Lipids, Nucleic Acids & Proteins

the ‘other’ fuel sources

Lipids

• water insoluble– hydrophobic

• long term NRG storage– adipose tissue

• TWICE as much NRG as carbs and proteins• composed of:

– CARBON– HYDROGEN– oxygen

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NONPOLAR!!!

Lipids

• weird: – not huge molecules – not built from monomers

• big variations in:– structure– function (didn’t I just say that?)

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Lipids

• Fats– glycerol + 3 fatty acids (FA)

• Phopholipids– glycerol + 2 FA + phosphate group

(hey-aren’t they polar?)

• Steroids (aka. stereos)– ring structures built on cholesterol

(evil or not? NOT!!)

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FATS

• glycerol + 3 FA– each FA attached to glycerol through dehydration

synthesis– each FA can be different from the others

• vary in length of carbon chain• vary in numbers of double bonds• vary in placement of double bonds

• aka. TRIGLYCERIDES

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Figure 3.8B

Fatty acid

Glycerol

p. 40

Figure 3.8C

Fatty acids

Glycerol

p. 40

Fatscarbon chains that have ALL single bonds

SATURATED(as full of H as possible!)

b/c straight chains they can pack togethertend to be solid (at room temp)

http://www.fishoilbenefits.tk/saturated-fatty-acids.html

http://www.biochem.arizona.edu/classes/bioc462/462a/NOTES/LIPIDS/Lipids.html

Fatscarbon chains that have one or more double bonds

UNSATURATED(not as full of H as possible!)

chains are kinked can’t pack together too tightlytend to be liquid(at room temp)

http://www.fishoilbenefits.tk/saturated-fatty-acids.html

http://www.biochem.arizona.edu/classes/bioc462/462a/NOTES/LIPIDS/Lipids.html

http://www.natural-health-information-centre.com/trans-fats.html

Phospholipids

• glycerol backbone + 2 FA + phosphate group

• MAJOR component of ALL cells

• biggest constituent of the cell membrane

© 2012 Pearson Education, Inc.

Phospholipids: cell membrane

• phospholipids cluster into a bilayer

• hydrophilic heads are in contact with– the water of the environment and – the internal part of the cell.

• hydrophobic tails band in the center of the bilayer.

Steroids

• based on structure of cholesterol• four fused rings of carbon

Nucleic Acids

• storage, transmission & use of genetic information• NRG transfer

• deoxyribonucleic acid: DNA• ribonucleic acid: RNA

• monomers bonded to others to create polymers• monomers = nucleotides

Nucleotides

• pentose sugar– ribose– Deoxyribose

• phosphate group

• nitrogenous base– adenine thymine (DNA only)– guanine cytosine uracil (RNA only)

Figure 3.15A

Phosphategroup

Sugar

Nitrogenousbase

(adenine)

3C

5C

3C

5C

Figure 3.15C

Basepair

A

C

T

GC

C G

T A

C G

A T

TA

G C

TA

TA

AT

DNA vs. RNA

DNA• deoxyribose sugar• nitrogenous bases

– adenine thymine– cytosine guanine

• double helix

RNA• ribose sugar• nitrogenous bases

– adenine uracil– cytosine guanine

• single stranded

DNA to RNA to proteins

• DNA contains genes: codes for proteins• lives in the nucleus• protein machinery is in the cytoplasm• DNA transcribed into mRNA• mRNA leaves nucleus• mRNA is translated into proteins

DNA to RNA

• DNA monomers = nucleotides– language monomers = alphabet letters

• mRNA monomers = nucleotides• transcribe DNA into mRNA

– uses the same alphabet/same language

RNA to protein

• mRNA monomers = nucleotides• protein monomers = amino acids

• information written in nucleotide language needs to be translated into amino acid language

Nucleotides & NRG Transfer• Adenosine triphosphate (ATP) is a universal

energy-carrying nucleotide found in all living organisms