Download CLEP BIOLOGY STUDY GUIDE COMPLETE QUESTIONS AND ANSWERS and more Exams Biology in PDF only on Docsity!
Prokaryotic Cell - A type of cell lacking a membrane-enclosed nucleus and membrane-enclosed organelles. Organisms with prokaryotic cells (bacteria and archaea) are called prokaryotes.
CLEP BIOLOGY STUDY GUIDE COMPLETE
QUESTIONS AND ANSWERS
Evolution - Evolution is the process of change that has transformed life on Earth DNA - Deoxyribonucleic acid: a long linear polymer found in the nucleus of a cell and formed from nucleotides and shaped like a double helix Biology - The scientific study of life Eukaryotic Cell - A type of cell with a membrane-enclosed nucleus and membrane-enclosed organelles. Organisms with eukaryotic cells (protists, plants, fungi, and animals) are called eukaryotes. Biosphere - The entire portion of Earth inhabited by life; the sum of all the planet's ecosystems. Ecosystems - All the organisms in a given area as well as the abiotic factors with which they interact; one or more communities and the physical environment around them Community - All the organisms that inhabit a particular area; an assemblage of populations of different species living close enough together for potential interaction. Population - A group of individuals of the same species that live in the same area and interbreed, producing fertile offspring. Organism - a creature such as a plant, animal or a single-celled life form, or something that has interdependent parts and that is being compared to a living creature Organs - A specialized center of body function composed of several different types of tissues. Organ Systems - A group of organs that work together in performing vital body functions. Tissues - An integrated group of cells with a common structure, function, or both. Organelles - Any of several membrane-enclosed structures with specialized functions, suspended in the cytosol of eukaryotic cells. Cell - The part of a neuron that houses the nucleus and most other organelles.
Why is evolution considered the core theme of biology? - Evolution accounts for the unity and diversity of life and it explains the most fundamental aspects of all life on earth. It accounts for the common features shared by all forms of life due to the descent from a common ancestor. Metabolism - The totality of an organism's chemical reactions, consisting of catabolic and anabolic pathways, which manage the material and energy resources of the organism. Molecule - Two or more atoms held together by covalent bonds. Negative Feedback - A form of regulation in which accumulation of an end product of a process slows the process; in physiology, a primary mechanism of homeostasis, whereby a change in a variable triggers a response that counteracts the initial change. Positive Feedback - A form of regulation in which an end product of a process speeds up that process; in physiology, a control mechanism in which a change in a variable triggers a response that reinforces or amplifies the change. Adaptation - Inherited characteristic of an organism that enhances its survival and reproduction in a specific environment. What are the 7 Characteristics of Life? - 1. Order
- Regulation
- Energy Processing
- Evolutionary Adaptation
- Response to the Environment
- Reproduction
- Growth and Development What are the three domains by which all living organisms are classified? - Domain Bacteria Domain Archaea Domain Eukarya What are the 4 kingdoms in the Domain Eukarya? - Plantae Animalia Fungi Protista What are Bacteria? - All unicellular prokaryotic (no nucleus) organisms with peptidoglycan in their cell walls What is the Theory of Natural Selection? - A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits.
