Proteins…Proteins…

►Let’s Review…… then…..Let’s Review…… then…..►Let’s discover proteins….Let’s discover proteins….►PollEv.com/tinalambiase209PollEv.com/tinalambiase209

Functions of Proteins …Functions of Proteins …

► Enzymes – reduces activation energyEnzymes – reduces activation energy Ex: amylase – helps to digest amyloseEx: amylase – helps to digest amylose ATP synthase – helps to make ATPATP synthase – helps to make ATP

Structural Proteins – provide supportStructural Proteins – provide support

ex: elastin, horn, silk (web), keratin (hair & ex: elastin, horn, silk (web), keratin (hair & nails)nails)

Movement – actin and myosin musclesMovement – actin and myosin muscles

Defense – antibodies in bloodstreamDefense – antibodies in bloodstream

Storage – albumin in egg whitesStorage – albumin in egg whites

Signaling – growth hormones in bloodstreamSignaling – growth hormones in bloodstream

What do you think is happening What do you think is happening to the proteins within these to the proteins within these

eggs????eggs????►!!

ProteinsProteins

►C, H, O, N and sometimes SC, H, O, N and sometimes S►Made in ribosomesMade in ribosomes►Cell membranesCell membranes►Hormones (insulin)Hormones (insulin)►HemoglobinHemoglobin►Enzymes (control the rate of Enzymes (control the rate of

reactions)reactions)

Building Blocks of Building Blocks of ProteinsProteins

Amino AcidsAmino Acids►Amino Amino

Group –NHGroup –NH22

►Carboxyl Carboxyl group –group –COOHCOOH

►Variable Variable group –Rgroup –R

Dehydration Synthesis ofDehydration Synthesis ofProteinsProteins

►Removal of a water molecule from Removal of a water molecule from amino acids to make proteins.amino acids to make proteins. DipeptideDipeptide – two amino acids together – two amino acids together TripeptideTripeptide – three amino acids – three amino acids

togethertogether PolypeptidePolypeptide – more than three amino – more than three amino

acids together acids together

All linked together with All linked together with ““Peptide Peptide BondsBonds””

Dehydration Synthesis ofDehydration Synthesis ofProteinsProteins

► Amino Acid + Amino Acid -- Dipeptide + Amino Acid + Amino Acid -- Dipeptide + WaterWater

Removing the water Removing the water moleculemolecule

►Producing a peptide bondProducing a peptide bond

Dehydration Synthesis of Dehydration Synthesis of ProteinsProteins

DipeptideDipeptide►Locate your peptide Locate your peptide bond!!!bond!!!

Can you draw a peptide Can you draw a peptide bond?bond?

►Which two functional Which two functional groups join to make the groups join to make the peptide bond???peptide bond???

How do we break proteins How do we break proteins down??down??

HYDROLYSISHYDROLYSIS

►Add the water molecule back Add the water molecule back in to replace the peptide bondin to replace the peptide bond

►Put the amino acids back to Put the amino acids back to the way they were!!!the way they were!!!

►Each amino acid must have an Each amino acid must have an amino group –NHamino group –NH22 and a and a carboxyl group --COOHcarboxyl group --COOH

HydrolysisHydrolysis►Dipeptide + water = amino acid + Dipeptide + water = amino acid +

amino acidamino acid

►Tripeptide + 2 water molecules = Tripeptide + 2 water molecules = amino acid + amino acid + amino amino acid + amino acid + amino acidacid

►NOW YOU TRY……NOW YOU TRY……

Hydrolysis of ProteinsHydrolysis of Proteins

Hydrolysis is the Hydrolysis is the OPPOSITEOPPOSITE

of dehydration synthesisof dehydration synthesis►What reaction is this?What reaction is this?►Can you locate the peptide Can you locate the peptide

bond?bond?