Exam 1 Material Flashcards
biology
the science that studies life.
what are some key characteristics/functions that all organisms share?
-order
-sensitivity
-response to stimuli
-reproduction
-adaptation
-growth & development
-regulation/homeostasis
-energy processing
-evolution
how are multicellular organisms advantaged over single-celled organisms?
their cells can be specialized to perform specific functions, and even sacrificed in certain situations for the good of the organism as a whole.
a positive response
movement toward a stimulus
a negative response
movement away from a stimulus
adaptation
organisms exhibit a “fit” to their environment.
homeostasis
to the relatively stable internal environment required to maintain life.
mutations
random changes in hereditary material over time.
the diversity of life on Earth is a result of what 2 things?
mutations and evolution
atom
the smallest and most fundamental unit of matter that retains the properties of an element.
what does a atom consist of?
consists of a nucleus surrounded by electrons.
what do atoms form?
molecules
molecule
a chemical structure consisting of at least two atoms held together by a chemical bond.
macromolecules
large molecules that are typically formed by combining smaller units called monomers.
organelles
small structures that exist within cells and perform specialized functions.
cell
the smallest fundamental unit of structure and function in living organisms.
prokaryotes
single-celled organisms that lack organelles surrounded by a membrane and do not have nuclei surrounded by nuclear membranes.
eukaryotes
do have membrane-bound organelles and nuclei.
what do cells combine to make?
tissues
tissues
groups of similar cells carrying out the same function.
organs
collections of tissues grouped together based on a common function.
organ system
a higher level of organization that consists of functionally related organs.
organisms
individual living entities.
population
all the individuals of a species living within a specific area.
community
the set of populations inhabiting a particular area.
ecosystem
consists of all the living things in a particular area together with the abiotic, or non-living, parts of that environment such as nitrogen in the soil or rainwater.
biosphere
the collection of all ecosystems, and it represents the zones of life on Earth. It includes land, water, and portions of the atmosphere.
evolution
the process of gradual change during which new species arise from older species.
Carl Linnaeus
first proposed organizing the known species of organisms into a hierarchical taxonomy.
hierarchical taxonomy
In this system, species that are most similar to each other are put together within a grouping known as a genus. Furthermore, similar genera (the plural of genus) are put together within a family. This grouping continues until all organisms are collected together into groups at the highest level.
the taxonomic system from lowest to highest (8 levels)
- species
- genus
- family
- order
- class
- phylum
- kingdom
- domain
what are the 3 domains of life?
the Eukarya, the Archaea, and the Bacteria.
what does the domain Eukarya contain?
organisms that have cells with nuclei. It includes the kingdoms of fungi, plants, animals, and several kingdoms of protists.
what does the domain Archaea contain?
single-celled organisms without nuclei and include many extremophiles that live in harsh environments like hot springs.
what does the Bacteria domain contain?
single-celled organisms without nuclei
are Archaea prokaryotes or eukaryotes?
prokaryotes
are Bacteria prokaryotes or eukaryotes?
prokaryotes
binomial naming system
consist of the genus name (which is capitalized) and the species name (all lower-case). Both names are set in italics when they are printed.
phylogenetic tree
a diagram showing the evolutionary relationships among biological species based on similarities and differences in genetic or physical traits or both.
bioethics
an important and continually evolving field, in which researchers collaborate with other thinkers and organizations. They work to define guidelines for current practice, and also continually consider new developments and emerging technologies in order to form answers for the years and decades to come.
science
knowledge about the natural world.
what happened in the Tuskegee study?
399 African American men were diagnosed with syphilis but were never informed that they had the disease, leaving them to live with and pass on the illness to others. Doctors even withheld proven medications because the goal of the study was to understand the impact of untreated syphilis on Black men.
what can science not investigate?
things as answering purely moral questions, aesthetic questions, or what can be generally categorized as spiritual questions.
scientific method
a method of research with defined steps that include experiments and careful observation.
hypothesis
a suggested explanation for an event, which can be tested.
scientific theory
generally accepted scientific theory is thoroughly tested and confirmed explanation for a set of observations or phenomena.
scientific laws
often expressed in mathematical formulas, which describe how elements of nature will behave under certain specific conditions.
