Introductory Chemistry and Cytology Flashcards
Why is it important to understand chemistry when learning about the human body?
Everything we eat
and drink play vital roles in the body on a molecular level; the body is composed of chemicals and all
body activities are chemical in nature; all living things are composed of chemicals
Chemistry
The science of the structure and interactions of matter
Matter
anything that occupies space and has mass
Mass
the amount of matter in any living organism or nonliving thing
Chemical Elements
(112) building blocks that make up all forms of matter; cannot be broken down
into a simpler form by ordinary chemical means
Chemical Symbol
one or two letters of an element’s name that designate the element
Elements in the body
26 different elements are normally present in the body
Major elements
constitute about 96% of the body’s mass; oxygen, carbon, hydrogen, and
nitrogen
lesser elements
constitute about 3.6% of the body’s mass; calcium, phosphorus, potassium,
sulfur, sodium, chlorine, magnesium, and iron
Trace elements
constitute about 0.4% of the body’s mass; aluminum, boron, chromium, cobalt,
copper, fluorine, iodine, manganese, molybdenum, selenium, silicon, tin, vanadium, and zinc
Atom
the smallest unit of matter that makes up each element and retains the properties and
characteristics of the element; consists of a nucleus (positively charged) and one or more electrons
Electrons
tiny, negatively charged particles that move about in a large space surrounding the
nucleus
the number of electrons in an atom
equals the number of protons which results in a neutral or uncharged atom
ion
when an atom loses or gains electrons
an atom with a positive or negative charge because the protons and electrons are unequal
Molecules
when two or more atoms share electrons, they form a molecule (may
contain one or more different elements)
Compound
is a substance containing atoms of two or more different elements
free radical
is an ion or molecule that has an unpaired electron in its outermost shell
(unstable and destructive)
Chemical reactions
when new bonds form and/or old bonds break between atoms
Synthesis Reactions
when two or more atoms, ions, or molecules combine to form new and larger molecules; in the body, synthesis reactions are collectively referred to as anabolism
Decomposition Reactions
when a molecule is split apart; in the body, decomposition reactions
are collectively referred to as catabolism
Metabolism
the sum of all the chemical reactions in the body (anabolism + catabolism)
Inorganic Compounds
do not contain carbon
Organic Compounds
always contain carbon
Water
most important and abundant inorganic compound in all living systems; makes up 55-60% of body mass in lean adults
Excellent Solvent
carries nutrients, oxygen, and wastes throughout the body
Solvent
liquid or gas in which a solute has been dissolved
Solute
a material that is dissolved in a solvent
Solution
combination of solvent plus solute
Concentration
the amount of solute in a solution
Concentration gradient
– a difference in concentration between two different areas; solutes moving from a high-concentration area to a low-concentration area are said to
move down or with the concentration gradient; the opposite is moving up or against the
concentration gradient
Acid
substance that breaks apart or dissociates into one or more hydrogen ions when it dissolves in water
Base
usually dissociates into one or more hydroxide ions when it dissolves in water
Acid-base balance
to ensure homeostasis, body fluids must contain almost balanced quantities of acids
and bases
Acidity
is expressed on the pH scale (0-14) based on the number of
hydrogen ions in a solution; more hydrogen ions is acidic (pH below 7); less hydrogen ions is alkaline (pH above 7); the pH of various body fluids differ, but are very specific
Buffers
chemical compounds that act quickly to temporarily bind hydrogen ions, removing them from the solution but not from the body
Enzymes
speed up chemical reactions by increasing the frequency of collisions and orientation of
colliding molecules; mostly proteins; usually end in “–ase”; important properties of enzymes:
Specificity
each particular enzyme catalyzes a particular chemical reaction that involves
specific substrates
Efficiency
a single enzyme molecule can convert substrate molecules to product molecules at
rates as high as 600,000 per second
Control
the rate of synthesis and concentration of enzymes are controlled by the cells
Nucleic acids
– huge organic molecules in the nuclei of cells; composed of repeating building blocks
called nucleotides; 2 kinds of nucleic acids
DNA
Deoxyribonucleic Acid; comprises genes and is composed of a double-stranded double
helix
RNA
Ribonucleic Acid; copied from DNA but is single-stranded and carries out instructions
from the DNA
Adenosine triphosphate ( ATP)
-“energy currency” of living organism ; transfers energy from energyreleasing
reactions to energy-requiring reactions that maintain cellular activities; when a phosphate is
released from ATP during a chemical reaction, energy is released and adenosine diphosphate (ADP)
remains; as energy is required, ATP synthase promotes the addition of a phosphate to the ADP, resulting
in more ATP
Cell biology/ cytology
the study of cellular structure and function; about 200 different types of cells compose
your body; a cell is a living structural and functional unit
3 main parts of a cell
Plasma membrane
cytoplasm
nucleus
Plasma Membrane
flexible outer surface of the cell; separates internal from external
environment and regulates the flow of materials into and out of the cell
flexible and sturdy; consists mostly of lipids and proteins
lipid bilayer
Cytoplasms
all the cellular contents between the plasma membrane and the nucleus; contains
cytosol and organelles
Cytosol
the liquid portion of cytoplasm; mostly water plus dissolved solutes and
suspended particles; intracellular fluid
Organelles
within the cytosol; different characteristic structures and functions
Nucleus
the largest organelle of a cell; acts as the control center for a cell; contains the genes
Lipid bilayer
two back-to-back layers made up of three types of lipid molecules:
phospholipids, cholesterol, glycolipids
Integral proteins
extend into or through the lipid bilayer forming ion channels
Peripheral proteins
loosely attached to the exterior or interior surface of the membrane
Selective permeability
allows some substances to move into and out of the cell but restricts the
passage of other substances; permeable to water and to lipid-soluble molecules (fatty acids, fat-
soluble vitamins, steroids, oxygen, and carbon dioxide); not permeable to ions and large,