Secondary Structure - - Arises through hydrogen bonding between carbonyl oxygen and amino hydrogens located on the peptide backbone (main chain)
- Two most common are alpha helices and beta sheets
- DOES NOT involve H-bonding of side chains, but the type of secondary structure that's formed can be influenced by side chains Tertiary Structure - - Refers to interactions of secondary structures
- Side chain and main chain H-bonding are important - Also ionic, hydrophobic, and van der Waals Quaternary Structure - - Interactions between different polypeptide chains
- Interactions mediated by same forces important for tertiary structure
- Relative orientation of subunits can change to regulate function of the complex Interactions Governing S,T, and Q Structures of Protein - 1. H-Bonds
- Especially important for secondary structure
- Ionic
- Between side chains of charged AAs - "salt bridges"
- Hydrophobic
- Hydrophobic side chains exclude water and get packed together - E favorable, an entropic effect
- Van der Waals - not strong on own but yes in aggregate
- Between any two atoms
- Important in tightly packed regions of the protein H-Bonding in an Alpha Helix - - Alpha helix stabilized by main chain H-bonds
- Occurs between every fourth residue (red arrows)
- Happens between partially negative O and hydrogens on partially positive N (due to partial double bond character of peptide bond)
- Turns once ever 3.6 AAs
- This makes alpha helix E favorable for spanning a lipid bilayer - the H on the N and the Carbonyl O are already interacting with each other - dont need to interact with water
- Though side chains ARE NOT directly involved in forming H-bonds, the nature of the side chain helps determine which secondary structure will form Structure of Alpha Helix - - All opportunities for H-bonding in a peptide backbone are satisfied Protein Structure - - A series of secondary structure elements linked together by flexible connectors (loops or unstructured regions)
- NOT ALL AAs in a protein are part of a secondary structure - some just exist as a short segment connecting one 2ndary to another Parallel Beta Sheets - - All strands run in same direction
- Notice that H-Bond alignment is slightly different H-Bonds and Tertiary Structure - 1. Bonds between main chains of 2 different strands
- Bonds between the peptide bond and a side chain
- Bonds between two side chains Ionic and van der Waals Interactions - 1. Ionic (salt bridges)
- Important in tertiary and quaternary structures
- Negative AA interacts with Positive AA
- Van der Waals
- Occur by close packing of AA side chains
- Often important in stabilization at center of protein Hydrophobic Interactions - - In terms of E, strongest force driving protein folding is hydrophobic interaction - in the interior of a protein
- Just want to get away from water - move to center of protein to do so - then have van der Waal interactions Hypothetical Protein Folding Pathway - 1. Secondary structures acquired
- Tertiary structures acquired Proteins composed of Beta Sheets - Immunoglobulin Fold - found in IgG and other proteins
Energy, - Capacity to cause change. Potential energy: - The energy matter possesses because of its location or structure. (Water on a hill has potential energy because of it's altitude) Electron Shells: - Different levels (like a staircase) where electrons can be found. The higher the level (father the distance) the more potential energy on the electron. Valence electrons, - Electrons in the outermost shell of an atom. Valence shell, - The outermost electron shell of an atom. Valence, - The bonding capacity of an atom; the number of unpaired electrons required to complete the valence shell. Oxygen has a valence of 2. Completed valence shell, - The atom with a full valence shell will not react readily with other atoms. Called inert. Shell limits, - 1:2, 2:8, 3: Orbital, - The 3dimensional space where an electron is found 90% of the time. Molecule, - Two or more atoms held together by COVALENT bonds. Compound, - Combination of two or more different elements. Electronegativity, - The attraction of an atom for the electrons of a covalent bond. Greater atom's elecneg, the more it pulls electrons toward itself. Ion, - A charged atom or molecule Cation, - A positively charged Ion Anion, - A negatively charged Ion Ionic Bond - attraction between anions and cations Ionic compounds are called, - Salts Polar molecule, - the overall charge of a molecule is unevenly distributed Cohesion, - ex. water has high cohesion because of the abundance of hydrogen bonds. capacity to hold itself together.
chromosomes, - structures that carry genetic information. discrete units of dna. each chromosome contains one long DNA molecule associated with many proteins. Adhesion, - the clinging of one substance to another. kinetic energy, - the energy of motion. anything that moves has kinetic energy. Atoms and molecules have kinetic energy. heat, - a form of energy. the measure of a matter's total kinetic energy due to motion of its molecules; depends in part on the matter's volume. not temperature Light Microscope, - visible light is passed through the specimen and then through the glass lenses. up to x Organelles, - membrane-enclosed structures within eukaryotic cells. Electron microscope, - Uses a beam of electrons instead of light. Elecron microscopes kill the cells in preparation unlike light microscopes. Scanning electron microscope, - electron beam scans the surface of the sample, usually coated with gold.results in a 3d image of the specimen's surface. Transmission Electron Microscope, - used to study internal structure of cells. Cell fractionation, - takes cells apart and separates major organelles and other subcellular structures. eukaryotic cell, - most of DNA inside nucleus, bounded by a double-membrane. prokaryotic cell, - DNA is concentrated in a region that is not membrane enclosed, called the nucleoid. cytoplasm, - interior of a cell, in euk cells: the region between the nucleous and plasma membrane. plasma membrane, - selective barrier that allows passage of enough oxygen, nutrients, and wastes to service the entire cell. nucleus, - contains most of the genes in a eukaryotic cell (also in mitochondria and chloroplasts). nuclear envelope, - encloses the nucleus seperating its contents from the cytoplasm. Double membrane.
