The Chemistry of Life

What are living creatures made of?

Why do we have to eat?

96% of living organisms is made of: carbon (C) oxygen (O) hydrogen (H) nitrogen (N)

Elements of Life

Molecules of Life Put C, H, O, N together in different

ways to build living organisms What are bodies made of?

carbohydrates sugars & starches

proteins fats (lipids) nucleic acids

DNA, RNA

Why do we eat? We eat to take in more of these

chemicals Food for building materials

to make more of us (cells) for growth for repair

Food to make energy calories to make ATP

ATP

What do we need to eat? Foods to give you more building

blocks & more energy for building & running bodies

carbohydrates proteins fats nucleic acids vitamins minerals, salts water

Water 65% of your body is H2O water is inorganic

doesn’t contain carbon

Rest of you is made of carbon molecules organic molecules

carbohydrates proteins fats nucleic acids

Don’t forget water

2006-2007

How do we make these molecules?

We build them!

Building large molecules of life Chain together smaller molecules

building block molecules = monomers

Big molecules built from little molecules polymers

Small molecules = building blocks

Bond them together = polymers

Building large organic molecules

Building important polymers

sugar – sugar – sugar – sugar – sugar – sugar

nucleotide – nucleotide – nucleotide – nucleotide

Carbohydrates = built from sugars

Proteins = built from amino acids

Nucleic acids (DNA) = built from nucleotides

aminoacid

aminoacid–

aminoacid–

aminoacid–

aminoacid–

aminoacid–

How to build large molecules Synthesis

building bigger molecules from smaller molecules

building cells & bodies repair growth reproduction

+

ATP

H2O

HO

HO H

H HHO

How to build a polymer Synthesis

joins monomers by “taking” H2O out one monomer donates OH–

other monomer donates H+ together these form H2O

requires energy & enzymes

enzymeDehydration synthesisDehydration synthesis

Condensation reactionCondensation reaction

How to take large molecules apart Digestion

taking big molecules apart getting raw materials

for synthesis & growth making energy (ATP)

for synthesis, growth & everyday functions

+

ATP

H2O

HO H

HO H HO H

How to break down a polymer Digestion

use H2O to breakdown polymers reverse of dehydration synthesis break off one monomer at a time

H2O is split into H+ and OH–

H+ & OH– attach to ends

requires enzymes releases energy

HydrolysisHydrolysis

DigestionDigestion

enzyme

Example of digestion

starch glucose

ATP

ATP

ATP

ATP

ATP

ATPATP

Starch is digested to glucose

Example of synthesis

amino acids protein

amino acids = building block

protein = polymer

Proteins are synthesized by bonding amino acids

Carbohydrates

Carbohydrates:

OH

OH

H

H

HO

CH2OH

HH

H

OH

O

Energy molecules

Carbohydrates

Building block molecules =

sugar sugar sugar sugar sugar sugar sugarsugar

sugar - sugar - sugar - sugar - sugar

sugars

sucrose

Carbohydrates Function:

quick energy energy storage structure

cell wall in plants

Examples sugars starches cellulose (cell wall)

glucoseC6H12O6

starch

Sugars = building blocks Names for sugars usually end in

glucose fructose sucrose maltose OH

OH

H

H

HO

CH2OH

HH

H

OH

O

glucoseC6H12O6

sucrose

fructose

maltose

-ose

Building carbohydrates Synthesis

|glucose

|glucose

1 sugar = monosaccharide

2 sugars = disaccharide

|maltose

mono = onesaccharide = sugar

di = two

Building carbohydrates Synthesis

|fructose

|glucose

1 sugar = monosaccharide

|sucrose

(table sugar)

2 sugars = disaccharide

How sweetit is!

BIG carbohydrates Polysaccharides

large carbohydrates starch

energy storage in plants potatoes

glycogen energy storage in animals

in liver & muscles cellulose

structure in plants cell walls

chitin structure in arthropods & fungi

exoskeleton

poly = many

Building BIG carbohydratesglucose + glucose + glucose… =

starch(plant)

glycogen(animal)

energystorage

polysaccharide

Digesting starch vs. cellulose

starcheasy todigest

starcheasy todigest

cellulosehard todigest

cellulosehard todigest

enzyme

enzyme

Cellulose Cell walls in plants

herbivores can digest cellulose well most carnivores cannot digest

cellulose that’s why they

eat meat to get their energy & nutrients

cellulose = roughage stays undigested keeps material

moving in your intestines

Proteins

Proteins:

Multipurpose molecules

collagen (skin)

Proteins

insulin

Examples muscle skin, hair, fingernails, claws

collagen, keratin pepsin

digestive enzyme in stomach

insulin hormone that controls blood

sugar levels

pepsin

Proteins Function:

many, many functions hormones

signals from one body system to anotherinsulin

movementmuscle

immune systemprotect against germs

enzymeshelp chemical reactions

Proteins

Building block =

aminoacid

aminoacid–

aminoacid–

aminoacid–

aminoacid–

—N—H

H

H|

—C—|

C—OH||O

variable group

amino acids

20 different amino acidsThere’s

20 of us…like 20 different

letters in analphabet!