natural sciences
those fields of science related to the physical world and its phenomena
life sciences
which study living things and include biology,
physical sciences
which study nonliving matter and include astronomy, physics, and chemistry.
inductive reasoning
is a form of logical thinking that uses related observations to arrive at a general conclusion. This type of reasoning is common in descriptive science.
qualitative
descriptive
quantitative
consisting of numbers
deductive reasoning
the type of logic used in hypothesis-based science. a form of logical thinking that uses a general principle or law to predict specific results. From those general principles, a scientist can deduce and predict the specific results that would be valid as long as the general principles are valid.
descriptive science
aims to observe, explore, and discover
hypothesis-based science
begins with a specific question or problem and a potential answer or solution that can be tested.
the scientific process
-observation
-ask a question
-hypothesis
-experiment
-analyze results
-report findings
a hypothesis must be
testable and falsifiable
falsifiable
that it can be disproven by experimental results.
variable
any part of the experiment that can vary or change during the experiment.
control
a part of the experiment that does not change.
basic science
science seeks to expand knowledge regardless of the short-term application of that knowledge. It is not focused on developing a product or a service of immediate public or commercial value. The immediate goal of basic science is knowledge for knowledge’s sake, though this does not mean that in the end it may not result in an application.
applied science
“technology,” aims to use science to solve real-world problems, making it possible, for example, to improve a crop yield, find a cure for a particular disease, or save animals threatened by a natural disaster. In applied science, the problem is usually defined for the researcher.
matter
occupies space and has mass.
peer-reviewed articles
scientific papers that are reviewed, usually anonymously by a scientist’s colleagues, or peers.
elements
substances that cannot be broken down or transformed chemically into other substances.
what are elements made of?
atoms
proton
a positively charged particle that resides in the nucleus
nucleus
(the core of the atom) of an atom and has a mass of 1 and a charge of +1.
electron
a negatively charged particle that travels in the space around the nucleus. In other words, it resides outside of the nucleus. It has a negligible mass and has a charge of –1.
neutrons
reside in the nucleus of an atom. They have a mass of 1 and no charge.
atomic number
is equal to the number of protons that element contains.
mass number
or atomic mass, is the number of protons plus the number of neutrons of that element.
periodic table of elements
a chart of the elements that includes the atomic number and relative atomic mass of each element.
isotopes
different forms of the same element that have the same number of protons, but a different number of neutrons.
radioactive isotopes
some isotopes are unstable and will lose protons, other subatomic particles, or energy to form more stable elements.
the closest shell can hold
up to 2 electrons. always filled first, before any other shell can be filled.
the second and third energy levels can hold
up to 8 electrons. The eight electrons are arranged in four pairs.
what do the rows in the periodic table mean?
correspond to the number of shells that the elements within that row have. The elements within a particular row have increasing numbers of electrons as the columns proceed from left to right.
octet rule
the outermost shell can hold up to 8 electrons
chemical bonds
interactions between two or more of the same or different elements that result in the formation of molecules.
ion
when an atom does not contain equal numbers of protons and electrons
cations
positive ions are formed by losing electrons
anions
negative ions are formed by gaining electrons
electron transfer
movement of electrons from one element to another
ionic bond
a bond between ions. The elements bond together with the electron from one element staying predominantly with the other element.
covalent bond
these bonds form when an electron is shared between two elements and are the strongest and most common form of chemical bond in living organisms. Covalent bonds form between the elements that make up the biological molecules in our cells. Unlike ionic bonds, covalent bonds do not dissociate in water.
nonpolar covalent bonds
form between two atoms of the same element or between different elements that share the electrons equally.
polar covalent bond
the electrons shared by the atoms spend more time closer to one nucleus than to the other nucleus. Because of the unequal distribution of electrons between the different nuclei, a slightly positive (δ+) or slightly negative (δ–) charge develops.
hydrogen bond
when polar covalent bonds containing a hydrogen atom form, the hydrogen atom in that bond has a slightly positive charge. This is because the shared electron is pulled more strongly toward the other element and away from the hydrogen nucleus. Because the hydrogen atom is slightly positive (δ+), it will be attracted to neighboring negative partial charges (δ–). When this happens, a weak interaction occurs between the δ+ charge of the hydrogen atom of one molecule and the δ– charge of the other molecule.
