Chapter 3 BioChemistry & Cell Biology

What are macromolecules and what are the 4 general classes?

Macromolecules are polymers that are built by linking monomers.

e.g. carbohydrates, lipids, proteins, nucleic acids

How are macromolecules formed

Through dehydration, where a molecule of water is removed; an OH group is removed from one monomer and a H atom is removed from the other to form a covalent bond between two monomers.

How does macromolecules break down

Through hydrolysis, where a molecule of water is added; a H atom is attached to one subunit and a OH group to the other, breaking the covalent bond in the macromolecule.

What are carbohydrates

carbohydrates is a group of molecules that contain carbon, hydrogen and oxygen in the molar ratio of 1:2:1

what are the 3 main groups of carbohydrates

monosaccharides, disaccharides, polysaccharides

define monosaccharides

monosaccharides are simple sugar that can contain as few as 3 carbon atoms and are often used as building blocks to form larger molecules.

types of monosaccharides

glucose, fructose, galactose

what is an isomer

isomers are organic molecules that have the same molecular or empirical formula.

- structural isomers: difference in the structure of carbon skeleton

- stereoisomers: same carbon skeleton but differ in how the groups attached to this skeleton are arranged in space

what are disaccharides

disaccharides are transport sugar, that are made up of 2 monosaccharides linked together by dehydration synthesis

examples of disaccharides

sucrose, lactose, maltose

what is sucrose

glucose + fructose

table sugar, the form plants use to transport glucose.

what is lactose

glucose + galactose

milk sugar, the form many mammals supply energy to their young

what is maltose

glucose + glucose, it is used in grain for storage

what are polysaccharides

polysaccharides are long chains of monosaccharides linked through dehydration syn thesis.

used for energy storage or structural support in animals and plants

examples of polysaccharides

starch, cellulose, glycogen, chitin

what is starch

it is an energy storage in plants and is made up of alpha glucose subunit. there are 2 kinds of starch; amylose and amylopectin

what is amylose

(what is it made of, what is it's linkage, solubility in water)

it is made up of many hundreds of alpha glucose molecules linked together in LONG, UNBRANCHED CHAINS.

each linkage is between carbon 1 of one glucose and carbon 4 of another glucose, making them alpha 1-4 linkages.

it coils up in water is is insoluble.

what is amylopectin

(what is it made of, what is it's linkages, what does the short branches consist of, solubility in water)

it is made of hundreds of a-glucose molecules joined by a 1-4 linkages but it forms branches.

branches occurs at carbon 1 and carbon 6, making it alpha 1-6 linkages.

short branches; contain 20 to 30 glucose subunits

insoluble in water and forms starch granules in plants cells.

where can you find amylopectin

in most plant starch, e.g. potatoes: 20% amylose and 80% amylopectin

what is glycogen

(what does it do, what is it made of, solubility in water, chains)

it is a storage form of sugar in mammals and is made up of a-glucose subunits

insoluble in water

contains branched chains but has a longer average chain length and more branches than plant starch.

polymers of glucose

starch and glycogen

where can you find starch and what is it composed of

you can find it in plants and it is composed of amylose (unbranched) and amylopectin (branched)

branched - insoluble and forms starch granules in plant cells

where is glycogen found in

glycogen is found in animal cells and is highly branched and insoluble, forming glycogen granules

what is cellulose

it is a structural polysaccharides that is made up of beta-glucose subunits. it is long and unbranched, linked by the beta 1-4 linkages

function of cellulose

form long fibers that is strong and quite resistant to metabolic breakdown.

chief component of plant CELL WALL

cannot be broken down by enzymes in most organisms since their enzyme only recognize alpha linkages and not beta linkages.

what are proteins made of

made of one or more long, unbranched chains of long, linear polymers of amino acids chains linked by peptide bond. also known as polypeptide.

where are proteins found and what can it do.

it is encoded by genes found in DNA, it synthesizes in the cell by the process of translation using mRNA as a template.

it is essential for cellular functions as it is involved in many cellular processes and activities.

