Biology Flashcards
Define Biosphere
- consists of all life on Earth & all the places where life exists
Define Ecosystem
- consists of all the living things in a particular area along with all the nonliving components of the environment with which life interacts
Define Communities
- hold the entire array of organisms inhabiting a particular ecosystem
Define Population
- consists of all the individuals of a species living with the bounds of a specified area
Define Organisms
- individual living things
Define Tissue
- made up of a group of cells that work together performing a specialized function
What is a Cell?
- life’s fundamental unit of structure and function
What are Organelles?
- the various functional components present in cells
What is Matter?
- defined as anything that takes up space & has a mass
Define Element
- a substance that cannot be chemically broken down into a simple substance
What is a Compound?
- a substance composed of 2 or more elements in fixed, definite proportions
What is an Atom?
- the smallest unit of matter that still retains the properties of an element
Can the number of Protons, Neutrons, and Electrons change in an atom?
- the number of protons NEVER changes in an element because it is the identifier of the element on the periodic table
- if the number of protons ever changed, then the entire atom transforms into another atom
- neutrons and electrons can change depending what type of change it is going through (either becomes an isotope or an ion
What are the 6 Elements Found in Bio-molecules?
- oxygen O 8 protons
- hydrogen H 1 proton
- carbon C 6 protons
- nitrogen N 7 protons
- sulfur S 16 protons
- phosphorous P 15 protons
Define Valence
- the number of electrons that are found on the outermost shell of an atom
What is the “Rule of 8”?
- it states that chemistry is the process of atoms trying to have a complete outer ring of 8 electrons aka become like the Noble Gases
What are the 4 Types of Chemical Bonds?
- Covalent Bond
- Ionic Bond
- Hydrogen Bond
- Van der Waals Forces
What is a Covalent Bond?
- the sharing of a pair of valence electrons by 2 atoms
if it has 8 electrons, then it is happy
What is an Ionic Bond?
- a chemical bond resulting from the attraction between oppositely charged ions
(becomes a cation or an anion)
What is an Anion?
- an ion that has gained one or more electrons, acquiring a negative charge
What is a Cation?
- an ion that has lost one or more electrons, gaining a positive charge
What is a Hydrogen Bond?
- a type of weak chemical bond that is formed when the slightly positive hydrogen atom of a polar covalent bond in one molecule is attracted to the slightly negative atom of a polar covalent bond in another molecule or in another region of the same molecule
(extremely weak but strong if there is a lot of them)
What are Van der Waals Forces?
- individually weak and occur only when atoms and molecules are very close
What are the 2 Types of Molecular Polarity?
- Polar Covalent Bond
- Non-polar Covalent Bond
Define Polar Covalent Bond
- when one atom is bonded to a more electronegative atom thus the electrons of the bond are not shared equally
Define Non-Polar Covalent Bond
- when the electrons are shared equally because the 2 atoms have the same electronegativity
What is the pH?
- the negative logarithm of hydrogen ion concentration
( pH = -log[H^+] ) - on the scale 0-6.99, it is acidic [H^+] > [OH^-]
- on the scale 7.01-14, it is basic [H^+]
What Elements Make Up Hydrocarbons?
- hydrogen & carbons
ex) methane, propane
What is a Double Bond?
- a chemical bond between two chemical elements involving four bonding electrons instead of the usual two
What is a Triple Bond?
- a chemical bond between two atoms involving six bonding electrons instead of the usual two in a covalent single bond
Hydroxyl Group
- a molecule in this group has a hydrogen atom bonded to an oxygen atom, which in turn is bonded to the carbon skeleton of the organic molecule
Define Isomers
- compounds that have the same number of atoms of the same elements but different structures
Define Carbohydrates
- a sugar or one of its dimers or polymers
What are Monosaccharides?
- generally have molecular formulas that are some multiple of the unit CH2O
What are Polysaccharides?
- they are macromolecules
- polymers that can go up to a few thousand monosaccharides joined by glycosidic linkages
What are Disaccharides?
- consists of two monosaccharides joined by glycosidic linkage
Define Glycosidic Linkage
- a covalent bond formed between two monosaccharides by a dehydration reaction
Forming/breaking bond require what?
- forming bonds requires energy input, and breaking bonds releases energy
What is a Dehydration Reaction?
- the process of two molecules covalently bonding to each other by losing a water molecule
What is Hydrolysis?
- a process that is essentially the reverse of the dehydration reaction
- literally means to break using water
What are Some Uses of Polysaccharides for Plants & Animals?
- serve as storage material
- serve as building material for structures that protect the cell or the whole organism
Define Amylose
- the crystallizable form of starch
- consisting of long unbranched polysaccharide chains
Define Amylopectin
- the noncrystabillizable form of starch
- consisting of branched polysaccharides
Define Glycogen
- a poymer of glucose that is like amylopectin but more extensively branched
Define Cellulose
- a major component of the tough walls that enclose plant cells
- made out of glucose
- not digestible because humans lack enzymes to break down acetal linkages
Define Hydrophobic
- literally means “water-fearing”
- describes the segregation and apparent repulsion between water and nonpolar substances
Define Hydrophilic
- having a tendency to mix with, dissolve in, or be wetted by water
What are Light Microscopes?
