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116 terms

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