Fig. 10.01

Fig. 10.02

• Membranes are composed of diacylglycerols – Glycerol with two fatty acids

• Storage lipids are triglycerides – a glycerol with three fatty acids

Fig. 10.5

Fig. 10.03

Oleic acid

18:1

18:1

Elaidic acid

Δ9

Δ9t

Box 10.1

• Palmitic acid C16:0

• Stearic acid C18:0

• Oleic acid C18:1

• Linoleic acid C18:2

Some Common Lipids (See Table 10.2)

Δ9

Δ9, 12

• Fatty acids are made from acetyl-CoA

Fig. 10.9

Fig. 10.11

Fig. 2.08

Fig. 10.8

Fig. 10.16

• Most plant membranes are made of phospholipids

• However the chloroplast is composed mostly of galactolipids (MGDG and DGDG) and sulfolipids

Box 10.4

• Fatty Acids are synthesized in chloroplasts

• Diacylglycerols (DAG) are made in both chloroplast envelopes and the ER

• If the 2-position has a 16:0 lipid the DAG was made in the chloroplast envelope

• If the 2 position is 18:1 then the DAG was made in the ER

LIPIDS

Fig. 10.5

See Table 10.3 for structures of head groups

Fig. 10.21

(7)

Prokaryotic pathway (in the plastid)

Eukaryotic pathwayIn the ER

Fig. 10.18

Fig. 10.25

Fig. 10.26

Fig. 10.29

Fig. 10.30

Fig. 10.31

Fig. 10.33

Fig. 10.34

Fig. 10.37

Fig. 10.39

Fig. 10.40

Fig. 10.42

Fig. 10.44

Plants store lipids in oil bodies

• These are composed of triglycerides

• Oil bodies bud off of the ER

• A number of plants contain unusual fatty acids in their oli bodies– Rape seed – Erucic acid (C22:1 )– Caster oil – ricinoleic acid (12-OH C18:1 )Δ9

Δ13

Fig. 10.63

Fig. 10.64

Fig. 10.65

Fig. 10.66

Breakdown of stored lipids

• This occurs in germinating seeds

• Plants can convert stored lipids to hexoses for transport

• Fatty acids hexoses sucrose

• Sucrose is transported to the growing tissues

Breakdown of stored lipids• Fatty acids are broken down to acetyl

CoA via beta oxidation• Occurs in the glyoxysome• Acetyl CoA is then converted to

succinate via the glyoxylate cycle also in the glyoxysome

• Succinate is converted to PEP in the mitochondria and cytoplasm

• PEP is converted to sugar via gluconeogenesis

Fig. 10.67

Fig. 10.68

Peroxide is a toxic biproduct