Chapter 17 Lipid catabolism Flashcards
____ Bodies are an alternative fuel source to sugars & fats.
Ketone
_____ & _____ (as well as Pyruvate) are used to make acetyl - CoA
Amino Acids , Fatty Acids
Are lipids soluble in water?
No
Lipids are hydrophobic or hydrophilic generally?
hydrophobic
What are the 5 classes of Lipids?
Triacylglycerols (triglycerides) Phospholipids Glycolipids Sterols Fatty Acids
Sterols are used to make what 3 things?
Cholesterol
bile salts
hormones
What is a better source of energy? Glucose or lipids?
lipids are much better.
What are the 5 major functions of lipids?
- major source of energy
- barriers
- cell recognition
- hormones
- signalling molecules
What process allows lipids to become a major source of energy?
fatty acid oxidation
What class of lipid is used for barriers?
phospholipids
What class of lipid is used in cell recognition?
glycolipids
what are the 2 types of lipid hormones?
steroids, eicosanoids
signalling molecules are made from what type of lipid?
phospholipids
Are fatty acids a source of energy?
yes
Do every fatty acid have a carboxyl on the end?
yes
What are 2 ways that fatty acids are distinguished?
Length, saturation
saturation refers to what?
the number of double bonds or lack of
Saturated fatty acids are in what state at room temperature?
solid
Polyunsaturated fatty acids are in what state at room temperature?
liquid
Saturated fatty acids have higher or lower melting point?
higher melting point
Polyunsaturated fatty acids have higher or lower melting points?
lower melting points
T or F: Humans naturally produce transunsaturated fatty acids.
False; hard to find trans fatty acids in humans
Trans unsaturated fatty acids are found in what type of organisms?
cows, bacteria, plants
In FA Nomenclature what comes very first?
length of fatty acid
in FA nomenclature what comes after the “ : “
first position of the double bond
What goes in the brackets in FA nomenclature?
position of double bond
Which carbon is known as the alpha carbon?
carbon # 2
which carbon is known as the beta carbon?
carbon # 3
What are fatty acids stored as?
triacylglycerols
T or F: Fatty acids are toxic and must be stored until used.
True;
What is the backbone of triacylglycerols?
glycerol
What type of bond connects Fatty acids to their glycerol backbone?
Ester bond
What is the most concentrated form of biological energy?
triacylglycerols
How much more energy does Triacylglycerides have than carbs or proteins per gram?
2x
How many kJ/g does Triacylglycerol provide?
37 kJ/g
How many kJ/g does Carbohydrate provide?
16 kJ/g
How many kJ/g does Protein provide?
17 kJ/g
Are triacylglycerols chemically inert?
yes
are triacylglycerols highly oxidized?
No ; reduced
What does the brain use for energy?
glucose + ketone bodies
What does the heart use for energy?
80% Fatty acids , 20% glucose
T or F: Triacylglycerols are soluble in water and can be stored in large quantities.
False; insoluble ; allows it to be stored in large quantites
Why can’t the brain use Triacylglycerols for energy?
can’t cross the Blood Brain Barrier
Why does the heart use triacylglycerols for energy?
because it requires more energy
What allows hummingbirds to be able to sustain flight non-stop (500 miles)?
store triacylglycerol in the fall; metabolize
What percent of Hummingbird’s weight is Triacylglycerol?
70% dry
Triacylglycerols are stored in what form?
anhydrous form ( no water)
How much ATP comes from a single fatty acid?
~100atp
How much ATP comes from a single glucose molecule?
30-32 AtP
T or F: glycogen is stored in a hydrous form
True; bound to water
What are the 2 types of energy reserves in the body?
- adipose/triacylglycerols
2. Liver/glycogen & muscle/glycogen
How long can you live on strictly triacyglycerols? (sedentary)
a month (30 days)
How long can you live on strictly triacyglycerols? (marathon)
3 days
how long can you live off muscle glycogen (sedentary)?
14 hours
how long can you survive off liver glycogen (sedentary) ?
4 hours
how long can you live off muscle glycogen (walking)?
5 hours
how long can you live off liver glycogen (walking)?
1 hour
1 glycogen molecule is bound to how many grams of Water?
2g
Excessive triacylglycerol is stored as what?
adipose tissue
too much storage of triacylglycerol leads to what clinical condition?
obesity and diabetes
High levels of tracylglycerol in blood can lead to what clinical condition?
Atherosclerosis - narrowing of blood arteries (heart attacks)
What enzyme breaks down Triacylglycerol into its subgroups?
Lipases
What activates a fatty acid so that it can enter the mitochondria?
CoA
Where does the cleaving of fatty acids from glycerol back bone take place?
extracellular fluid?
