Shared Flashcard Set

Details

Foundations of biology test 1
help for us all
84
Biology
Undergraduate 3
09/17/2012

Additional Biology Flashcards

 


 

Cards

Term
Hypothesis
Definition
Guess about particular phenomena
Term
Theory
Definition
hypothesis that has graduated because it is strongly supported by empirical observation. Unlikely to be altered
Term
Natural Selection
Definition
the increase in frequency of genes that produce phenotypes that increase the likelihood that animals will survive and reproduce
Term
Scientific method
Definition
a deductive system of acquiring knowledge with the purpose of producing models of reality that allows useful predictions
Term
Science
Definition
Methodical Objective Rational Analytical Demonstrable
and not a static process but a vivid ongoing process
Term
Biological Literacy
Definition
the ability to use the process of scientific inquiry to think creatively about real-world issues, communicate those thoughts to others, and integrate them into your decision-making.
Term
Experiments
Definition
Experiments should begin with a well-formed hypothesis; The goal of experimentation is to test the validity of the hypothesis; A hypothesis is useless unless a feasible experiment can be designed to support it or disprove it
Term
Independent Variables
Definition
Also know as explaining variables, Intentionally manipulated by the researcher, Presumed cause or antecedent
Term
Dependent Variables
Definition
Also know as response variables, Something that might be affected by the change in the independent variable; A consequence of the independent variable
Term
Experimental Controls
Definition
the most important feature of a good experiment
the attempt to minimize any differences between a control group and an experimental group other than the treatment itself
Term
A Useful Hypothesis
Definition
It must clearly establish mutually exclusive alternative explanations for a phenomenon.
It must generate testable predictions.
Term
Take home message
Definition
The scientific method is a flexible, adaptable, and efficient pathway to understanding the world because it tells us when we must change our ideas.
Term
Cell theory
Definition
1. all known living things are made up of cells.

2. the cell is structural & functional unit of all living things.
3. all cells come from pre-existing cells by division.(Spontaneous Generation does not occur).
4. cells contains hereditary information which is passed from cell to cell during cell division.
5. All cells are basically the same in chemical composition.
6. all energy flow (metabolism & biochemistry) of life occurs within cells.
Term
five characteristics of life
Definition
Cells and organization
Metabolism - conversion of energy
Information - genetic material
Replication
Evolution
Homeosasis
Term
Organization
Definition
Various degrees of organization
Atoms -> Molecules -> Organelles -> Cells…
Term
Metabolism
Definition
processes that allow organisms to grow and reproduce,
maintain their structures, and respond to their environments
Term
Genetic material
Definition
Hereditary material (DNA) encoded in units called genes
It holds the information to build and maintain an organism's cells
Term
Reproduction
Definition
new "offspring" individual organisms are produced from their "parents”
Almost everything an organism does contributes to one goal, replicating itself.
Term
evolution
Definition
The change in genetic composition of a population over successive generations,
which may be caused by natural selection, inbreeding, hybridization, or mutation
Term
Theory of Chemical evolution
Definition
Continuous input of solar energy was converted to chemical energy: Simple chemical compounds combined to form more complex carbon-containing substances that could copy itself.
Term
Characteristics of Atoms
Definition
The chemical characteristics of an atom depend upon number of electrons in their outermost shells. Atoms are most stable and least likely to bond with other atoms when their outermost electron shell is full.
Term
Covalent Bonds
Definition
are strong bonds formed when two atoms share electrons.

in which atoms share electrons, are the strongest.
Term
Polar Covalent bonds, hydrogen bonds
Definition
Share electrons with some distributed charge between the;, the weakest, involve the attraction between a hydrogen atom and another polar atom or molecule.
Term
Ionic Bonds
Definition
When a electron jumps to a new atom and the atoms bond because of resultant charge difference;the next strongest, one atom transfers its electrons to another and the two oppositely charged ions are attracted to each other, forming a compound.
Term
Early oceans and the importance of water
Definition
Water is vital because is an excellent solvent - agent for getting substances into solution, because of polar nature, good at pulling apart charged molecules,
Substances are most likely to come into contact and react as solutes
Term
Hydrophilic
Definition
polar molecules and ions that dissolve in water
Term
Hydrophobic
Definition
uncharged and non-polar molecules, that don't dissolve in water
Term
Characteristics of water from hydrogen bonds
Definition
The hydrogen bonds between water molecules give water several of its most important characteristics:
Cohesiveness
Adhesiveness
low density as a solid
the ability to resist temperature changes
broad effectiveness as a solvent
Term
Importance of carbon
Definition
Carbon is the most versatile atom on Earth. Because of its four valence electrons, carbon can form many covalent bonds. Carbon-containing molecules can form an almost limitless array of molecular shapes with different combinations of single and double bonds.
The formation of carbon–carbon bonds was an important event in chemical evolution;The carbon atoms in an organic molecule furnish the skeleton that gives the molecule its overall shape
Term
Energy sources that started life
Definition
Formation of formaldehyde (H2CO) and hydrogen cyanide (HCN) is the first step in chemical evolution and requires energy input.
Term
Photons
Definition
are packets of light energy emitted by the Sun.

