O

OH C C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

H

C

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

H

C

O

OH C C

H

HH

C

H

H

C

H

H

C

H

H

C

H H

H

C

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• Phospholipids

• Building blocks are 1 glycerol, 2 fatty acids, and 1 phosphate per molecule -Triglyceride with the substitution of a polar phosphate group (PO4) for one fatty acid

• Hydrophilic and hydrophobic

• Function = Major component of cell membranes

C

H

C

OH

CH

H

Glycerol portion

(a) A fat molecule

O

O

Fatty acid

Fatty acid

Fatty acid

H

C

H H

HH

C

H

H

N

O

O

Fatty acid

Fatty acid

O

POCH

O–

Phosphate portion

(b) A phospholipid molecule(the unshaded portion may vary)

H

CH

C

H

H

O

(c) Schematic representationof a phospholipid molecule

Water-insoluble (hydrophobic) “tail”

Water-soluble(hydrophilic)“head”




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Organic Substances Lipids

• Steroids• Four connected rings of carbon• Widely distributed in the body, various functions• Function = Component of cell membrane; Used to synthesize hormones• Cholesterol

(a) General structure of a steroid

CC

CH2C

H2C C

H

(b) Cholesterol

C

CH CH2

CH2

CH

CH3

CH2

HC

HC

H2

H2

CH2 CHCH2

CH3

CH3

CH2

CH

CH3

HO C

CH3

CH2

CHC

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Organic SubstancesProteins

• Amino Acid Structure•Amino group •R group•Carboxyl group

• Protein building blocks are amino acids• Amino acids held together with peptide bonds

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H N

H

C

H

C

O

OH

S

C

H

HH

H N

H

C

H

C

O

OH

C

C

C

H

H

C H

C H

H

CH

CH

H N

H

C

H

C

O

OH

R

(a) General structure of an aminoacid. The portion common to allamino acids is within the oval.It includes the amino group(—NH2) and the carboxyl group(—COOH). The "R" group,or the "rest of the molecule,“is what makes each aminoacid unique.

(b) Cysteine. Cysteine has an R group that contains sulfur.

Phenylalanine. Phenylalaninehas a complex R group.Improper metabolism ofphenylalanine occurs in thedisease phenylketonuria.

•Types of amino acid20 different based on R-groups or side chains


Function of Proteins• Structural material

•Keratin in hair, nails, and skin

• Transport•hemoglobin

• Chemical Messengers•Hormones•Neurotransmitters

•Movements•Actin and myosin in muscle

•Catalysts•Enzymes

•Defense •Antibodies

• Protein building blocks are amino acids

• Amino acids held together with peptide bond•Length of amino acid change may vary;

•Peptide = 2-100 aa’s•Polypeptide = 100 –thousands of aa’s with a function •Protein = 100-thousands of aa’s with a specific function.

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Four Levels of Protein Structure

Pleatedstructure

Coiledstructure

Amino acids

N

N

N

NN

HH

HH

H

C

CC

C

O

O

O

CC

C

C

CC

OC

O

NN

H H

C

OC

C

OC

H

NN

H

O

O

C

CC

C

N

N

N

N H

H

H O C

CC

O

O

CC

C

H OC

C

C

N

C

NHO

CC

H OC

C

N

N

N

N H

H

H O C

O

O

CC

C

H OC

H

R

H

R

H

R

H

R

H

R

H

R

H

R

H

R

H

R

H

H

R

H

H

R

H

R

H

R

HHRR

HHRR

CH

CH

(b) Secondary structure—Thepolypeptide chain of a proteinmolecule is often either pleatedor twisted to form a coil. Dottedlines represent hydrogen bonds.R groups (see fig. 2.17)are indicated in bold.

(a) Primary structure—Eachoblong shape in thispolypeptide chain representsan amino acid molecule. Thewhole chain represents aportion of a protein molecule.



Three-dimensionalfolding

H H

(c) Tertiary structure—The pleated and coiledpolypeptide chain of aprotein molecule foldsinto a unique three-dimensional structure.

(d) Quaternary structure—Two ormore polypeptide chains may be connected to form a singleprotein molecule.

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Protein Denaturation

The loss of 3-dimensional conformation (shape) of a protein. The results in loss of function.• Reasons for denaturation;

•Extreme pH values•Extreme temperature values•Harsh chemicals (disrupt bonding)•High salt concentrations

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Animation:Protein Denaturation

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Organic SubstancesNucleic Acids

• Carry genes• Encode amino acid sequences of proteins• Building blocks are nucleotides – 3 parts

• DNA (deoxyribonucleic acid) – double polynucleotide• RNA (ribonucleic acid) – single polynucleotide

S

P B


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• Carry genes• Encode amino acid sequences of proteins• Building blocks are nucleotides – 3 parts

•Pentose sugar (5-C)•Nitrogenous base•Phosphate group

S

P B

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• DNA (deoxyribonucleic acid) – double polynucleotide•Structure:•Sugar deoxyribose•Base – adenine (A), thymine (T), cytosine (C), guanine (G)•Double stranded; strands held together by H-bonds between bases on the opposite strands;

•A complements T (2 hydrogen bonds)•C complements G (3 hydrogen bonds)

•Function = genetic material•DNA directs protein synthesis

• DNA contains all necessary information needed to sustain and• reproduce life

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• RNA (ribonucleic acid) – double polynucleotide•Structure: •Sugar = ribose•Base – adenine (A), cytosine (C), guanine (G), uracil (U) (replaces thymine),

•Function = transport DNA code during protein systhesis•DNA directs protein synthesis

1 chemical constituents of cells organic v. inorganic molecules organic molecules contain c and h...

Documents

ions water

water molecule

inorganic molecules

hydrolysis degradation

chemical reactions cells

organic liquids carbohydrates

monomerand removal of

o ratio of h