uncharged polar molecules (glucose and amino acids)
Ions channels
formed by integral proteins that assist small and medium-sized water-soluble
materials to cross the membrane
Carriers ( transporters)
change shape as they move a substance from one side of the membrane
to the other
Receptors
recognize and bind a specific molecule that governs some cellular function
Enzymes
some integral proteins; speed up specific chemical reactions
Cell identity makers
enable a cell to recognize other cells of its own kind during tissue
formation, or to recognize and respond to potentially dangerous foreign cells
Intracellular fluid
fluid contained inside body cells; 2/3 of the fluid in your body
Extracellular fluid
fluid outside body cells; for example: interstitial fluid (in the microscopic spaces
between the cells of tissues), plasma (in blood vessels), lymph (in lymphatic vessels), cerebrospinal fluid
(within and around the brain and spinal cord)
Passive Processes
a substance moves down into concentration gradient through the membrane using
only its own energy of motion
Osmosis
a passive process in which there is a net movement of water through a selectively
permeable membrane from higher water concentration to lower water concentration, or from
lower solute concentration to higher solute concentration
Osmotic pressure
pressure exerted on the membrane by a solution containing solute
particles that cannot pass through the membrane; the higher the solute concentration, the
higher the solution’s osmotic pressure
Diffusion
a passive process in which a substance moves due to its kinetic energy
Active processes
cellular energy, usually ATP, is used to push the substance through the membrane uphill against its concentration gradient
Active transport
an active process in which cellular energy is used to transport substances
across the membrane against a concentration gradient
Pump
a carrier protein whose shape has been changed by energy derived from ATP;
Sodium-potassium pump
the most important active transport pump; expels sodium ions from cells and brings in potassium ions; acts as an enzyme to split
ATP; all cells have thousands in their membranes; because Na and K leak through
the membrane, the pumps must be going continually against the gradient;
necessary for the ability of some cells to generate electrical signals such as action
potentials
Vesicle
– a small round sac formed by budding off from an existing membrane; transport
substances from one structure to another within cells, take in substances from extracellular fluid,
and release substances into extracellular fluid; movement of vesicles requires energy supplied by
ATP
Cytoplasms
consists of all of the cellular contents between the plasma membrane and the nucleus and
includes both cytosol and organelles
Cytosol
the liquid portion of the cytoplasm that surrounds organelles and accounts for about
55% of the total cell volume
Microvilli
fingerlike projections of the plasma membrane that increase the surface area of the cell for absorption; may help some cells attach to one another or to extracellular materials
Organelles
specialized structures inside cells that have characteristic shapes and specific
functions
Cilia and flagella
motile projections of the cell surface
Cilia
numerous, short, hair-like projections that extend from the surface of the cell to
move fluid and particles over the surface of the cell
Flagella
similar to cilia but much longer; usually move an entire cell; sperm cell
Ribosomes
the sites of protein synthesis; high concentration of RNA; synthesize proteins
destined for specific organelles, for insertion in the plasma membrane, for export from the cell,
proteins used in the cytosol, or mitochondrial proteins depending on the location of the ribosome
Endoplasmic reticulum
a network of folded membranes in the form of flattened sacs or tubules;
extends throughout the cytoplasm; 2 types of endoplasmic reticulum:
rough
smooth
rough ER
covered with ribosomes; factory for synthesizing secretory proteins and
membrane molecules
Smooth ER
lack of ribosomes; where fatty acids and steroids are synthesized; different
roles in different types of cells
Mitchondria
“powerhouse of the cell”; site of most ATP production; a cell may have as few
as 100 or as many as several thousand mitochondria
Nucleus
a spherical or oval structure that usually is the most prominent feature of a cell; most cells
have a single nucleus, some have none, some have several
Cell division
the process whereby cells reproduce themselves; 2 types:
reproductive cell division
somatic cell division
Reproductive cell division (meiosis)
the process that produces gametes (sperm and oocytes)
Somatic cell division
all other body cells (besides gamates) are somatic cells and divide into
two identical cells during cell division; DNA is replicated so that the two cells are genetically identical
Cellular diversity
the body of an average human adult is composed of nearly 100 trillion cells that vary
in size and shape; may be round, oval, flat, cube-shaped, column-shaped, elongated, star-shaped,
cylindrical, or disc-shaped depending on their function in the body
Aging
a normal process accompanied by a progressive alteration of the body’s homeostatic adaptive
responses; many normal cells divide a certain number of times, then stop
Telomeres
specific DNA sequences found only at the tips of each chromosome; protect the tips of
chromosomes from erosion and from sticking to one another; each cycle of cell division shortens them
and eventually they are completely gone – contributes greatly to aging and death of cells
Atrophy
a decrease in the size of cells with subsequent decrease in the size of the affected tissue or organ; wasting away
Dysplasia
alteration in the size, shape, and organization of cells due to chronic irritation or inflammation
Hyperplasia
increase in the number of cells of a tissue due to an increase in the frequency of cell
division
Hypertrophy
increase in the size of cells in a tissue without cell division
Metaplasia
the transformation of one type of cell into another
Necrosis
a pathological type of cell death, resulting from tissue injury
Local disease
one that affects one part or a limited area of the body
Systemic disease
one that affects the entire body or several parts
Epidemiology
the science that deals with why, when, and where diseases occur and how they are
transmitted within a defined human population
Geriatrics
the science that deals with the medical problems and care of elderly persons
Pathology
The science that deals with the nature, causes, and development of abnormal conditions and the structural and functional changes that diseases produce
