Chapter 2: Physical, Chemical and Cellular Basis of Life

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Carbohydrate

organic compounds composed of carbon, hydrogen, and oxygen in a ratio of 2H:1O

Protein

organic compounds composed mainly of carbon, hydrogen, oxygen and nitrogen

Amino Acid

the 20 monomer building blocks of proteins

Lipid

fats-large, nonpolar molecules that do not dissolve in water

Nucleic Acid

very large and complex organic molecules that store important information in the cell

Nucleotide

monomers that compose DNA and RNA

Organic Compound

contain carbon bonded to other carbon and to other elements- H, O and N

Carbon Bonding

Carbon bonds with itself, forming straight chains, branched chains or rings

Monomer

a repeated, single-molecule unit- a building block

Polymer

more complex carbon molecules consisting of repeated, linked monomers

Condensation reaction

allows monomers to link together to form polymers- result in a "leftover" OH- and an H+, that bond to form a water molecule

Hydrolysis

results in the breakdown of complex molecules like polymers-a reversal of a condensation reaction- water is added and can break the bonds that hold molecules together

Monosaccharide

a monomer of a carb- also called a simple sugar- contains carbon, hydrogen and oxygen in a ratio of 1:2:1

Isomer

compounds with a single chemical formula but different forms

Disaccharide

a double sugar formed when two monosaccharides combine

Polysaccharide

a complex sugar composed of three or more monosaccharides

Dipeptide

the bonding of two amino acids through a condensation reaction

Polypeptide

a long chain of amino acids bonded together

Fatty acid

unbranched carbon chains that make up most lipids

Hydrophilic

water loving- refers to the carboxyl end of the fatty acid chain that is attracted to water

Hydrophobic

water fearing- refers to the hydrocarbon end of the fatty acid chain that tends not to interact with water molecules

Saturated fatty acid

fatty acids with carbons single bonded to four molecules

Unsaturated fatty acid

fatty acids with carbons double bonded to themselves instead of four individual molecules

Triglyceride

three molecules of fatty acid joined to one molecule of the alcohol glycerol

Phospholipid

composed of two fatty acids joined together by a molecule of glycerol

Lipid bilayer

cell membranes are composed of two layers of phospholipids

DNA

deoxyribonucleic acid- contains information that is essential cell activities-genetic information

RNA

ribonucleic acid- stores and transfers information that is essential for making proteins

Parts of a Nucleotide

a phosphate group, a five-carbon sugar, and a ring-shaped nitrogen base

Microscope

an instrument that produces an enlarged image of an object

Magnification

the apparent increase in an object's size when looking through a microscope

Resolution

the power to show details very clearly

Compound light microscope

uses light to shine through a very thin slice of a specimen.

Electron microscope

a beam of electrons rather than a beam of light produces an enlarged image of the specimen

Transmission electron microscope

transmits a beam of electrons through a thin slice of specimen

Scanning electron microscope

provides 3-D images by scanning the surface of the object with a beam of electrons

Homeostasis

the ability of a cell or organism to regulate its internal conditions despite changes to the environment

pH

the pH of a solution describes whether it is an acid or a base

Acid

if the number of hydronium ions in a solution is greater than the number of hydroxide ions

Base

if the solution contains more hydroxide ions than hydronium ions

Metabolism

the sum total of the body's chemical activities

Diffusion

the simplest type of passive transport-the movement of molecules from an area of higher concentration to an area of lower concentration

Osmosis

passive transport- the process by which water molecules diffuse across a cell membrane from an area of high concentration to an area of low concentration

Facilitated diffusion

passive transport- a process used for molecules that cannot diffuse rapidly across a membrane, even when there is a concentration gradient

Concentration gradient

the difference in the concentration of molecules across a pace

Hypertonic

when the concentration of molecules in solution outside the cell is higher-water diffuses out of the cell to establish equilibrium

Hypotonic

when the concentration of molecules in solution inside the cell is higher-water diffuses into the cell to establish equilibrium

Isotonic

when the concentration of molecules in solution is equal inside and outside the cell

Equilibrium

when the concentration of the molecules of a substance is the same throughout a space

Passive transport

some substances can cross the cell membrane without any input of energy by the cell

Active transport

movement of materials across the cell membrane from an area of lower concentration to an area of higher concentration (i.e. against the concentration gradient)

Dissociation of water

The breaking apart of a water molecule into two ions of opposite charge is called dissociation.
H2O↔ H++OH -

Hydroxide ion

OH-

Hydronium ion

H3O+

pH scale

scale from 0-14: pH of '0' is very acetic, pH of '7' is neutral, pH of '14' is very alkaline

Buffer

a weak acid or base that can react with strong acids or bases to prevent sudden changes in pH -buffers help to resist changes in pH

Autotroph

organisms that obtain their energy by making their own foods (plants)

Heterotroph

organisms that must take in food to meet their energy needs (animals, fungi, bacteria)

