Biology 137 1st Exam

Taxonomy

discipline of naming and classifying organisms according to certain rules

Kingdom

Fungi, Plantae, Animalia: Protists

Levels and Classification

Phylum

Class

Order

Family

Genus

Species

Domain

most inclusive and most general classification

Prokaryote

unicellular/single-celled, lacks membrane-bound nucleus. Examples include: Domain Archae + Doamin Bacteria/Eubacteria

Eukaryote

membrane-bound nucleus

The Five Fundamental Properties of Life

1) Cellular organization

2) Energy utilization

3) Homeostasis

4) Growth, development, & reproduction

5) Heredity

Levels of Biological Organization

1) Biosphere

2) Ecosystem

3) Community

4) Population

5) Organism

6) Organ System

7) Organ

8) Tissue

9) Cell

10) Molecule

11) Atom

Biosphere

regions of the Earth’s crust. waters, and atmosphere inhabited by living organisms

Ecosystem

a community plus the physical environment (soil, sunlight, water, etc)

Community

interacting population of species in a particular area; *similar organisms that are capable of interbreeding

Molecule

e.g., O2, H2O, CO2, NaCl

Atom

smallest unit of an element; electrons, protons, neutrons

Science aim to understand the world through _________ and ___________.

observation; reasoning

Deductive Reasoning

applies general principles to predict specific results e.g. mammals

Inductive Reasoning

Uses specific observations to construct general; scientific principles e.g.. poodle and terriers.

Observation

must generate testable predictions

Hypothesis

• is tested by experiments

• is either supported or rejected

• if rejected, it can be modified or written anew

Prediction

Supported hypotheses are subjected to replication, additional testing, and being refined with new data

Experiment

Test the hypothesis

Conclusion + Theory

Consists of an experimental treatment and a control group

Experimental group/ treatment

will receive a certain treatment (or have characteristics)

Control group

will be identical to an experimental group except for the independent variable under investigation, i.e. it will not receive a certain treatment

Dependent variable

observed result that is influenced by the experimental variable/ independent variable

Matter

refers to anything that takes up space and mass

Element

substance that cannot be broken down into another substance by ordinary chemical means; each of it is made up of 1 kind of atom

Four elements make up about 96% of the body weight of most living organisms

• Carbon (C)

• Hydrogen (H)

• Oxygen (O)

• Nitrogen (N)

What are subatonic particles?

• Protons

• Electrons

• Neutrons

Protons

positive charge

Electrons

negative charge

Neutrons

no change

Atomic Number

represents the number of protons

Atomic Mass Number

represents the number of protons and neutrons

Shell Model

helps us visualize how electrons populate atoms

The farther an electron is from the nucleus, _______________.

the greater its energy

If atom has two or more shells, the outer shell is most stable when it has ___ electrons.

8

Valence Shell

The outer shell/ energy level in the number of electrons in an atom’s outer shell determines its chemical reactivity

Hydrogen (H)

1 electron

Helium (He)

2 electrons

Nitrogen

7 electrons

Oxidation

loss of an electron

Reduction

gain of an electron

Compound

molecule containing atoms of more than one element.

• H2O, C6H12O6, not O2, N2

Ionic

attraction between opposite changes

Covalent

sharing of one or more pairs of electrons

Chemical bond

an attraction force that arises between two atoms when their electrons interacts; this bond makes molecules out of atoms

Ionic Bonding

• attraction between ions — charged atoms

• charges are formed when atoms transfer their outermost electrons and when atoms receive electrons

Ionic compounds are often called ______.