hydrogen bond - a chemical bond consisting of a hydrogen atom between two electronegative atoms (e.g., oxygen or nitrogen) with one side be a covalent bond and the other being an ionic Plasmodesmata, - cytoplasmic chanels through cell walls that connect the cytoplasms of adjacent cells. Cell wall, - outer layer that maintains cell's shape and protects cell from mechanical damage; made of cellulose, other polysaccharides and protein. Metabolic function, - the processes necessary for the maintenance of a living organism. covalent bond - a chemical bond that involves sharing a pair of electrons between atoms in a molecule ionic bond - a chemical bond in which one atom loses an electron to form a positive ion and the other atom gains to electron to form a negative ion bond Four base pairs found in DNA and how they pair. - Adenine:Thymine Guanine:Cytosine MRNA - the template for protein synthesis The form of RNA that carries information from DNA in the nucleus to the ribosome sites of protein synthesis in the cell RNA - (biochemistry) a long linear polymer of nucleotides found in the nucleus but mainly in the cytoplasm of a cell where it is associated with microsomes transcription - (genetics) the organic process whereby the DNA sequence in a gene is copied into mRNA chromosome - in a eukaryotic cell, one of the structures in the nucleus that are made up of DNA and protein; in a prokaryotic cell, the main ring of DNA nonpolar covalent bond - A covalent bond in which the bonding electrons are shared equally by the bonded atoms, resulting in a balanced distribution of electrical charge polar covalent bond - A covalent bond between atoms that differ in electronegativity. The shared electrons are pulled closer to the more electronegative atom, making it slightly negative and the other atom slightly positive. single, double, and triple covalent bonds - two, four and six electrons are shared respectively hydrogen bonds - the weak bond bridging hydrogen atoms and atoms of the opposite charge
heat capacity - The amount of heat required to raise the temperature of a specified amount of a substance by 1°C or 1 K. The degree to which a substance changes temperature in response to a dissolve - A mixture in which particles of one or more substances (the solute) are distributed uniformly throughout another substance (the solvent), so that the mixture is homogeneous. solvent - substance doing the dissolving gain or loss of heat. capillary action - A proccess powered by adhesion that causes water molecules to move upward through a narrow tube such as the stem of a plant. organic molecules are those that have - carbon atoms macromolecules - large molecules such as proteins, carbohydrates, nucleic acids, or lipids. hundreds or thousands of atoms. usually polymers polymer - a naturally occurring or synthetic compound consisting of large molecules made up of a linked series of repeated simple monomers monomer - The subunit that serves as the building block of a polymer. functional groups - A specific configuration of atoms commonly attached to the carbon skeletons of organic molecules and usually involved in chemical reactions. monosaccharide - A single sugar molecule such as glucose or fructose, the simplest type of sugar. disaccharide - Consists of two monosaccharides joined by a glycosidic linkage. During the process of joining, a water molecule is lost. this is a condensation reaction, or specifically a dehydration reaction. glucose+fructose - sucrose glucose+galactose - lactose glucose+glucose - maltose polysaccharide - macromolecules, polymers with a few hundred to a few thousand monosaccharides joined by glyco- sidic linkages starch - polymer of a-glucose molecules. the principal energy storage molecule in plant cells. glycogen - polymer of a-glucose molecule. major energy storage molecule in animal cells.
Defensive proteins - provide protection against foreign substances that enter the bodies (antibodies) Enzyme - a globular protein that activate or accelerate metabolic reactions (act as catalysts) in either direction. enzymes are unchanged as a result of this reaction. It can perform it's function repeatedly. standard suffix of "ase". peptide bonds - The bonds connecting amino acids together to form polypeptide chains. primary structure - The level of protein structure referring to the specific sequence of amino acids. ex: cys-tyr-phe-gln secondary structure - 3d shape. The localized, repetitive coiling or folding of the polypeptide backbone of a protein due to hydrogen bond formation between peptide linkages. alpha helix - the spiral shape resulting from the coiling of a polypeptide in a protein's secondary structure beta pleated sheet - One form of the secondary structure of proteins in which the polypeptide chain folds back and forth, or where two regions of the chain lie parallel to each other and are held together by hydrogen bonds. fibrous proteins - proteins whose shape is dominated by alpha helix and beta pleated sheets tertiary structure - includes 3dimensional shaping and often dominates the structure of globular proteins. factors contributing to structure: hydrogen bonding between R groups of amino acids, Ionic bonding between R groups... hydrophobic effect that occurs when hydrophobic R groups move toward the center of the protein, formation of disulfide bonds (disulfide bridge) quaternary structure - protein that is assembled by two or more separate peptide chains. nucleic acids - DNA and RNA nucleotide - 3 parts: a nitrogen base, a 5-carbon sugar called deoxyribose, and a phosphate group. there are 4 dna nucleotides: adenine: a double ring base, thymine: a singe ring base, cytosine: a single ring base, guanine: a double ring base. Single ring: purine, double ring: pyrimidine. RNA differences - Sugar is ribose (not deoxyribose), adenine pairs with uracil (not thymine), and is single stranded.
