Lecture 15: Primary Metabolism - 11/3 Flashcards
Metabolism
The biochemical reactions that create molecules
Primary metabolites
Molecules produced by all plants that are essential for their survival
Secondary metabolism
The biochemical reactions that create molecules not necessary for plant survival. These molecules are called secondary metabolites and are often unique to one group of plants
What are the 4 primary metabolites?
Amino acids
Fatty acids
Carbohydrates
Nucleobases
What are the 3 parts of a nucleotide?
Phosphate group
Pentose sugar group (5C)
Nitrogenous base
What is the most abundant class of metabolites?
Carbohydrates
What elements make up carbohydrates?
C, H, and O
What uses do carbohydrates have?
They provide energy or are used in cellular structure
Hydroxyl group
Has a significant effect of the properties of the polysaccharides formed from glucose. This group is attached to the carbon 1
a (alpha) or b (beta) orientations
Sucrose
A disaccharide with a glycosidic bond linking glucose and fructose
Starch
A complex polysaccharide with the C rings of C1 and C4 linked by an alpha bond
Cellulose
Makes up plant walls consisting of long linear chains of glucose (with beta 1-4 linkages). Every other glucose in cellulose is flipped over. This promotes intra- and inter-chain bonding, causing cellulose chains to be straight and rigid
What is the difference between starch and cellulose’s bonds?
Starch has alpha bonds, so it is digestible. Cellulose has beta bonds, so it is indigestible
Fatty acid structure
A carboxyl group (COOH) and a long, unbranched carbon chain
Saturated vs. unsaturated fatty acid
Saturated fatty acids have a straight C (carbon) chain, whereas unsaturated fatty acids have a bent C chain.
This is because saturated fatty acids only have C-C single bonds, whereas unsaturated fatty acids have at least one C=C double bond
Where are fatty acids synthesized?
Within plastids, or within chloroplasts in photosynthetic tissue
What are free fatty acids?
They are very reactive molecules. The cell adds them to glycerol to reduce their reactivity (esterifying them)
Esterification reaction
When an alcohol and an acid become linked by an ester bond
Triacylglycerols
Used as carbon storage by plants and are mostly found in seeds
Diacylglycerols
Have a polar head and make up membranes
Amino acid structure
Small molecules with an amino group (NH2), a carboxyl group (COOH), a hydrogen, and a variable side chain R
Where does amino acid synthesis branch off from?
Glycolysis and the Krebs cycle
What is an essential amino acid?
An amino acid that can’t be synthesized by humans
Out of the 20 common amino acids, how many are considered essential amino acids?
There are 8 essential amino acids
Protein structure
Composed of long, unbranched chains of amino acids held together by peptide bonds
How are peptide bonds formed?
Through dehydration reactions
