one of 3 fatty acids in triglyceride is replaced with a phosphate group.

...a phosphate head (hydrophilic) with two fatty tails (hydrophobic).

Phosphate groups tend to ionize, so the head is hydrophilic.

- Fat tails hate water.

- Arrange themselves in phospholipid bilayer, foundation of cell membrane

foundation of the cell membrane

Fats are essential to properly functioning organism, but not in excess.

- no lipids = no phospholipids = no/weak cell membranes

Phospholipids

Triglycerides

Others with different structures are steroids: Cholesterol, Vitamin D2, Cortisol, Testosterone

Strong of several (hundreds) amino acids;

polymers of amino acids

aa-aa-aa-aa-aa-aa-aa-aa-aa-aa-aa-aa-aa-aa-aa-aa-aa-aa-aa...

- each "aa" can be one of 20 common aa's

- Makes up a protein

- folds into primary, secondary and tertiary structure

- highly complex molecules of one or more polypeptides connected together.

- can be be with an unlimited combo of the 20 aa's.

folding of a polypeptide.

- regular pattern due to H-bonding between amine group of one aa and carboxyl group of another.

alpha-helix & ß beta-pleat

additional folding of polypeptide, depending on order of aa.

Due to:

- H-bonding between polar aa's and van der waals forces between non-polar aa's.

- disulfide bonding between thiol groups of cysteine aa's

- hydrophilic polar and ionic aa's are outside of folded polypeptide and touch water, while hydrophobic non-polar aa's are inside, away from H2O

Functions depend on its 3D shape...

1. structural

2. signaling (ex: receptors, hormones, neurotransmitters)

3. Enzymes (catalysts)

4. Immune system antibodies

they are receptors for (detect) signaling molecules (chemical messengers for the body)

- detect signaling molecules by binding to them

substance that promotes reaction (formation/destruction of chemical molecules), but isn't changed by it

- in cells, they are proteins aka enzymes

Protein as a catalyst in a cell.

- determine what reactions will occur in a cell

aldehydes or ketones containing repetitions of

H-C-OH -- carbon and a hydrate (H2O ratio))

- simplest: monosaccharides (simple sugars)

- carbons + pentoses + hexoses

- straight line or ring (hydroxyl group reacts with aldehyde group)

6-carbon sugars

- structural isomers.

ex: glucose, mannose, glactose, fructose

5-carbon sugars

- NOT isomers

ex: deoxyribose has one fewer oxygen than ribose

two simple sugars connected

ex: glucose + fructose = double sugar sucrose

lactose, maltose

chain of several monosaccharides (up to 20)

- common components of cell membranes

- important for cell recognition

many simple sugars joined in a chain

ex: starch, cellulose, glycogen

monosaccharides with functional groups (amine, sulfate)

ex: cartilage is composed of polysaccharide chondroitin sulfate, containing amine and sulfate

- important for cell signaling

composed of:

- 5-carbon sugar

- phosphate (P and O)

- nitrogen base (8 types: 4 combine with ribose: A, C, G, U; 4 combine with  deoxyribose: A, C, G, T)

- 4 types of nucleotides based on ribose, 4 types based on deoxyribose

nucleic acides linked with deoxyribose

- double-stranded: two strands of nucleotides linked by nitrogen bases and form double helix

AT

GC

responsible for genetic inheritance

- biochemical information that determines resemblance to parents

DNA specifies order of aa's in the proteins a cell can make.

- nucleotide sequence codes the amino acid sequence of polypeptide

- 3 nucleotides code 1 amino acid (triplet code)

- primary strand codes polypeptide

- one gene=one polypeptide

based on DNA and proteins:

- enzyme determines chemical reactions (cell function)

- chemical reactions determine what cell makes

- what cell makes (proteins, lipids, carbs) determine its structure

- both structure and function are determined by proteins, which are determined by DNA!

3 nucleotides code one amino acid

Ex: ACG: cysteine

TTC: lysine