chemical equilibrium - the condition where the rate of reaction in the forward direction equals the rate in the reverse direction and so there is no net production of reactants or products. activation energy - the energy that an atomic system must acquire before a process (such as an emission or reaction) can occur. "catalysts are said to reduce the energy of activation during the transition phase of a reaction" catalysts - substance that speeds up (reduces the activation energy of) a chemical reaction but is not used up itself or permanently changed metabolism - chemical reactions that occur in biological systems. Includes the breakdown of substances (catabolism), the formation of new products (synthesis or anabolism) or the transferring of energy from one substance to another. substrate - the substance or substances upon which the enzyme acts. ex. the enzyme amylase catalyzes the substrate amylose. enzymes are substrate specific... work only in a particular way with a particular substrate. efficiency of an enzyme is effected by - temperature and pH denatured - loss of an enzyme's normal shape so that it no longer functions; caused by a less than optimal pH and temperature cilia - Short, hair-like structures made of microtubules that enable movement of cells or movement of materials outside a cell centrioles and basal bodies are? and they act as? - act as microtubule organizing centers. centrioles are one of two small cylindrical cell organelles composes of 9 triplet microtubules. basal bodies are centrioles forming the bases of cilia and flagella vacuoles and vesicles are - fluid filled membrane bound bodies. transport vesicles - move materials between organelles or between organelles and the plasma membrane. food vacuoles - temporary receptacles of nutrients. Food vacuoles often merge with lysosomes, whose digestive enzymes break down the food. Storage vacuoles - in plants. store starch, pigments, and toxic substances. contractile vacuoles - specialized organelles in single-celled organisms that collect and pump excess water out of the cell. cell wall is composed mainly of? - cellulose
Receptor-mediated endocytosis - occurs when -specific molecules- in the fluid surrounding the cell bind to specialized receptors that concentrate in coated pits in the plasma membrane. The osmosis - diffusion of water through a selectively permeable membrane dialysis - diffusion of solutes across a selectively permeable membrane. term used usually when different solutes are separated by a selectively permeable membrane. plasmolysis - the movement of water out of a cell (osmosis) that results in the collapse of the cell. facilitated diffusion - the transport of substances through a cell membrane along a concentration gradient with the aid of carrier proteins countercurrent exchange - the opposite flow of adjacent fluids that maximizes transfer rates; for example, blood in the gills flows in the opposite direction in which water passes over the gills, maximizing oxygen uptake and carbon dioxide loss. active transport - movement of solutes against a gradient and requires expenditure of energy (usually ATP). vesicular transport - uses vesicles or other bodies in the cytoplasm to move macromolecules or large particles across the plasma membrane. Exocytosis - vesicles fusing with the plasma membrane and releasing their contents to the outside of the cell. Common when a cell produces substances for export. Endocytosis - capture of a substance outside the cell when the plasma membrane merges to engulf it. The substance then enters the cytoplasm enclosed in a vesicle. Phagocytosis - (Endocytosis)"cellular eating" occurs when -undissolved- material enters the cell. The plasma membrane merges to engulf it, forming a phagocytic vesicle.Phagocytic cells attack and engulf bacteria in this manner. Pinocytosis - (endocytosis) "cellular drinking" occurs when -dissolved- substances enter a cell. plasma membrane folds inward to form a channel allowing the liquid to enter. plasma membrane then closes off the channel, encircling the liquid inside a vesicle. membrane pits, receptors, and their specific molecules (ligands) flod inward and the formation of a vesicle follows. Primary Structure - Sequence of AAs attached by peptide bonds
Secondary Structure - - Arises through hydrogen bonding between carbonyl oxygen and amino hydrogens located on the peptide backbone (main chain)
- Two most common are alpha helices and beta sheets
- DOES NOT involve H-bonding of side chains, but the type of secondary structure that's formed can be influenced by side chains Tertiary Structure - - Refers to interactions of secondary structures