Salts

Covalent Bonding

sharing of pairs of electrons to complete their valence shells

Electronegativity

• Atom’s affinity for electrons

• dictate how electrons are distributed in colvalent bonds

Nonpolar covalent bonds

equal sharing of electrons

Structural formula

• uses straight lines

• one line indicates one pair of shared electrons

Molecular formula

simply shows number of atoms involved

Polar covalent bond

Atoms do not share electrons equally

Oxygen

8 electrons

____ is more electronegative than hydrogen

Oxygen

3 Important Things About Water

• Life began in water

• Single most important molecules on Earth

• All organisms are 70-80% water

Hydrogen bond

the slightly positive charge of the hydrogen atom in water molecule is attracted to the slightly negative charge of an oxygen atom in a nearby water molecule

Properties of water

• Cohesion vs Adhesion

• High specific heat

• High heat of vaporization

• Solid water less dense than liquid water

Increasing Strength

Hydrogen Bond —> Ionic Bond —> Covalent Bond

pH scale ranges from 0 to 14

• Cells are sensitive to pH changes. Biological systems contain buffers that help keep the pH within a normal range

• The more acidic, the more hydrogen ions

Organic molecules contain

C, H, O, N, P, S

Monomers

chemical subunit

Polymer

monomers joined together

Dehydration reaction

Joins monomers to form polymers; equivalent of removing a water molecule

Hydrolysis Reaction

water is added — whereby H from water attached to one monomer and OH group attached to another monomer; used to break bonds in a polymer

Four General Classes of Biomacromolecules

• Carbohydrates

• Proteins

• Nucleic Acids

• Lipids

Carbohydrates

sugars; mainly used for immediate energy source; may also be used for structural component

Monosaccharide

single—unit sugar; e.g. glucose, galactose

Disaccharide

formed by 2 monosaccharides by dehydration reaction; e.g. sucrose, lactose, maltose

Polysacchride

polymers of monosaccharides; some function as energy storage molecules

• Some function as functional compounds

Plants

store glucose molecules as starch

Animals

store glucose molecules as glycogen

Cellulose

plant cell walls

Chitin

crab, lobster, insect exoskeletons

Proteins

many functions: enzymes, support, transport, defense, regulation, motion and storage

Proteins are composed of ________.

amino acid monomers

Proteins have

hemogoblin, antibody, acting, myosin, hair

Primary Structure

sequence of amino acids polypeptide

Secondary structure

portions of chain form helices or pleated sheets via hydrogen bonds

Tertiary Structure

overall three-dimensional shape of interacting secondary structures; globular shape

Quaternary Structure

more than one polypeptide chain interacting

Nucleic Acids

• DNA, RNA

• Polymers of nucleotide monomers

Nucleotide composed of

1. A phosphate group

2. 5 carbon sugar (pentose sugar)

3. nitrogenous base

Nucleotide ATP

1. adenosine triphosphate

2. primary energy currency of the cell

Nucleotides; NAD+

1. nicotinamide adenine dinucleotide, and FAD, flavin adenine dinucleotide

2. electron carriers for many cellular reactions

Deoxyribonucleic acid, DNA

• double helix

• stores genetic information

• Deoxyribose as sugar

DNA

• A — Adenine

• T — Thymine

• G — Guanine

• C — Cytosine

Ribonucleic acid, RNA

• usually single — stranded

• Helps to make proteins, with the aid of ribosomes

• Ribose as sugar

• E.g., mRNA, rRNA, tRNA

RNA

• A — Adenine

• U — Uracil

• G — Guanine

• C — Cytosine

Lipids

• All are insoluble in water

• Long no polar hydrocarbon chains

Fats and oils

triglycerides

Fats are ______ at room temperature.

solid

Olis are _______ at room temperature.

liquid

Fats and oils are made up of 2 subunit molecules

Glycerol & Fatty Acid

Glycerol

a three—carbon chain that has 3-OH groups

Fatty Acid

a long chain of carbon atoms bonded only to hydrogen, with a carboxyl group at one end

Unsaturated fatty acids

have double bonds in the carbon chain wherever the number of hydrogen is less than two per per carbon atom

Saturated fatty acids

have no double bonds between the carbon atoms

Phospholipids

• One end of the molecule is water-soluble

• Polar phosphate head

• Glycerol