what are amino acids

building blocks of proteins

what can amino acids be linked to

- nh2

- cooh

- h

- r : determines the chemistry of amino acids

what are the 5 different chemistry or amino acid

1: non polar amino acid - contains ch2 or ch3

2: polar-uncharged - contains oxygen

3: charged amino acids - contains acid or base that ionizes

4: aromatic amino acids - contains carbon ring with alternating single or double bond

5: amino acids with unique properties

how do peptide bond form

it is formed when the amino end of one amino acid joins to the carboxyl end of another to form a covalent peptide bond.

what are the four structural proteins

1: primary - sequence of amino acids

2: secondary

- 1: alpha helix - coiled into a spiral sheet

- 2: beta sheets - regions of peptide aligned next to each other to form a planar structure

3: tertiary - final folded shape of a polypeptide chain

4: quaternary - arrangement of individual chains in a protein with 2 or more polypeptide chain

what is the structure of hemoglobin

each chain is associated with a heme group and each heme group has a central iron atom that binds to oxygen.

interactions that contribute to protein tertiary structure

1: hydrogen bond - form between amino acids

2: covalent disulfide bridge - form between 2 cysteine side chains

3: ionic bonds - weak attractions between atoms due to oppositely polarized electron clouds

4: hydrophobic exclusion - nonpolar gather in the interior, polar gather outside & interact with water

what is protein denaturation

the shape changes and the protein unfolds due to the change of environment like the pH, temperature and ionic compound. this leads to the loss of function. but renaturation can happen to small proteins when it is in it's normal protein environment.

what are nucleic acids

polymers of nucleotides that are connected through phosphodiester bonds.

types of nucleic acids

- dna : found in nucleus, contains genes that code for protein

- rna : 3 types, mRNA rRNA tRNA

what are nucleotides made of

5-carbon sugar, nitrogenous base, phosphate group

structure of nucleic acid

nucleotides are linked to one another via phosphodiester bonds between phosphate of one nucleotide and sugar of another organic base protruding from sugar-phosphate backbone.

structure of dna

made of 2 polynucleotide chains opposite of each other that forms into a double helix that is joined by hydrogen bonds between complementary bases.

a -> t

g -> c

uses thymine for its nitrogenous base

uses deoxyribose in its sugar-phosphate backbone.

function of dna

contain gene that code for protein

what is rna

it is single stranded

uses uracil instead of thymine

uses ribosomes in its back bone

function: translation

what are lipids

loosely defined group of non-polar molecules that are insoluble in water. (e.g. fat/oil/wax)

high proportions of non polar C-H bonds

excellent form of energy storage

structure of fat

it is a long chain hydrocarbons with a carbonyl at the end, built by 3 fatty acids and 1 glycerol (attached by dehydration synthesis)

AKA triglyceride

what are fatty acids

long chain hydrocarbons with carboxyl, connected to 14-20 carbons

types of fatty acids

saturated fatty acids: internal carbons are bonded to at least 2 hydrogen atom

unsaturated fatty acids: internal carbon bonds double bonded between one or more pairs of successive carbon atoms

2 types of unsaturated fatty acids

monounsaturated : contains 1 double bond

polyunsaturated : contains more than 1 double bond

what are saturated fats

it is triglycerides that contains three saturated fatty acids

it has a max no. of carbon atoms that can be bonded (single bond)

structure of unsaturated fats

it composes of triglycerides that contains one or more unsaturated fatty acids (double bond)

it is liquid in room temperature due to the kinks in the double bond that prevents the triglyceride from closely aligning.

structure of trans fat

it is a natural occurring unsaturated fatty acid that has a double bond with a cis configuration

when it is partially hydrogenated, it produces double bond with trans configuration

overconsumption of trans fat

as trans fat has elevated levels of low density lipoprotein (LDP) which is a bad cholesterol and lowered levels of high density lipoprotein (HDL) which is a good cholesterol, it can cause increased risk of coronary heart disease.

what are phospholipids

it is a triglyceride with 1 fatty acid replaced by a phosphate group

structure of phospholipid

made of 1 glycerol, 2 fatty acids and 1 phosphate

phosphate forms a hydrophillic head, fatty acids form hydrophobic tails

forms a phospholipid bilayer

phosphate in water

the polar heads which are hydrophilic would be in the water, while the nonpolar tails which are hydrophobic would be held away from the water. thus forming a bilayer.