Ectotherm

reptiles, fish and amphibians- organisms who warm their bodies by absorbing heat from their surroundings

Endotherm

mammals and birds-organisms who have a rapid metabolism and generate the heat needed to warm the body

Chemical reaction

occurs when one or more chemical substances are converted into new substances

Reactant

compounds or elements in a chemical reaction that are combining or separating. The reactants are located on the left side of a chemical equation

Product

compounds or elements that are the result of a chemical reaction. The products are located on the right side of a chemical equation

Exothermic reaction

chemical reactions that involve a net release of free energy

Endothermic reaction

chemical reactions that involve a net absorption of free energy

Activitation energy

the energy necessary to start a chemical reaction

Free energy

the energy in a system that is available for work

States of matter

determined by the rate at which the atoms or molecules in a substance move
• solid- slow moving
• liquid- medium moving
• gas- fast moving

Energy

the ability to do work or cause change

Catalyst

certain chemical substances that reduce the amount of activation energy that is needed for a chemical reaction

Enzyme

an important class of catalysts that occur in living things

Redox reaction

short for reduction-oxidation reaction- reactions in which electrons are transferred between atoms

Reduction reaction

a reactant gains one or more electrons and becomes more negative in charge

Oxidation reaction

a reactant loses one or more electrons and becomes more positive in charge

Substrate

the reactants being catalyzed by an enzyme

Active site

the location on the enzyme where the substrate binds

Anaerobic respiration

begins with glycolysis, but the absence of oxygen at that point, glycolysis leads to fermentation

ATP-ADP Cycle

The continuous process of forming new ATP from ADP

Glycolysis

the first step in cellular respiration- a biochemical pathway in which one six-carbon molecule is oxidized to produce two three-carbon sugars of pyruvic acid

Cellular Respiration

the complex process in which cells make ATP by breaking down organic compounds producing carbon dioxide and water
C6H12O6 + 6O2 → CO2 + H2O + Energy

Aerobic

requires oxygen

Anaerobic

does not require oxygen

Krebs Cycle

The part of aerobic respiration that produces: six NADH, two FADH2, two ATP and four CO2 molecules

Electron Transport Chain

the high energy electrons from the Kreb's Cycle (in the form of hydrogen) are passed along the ETC to convert ADP to ATP

ATP

adenosine triphosphate- a compound that contains a large amount of energy in its overall structure and provides energy to cell. Composed of adenine (a nucleotide), ribose (a sugar) and three phosphate groups (PO4)

Aerobic respiration

cellular respiration that requires oxygen

Lactic Acid Fermentation

an enzyme converts the pyruvic acid from glycolysis into a compound called lactic acid- produces yogurt, cheese

Alcohol Fermentation

pyruvic acid from glycolysis is broken down by single-celled organisms (yeast) and converted into ethyl alcohol- produces beer, wine and bread

Photosynthesis

Carbon dioxide from the air is combined with water in the presence of sunlight to produce organic compounds (glucose) and oxygen
6CO2 + 6H2O+ Light Energy → C6H12O6 + 6O2

Chlorophyll

the most common pigment, absorbs all wavelengths of light except green

Producers

organisms in an ecosystem that produce food- plants

Consumers

organisms in an ecosystem that consume food- animals, fungi

Chloroplast

the organelle where photosynthesis takes place

Stomata

pores located on the undersides of leaves

Cell

the smallest unit of matter than can carry on the processes of life

Organelle

a cell component that performs specific functions for the cell

Nucleus

contains genetic information; directs activities of the cell; brain of the cell

Cell membrane

surrounds the cell, acts as a barrier between the inside and outside of cell

Semipermeable

the characteristic of the cell membrane that allows certain things to pass through and keeps others out

Cytoplasm

the jelly-like liquid (cytosol) between the cell membrane and the nucleus-contains all organelles

Ribosome

site of protein synthesis

Endoplasmic reticulum

system of membranes and sacs that acts like a highway to move molecules within and between cells

Golgi apparatus

packages substances produced by the cell; the post office of the cell

Mitochondria

makes ATP; the power plant of the cell

Lysosome

digests molecules, old organelles and foreign substances; the trash collector of the cell

Cell Wall

supports and protects the plant; the plant's skeleton

Vacuole

store enzymes, water and wastes

Plastid

storage organelles that can store starches or colors

Eukaryote

organisms whose cells contain a membrane-bound nucleus and other organelles

Prokaryote

unicellular organisms that lack a membrane-bound nucleus and other organelles

Unicellular

organisms that are composed of only one cell

Multicellular

organisms composed of more than one cell

Tissue

groups of cells that carry out specific functions

Organ

several types of tissues that interact to perform a specific function

Organ system

a group of organs that work together to perform a set of related tasks

Cell Theory

1.All living things are composed of cells
2.Cells are the basic units of structure and function in an organism
3.Cells come only from the reproduction of existing cells

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