van der waals interactions
weak attractions or interactions between molecules. They occur between polar, covalently bound, atoms in different molecules.
hydrogen and oxygen atoms within water molecules form what?
polar covalent bonds
hydrophilic
when a substance readily forms hydrogen bonds with water, it can dissolve in water
hydrophobic
(“water-fearing”) and will not dissolve in water.
evaporation
in the release of individual water molecules at the surface of the liquid
temperature
a measure of the motion (kinetic energy) of molecules. As the motion increases, energy is higher and thus temperature is higher.
solvent
a substance capable of dissolving another substance.
cohesion
water molecules are attracted to each other (because of hydrogen bonding), keeping the molecules together at the liquid-air (gas) interface, although there is no more room in the glass.
surface tension
the capacity of a substance to withstand rupture when placed under tension or stress.
adhesion
the attraction between water molecules and other molecules.
pH
a measure of its acidity or bascicity.
pH scale
the more hydrogen ions present, the lower the pH; conversely, the fewer hydrogen ions, the higher the pH.
litmus paper
paper that has been treated with a natural water-soluble dye so it can be used as a pH indicator, to test how much acid or base (basicity) exists in a solution.
what does the pH scale range from?
0-14
pure water is
neutral. has a pH of 7.
anything below 7 on the pH scale is
acidic
anything above 7 on the pH scale is
alkaline
acids
substances that provide hydrogen ions (H+) and lower pH
bases
provide hydroxide ions (OH–) and raise pH.
buffers
readily absorb excess H+ or OH–, keeping the pH of the body carefully maintained in the aforementioned narrow range.
what does carbon dioxide do in the body as a buffer?
it keeps the pH within the proper range.
macromolecules
the large molecules necessary for life that are built from smaller organic molecules
life is “carbon-based”
carbon atoms, bonded to other carbon atoms or other elements, form the fundamental components of many, if not most, of the molecules found uniquely in living things.
how many electrons are in carbons outer shell?
4
how many covalent bonds can carbon form?
4
carbohydrates
macromolecules with which most consumers are somewhat familiar. To lose weight, some individuals adhere to “low-carb” diets.
what are some natural sources of carbohydrates?
grains, fruits, and vegetables
carbohydrates provide energy to the body, particularly through what?
glucose
monosaccharides
simple sugars, the most common of which is glucose. In monosaccharides, the number of carbon atoms usually ranges from three to six. Most monosaccharide names end with the suffix -ose.
carbohydrates are classified into what three subtypes?
monosaccharides, disaccharides, and polysaccharides.
disaccharides
form when two monosaccharides undergo a dehydration reaction (a reaction in which the removal of a water molecule occurs). During this process, the hydroxyl group (–OH) of one monosaccharide combines with a hydrogen atom of another monosaccharide, releasing a molecule of water (H2O) and forming a covalent bond between atoms in the two sugar molecules.
examples of common disaccharides
lactose, maltose, and sucrose.
polysaccharide
a long chain of monosaccharides linked by covalent bonds.
examples of polysaccharides
Starch, glycogen, cellulose, and chitin
starch
the stored form of sugars in plants and is made up of amylose and amylopectin (both polymers of glucose).
glycogen
the storage form of glucose in humans and other vertebrates, and is made up of monomers of glucose. Glycogen is the animal equivalent of starch and is a highly branched molecule usually stored in liver and muscle cells.
cellulose
one of the most abundant natural biopolymers. The cell walls of plants are mostly made of cellulose, which provides structural support to the cell.
cellulose passing through our digestive system is called what?
dietary fiber
chitin
biological macromolecule. a nitrogenous carbohydrate. It is made of repeating units of a modified sugar containing nitrogen.
lipids
hydrophobic (“water-fearing”), or insoluble in water, because they are nonpolar molecules.
functions of lipids
-cells store energy for long-term use in the form of lipids called fats
-lipids also provide insulation from the environment for plants and animals
-lipids are also the building blocks of many hormones and are an important constituent of the plasma membrane
what do lipids include?
fats, oils, waxes, phospholipids, and steroids.
fat
consists of two main components—glycerol and fatty acids.
fatty acids may be what?
saturated or unsaturated
saturated fatty acids
saturated with hydrogen; in other words, the number of hydrogen atoms attached to the carbon skeleton is maximized.
