biology chapter 1 Flashcards
metabolism
the sum of all chemical reactions that occur in the body
catabolic reactions
break down large chemicals and release energy
anabolic reactions
which build up large chemicals and require energy
ingestion
the acquisition of food and other raw materials
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
absorption
the passage of nutrient molecules through the living of the digestive tract into the body proper
transport
the circulation of essential compounds required to nourish the tissues, and the removal of waste products from the tissue
assimilation
the building up of new tissues from digested food materials
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
excretion
the removal of waste products (such as carbon dioxide, water, and urea) produced during metabolic processes like respiration and assimilation
synthesis
the creation of complex molecules from simple ones (anabolism)
regulation
the control of physiological activies
homeostasis
the body’s metabolism functions to maintain its internal environment in a changing external environment
irritability
is the ability to respond to a stimulus and is part of regulation
growth
an increase in size due to synthesis of new materials
photosynthesis
the process by which plants convert CO2 and H2O into carbohydrates. Sunlight is harnessed by chlorophyll to drive this reaction
reproduction
the generation of additional individuals of a species
protoplasm
the substance of life
atoms
are joined by chemical bonds to form compounds
inorganic compounds
are compounds that do not contain the element carbon including salts and HCl
organic compounds
are made by living systems and contain carbon. They include carbohydrates, lipids, proteins, and nucleic acids
carbohydrates
are composed of the elements carbon, hydrogen, and oxygen in a 1:2:1 ratio, respectively
monosaccharide
like glucose and fructose are single sugar subunits
disaccharide
like maltose and sucrose are composed of two monosaccharide subunits joined by dehydration synthesis which involves loss of a water molecule
polysaccharide
are polymers or chaings of repeating monosaccharide subunits. Examples are glycogen and starch
hydrolysis
by adding water lage polymers can be broken down into smaller subunits
triglyceride
consists of 3 ftty acid molecules bonded to a single glycerol backbone
lipids
are the chief means of food storage in animals
phospholipids
contain glycerol, two fatty acids, a phosphate group, and nitrogen containing alcohol and cephalin
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
steroids
have three cyclohexane rings and one fused cyclopentane ring. They include cholesterol, the sex hormones, and corticosteroids
carotenoids
these are fatty acid like carbon chains containing conjugated double bonds and carrying six membered carbon rings at each end
porphyrins
also called tetrapyrroles, contain four joined pyrrole rings. They are often complexed with a metal
proteins
are composed primarily of the elements C, H, O, and N but may also contain phosphorus (P) and sulfur (S)
amino acids
are joined by peptide bonds through dehydration reactions
polypeptide
chains of peptide bonds produce a polymer called a polypeptide, or simply peptide
primary structure
the sequence of amino acids in a protein
secondary structure
proteins that form a coil or fold to form helices and beta pleated sheets
simple proteins
these are composed entirely of amino acids
albumins and globins
these are primarily globular in nature. They are functional proteins that act as carriers or enzymes
scleroproteins
these are fibrous in nature and act as structural proteins. Collagen is a scleroprotein
conjugated proteins
these contain a simple protein portion, plus at least one nonprotein fraction
lipoproteins
protein bound to lipid
glycoproteins
protein bound to carbohydrate
chromoproteins
protein bound to pigmented molecules
metalloproteins
protein complexed around a metal ion
nucleoproteins
proteins associated with nucleic acids
hormones
these are proteins that function as chemical messenger secreted into the circulation. Insulin, and ACTH are protein hormones
enzymes
these are biological catalysts that act by increasing the rate of chemical reactions important for biological functions. For example: amylase, lipase, ATPase
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)
transport proteins
these are carriers of important materials. For example, hemoglobin carries oxygen in the circulation and the cytochromes carry electrons during cellular respiration
antibodies
these bind to foreign particles (antigens) including disease causing organisms, that have entered the body
catalyst
is any substance which affects the rate of a chemical reaction without itself being changed
enzyme specificity
are very selective; they may catalyze only one reaction, or one specific class of closely related reactions
substrate
the molecule upon which an enzyme acts
active site
the area on each enzyme to which the substrate binds
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
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
enzyme reversibility
most enzyme reactions are reversible. the product synthesized by an enzyme can be decomposed by the same enzyme.
enzyme action
enzyme action and the reaction rate depend on several environmental factors including temperature, pH, and the concentration of enzyme and substrate
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
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
pepsin
which works best in the highly acidic conditions of the stomach (pH=2)
pancreatic enzymes
which work optimally in the alkaline conditions of the small intestine (pH= 8.5)
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
hydrolysis
hydrolysis reactions function to digest large molecules into smaller components
lactase
hydrolyzes lactose to the monosaccharides glucose and galactose
proteases
degrade proteins to amino acids
lipases
break down lipids to fatty acids and glycerol
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
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
prosthetic groups
cofactors which bind to the enzyme by strong and sometimes covalent bonds
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
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
microscopy
of the most tool used by scientists to study cells, the microscope is the most basic
magnification
is the increase in apparent size of an object
resolution
is the difference of two closely situated objects
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
total magnification
equals magnification of eyepiece x magnification of objective
diaphragm
controls the amount of light passing through the specimen
coarse adjustment
knob roughly focuses the image
fine adjustment
knob sharply focuses the image
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
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
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
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
cell membrane
encloses the cell and exhibits selective permeability; it regulates the passage of materials into and out of the cell
fluid mosaic model
the cell membrane consists of a phospholipid bilayer with proteins embedded throughout
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
nucleolus
is a dense structure in the nucleus where ribosomal RNA (rRNA) synthesis occurs
ribosome
are the sites of protein production and are synthesized by the nucleolus
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
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
mitochondria
are the sites of aerobic respiration within the cell and hence the suppliers of energy
cytoplasm
most of the cells metabolic activity occurs in the cytoplasm
cyclosis
transport within the cytoplasm. Streaming movement within the cell
vacuole
are membrane bound sacs involved in the transport and storage of materials that are ingested, secreted, processed, or digested by the cell
centrioles
are involved in spindle organization during cell division and are not bound by a membrane
lysosomes
are membrane bound vesicles that contain hydrolytic enzymes involved in intracellular digestion. Break down material ingested by the cell
cytoskeleton
supports the cell, maintains its shape, and functions in cell motility
tubulin
hollow rods which radiate throughout the cell and provide it with support
microtubules
provide a framework for organelle movement within the cell
microfilaments
move materials across the plasma membrane, for instance, in the contraction phase of cell diivision, and in amoeboid movement
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
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
osmosis
is the simple diffusion of water from a region of lower solute concentration to a region of higher solute concentration
hypertonic
when the cytoplasm of a cell has a lower solute concentration than the extracellular medium and water will flow out of the cell
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
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
active transport
is the net movement of particles against their concentration gradient with the help of transport protein. Requires energy
endocytosis
is a process in which the cell membrane invaginates, forming a vesicle that contains extracellular medium
pinocytosis
is the ingestion of fluids or small particles
phagocytosis
is the engulfing of large particles
exocytosis
a vesicle within the cell fuses with the cell membrane and releases its contents to the outside
circulation
is the transportation of material within cells and throughout the body of a multicellular organism
brownian movement
the movement of particles due to kinetic energy which spreads small suspended particles througout the cytoplasm of the cell
cyclosis
the circular motion of the cytoplasm around the cell transport molecules
endoplasmic reticulum
this provides channels throughout the cytoplasm, and provides a direct continuous passageway from the plasma membrane to the nuclear membrane
