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1

metabolism

the sum of all chemical reactions that occur in the body

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catabolic reactions

break down large chemicals and release energy

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anabolic reactions

which build up large chemicals and require energy

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ingestion

the acquisition of food and other raw materials

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digestion

the process of converting food into a usable soluble form so that it can pass through membranes in the digestive tract and enter the body

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absorption

the passage of nutrient molecules through the living of the digestive tract into the body proper

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transport

the circulation of essential compounds required to nourish the tissues, and the removal of waste products from the tissue

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assimilation

the building up of new tissues from digested food materials

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respiration

the consumption of oxygen and glucose by the body. Cells use oxygen to convert glucose to ATP, a ready source of energy for cellular activities

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excretion

the removal of waste products (such as carbon dioxide, water, and urea) produced during metabolic processes like respiration and assimilation

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synthesis

the creation of complex molecules from simple ones (anabolism)

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regulation

the control of physiological activies

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homeostasis

the body's metabolism functions to maintain its internal environment in a changing external environment

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irritability

is the ability to respond to a stimulus and is part of regulation

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growth

an increase in size due to synthesis of new materials

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photosynthesis

the process by which plants convert CO2 and H2O into carbohydrates. Sunlight is harnessed by chlorophyll to drive this reaction

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reproduction

the generation of additional individuals of a species

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protoplasm

the substance of life

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atoms

are joined by chemical bonds to form compounds

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inorganic compounds

are compounds that do not contain the element carbon including salts and HCl

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organic compounds

are made by living systems and contain carbon. They include carbohydrates, lipids, proteins, and nucleic acids

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carbohydrates

are composed of the elements carbon, hydrogen, and oxygen in a 1:2:1 ratio, respectively

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monosaccharide

like glucose and fructose are single sugar subunits

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disaccharide

like maltose and sucrose are composed of two monosaccharide subunits joined by dehydration synthesis which involves loss of a water molecule

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polysaccharide

are polymers or chaings of repeating monosaccharide subunits. Examples are glycogen and starch

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hydrolysis

by adding water lage polymers can be broken down into smaller subunits

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triglyceride

consists of 3 ftty acid molecules bonded to a single glycerol backbone

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lipids

are the chief means of food storage in animals

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phospholipids

contain glycerol, two fatty acids, a phosphate group, and nitrogen containing alcohol and cephalin

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waxes

are esters of fatty acids and monohydroxylic alcohols. They are found as protective coatings on skin, fur, leaves of higher plants, and on the exoskeleton of many insects

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steroids

have three cyclohexane rings and one fused cyclopentane ring. They include cholesterol, the sex hormones, and corticosteroids

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carotenoids

these are fatty acid like carbon chains containing conjugated double bonds and carrying six membered carbon rings at each end

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porphyrins

also called tetrapyrroles, contain four joined pyrrole rings. They are often complexed with a metal

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proteins

are composed primarily of the elements C, H, O, and N but may also contain phosphorus (P) and sulfur (S)

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amino acids

are joined by peptide bonds through dehydration reactions

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polypeptide

chains of peptide bonds produce a polymer called a polypeptide, or simply peptide

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primary structure

the sequence of amino acids in a protein

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secondary structure

proteins that form a coil or fold to form helices and beta pleated sheets

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simple proteins

these are composed entirely of amino acids

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albumins and globins

these are primarily globular in nature. They are functional proteins that act as carriers or enzymes

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scleroproteins

these are fibrous in nature and act as structural proteins. Collagen is a scleroprotein

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conjugated proteins

these contain a simple protein portion, plus at least one nonprotein fraction

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lipoproteins

protein bound to lipid

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glycoproteins

protein bound to carbohydrate

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chromoproteins

protein bound to pigmented molecules

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metalloproteins

protein complexed around a metal ion

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nucleoproteins

proteins associated with nucleic acids

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hormones

these are proteins that function as chemical messenger secreted into the circulation. Insulin, and ACTH are protein hormones

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enzymes

these are biological catalysts that act by increasing the rate of chemical reactions important for biological functions. For example: amylase, lipase, ATPase

