bsc 197

Scientific Method

Observation, Hypothesis, Prediction, Experiment, Theory

What is the scientific method used for?

It's an attempt to falsify your hypothesis

Theory

Backed up by substantial amount of evidence, well-tested comprehensive explanation for how something works

Law

Process that can be explained by mathematical equations

Three domains of organisms

Backteria, Archaea, Eukarya

Archea

ancient bacteria- extremophiles

Backteria

Eubacteria - true bacteria

Eukarya

plants, animals, fungi, protists

Prokaryote

Dont have a nucleus and derive from existing cells

Eukaryote

true cells that have a nucleus and drive from existing cells

Law of Thermodynamics

Energy cannot be created or destroyed, only transformed.

Entropy/Disorder increases

Most important elements for life

Carbon(6- 4V), Oxygen(8- 6V), Hydrogen(1- 1V), Nitrogen(7- 5V). Held by covalent bonds.

Atomic Structure

Electron on outer shell, neutron and proton in center, nuclei.

Atomic mass

The average mass of all the isotopes of an element

Atomic number

the number of protons in the nucleus of an atom

electron configuration- oxygen

1s2 2s2 2p4

electron configuration- hydrogen

1s1

electron configuration- carbon

1s2 2s2 2p2

electron configuration- nitrogen

1s2 2s2 2p3

Purpose of chemical bonding

Takes place to allow filling valence shells. Active elements don't have full outer shells and Stable elements do

Covalent bond

A chemical bond that involves sharing a pair of electrons between atoms in a molecule

Ionic Bond

Formed when one or more electrons are transferred from one atom to another

polar covalent bond

A covalent bond in which electrons are not shared equally. Electronegative forces are unequal

Ex of polar covalent bond

Nitrogen to hydrogen

Sulfur to hydrogen

Oxygen to hydrogen

Hydrogen bond

weak attraction between a hydrogen atom and another atom that are made and broken easily. One molecule can make bonds with 4 hydrogen bonds

Biological activity is determined how

by its 3d shape

Cohesion

water molecules bond together and allow surface tension. Allows capillary flow

Adhesion

Water molecules bond to other surfaces allowing it to cling to vertical surfaces

Evaporation of water

Most active molecule becomes vapor leaving the less active. Results in cooling surfaces

Freezing of water

Hydrogen bonds form a lattice structure and decreases its density by 10%.

It floats because it expands and is lighter

Hydrophobic

"water-fearing"; will not dissolve in water (oil, polystyrene). Nonpolar

Hydrophilic

water loving, molecules that are able to dissolve in water (sugar, cotton) Polar/ion

How does water act as a solvent

It dissolves substances with ionic or polar properties by interaction with charged regions

Dissociation

Molecules randomly dissociate into OH- and H+

What does amount of H+ in water determine

Acidity

Buffers

weak acids or bases that can react with strong acids or bases to prevent sharp, sudden changes in pH. Keeps it in neutral.

organic molecules

molecules that have a carbon base

carbon based molecules are diverse because

they vary in chain length, chain branching, double or triple bonds position, and chain vs ring configuration. They make 4 bonds making them versatile

What carbon-based molecules (biological macromolecules) are all organisms made up of

Carbohydrates, lipids, proteins, and nucleic acid

Polymerization

Covalent bonds. relatively small molecules, called monomers, combine chemically to produce a very large chainlike or network molecule, called a polymer.

Dehydration

how polymerization takes placed by produces a water molecule from bonding of OH and H

Hydrolysis

the reverse of dehydration synthesis. Addition of water

Carbohydrate functions

Short term energy storage, simple sugars, and its structural components are chitin and cellulose.

Polymer of sugars

Monosaccharides

Simple sugars (monomers) existing in chains of CxHx2Ox.

Disaccharide

2 monosaccharides formed by dehydration with a glycosidic linkage

Sugars are classified by

of carbon in chain, location of carbonyl group, and position of side groups.

Starches vs Glycogen

plants use starch for energy storage

animals use glycogen as 1 days worth of energy storage

Celluose

most abundant organic compound. Plants use for their cell walls and animals cant digest so it is a cleansing mechanism

Cellulose vs Strach chains

cellulose = straight chain bonds

starch = curved

What indicates carbohydrate

-ose ending or sacch root

Lipids molecule structure

Found as fatty-acids with a carboxyl at one end of a carbon hydrogen chain

Saturated fats

Each carbon is bound to the max # of hydrogen atoms (except carboxyl) it is linear and able to pack tightly making it solid at room temp

Animals

Unsaturated fats

Contains more carbon-carbon double bonds. Has angles making it not pack tightly and liquid at room temp

Plants

Lipid functions

• long term energy storage

Lipid structure in general

3 fatty acid chains bound to glycerol backbone (triaclyglcerol)

Formed by dehydration reaction and bound to glycerol through ester linkage

NOT A POLYMER

Hormones

part of lipids derived from cholesterol molecule. Complicated ring structure & essential for homeostasis

Nucleotides

Monomer used to assemble nucleic acids & comprised of a pentose sugar, nitrogen containing base, and an organic phosphate group

function of nucleic acids

-Deoxyribonucleic acid & ribonucleic acid.

-Store cellular info.

-largest & complex

-template for protein

-control regulation of cellular function

deoxyribose vs ribose- tell the difference

Deoxyribose lacks an oxygen molecule when being compared to Ribose meaning it is missing an alcohol bond between one of the carbon molecules.

Two kinds of bases

pyrimidines and purines

Pyrimidines

Cytosine and Thymine (uracil- RNA) have a single ring structure

Purines

Adenine and Guanine. have a double ring structure

DNA interactions

G-C = 3 hydrogen bonds

A-T = 2 hydrogen bonds

High temperature of DNA

high content G-C causing it to be difficult to break

Structure of DNA

phosphate group is attached to carbon 5 of pentose.

Phosphodiester bond in DNA

bond from oxygen of phosphate to OH group of carbon 3 on the pentose

Strands of DNA have

have a 5' end and 3' end

(5' is 1st phosphate group not linked)

(3' is last hydroxyl not linked)

DNA vs RNA functions

-both important in cell function.

-DNA is double stranded and longer lived = opposite of RNA

-both can serve as template for synthesis

Transcription and Reverse Transcription

DNA - RNA

RNA - DNA

Double helix

antiparallel strand 5' to 3'.

Base pairs by hydrogen bonding between nitrogenous bases

sugar phosphate backbone

Scientists who described the DNA from who's experiments

Elucidated by Watson and Crick. Performed by Wilkens and Franklin

Central Dogma

DNA -> RNA -> Protein

Functions of Proteins

transport hemoglobin, stores casein and ovalbumin, not good at info storage, performs most functions

Protein structure

polymer of amino acids. 20 natural amino acids each with different R groups

Has high levels of sequence variation

R groups of proteins

H/CH - nonpolar because of weak charges and hate water

OH/NH - polar and love water