High-energy photons can break molecules apart by knocking electrons away from valence shells. The resulting free radicals have unpaired electrons and are extremely unstable and highly reactive.
Term
Chemical Energy
Definition
Potential energy stored in chemical bonds Significant amounts of H2CO and HCN could form under the temperature and concentration conditions that were likely on ancient Earth.
These products have more potential energy than the reactants.

Thus: solar energy (energy of the Sun) was converted into chemical energy (in H2CO and HCN).
Term
Importance of molecular shape
Definition
3D configuration determines function

Determine likelihood of
bonding with other molecules
Determine tastes or smells
or hormone activity
Depend upon the shape in which the atoms are
linked together and the electrons in their
outermost shells!
Term
Macromolecules
Definition
made from repeating subunits (monomers), during dyhdration synthesis, loss of h2o molecules
Term
Hydolosis
Definition
When water is added breaking down macromolecules
Term
Carbohydrates
Definition
Monosacchrides, primary an energy source; Starch: plants
Glycogen: animals
Cellulose: cells walls of plants
Chitin: tough carbohydrate that forms the external skeleton of arthropods (bugs, crayfish)

Carbohydrates are the primary
fuel for running all cellular machinery
and also form much of the structure of cells in all life forms.

consist of mostly
C, H, O (1:2:1)
primary function energy for metabolism
not all carbs are digestable cellulose
chitin
Term
Lipids
Definition
Fatty acids
Oleic acid (omega-9)
Structure membranes, energy storage, insulating

do not dissolve in water
long-term energy storage
membrane components
protection & insulation
certain hormones

Lipids are made primarily from atoms of C, H, O, just as carbohydrates are, but the atoms are in different proportions (a lot more H.)
Term
Types of Lipids
Definition
Fats- long term energy storage and insulation
Sterols- regulate growth and development
Phospholipids- form membrane inclosing cells
Term
Structure of fats
Definition
Head of molecule is Glycerol, fatty acids are tails of head
Term
Saturated and unsaturated fats
Definition
difference is subtle, just a double bond in tails do to having only one hydrogen instead of two, as the rest do
Term
Cholesterol
Definition
important component of most cell membranes; influences membrane fluidity
can attach to blood vessel walls and cause them to thicken; arteriosclerosis
liver cells produce almost 90% of the circulating cholesterol from saturated fats in diet
Term
Steroid hormones
Definition
regulate sexual development, maturation, and sex cell production.
estrogen influences memory and mood
testosterone stimulate muscle growth
Term
Phospholipids
Definition
are the major component of the cell membrane,
Term
Waxes
Definition
Hydrophobic, composed of a single fatty acid linked to a long-chain alcohol
waxes have an important “sealing” function in the living world
almost all plant surfaces exposed to air, for example, have a protective covering made largely of wax
many birds have waxy coating on feathers
Term
Proteins
Definition
Aminoacids
Alanine

Structural, carriers, signaling, enzymes
proteins perform a variety of functions; however, all are built the same way and from the same raw materials
Term
Amino Acids
Definition
comprised of amino group (nh3), carboxyl group (ch2) and varying side chain, there are twenty different side chains for the twenty different amino acids
Term
importance of amino acids
Definition
Unique combinations of 20 amino acids give rise to proteins, the chief building blocks of physical structures that make up all organisms.

Proteins are an essential dietary component
growth
repair
replacement
Term
Protein function and shape
Definition
functions are influence by three dimensional shape, peptide bonds determine shape,
Term
Proteins are formed by
Definition
dehydration synthesis, between peptide bonds

proteins can be small:
peptides (up to ~ 50 aa’s)
polypeptides (up to
thousands of aa’s long)

proteins get their shape from
the order of aa’s and the R groups on those aa’s

with 20 aa’s, you can put
them together in a combination to do almost anything
Term
Enzymes
Definition
help bring about chemical changes in a variety of ways, by creating an a receptive site for the components of a molecule that break the bonds and release the energy

Enzymes are proteins that help initiate and speed up chemical reactions.