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structural proteins

these contribute to the physical support of a cell or tissue. They may be extracellular (eg collagen in cartilage, bone, and tendons) or intracellular (eg proteins in cell membranes)

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transport proteins

these are carriers of important materials. For example, hemoglobin carries oxygen in the circulation and the cytochromes carry electrons during cellular respiration

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antibodies

these bind to foreign particles (antigens) including disease causing organisms, that have entered the body

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catalyst

is any substance which affects the rate of a chemical reaction without itself being changed

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enzyme specificity

are very selective; they may catalyze only one reaction, or one specific class of closely related reactions

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substrate

the molecule upon which an enzyme acts

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active site

the area on each enzyme to which the substrate binds

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lock and key theory

this theory hold that the spatial structure of an enzyme's active site is complementary to the spatial structure of its substrate

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induced fit theory

describes the active site as having flexibility of shape. When the appropriate substrate comes in contact with the active site, the conformation of the active site changes to fit the substrate

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enzyme reversibility

most enzyme reactions are reversible. the product synthesized by an enzyme can be decomposed by the same enzyme.

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enzyme action

enzyme action and the reaction rate depend on several environmental factors including temperature, pH, and the concentration of enzyme and substrate

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effects of temperature

as the temperature increases, the rate of enzyme action increases, until an optimum temperature is reached. Beyond optimal temperature, heat alters the shape of the active site of the enzyme molecule and deactivates it, leading to a rapid drop in rate

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effects of pH

for each enzyme there is an optimal pH above and below which enzymatic activity declines. Maximal activity of many human enzymes occur around pH 7.2, which is the pH of most body fluids

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pepsin

which works best in the highly acidic conditions of the stomach (pH=2)

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pancreatic enzymes

which work optimally in the alkaline conditions of the small intestine (pH= 8.5)

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effects of concentration

the concentrations of substrate and enzyme greatly affect the reaction rate. When the concentrations of both enzyme and substrate are low, many of the active sites on the enzyme are unoccupied and the reaction rate is low

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hydrolysis

hydrolysis reactions function to digest large molecules into smaller components

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lactase

hydrolyzes lactose to the monosaccharides glucose and galactose

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proteases

degrade proteins to amino acids

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lipases

break down lipids to fatty acids and glycerol

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synthesis

(include dehydrations) can be catalyzed by the same enzymes as hydrolysis reactions, but the directions of the reactions are reversed. Is required for growth, repair, regulation, protection and production of food reserves such as fat and glycogen, by the cell

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cofactors

many enzymes require the incorporation of a nonprotein molecule to become active. Can be metal cations like Zn2+ or Fe2+, or small organic groups called coenzymes

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prosthetic groups

cofactors which bind to the enzyme by strong and sometimes covalent bonds

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nucleic acids

contain the elements C, H, O, N, and P. they are polymers of subunits called nucleotides. Nucleic acids code all of the information required by an organism to produce proteins and replicate

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cell theory

1) all living things are composed of cells. 2) the cell is the basic functional unit of life. 3) cells arise only from pre-existing cells. 4) cells carry genetic information in the form of DNA. This genetic material is passed from parent cell to daughter cell

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microscopy

of the most tool used by scientists to study cells, the microscope is the most basic

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magnification

is the increase in apparent size of an object

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resolution

is the difference of two closely situated objects

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compound light microscope

uses two lenses or lens systems to magnify an object. The total magnification is the product of the magnification of the eyepiece and the magnification of the object

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total magnification

equals magnification of eyepiece x magnification of objective

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diaphragm

controls the amount of light passing through the specimen

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coarse adjustment

knob roughly focuses the image

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fine adjustment

knob sharply focuses the image

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phase contrast microscopy

is a special type of light microscope that permits the study of living cells. Differences in refractive index are used to produce contrast between cellular structures

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electron microscopy

uses a beam of electrons to allow a thousandfold higher magnification than is possible with light microscopy. Unfortunately, examination of living specimens is not possible because of the preparations necessary for electron microscopy; tissues must be fixed and sectioned, and sometimes stained with solutions of heavy metals

