Biomolecules & Chemistry

Compounds

2 or more elements chemically combined (bonded) in a definite ratio

Organic Compounds

- contain carbon and hydrogen (sometimes oxygen)
- ALWAYS covalent bonds
- form large/complex molecules
- make up & made by living things
- main nutrients of life: carbohydrates, lipids (fats), nucleic acids, and proteins

Inorganic Compounds

- do not contain carbon & hydrogenTOGETHER
- ionic or covalent
- not large/complex

Carbon

- small
- 4 valence electrons = 4 covalent bonds
- limitless sizes and arrangements of organic molecules (especially when carbon bonds to itself)

Hydrocarbons

Compounds composed of only carbon and hydrogen, contain a lot of energy because of all the bonds, ALWAYS nonpolar/hydrophobic (will not dissolve in water of form hydrogen bonds)

Carbon skeleton

The chain of carbon atoms in an organic molecule

Functional Groups

Attached to the carbon skeleton and are groups of atoms that participate in chemical reactions and give the molecule its overall properties

Hydroxyl group

polar and allows H-bonding in that region (O is electronegative)

Carbonyl group

aldehydes & ketones (found in sugars)

Carboxyl group

organic acid (carbonyl + hydroxyl)

Amino group

acts as a base

Phosphate group

will make hydrogen bonds (polar), very electronegative, found in energy molecule ATP

Chemical energy is a molecule stored in

chemical bonds (so more bonds in carbon = more stored energy)

Energy is released (not absorbed) from a molecule by

breaking the bonds (unlike water, covalent bonds are broken through chemical reactions)

The body's number one nutrient to use for energy is

carbohydrates

When carbohydrate molecules are all used up, the body will break the bonds contained in

lipids (fats)

Calorie

A measure of energy content in food
- carbs & proteins have 4 calories per gram
- lipids have 9 calories per gram
- 3500 calories to gain 1 pound or burn 3500 calories to lose 1 pound

Nutrients of life

Chemicals in food that the body requires for energy, growth, repair, and maintenance

Monomers to polymers

synthesis

Polymers to monomers

hydrolysis

(def.) Dehydration synthesis reactions

Remove a water molecule forming a new bond

Hydrolysis

Adds a water molecule to break a bond

Isomers

Compounds with the same chemical formula, but different structural formulas
- glucose, fructose, galactose = C6H12O6

Carbohydrates

- contain carbon, hydrogen, and oxygen ONLY
- monomer = monosaccharide
- 2H: 1O
- "ose"

Carbohydrates function: useable energy

- immediate energy goes into bloodstream, comes from simple sugars (monosaccharides and disaccharides)
- stored energy (long chains of glucose), comes from starches (polysaccharides):
- humans = glycogen (animal starch); stored in liver and muscle
- plants = starch/amylose (vegetables, grains, pasta, potato, bread, rice)

Carbohydrates function: structural carbohydrates

- NOT USED FOR ENERGY
- cellulose: structural polysaccharide, found in plant cell walls and gives plants a boxy, rigid structure, not digestible (bread, cereal, veggies) = fiber helps in digestion, lowers bad cholesterol, regulate blood sugar levels

Monosaccharides are

simple or single sugars (monomers in sugar polymers like glucose fructose and galactose)

Glucose

#1 energy source for most organisms - 6 rings

Fructose

sweetest monosaccharide (honey, flower nectar, fruits) - 5 rings

Galactose

found combines with glucose to make lactose (milk sugar) - 6 rings

Disacharrides are

two sugars joined by an o-glycosidic bond = sucrose, maltose, lactose

Dehydration synthesis reactions

build disaccharides by removing a water molecule to put monomers together

Glucose + Glucose =

Maltose (seeds)

Glucose + Fructose

Sucrose (table sugar)

Galactose + Glucose

Lactose (milk sugar)

Hydrolysis reactions

break down disaccharides by adding water back to break it and restore 2 monosaccharides

Polysaccharides are

many monosaccharides together (hundreds of glucose monomers)

Polysaccharides are made by

dehydration synthesis

Polysaccharides are broken down by

hydrolysis

(Polysaccharide) plant starch/amylose

stores sugar used for energy, chains of glucose monomers coil up in water making them insoluble and good for storage, straight chains

(Polysaccharide) animal starch/glycogen

stores sugar in liver and muscle (long term energy), in animals glucose is stored as glycogen, insoluble in water BUT glycogen chains are longer and highly branches

(Polysaccharide) cellulose

not used for energy, found in plant cell walls (fiber), no enzyme (amylase) to break down bonds between glucose subunits in structural polysaccharides

Lipids (fats)

- contain carbon, hydrogen, and very little oxygen
- do not dissolve in water they are nonpolar molecules

Hydrophobic

water fearing

Hydrophilic

water loving

(Lipids) triglycerides (fats & oils; dietary fats)

- stored energy, heat insulation/padding (body fat is stored under the skin but over the muscle: adipose tissue)

(Lipids) phospholipids

- cell membrane structure

(Lipids) steroid hormones (made from cholesterol)

- hormones send chemical systems in the body (cortisone, testosterone, estrogen, growth hormone)

(Lipids) waxes

- protective coating from water that prevents dehydration (surface of leaves & fruits, inside ears)

Lipids (monomers)