unsaturated fatty acid
when the hydrocarbon chain contains a double bond
oils
most unsaturated fats are liquid at room temperature
examples of saturated fats
animal fats
examples of unsaturated fats
oils
unsaturated fats help to improve
blood cholestorol levels
saturated fats might contribute to
plaque formation in the arteries which can lead to heart attack
trans-fat
double bonds of the cis-conformation in the hydrocarbon chain may be converted to double bonds in the trans-conformation.
examples of omega-3 fatty acids
salmon, trout, and tuna
important functions of fats
-long-term energy storage
-insulation for the body
phospholipids
the major constituent of the plasma membrane. Like fats, they are composed of fatty acid chains attached to a glycerol or similar backbone.
steroids
have a ring structure. Although they do not resemble other lipids, they are grouped with them because they are also hydrophobic. All steroids have four, linked carbon rings and several of them, like cholesterol, have a short tail.
proteins
one of the most abundant organic molecules in living systems and have the most diverse range of functions of all macromolecules. Proteins may be structural, regulatory, contractile, or protective; they may serve in transport, storage, or membranes; or they may be toxins or enzymes.
enzymes
which are produced by living cells, are catalysts in biochemical reactions (like digestion) and are usually proteins. Each enzyme is specific for the substrate (a reactant that binds to an enzyme) upon which it acts. Enzymes can function to break molecular bonds, to rearrange bonds, or to form new bonds.
hormones
chemical signaling molecules, usually proteins or steroids, secreted by an endocrine gland or group of endocrine cells that act to control or regulate specific physiological processes, including growth, development, metabolism, and reproduction.
denaturation
changes in temperature, pH, and exposure to chemicals may lead to permanent changes in the shape of the protein, leading to a loss of function
amino acids
the monomers that make up proteins. Each amino acid has the same fundamental structure, which consists of a central carbon atom bonded to an amino group (–NH2), a carboxyl group (–COOH), and a hydrogen atom.
polypeptide
technically a polymer of amino acids, whereas the term protein is used for a polypeptide or polypeptides that have combined together, have a distinct shape, and have a unique function.
what is critical to the function of a protein?
its shape
nucleic acids
key macromolecules in the continuity of life. They carry the genetic blueprint of a cell and carry instructions for the functioning of the cell.
deoxyribonucleic acid (DNA)
the genetic material found in all living organisms, ranging from single-celled bacteria to multicellular mammals.
ribonucleic acid (RNA)
mostly involved in protein synthesis. The DNA molecules never leave the nucleus, but instead use an RNA intermediary to communicate with the rest of the cell.
nucleotides
DNA and RNA are made up of monomers known as nucleotides.
a nucleotide is made up of what three components?
a nitrogenous base, a pentose (five-carbon) sugar, and a phosphate group
what kind of structure does DNA have?
double-helical structure
microscope
an instrument that magnifies an object.
most student microscopes are classified as
light microscopes
light microscopes
visible light both passes through and is bent by the lens system to enable the user to see the specimen. Light microscopes are advantageous for viewing living organisms, but since individual cells are generally transparent, their components are not distinguishable unless they are colored with special stains.
electron microscopes
use a beam of electrons instead of a beam of light. Not only does this allow for higher magnification and, thus, more detail, it also provides higher resolving power. Preparation of a specimen for viewing under an electron microscope will kill it; therefore, live cells cannot be viewed using this type of microscopy.
dissecting microscope
microscopes have a lower magnification (20 to 80 times the object size) than light microscopes and can provide a three-dimensional view of the specimen. Thick objects can be examined with many components in focus at the same time. These microscopes are designed to give a magnified and clear view of tissue structure as well as the anatomy of the whole organism.
unified cell theory
states that all living things are composed of one or more cells, that the cell is the basic unit of life, and that all new cells arise from existing cells. These principles still stand today.
all cells share four common components
1) a plasma membrane, an outer covering that separates the cell’s interior from its surrounding environment;
2) cytoplasm, consisting of a jelly-like region within the cell in which other cellular components are found;
3) DNA, the genetic material of the cell; and
4) ribosomes, particles that synthesize proteins.
prokaryotic cell
a simple, single-celled (unicellular) organism that lacks a nucleus, or any other membrane-bound organelle.