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centrifugation

differential centrifugation can be used to separate cells or mixtures of cells without destroying them in the process. Spinning fragmented cells at high speeds in the centrifuge will cause their components to sediment at different levels in the test tube on the basis of their respective densities. denser parts such as nuclei, endoplasmic reticulum, and mitochondria will sink to the bottom

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organelles

the components of the cell are specialized in their structure and function. These include the nucleus, ribosomes, endoplasmic reticulum, golgi apparatus, vesicles, vacuoles, lysosomes, mitochondria, chloroplasts, and centrioles

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cell membrane

encloses the cell and exhibits selective permeability; it regulates the passage of materials into and out of the cell

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fluid mosaic model

the cell membrane consists of a phospholipid bilayer with proteins embedded throughout

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nucleus

controls the activities of the cell, including cell division. It is surrounded by a nuclear membrane. Contains the DNA, which is complexed with structural proteins

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nucleolus

is a dense structure in the nucleus where ribosomal RNA (rRNA) synthesis occurs

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ribosome

are the sites of protein production and are synthesized by the nucleolus

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endoplasmic reticulum

is a network of membrane-enclosed spaces involved in the transport of materials throughout the cell, particularly those materials destined to be secreted by the cell

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golgi apparatus

recieves vesicles and their contents from the smooth ER, modifies them, repackages them into vesicles, and distributes them to the cell surface by exocytosis

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mitochondria

are the sites of aerobic respiration within the cell and hence the suppliers of energy

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cytoplasm

most of the cells metabolic activity occurs in the cytoplasm

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cyclosis

transport within the cytoplasm. Streaming movement within the cell

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vacuole

are membrane bound sacs involved in the transport and storage of materials that are ingested, secreted, processed, or digested by the cell

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centrioles

are involved in spindle organization during cell division and are not bound by a membrane

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lysosomes

are membrane bound vesicles that contain hydrolytic enzymes involved in intracellular digestion. Break down material ingested by the cell

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cytoskeleton

supports the cell, maintains its shape, and functions in cell motility

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tubulin

hollow rods which radiate throughout the cell and provide it with support

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microtubules

provide a framework for organelle movement within the cell

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microfilaments

move materials across the plasma membrane, for instance, in the contraction phase of cell diivision, and in amoeboid movement

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plant cells

have no centrosome, presence of cell wall composed of cellulose, chloroplasts in many cells of green plants. Site of synthesis of organic compounds, no lysosomes, many vacuoles. Mature plant cells usually contain one large vacuole

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simple diffusion

is the net movement of dissolved particles down their concentration gradients-- from a region of higher concentration to a region of lower concentration. A passive process that requires no external source of energy

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osmosis

is the simple diffusion of water from a region of lower solute concentration to a region of higher solute concentration

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hypertonic

when the cytoplasm of a cell has a lower solute concentration than the extracellular medium and water will flow out of the cell

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hypotonic

if the extracellular environment is less concentrated than the cytoplasm of the cell and water will flow into the cell causing it to swell and burst

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facilitated diffusion

(passive transport) is the net movement of dissolved particles down their concentration gradient through special chennels or carrier proteins in the cell membrane. Does not require energy

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active transport

is the net movement of particles against their concentration gradient with the help of transport protein. Requires energy

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endocytosis

is a process in which the cell membrane invaginates, forming a vesicle that contains extracellular medium

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pinocytosis

is the ingestion of fluids or small particles

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phagocytosis

is the engulfing of large particles

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exocytosis

a vesicle within the cell fuses with the cell membrane and releases its contents to the outside

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circulation

is the transportation of material within cells and throughout the body of a multicellular organism

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brownian movement

the movement of particles due to kinetic energy which spreads small suspended particles througout the cytoplasm of the cell

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cyclosis

the circular motion of the cytoplasm around the cell transport molecules

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endoplasmic reticulum

this provides channels throughout the cytoplasm, and provides a direct continuous passageway from the plasma membrane to the nuclear membrane