- visible light is passed through the specimen and through glass lenses
- it can see things from frog eggs to cells to bacteria
- can magnify effectively to about 1,000 times the actual size of the specimen
What is an Electron Microscope?
- a microscope that focuses a beam of electrons through the specimen or onto its surface
- it can see things from cells to small bacteria to proteins
What is a Scanning Electron Microscope?
- a microscope used for detailed study of the topography of a specimen
- person sprays specimen with gold, scans the surface with a beam which excites electrons on the surface, & the secondary electrons are detected by a device that translates the pattern of electrons into an electronic signal to a video screen
What is a Transmission Electron Microscope?
- a microscope used to study the internal structure of cells
- it aims an electron beam through a very thin section of the specimen which has been stained with atoms of heavy metals; the stain attaches to certain cellular structures, thus enhancing the electron density of some parts of the cell more than others
What is an Eukaryotic Cell?
- a cell were most of the DNA is in an organelle called the nucleus which is bounded by a double membrane
- membrane bound organelles & the cytoplasm is in the region between the plasma membrane and nucleus
What is a Prokaryotic Cell?
- a cell where the DNA is concentrated in a region that is not membrane enclosed (nucleoid)
- it has no membrane bound organelles & the cytoplasm is Bound by the plasma membrane and nucleus
Which is bigger, an Eukaryotic Cell or a Prokaryotic Cell?
- Eukaryotic Cell
What is Cytosol?
- also known as cytoplasm
- semi fluid substance located inside the cell
Define Organelles
- the various function components present in cells
What is the Flagellum?
- motility structure present in some animal cells composed of a cluster of micro tubules within an extension of the plasma membrane
What is the Mircrovilli?
- projections that increase the cell’s surface area
What is the Plasma Membrane?
- a membrane that encloses the cell
- functions as a selective barrier that allows passage of enough oxygen, nutrients, and wastes to service the entire cell
- the general structure of a biological membrane is a double layer of phospholipids
- the top layer of the membrane is hydrophilic, the middle is hydrophobic and the other side is again hydrophilic
What is the Cytoskeleton?
- reinforces cell’s shape
- functions in cell movement
- the components are made of proteins which includes micro filaments, intermediate filaments, and micro tubules
What is the Mitochondria?
- an organelle where cellular respiration occurs and most ATP is generated
What is the Centrosome?
- a region where the cell’s microtubules are initiated
- contains a pair of centrioles
What is the Lysome?
- digestive organelle where macromolecules are hydrolyzed
What is the Peroxisome?
- an organelle with various specialized metabolic functions
- produces hydrogen peroxide as a by-product then converts it to water
What is the Golgi Apparatus?
- an organelle active in synthesis, modification, sorting, and secretion of cell products
What is the Endoplasmic Reticulum?
- a network of membranous sacs & tubes active in membrane synthesis and other synthetic & metabolic processes
- has a rough (ribosome-studded) and smooth regions
What are Ribosomes?
- complexes that make proteins
- free in cytosol or bound to rough ER or nucleus envelope
What are the 3 Parts of a Nucleus?
- nuclear envelope
- nucleolus
- chromatin
What is the Nuclear Envelope?
- double membrane enclosing the nucleus
- perforated by pores
- continuous with ER
What is the Nucleolus?
- non-membranous structure involved in production of ribosomes
- a nucleus has one or more mucleoli
What is the Chromatin?
- material consisting of DNA & proteins
- visible in a dividing cell as individual condensed chromosomes
What are Transmembrane Proteins?
- the bean like proteins that are found throughout the plasma membrane
- it has hydrophilic & hydrophobic regions like the membrane
What are the 4 Parts of the Transmembrane Proteins?
- primary structure
- secondary structure
- tertiary structure
- quaternary structure
What is the Primary Structure?
- apart of the transmembrane proteins
- a linked series of amino acids with a unique sequence
- there is an amino end & a carboxyl end
What is the Secondary Structure?
- apart of the transmembrane proteins
- the polypeptide chains repeatedly coiled or folded in patterns that contribute to the proteins overall shape
- the result of hydrogen bonds between the repeating constituents of the polypeptide backbone
- there are 2 types: alpha helix and beta pleated sheet
What is the Alpha Helix?
- apart of the secondary structure of the transmembrane proteins
- a delicate coil held together by hydrogen bonding between every fourth amino acid
What is the Beta Pleaded Sheet?
- apart of the secondary structure of the transmembrane
- 2 or more strands of polypeptide chain lying side by side are connected by hydrogen bonds between parts of the 2 parallel polypeptide back bones
What is the Tertiary Structure?
- apart of the transmembrane proteins
- the overall shape of a polypeptide resulting from interactions between the side chains ( R groups) of the various amino acids
What is the Quaternary Structure?
- apart of the transmembrane proteins
the overall protein structure that results from the aggregation of these polypeptide subunits aka what we see between the plasma membranes
In the cell, what organelles are involved in the energy transfer?
- mitochondria
- chloroplasts
