Lecture 3 (Biomolecules) Flashcards
Monomer and polymer of carbohydrates
monomers - monosaccharides
polymer - polysaccharides
monomer and polymer of lipids
monomer - fatty acid
polymer - triglycerides
monomer and polymer of proteins
monomer - amino acids
polymer - polypeptides
monomer and polymer of nucleic acids
monomer - nucleotides
polymer - DNA, RNA
Hydrolysis reactions
break down polymers into monomers (H2O is added)
A-B +H2O –> A - OH + H - B
Dehydration (condensation) reactions
combine monomers into polymers (H2O removed)
Carbohydrates contain? general formula? Polar or non-polar? function/s?
contain carbon, hydrogen, and oxygen usually in a 1:2:1 ratio
general formula (CH2O)n
polar (contains many -OH groups) soluble in H2O
major energy source for all cells and required by CNS
Monosaccharides
Simple Sugars
Building blocks of polysaccharides and nucleotides
Energy Metabolism
Pentoses and hexoses
Pentose
is a monosaccharide 5 Carbon (C5H12O5) Ribose and deoxyribose
Hexoses
monosaccharide
6 Carbon (C6H12O6)
Glucose, galactose and fructose
Used to make ATP
Disaccharides
2 monomers joined together via dehydration synthesis
maltose = 2 glucose
surcose (table sugar) = glucose + fructose
Lactose = galactose + glucose
Polysaccharides
energy storage
- starch in plants
- glycogen in animals, stored in liver and muscle
Structural polysaccharides (Cellulose, Chitin, GAGs)
Lipids
Functions
Polar or non polar?
mostly non-polar organic molecules
rich in C-H bonds
mostly insoluble in water
Functions: cell membrane, energy reserves, signaling molecules
Classes of lipids
fatty acids Triglycerides Phospholipids Steroids Eicosanoids
Fatty acids
basic building blocks of lipids (monomers)
long chains of hydrocarbons with carboxyl at the end
Saturated fatty acids
contain all c-c single bonds hydrocarbon chains packed closely more solid straight chain (butter, lard, animal fat)
unsaturated fatty acids
contain c=c double bonds forms a kink in the chain making it more lipid and harder to stack (vegetable oil) monounsaturated 1 double bond polyunsaturated 2 or more double bonds
Trans fat
Partially hydrogenated oil
chemically modified
unsaturated fats
hydrogenation - adding H to Fa’s: unsaturated to saturated
double bonded Fa’s produced as a byproduct
produced in manufacturing of some margarine’s and vegetable shortening
increase risk of heart disease
lowers HDL (good cholesterol) increase LDL (bad C)
Triglycerides
3 fatty acids and a glycerol
gone through dehydration synthesis
energy rich molecules (high in calories)
2x energy as carbohydrates per gram
insoluble in H2O
Body fat (adipose tissue) functions as energy storage
Phospholipids
2 fatty acids + glycerol + phosphate group
phospholipid bilayer forms the basic structure of the plasma membrane
Polar head and non polar tails
amphipathic molecules
non-polar and polar
diglyceride
2 fatty acids + glycerol
steroids
4 hydrocarbon ring (cholesterol and derivatives)
Cholesterol - component of cell membrane, precursor to other steroids
steroid hormones: cortisol, aldosterone, testosterone, estrogen
related steroids
important in tissue metabolism and mineral balance
e.g. corticosteroids and calcitriol
Eicosanoids
modified fatty acids with a 5 C ring
many function as a paracrine substances, intercellular signaling
coordinate/direct local cellular activity
vasomotor effects, inflammation and pain
Types of eucisanoids
prostaglandins
prostacyclins
thromboxanes
Amino acids
building blocks or proteins
contains a central carbon atom, hydrogen atom, amino group, carboxyl group, and a variable R group
20 aa’s are used to make proteins, 9 are essential in diet
R groups
can be polar, non-polar, acidic (-), basic (+)
different amino acids have different R groups
R group affect protein shape and function
stuck out from chain
Peptides
combination of 2 or more amino acids
polymers of amino acids
peptide bond
links adjacent amino acids
carboxyl group + amino acids
polypeptide
primary structure
a long chain of covalently bonded amino acids
primary structure - “linear” amino acid sequence (peptide bonds)
Secondary structure
simple coiling/folding of the chain
bond formed between different amino acids
form alpha helix or pleated sheet
hydrogen bonds form spirals or pleats in polypeptides
Tertiary structure
higher order 3 dimensional folding (r group interactions)
internal and external impact
Disufide bonds
combine with weak bonds and stabilize tertiary structure of protein
Quaternary structure
interaction among multiple protein subunits
e.g. globular (hemoglobin) or fibrous (collagen or keratin)
protein denaturation
unfolding of proteins due to drop in pH and or increased temperature which causes hydrogen bonds to break (=shape change)
mild changes can be reversible but extreme changes are irreversible
Nucelotides
building blocks of DNA and RNA
3 components: pentose sugar (ribose or deoxyribose), phosphate group, nitrogenous base
Information molecules
store and transfer genetic information
DNA
sugar = deoxyribose double stranded, double helix sugar phosphate backbone (covalent bonds) Bases:(hydrogen bonds) A=T G---C
RNA
Sugar = ribose
mostly single stranded
base paring a instead of u
classes of RNA
messenger mRNA
Transfer tRNA
ribosomal rRNA
Other nucleotides
ATP - energy molecule
GTP, cAMP - regulatory and cell signaling molecules
NADH, FADH2 - coenzymes, carriers of electrons and H in cellular respiration
Why do bases only bond with specific ones
shape and polarity of bases allows formation
how delta + and delta - line up
Purines vs pyrimidines
Purines 2 ring, A and G
pyrimidines 1 rings, T and C
a purine always goes with a pyrimidine
