Ch. 6.4 Life substances-part 2

2006-2007

Proteins:

contain C, H, O,N, & sometimes SMultipurpose molecules

Proteins Function:

many, many functionshormones

signals from one body system to anotherinsulin

movementmuscle

immune systemprotect against germs

enzymeshelp chemical reactions

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 Building block =

aminoacid

aminoacid–

aminoacid–

aminoacid–

aminoacid–

—N—H

H

H|—C—|

C—OH

||O

variable group

amino acids

20 different amino acidsThere’s20 of us…like 20 differentletters in analphabet!Can make lots of differentwords

Proteins Building block =

aminoacid

aminoacid–

aminoacid–

aminoacid–

aminoacid–

—N—H

H

H|—C—|

C—OH

||O

variable group

amino acids

20 different amino acidsThere’s20 of us…like 20 differentletters in analphabet!Can make lots of differentwords

Amino acid chains Proteins

amino acids chained into a polymer

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

Amino acids can be linked by peptide bonds

Cells link amino acids together by dehydration synthesis

The bonds between amino acid monomers are called peptide bonds

Dehydrationsynthesis

Amino acid Amino acid

PEPTIDEBOND

Dipeptide

pepsin

For proteins: SHAPE matters!

collagen

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

Different shapes = different jobs

hemoglobingrowthhormone

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

folded

unfolded“denatured”

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

Enzymes

Enzymes are important proteins found in living things. An enzyme is a protein that speeds up the rate of a chemical reaction.

(SEE SEPARATE LECTURE.)

Nucleic acids

A nucleic (noo KLAY ihk) acid is a complex biomolecule that stores cellular information in the form of a code.

1. DNA (deoxyribonucleic acid) contains the instructions used to form all of an organism’s proteins.

2. RNA (ribonucleic acid) forms a copy of DNA for use in making proteins.

They ultimately control the life of a cell

DNADNA

Nucleic Acids Function:

genetic materialstores information

genesblueprint for building proteins

DNA RNA proteinstransfers 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

DNAdouble-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 hydrogen bonds between nitrogen bases join the 2 strandsA pairs with T

A :: TC pairs with G

C :: G the two strands can

separate when our cells need to make copies of it

weak hydrogenbonds