Can make lots of different

words

Amino acid chains Proteins

amino acids chained into a polymer (or polypeptide)

Each amino acid is different some “like” water & dissolve in it some “fear” water & separate from it

amino acid amino acid amino acid amino acid amino acid

pepsin

For proteins: SHAPE matters!

collagen

Proteins fold & twist into 3-D shape that’s what happens in the cell!

Different shapes = different jobs

hemoglobingrowth

hormone

Primary (1°) structure Order of amino acids in chain

slight change in amino acid sequence can affect protein’s structure & its function even just one amino acid

change can make all the difference!

lysozyme: enzyme in tears & mucus that kills bacteria

Secondary (2°) structure “Local folding”

folding along short sections of polypeptide

interactions between adjacent amino acids

forms sections of 3-D structure

Tertiary (3°) structure “Whole molecule folding”

interactions between distant amino acids

Quaternary (4°) structure More than one polypeptide chain bonded

together only then does polypeptide become

functional protein

collagen = skin & tendons hemoglobin

Protein structure (review)

amino acid sequence

peptide bonds

1°

determinedby DNA R groups

short 3D segments

R groupswhole molecule folding

3°

multiple polypeptides

4°

2°

It’s SHAPE that matters! Proteins do their jobs, because

of their shape Unfolding a protein destroys its

shape wrong shape = can’t do its job unfolding proteins = “denature”

temperature pH (acidity)

folded

unfolded“denatured”

In Biology,it’s not the size,it’s the SHAPEthat matters!

Lipids: Fats & Oils

LipidsConcentrated energy molecules

Lipids Examples

fatsoilswaxeshormones

sex hormonestestosterone (male)estrogen (female)

Lipids

Function: energy storage

very concentrated twice the energy as carbohydrates!

cell membrane cushions organs insulates body

think whale blubber!

Structure of Fat

not a chain (polymer) = just a “big fat molecule”

Saturated fats Most animal fats

solid at room temperature

Limit the amount in your diet contributes to

heart disease deposits in

arteries

Unsaturated fats Plant, vegetable & fish

fats liquid at room

temperature the fat molecules

don’t stack tightlytogether

Better choice in your diet

Saturated vs. unsaturatedsaturated unsaturated

Other lipids in biology Cholesterol

good molecule in cell membranes make hormones from it

including sex hormones but too much cholesterol in blood

may lead to heart disease

Other lipids in biology Cell membranes are made out of

lipids phospholipids heads are on the outside touching

water “like” water

tails are on inside away from water “scared” of water

forms a barrier between the cell & the outside

Nucleic Acids:

Information molecules

Nucleic Acids Examples

DNA DeoxyriboNuclei

c Acid RNA

RiboNucleic Acid

RNA

DNADNA

Nucleic Acids Function:

genetic material stores information

genesblueprint for building proteins

DNA → RNA → proteins transfers information

blueprint for new cellsblueprint for next generation

proteinsproteins

Nucleic acids

Building block =nucleotides

5 different nucleotides different nitrogen bases A, T, C, G, U

nucleotide – nucleotide – nucleotide – nucleotide

phosphate

sugar N base

Nitrogen basesI’m the

A,T,C,G or Upart!

Nucleotide chains Nucleic acids

nucleotides chained into a polymer DNA

double-sideddouble helixA, C, G, T

RNAsingle-sidedA, C, G, U

phosphate

sugar N base

phosphate

sugar N base

phosphate

sugar N base

phosphate

sugar N base

strong bonds

RNA

DNA Double strand twists into a double

helix weak bonds between nitrogen bases

join the 2 strands A pairs with T

A :: T C pairs with G

C :: G the two strands can

separate when our cells need to make copies of it

weak bonds

Copying DNA Replication

copy DNA 2 strands of DNA helix are

complementary they are matching have one, can build other have one, can rebuild the whole

Copying DNA pairing of the bases

allows each strand to serve as a pattern for a new strand

Newly copied strands of DNA

DNA replication