They aren't permanently altered in the process but rather can be used again and again.
Term
Nucleic Acids
Definition
Nucleotides
adenosine triphosphate (ATP)

intracellular energy transfer
informational molecules
Term
Nucleic acids store what and how
Definition
two types Deoxyribonucleic acid (DNA)
Ribonucleic acid (RNA)
both play central roles in directing the protein production in cells
Term
How DNA works
Definition
The information in a molecule of DNA is determined by its sequence of bases.
adenine, guanine, cytosine, and thymine
CGATTACCCGAT
A always pairs with T
C always pairs with G
Term
DNA spare facts
Definition
DNA is like a ladder in which the long vertical element of the ladder is made from a sequence of sugar-phosphate-sugar-phosphate molecules and rungs are nucleotide bases.

The sequence of nucleotide bases contains the information about how to produce a particular protein.

The nucleic acids DNA and RNA are macromolecules that store information by having unique sequences of molecules.

Both play central roles in directing protein production in organisms.
Term
Function of RNA
Definition
acts as a middleman molecule, it takes instruction for production of protein from DNA, moves them to another part of the cell and directs the building of a protein
Term
Ways RNA differs from DNA
Definition
the sugar molecule of the sugar-phosphate backbone
what is the name of the sugar?
how is it different from the sugar in DNA

single-stranded

Uracil (U) replaces thymine (T)
Term
Two types of cells
Definition
Eukaryotic and prokaryotic
Term
Eukaryotic
Definition
has a central control structure called a nucleus which contains the cell’s DNA
Term
Prokaryotic
Definition
does not have a nucleus; its DNA simply resides in the middle of the cell
Term
Domains of cells
Definition
According to phylogeny, or evolutionary history, there are three domains:
Bacteria-pro
Archaea-pro
Eukarya – eukaryotic
Term
Features of prokaryotic cells
Definition
) Each prokaryote has one or more circular loops or linear strands of DNA. No nucleus membrane
 
In addition to the characteristics common to all prokaryotes, some prokaryotes have additional unique features. Many have a rigid cell wall, for example, that protects and gives shape to the cell. Some have a slimy, sugary capsule as their outermost layer. This sticky outer coat provides protection and enhances the prokaryotes’ ability to anchor themselves in place when necessary.
 
Many prokaryotes have a flagellum, a long, thin, whip-like projection that rotates like a propeller and moves the cell through the medium in which it lives. Other appendages include pili, much thinner, hair-like projections that help prokaryotes attach to surfaces.
Term
Additional features of prokaryotic
Definition
Most prokaryotic species have one supercoiled circular chromosome found in the nucleoid region of the cell.
The chromosome contains a long strand of DNA and a few supportive proteins.

In addition to the large chromosome, many bacteria contain plasmids.
Small, supercoiled, circular DNA molecules
Plasmids usually contain genes that help the cell adapt to unusual environmental conditions.
Term
additional notes of prokaryotic
Definition
All prokaryotic cells contain ribosomes, consisting of RNA molecules and protein, for protein synthesis.
Many prokaryotes have internal photosynthetic membranes
Some prokaryotes have membrane-enclosed organelles.The inside of many prokaryotic cells is supported by a cytoskeleton of long, thin protein filaments
Term
What organisms are eukaryotes
Definition
all fungi plants and animals
Term
Features of eukaryotes
Definition
cells have compartments with specialized functions, DNA in nucleus, internal structures comparmentalized, larger than prokaryotes, usually ten times larger, cytoplasm contains specialized structures called organelles
Term
Benefits of organelles
Definition
Separation of incompatible chemical reactions
Increasing the efficiency of chemical reactions
Term
Difference in pro and eukaryotes
Definition
Bacteria and Archaea
DNA is Nucleoid (not membrane bound) plasmids common

Internal membranes only in photosynthetic species. Limited number of simple organelles