- Side chain and main chain H-bonding are important - Also ionic, hydrophobic, and van der Waals Quaternary Structure - - Interactions between different polypeptide chains
- Interactions mediated by same forces important for tertiary structure
- Relative orientation of subunits can change to regulate function of the complex Interactions Governing S,T, and Q Structures of Protein - 1. H-Bonds
- Especially important for secondary structure
- Ionic
- Between side chains of charged AAs - "salt bridges"
- Hydrophobic
- Hydrophobic side chains exclude water and get packed together - E favorable, an entropic effect
- Van der Waals - not strong on own but yes in aggregate
- Between any two atoms
- Important in tightly packed regions of the protein H-Bonding in an Alpha Helix - - Alpha helix stabilized by main chain H-bonds
- Occurs between every fourth residue (red arrows)
- Happens between partially negative O and hydrogens on partially positive N (due to partial double bond character of peptide bond)
- Turns once ever 3.6 AAs
- Though side chains ARE NOT directly involved in forming H-bonds, the nature of the side chain helps determine which secondary structure will form
B-Barrel - found in natrually fluorescent protein from jellyfish (GFP) - barrel shields the fluorophore from water hydroxyl group - consists of a hydrogen bonded to an oxygen. carbonyl group - a carbon linked by a double bond to an oxygen atom. also called an aldehyde or a ketone depending on its location. carboxyl group - consists of a carbon double-bonded to both an oxygen and a hydroxyl group amino group - composed of a nitrogen bonded to two hydrogen atoms and the carbon skeleton phosphate group - consists of a phosphorus atom bonded to four oxygen atoms aldehyde - the name for a carbonyl group (c=o) located at either end of a carbon skeleton. ketone - the name for a carbonyl group (c=o) located near the middle of a carbon skeleton. Element, - a substance that cannot be broken down to other substances by chemical reactions. (92) essential elements, - the 20-25% of natural elements that an organism needs to live a healthy life and reproduce. Trace elements, - elements required by an org. in only minute quantities Dalton, - 1.7 x 10^-24 g. same as amu (atomic mass unit). The mass of a proton or neutron. atomic number, - The number of protons in an element. 2He means there are 2 protons in the nucleus of helium. Equal number of electrons unless noted. mass number, - The sum of protons plus neutrons in the nucleus of an atom. 4/2He means there are 2 neutrons atomic mass, - Total mass of an atom. = approximately the mass number. isotope, - A different atomic forms of the same element. All atoms of same element have same number of protons, but isotopes have more neutrons giving greater mass. Radioactive isotope, - Isotope in which the nucleus decays spontaneously, giving off particles and energy. If # of protons changes it changes into a different element. Energy, - Capacity to cause change.
Potential energy: - The energy matter possesses because of its location or structure. (Water on a hill has potential energy because of it's altitude) Electron Shells: - Different levels (like a staircase) where electrons can be found. The higher the level (father the distance) the more potential energy on the electron. Valence electrons, - Electrons in the outermost shell of an atom. Valence shell, - The outermost electron shell of an atom. Valence - The bonding capacity of an atom; the number of unpaired electrons required to complete the valence shell. Oxygen has a valence of 2. Completed valence shell - The atom with a full valence shell will not react readily with other atoms. Called inert. Shell limits - 1:2, 2:8, 3: Orbital - The 3dimensional space where an electron is found 90% of the time. Molecule - Two or more atoms held together by COVALENT bonds. Compound - Combination of two or more different elements. Ion, - A charged atom or molecule Cation, - A positively charged Ion Anion, - A negatively charged Ion Ionic Bond - attraction between anions and cations Ionic compounds are called, - Salts Polar molecule, - the overall charge of a molecule is unevenly distributed Cohesion, - ex. water has high cohesion because of the abundance of hydrogen bonds. capacity to hold itself together. Adhesion - The clinging of one substance to another. Cohesion refers to water molecules sticking to each other, while adhesion refers to water molecules sticking to other substances. Other liquids have fewer interactions between the molecules.
