BIOL 151 - Unit 1

define carbohydrates (make-up/formula, 1. monomer, 2. function, 3. examples)

macromolecules made up of C, H, & O (C6H12O6) molecules — linear chain or ring-shaped molecules

1. monosaccharides

2. energy source & structure

3. glucose, starch → energy source, cellulose & chitin → structure

carbohydrate subgroups

1. monosaccharides (1 carb)

2. disaccharides (2 carbs)

3. oligosaccharides (3-10 carbs)

4. polysaccharides (100s of carbs)

oligosaccharides

3-10 monosaccharides vital for cell recognition (communication) & signaling — usually found on glycoproteins

what bonds link monosaccharides, how are they formed & broken?

glycosidic bonds (COVALENT) are formed with dehydration synthesis (condensation reactions) and broken with hydrolysis

dehydration synthesis/condensation reaction

creates a covalent glycosidic bond + 1 H2O molecule (water is removed from bond)

hydrolysis reaction

a water molecule is added to break bond

disaccharides

2 monosaccharides bonded tgtr w/ glycosidic bonds through dehydration/condensation reactions (H2O is removed)

polysaccharides (bonds + examples)

multiple monosaccharides that create long polymers connected by either hydrogen or peptide bonds

• energy storage: starch, glucose, glycogen

• cell structure: cellulose, chitin, peptidoglycan

glycosidic bond

a covalent bond that joins a carbohydrate to another molecule

lipids (define, functions, types)

macromolecule mostly made of C & H atom as the tail (hydrophobic) & a carboxyl group as the head (hydrophilic)

• monomers: glycerol & fatty acids

• largely nonpolar & hydrophobic → insoluble to water

• function: long-term energy storage, cell communication, signaling, cell membrane

• steroids, fats (triacylglycerols/cides), phospholipids, waxes

why don’t lipids bond with water?

lots of nonpolar C-C and C-H bonds and nonpolar doesn’t have a charge to form hydrogen bonds w/ water

hydrocarbons

molecules containing only C & H atoms (greatly abundant in lipids!)

• unsaturated contain C=C (double bonds)

• saturated don’t

amphipathic

phospholipids that contain both hydrophilic & hydrophobic regions

• lipids have hydrophilic heads & hydrophobic tails

• ex. detergent

phospholipids

lipids consisting of 2 fatty acid chains (uncharged, polar) attached to a glycerol linked to a phosphate group (negatively charged polar)

• major part of plasma membrane for animal cells

2 structures of amphipathic lipids when placed in water

1. micelles

2. lipid bilayer

micelles

tiny spherical lipid structures created when placed in water:

• prone to forming free fatty acids

• assemble spontaneously

lipid bilayer

amphipathic phospholipid lipids that align & layer tgtr

• assemble spontaneously

unsaturated lipids

multi-bond chains fatty acids with kinks b/c C=C (double bond) surrounded by hydrogens (fewer than max H)

• high permeability w/ low melting points

  • ex. oils

saturated lipids

a fatty acid where the hydrocarbon chain consists of only single bonds w/ carbons

• low permeability so can stack w/ nonpolar molecules due to van der waal interactions

• relatively high melting points

• solids at room temp (ex. butter, waxes)

steroids

ring structure lipids w/ 4 linked carbon rings

• ex. cholesterol, testosterone, estrogen

what type of bonds link lipids tgtr (& what process)?

ester bonds by dehydration synthesis/condensation reactions

fats aka triacylglycerols/triglycerides

nonpolar molecules made of 3 fatty acids linked to glycerol

• primary function: energy storage (2x more energy per gram than carbs b/c of more high energy bonds (C-C & C-H)

• linked w/ ester bonds (covalent bonds) through condensation reaction

ester bond

• for nucleotides = phosphoester

  • formed b/w a phosphate group with a ribose

• for lipids = carboxylic ester

  • formed b/w a glycerol’s hydroxyl group (-OH) with a fatty acid’s carboxyl group (double bonded O)

glycerol

organic compound w/ 3 carbons, 5 hydrogens, & 3 hydroxyl (OH) groups → C3H8O3

• backbone of triglycerides & phospholipids

fatty acid

a simple lipid consisting of a polar carboxyl group (-COOH) bonded to a hydrocarbon chain

• key building block for important lipids

• unsaturated or saturated

diffusion

spontaneous movement of molecules across a membrane

phospholipid diffusion

2 types:

1. lateral diffusion

2. transverse diffusion “flip flop”

lateral diffusion

lipid movement in plasma membrane side-to-side within same layer side

• occurs frequently

transverse diffusion

aka “flip flop” where a lipid moves within the plasma membrane to opposite layer

• occurs not so frequently

integral proteins

embedded within the phospholipid bilayer/membrane

• may or may not penetrate through both layers

• hydrophobic

peripheral proteins

located on either inner or outer surface of phospholipid bilayer

• not embedded within

• vital for cell recognition/identification (to allow immune system to ID body cells aka “self” & foreign cells aka “non-self”)

cholesterol

attached b/w phospholipids & 2 phospholipid bilayers of membrane

glycoprotein

protein w/ carbohydrate attached

glycolipid

lipid w/ carbohydrate attached

function of carbohydrates in plasma membranes

cell recognition/identification (to allow immune system to ID body cells aka “self” & foreign cells aka “non-self”)

glycocalyx

aka “fuzzy sugar coating” outer layer of plasma membrane of all glycoproteins & glycolipids

• highly hydrophilic

what molecules cannot easily cross the membrane?

polar molecules like sodium & potassium

fluid mosaic model

describes the cell membrane’s structure as a mosaic (flexible) of components

amino group

• -NH2

• component of amino acids (that form proteins)

• acts as a base

• can form peptide bonds (bonds b/w amino acids)

carboxyl

• -COOH

• component of amino acids (that form proteins)

• acts as an acid

• can form peptide bonds (bonds b/w amino acids)

proteins

polymers made of monomers called amino acids (structure in picture) of 20 types connected by peptide bonds consisting of:

1. hydrogen atom (H)

2. amino functional group (-NH2)

3. carboxyl group (-COOH)

4. R group (side chain)

more features

• legit does everything but carry genetic material

• 4 levels of structure: primary, secondary, tertiary, quatemary

r group (side chain)

abbreviation of the rest of the molecule which determines amino acid’s shape and function

• ionic — super hydrophilic b/c full charge

• polar — hydrophilic b/c partial charge

• nonpolar — hydrophobic b/c no charge

peptide bond

a C-N covalent bond formed b/w 2 amino acids via dehydration synthesis/condensation reaction

• amino acid A’s amino group (-COOH) with amino acid B’s carboxyl (-NH2)

polypeptide

a single linear, continuous chain of amino acids bonded by peptide bonds

• all proteins are made of polypeptides, but a single, flat polypeptide isn’t a protein

4 levels of protein structures (identify each)

1. primary — a single amino acid sequence/chain in a polypeptide; bonded by peptide bonds

2. secondary — a-helix & b-pleated sheet formations; hydrogen bonds b/w groups of peptide-bonded chains

3. tertiary — 3-dimensional shape consisting of 2ndary structures

4. quaternary — combo of (tertiary) polypeptides

pentose

5 carbon ring-shaped monosaccharides

hexose

6 carbon ring-shaped monosaccharides

nucleic acids

polymers made up monomers called nucleotides

• responsible for storage of genetic material (DNA & RNA)

• bonded w/ phosphodiester bonds (covalent) by dehydration synthesis/condensation

phosphodiester bonds

covalent bonds that forms b/w the phosphate group (PO4) attached to 5’ carbon of nucleotide sugar A & the 3’ hydroxyl (-OH) of nucleotide B’s sugar

• tgtr creating the “sugar-phosphate backbone” for

DNA vs RNA

DNA:

1. nucleotides contain deoxyribose

   1. lacks an O on 2nd carbon → chemically stable → good for long-term storage

2. stores genetic code/blueprint

3. double-stranded

4. uses bases A, T, C, G

RNA:

1. nucleotides contain ribose

   1. has an extra O on 2nd carbon → unstable & prone to breaking down (by hydrolysis) → good for temp genetic msgs so the cell can turn on-or-off specific genes, controlling gene expression and respond quickly)

2. interprets genetic code to help build proteins

3. single-stranded

4. uses bases A, U, C, G

3 parts of a nucleotide

dna: deoxyribose sugar

rna: ribose sugar

starch

carb for energy storage in plants

glycogen

carb for short-term energy storage in animals

cellulose

carb for structural support in plant cell walls

chitin

carb for structural support in exoskeletons, cell walls, & fungi

peptidoglycan

carb for structural protection & shape maintenance in bacterial cell walls