1-3 um

Eukaryotes

Inside nucleus (membrane), plasmids absent or rare

Large number or organelles, many types - many functions

10-100 um
Term
Functions of cell membranes
Definition
Just as skin covers our bodies, every cell of every living thing on earth, whether a prokaryote or a eukaryote, is enclosed by a plasma membrane, a two-layered membrane that holds the contents of a cell in place and regulates what enters and leaves the cell. Plasma membranes are thin (a stack of a thousand would be only as thick as a single hair) and flexible, and in photos or diagrams it often appears that the membranes resemble simple plastic bags, holding the cell contents in place. This image is a gross oversimplification, however. Membranes are indeed thin and flexible, but they are far from simple: a close look at a plasma membrane will reveal that its surface is filled with pores, outcroppings, channels, and complex molecules floating around within the two layers of the membrane itself (Figure 3-8 More than just an outer layer).
Functions:
cell adhesion, ion conductivity and cell signaling
Term
difference in lipid by layers in membranes
Definition
either some or no unsaturated fatty acids, no equals lower permeability, less fluid, some means higher permeability and more fluid
Term
Structure of phospholipid by-layers in membranes
Definition
hydrophilic head towards exterior, and hydrophobic tail towards interior
Term
Structure of cell membrane
Definition
mosaic of proteins that regulate interior of cell
Term
Four types of membrane proteins
Definition
Receptor proteins bind to chemicals in the cell’s external environment and, by doing so, regulate certain processes within the cell. Cells in the heart, for example, have receptor proteins that bind to adrenaline, a chemical released into the bloodstream in times of extreme stress or fright. When adrenaline binds to these heart cells, the cells increase the heart’s rate of contraction to pump blood through the body more quickly. You have experienced this reaction if you’ve ever been startled and felt your heart start to pound.
Recognition proteins give each cell a “fingerprint” that makes it possible for the body’s immune system (which fights off infections) to distinguish the cells that belong inside you from those that are invaders and need to be attacked. (Note that carbohydrates also play a role in recognition.) Recognition proteins also can help cells to bind to adhere to other cells or molecules.
Transport proteins are transmembrane proteins that help large and/or strongly charged molecules to pass through the plasma membrane. Transport proteins come in a variety of shapes and sizes, making it possible for a wide variety of molecules to be transported.
Enzymatic proteins accelerate chemical reactions on the cell membrane’s surface (a variety of different enzymatic proteins exist, with some accelerating reactions on the inside of the plasma membrane and other accelerating reactions on the outside of the plasma membrane).
Term
Two theories of eukaryotic complexity
Definition
endosymbiosis theory
invagination theory
Term
Endosymbiosis theory
Definition
We can’t go back two billion years to watch the initial evolution of eukaryotic cells, but we can speculate about how it might have occurred.
One very appealing idea, called the endosymbiosis theory, has been developed to explain the presence of two organelles in eukaryotes, chloroplasts in plants and algae and mitochondria in plants and animals. Chloroplasts help plants and algae convert sunlight into a more usable form of energy. Mitochondria help plants and animals to harness the energy stored in food molecules.
According to the theory of endosymbiosis, two different types of prokaryotes may have come to have close partnerships with each other.
For example, some small prokaryotes capable of performing photosynthesis (the process by which plant cells capture the light energy from the sun and transform it into the chemical energy stored in food molecules) may have come to live inside a larger “host” prokaryote.
The photosynthetic “boarder” may have made some of the energy from its photosynthesis available to the host.
Term
invagination
Definition
cell memebrane folds in on itself and forms organelles
Term
DNA synthesis
Definition
: a biological process in which DNA is replicated; occurs in all organisms.
Term
Four phases of division
Definition
There are a total of four phases in the cell cycle: M phase and an interphase consisting of the G1, S, and G2 phases
additionally, Gap phases allow the cell to grow large enough and synthesize enough organelles to ensure the daughter cells will be normal in size and function.
Term
Chromosomes
Definition
contain a single long double helix of deoxyribonucleic acid (DNA) wrapped around proteins.
Term
Gene
Definition
is a section of DNA that encodes a specific protein or RNA.
Term
Eukaryotic Chromosomes
Definition
consist of DNA associated with histone proteins.
In eukaryotes this DNA-protein material is called chromatin.

During interphase, most chromatin is “relaxed” or uncondensed, forming long, threadlike strands.
After replication during S phase, each chromosome consists of two genetically identical sister chromatids attached at the centromere.

At the start of mitosis the replicated chromosomes condense
Term
Two components of primary DNA Structure
Definition
A backbone made up of the sugar and phosphate groups of deoxyribonucleotides.
A series of nitrogen-containing bases that project from the backbone.
Term
Directionality
Definition
DNA has directionality—one end has an exposed hydroxyl group on the 3′ carbon of deoxyribose, and the other end has an exposed phosphate group on a 5′ carbon.
Term
DNA secondary structure
Definition
Watson and Crick proposed that two DNA strands line up in the opposite direction to each other, in what is called antiparallel fashion.

The antiparallel strands twist to form a double helix.

The secondary structure is stabilized by complementary base pairing:
Adenine (A) hydrogen bonds with thymine (T).
Guanine (G) hydrogen bonds with cytosine (C).
Term
Basic steps of DNA replication
Definition
DNA is opened and unwound Helicase

Proteins stabilize the unwound Single-strands

The leading strand is synthesized continuously
in the 5’____3’ direction DNA Polymerase

The lagging strand is synthesized discontinuously:
RNA primer is synthesized Primase
RNA primer is extended as DNA DNA Polymerase

RNA primer is replaced by DNA

Okasaki fragments are linked DNA Ligase
Supporting users have an ad free experience!