3 fatty acids and 1 glycerol

Fatty acid

hydrocarbon chain with a carboxyl group which makes it an organic acid

Fatty acids, nucleic acids, and amino acids all have

carboxyl groups

Triglycerides are made by

dehydration synthesis

Glycerol C3H8O3

Triglycerides have more bonds and more energy

so fats have more calories

Triglycerides are broken down by

hydrolysis

Do fats or carbohydrates store more energy?

fats because the molecules have more bonds

Saturated fatty acids

have all SINGLE carbon bonds (not including carboxyl group), saturated with hydrogen atoms, solid at room temp., animal sources: butter, lard, meat, fat, eggs, cream, cheese

Unsaturated fatty acid

one or more double bonds, unsaturated with hydrogen, kink prevents molecule from packing tightly, liquid at room temp., plant sources (vegetables oils, nut oil, omega-3 fatty acids, fish oil)

Monounsaturated

one double bond

Polyunsaturated

two or more double bonds

Hydrogenation

process that turns unsaturated oil more saturated by adding hydrogen and removing some of the double bonds (for better texture, taste, longer shelf life), forms trans-fats

Trans-fats

the trans bond (when hydrogens are on opposite sides) makes it solid and acts like it is saturated because stable structure making it difficult to digest which clogs arteries

Hydrogenation process adds

hydrogens to "cis" double bonds

Which is healthier, saturated or unsaturated?

Unsaturated fats (oils) lower bad cholesterol levels, metabolized faster due to bent structure, don't leave fatty streaks (plaque) in arteries because they are liquid

Atherosclerosis

hardening of the arteries from accumulation of cholesterol & saturated fats over time = narrowing arteries lead to hypertension (high blood pressure) and cardiovascular disease, heart attack, stroke

Proteins

- contain carbon, hydrogen, oxygen, and nitrogen (sometimes sulfur)
- each amino acid has 4 groups surrounding a central carbon
- R group/variable side chain: gives the amino acid its chemical properties
- one or more polypeptide chains folded into a highly specific 3D shape
- unique 3D shape determined by order of amino acids
- make up our entire structure and physical traits but also allow all metabolic functions to occur in all cells

Proteins (monomers)

20 amino acids

Amino acids are put together by

dehydration synthesis

Amino Acid + Amino Acid ---> Dipeptide + H2O

Building of Protein molecules with Dehydration Synthesis

Peptide bond

A covalent bond between the carboxyl group of one amino acid & the amino group of the next amino acid (carbon double bonded to oxygen and nitrogen next to it)

To add more amino acids

more dehydration synthesis reactions must occur

Dipeptide

Two amino acids bonded together

To break down a polypeptide or dipeptide

hydrolysis occurs

When more amino acids are added to a dipeptide

a polypeptide chain is formed

How does a polypeptide become a functional protein?

1. at least 50 amino acids
2. a specific shape/confirmation determined by structures

Primary (1°) structure

a specific sequence of amino acids determined by order of nucleotides in DNA - stabilized by peptide bonds, can't be denatured, NO SHAPE

Secondary (2°) structure

Polypeptide is coiled into a helix or folded into a pleated sheet - stabilized by hydrogen bonds (between amino and carboxyl groups of amino acids)

Tertiary (3°) structure

overall 3D shape results from interactions among R groups (all types of bonds: ionic, covalent, H-bond) proteins = globules,responsibleforfinalshape

Quaternary (4°) structure

proteins that contain 2 or more polypeptide chains (ex. hemoglobin has 4 polypeptides with an iron atom in each center)

If a protein changes shape and can no longer function, it is

denatured

Enzymes must keep their shape

to perform their functions

Temperature (human body temp = 37C)

- too hot can permanently denature a protein
- too cold can slow down function protein, but is usually reversible

Changes in pH

- proteins usually have an optimum pH where it functions best

Salts

- ions/charges attract parts of the protein, pulling it out of shape

Denaturing

- primary sequence is not affected by denaturing
- peptide bonds don't break

Functions of proteins are determined by their

shape; form = function

Enzymes (organic catalysts)

- start and speed up chemical reactions
- not used up in reaction
- recycled and used over and over again
- each reaction requires a different enzyme

Motor/contractile proteins

Muscle (actin & myosin), movement of cilia & flagella

Immune defense

Antibodies are special proteins made by white blood cells that inactivate and destroy viruses and bacteria - specific for specific pathogens

Transport proteins

Carry molecules into or out of cell membrane or throughout the body (ex. hemoglobin is the protein in red blood cells that carry oxygen to all cells)

Structural proteins

collagen (skin, wounds, tendons), keratin (hair, nails)

Storage proteins

not for energy to burn (ex. casein, protein of milk, is major source of amino acids for baby mammals)

Hormones/signaling (chemical messengers)

allows coordination of an organism's activity
- insulin regulates sugar in bloodstream
- receptors built into membrane of all cells which detect signaling molecules released by other cells (neurotransmitters, hormones)

Nucleic acids

- contain carbon, hydrogen, oxygen, nitrogen, phosphorus
- blueprints for proteins

Monomer of nucleic acid is

nucleotide

DNA (deoxyribonucleic acid)

- universal genetic code for all living things (all physically traits and metabolic functions)
- codes for sequence of amino acids (proteins)
- EVERYTHING (even prokaryotes) have DNA

Gene

a specific order of nucleotides which codes for a specific order of amino acids, found on physical structures (chromosomes)

Genome

all of the genes that make up an organism

Every 3 nucleotides (CODON) code for

1 amino acid