Ch. 6.4 Life substances-part 2

Proteins: contain C, H, O,N, & sometimes S Multipurpose molecules

Proteins  Function: many, many functions  hormones signals from one body system to another insulin  movement muscle  immune system protect against germs  enzymes help 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 = amino acid amino acid – amino acid – amino acid – amino acid – —N——N— H H H | —C— | C—OH || O variable group amino acids  20 different amino acids There’s 20 of us… like 20 different letters in an alphabet! Can make lots of different words

Proteins  Building block = amino acid amino acid – amino acid – amino acid – amino acid – —N——N— H H H | —C— | C—OH || O variable group amino acids  20 different amino acids There’s 20 of us… like 20 different letters in an alphabet! Can make lots of different words

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 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 Dehydration synthesis Amino acid PEPTIDE BOND 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 hemoglobin growth hormone

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 SHAPE that 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

DNA Nucleic Acids  Function: genetic material  stores information genes blueprint for building proteins  DNA  RNA  proteins  transfers information blueprint for new cells blueprint for next generation proteins

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 bases I’m the A,T,C,G or U part!

Nucleotide chains  Nucleic acids nucleotides chained into a polymer  DNA double-sided double helix A, C, G, T  RNA single-sided A, 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 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 hydrogen bonds