flagella are used for
locomotion
most pili are used to
exchange genetic material during a type of reproduction called conjugation.
eukaryotic cell
a cell that has a membrane-bound nucleus and other membrane-bound compartments or sacs, called organelles
organelles
sacs with specialized functions
prokaryotic cell size
0.1–5.0 µm in diameter (significantly smaller than eukaryotic cells)
eukaryotic cell size
which have diameters ranging from 10–100 µm
plasma membrane
made up of a phospholipid bilayer with embedded proteins that separates the internal contents of the cell from its surrounding environment. regulates the passage of some substances, such as organic molecules, ions, and water, preventing the passage of some to maintain internal conditions, while actively bringing in or removing others.
cytoplasm
comprises the contents of a cell between the plasma membrane and the nuclear envelope
cytosol
gel-like
cytoskeleton
network of protein fibers. helps to maintain the shape of the cell, secures certain organelles in specific positions, allows cytoplasm and vesicles to move within the cell, and enables unicellular organisms to move independently.
3 types of fibers within the cytoskeleton
-microfilaments
-intermediate filaments
-microtubules
microfilaments
the thinnest of the cytoskeletal fibers and function in moving cellular components, for example, during cell division. They also maintain the structure of microvilli, the extensive folding of the plasma membrane found in cells dedicated to absorption. These components are also common in muscle cells and are responsible for muscle cell contraction.
intermediate filaments
of intermediate diameter and have structural functions, such as maintaining the shape of the cell and anchoring organelles.
microtubules
the thickest of the cytoskeletal fibers. These are hollow tubes that can dissolve and reform quickly. Microtubules guide organelle movement and are the structures that pull chromosomes to their poles during cell division. They are also the structural components of flagella and cilia.
centrioles
two structures that lie perpendicular to each other. Each centriole is a cylinder of nine triplets of microtubules.
the centrosome
a region near the nucleus of animal cells that functions as a microtubule-organizing center. It contains a pair of centrioles
flagella
long, hair-like structures that extend from the plasma membrane and are used to move an entire cell. When present, the cell has just one flagellum or a few flagella.
cilia
they are many in number and extend along the entire surface of the plasma membrane. They are short, hair-like structures that are used to move entire cells (such as paramecium) or move substances along the outer surface of the cell.
endomembrane system
a group of membranes and organelles in eukaryotic cells that work together to modify, package, and transport lipids and proteins. It includes the nuclear envelope, lysosomes, and vesicles, the endoplasmic reticulum and Golgi apparatus.
nuclear envelope
a double-membrane structure that constitutes the outermost portion of the nucleus
nucleus
houses the cell’s DNA in the form of chromatin and directs the synthesis of ribosomes and proteins.
chromosome
a structure within the nucleus that is made up of DNA, the hereditary material, and proteins.
chromatin
combination of DNA and proteins
nucleolus
(plural = nucleoli), aggregates the ribosomal RNA with associated proteins to assemble the ribosomal subunits that are then transported through the nuclear pores into the cytoplasm.
endoplasmic reticulum (ER)
a series of interconnected membranous tubules that collectively modify proteins and synthesize lipids.
rough endoplasmic reticulum (RER)
named because the ribosomes attached to its cytoplasmic surface give it a studded appearance when viewed through an electron microscope.
smooth endoplasmic reticulum (SER)
is continuous with the RER but has few or no ribosomes on its cytoplasmic surface. The SER’s functions include synthesis of carbohydrates, lipids (including phospholipids), and steroid hormones; detoxification of medications and poisons; alcohol metabolism; and storage of calcium ions.
golgi apparatus
a series of flattened membranous sacs. apparatus has a receiving face near the endoplasmic reticulum and a releasing face on the side away from the ER, toward the cell membrane. The transport vesicles that form from the ER travel to the receiving face, fuse with it, and empty their contents into the lumen of the Golgi apparatus. As the proteins and lipids travel through the Golgi, they undergo further modifications. The most frequent modification is the addition of short chains of sugar molecules. The newly modified proteins and lipids are then tagged with small molecular groups to enable them to be routed to their proper destinations.
lysosomes
the cell’s “garbage disposal.” Digestive enzymes within the lysosomes aid the breakdown of proteins, polysaccharides, lipids, nucleic acids, and even worn-out organelles.
