A.P. Biology Mid-term
Terms
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- Covalent Bonding
- A sharing of a pair of electrons
- Chromosome Number
- Refers to the sum total of chromosomes in cells of a given type. (Example: Humans have 46)
- Compound Light Microscope
- Two or more sets of glass lenses bend light emanating from a cell or some other specimen in ways that form and enlarged image of it.
- Introns
- Base sepquences that must be removed before a pre-mRNA molecule can be translated
- Endergonic
- Energy in
- Allele Frequencies
- The abundance of each kind of allele in a population.
- Polar
- When atoms of different elements do not exert the same pull on electrons
- Electron Transport System
- Consists of enzymes, coenzymes, and other molecules organized for electron transfers at a cell membrane.
- Active Transport
- Energy driven mechanisms called "membrane pumps" make solutes cross membranes against concentration gradients.
- Chemoautotrophic
- Influence the global cycling of nitrogen; strip organic compounds for electrons and hydrogen
- Anabolism
- When the cell synthesizes energy-rich organic compounds from smaller, energy-poor compounds (photosynthesis).
- Exergonic
- Energy out
- Linkage Group
- A large number of linked genes on each type of chromosome.
- Prophase
- Mitosis begins. DNA and associated proteins begin to condense. New microtubules become assembled. Nuclear envelope begins to break up.
- Bottleneck
- A severe reduction in population size brought about by intense selection pressure of some natural calamity.
- Buffers
- A partnership between a weak acid and the base that forms when the acid dissolves in water; work as a pair to counter shifts in pH levels
- Sexual Dimorphism
- When males are larger, have flashier coloration and patterning, and are much more aggressive than the females.
- Degradative Pathways
- Large molecules are broken down to products with lower bond energies (yields energy).
- Incomplete Dominance
- Red, white, or pink flowers
- Karyotyping
- A preparation of metaphase chromosomes based on their defining features.
- Hydrolysis
- A cleavage reaction that is like condensation in reverse; enzymes recognize specific functional groups and split molecules into two or more parts then attach an -OH group (hydroxyl group) and a hydrogen atom derived from a molecule of water to the exposed sites.
- Pauling
- Discovered the helical shape of collagen; made a model of DNA but with phosphate groups instead of hydrogen bonds.
- G2
- A second gap after DNA replication when the cell prepares for division
- Hydrophobic
- Water-fearing, non-polar molecules, oils
- Characteristics of Living Things
- 1. Has DNA 2. Reproduction and development 3. Metabolism 4. Sense changes in environment and make controlled responses to them
- Recognition Proteins
- Have oligosaccharide chains that identify a cell as being a certain type.
- Biosynthetic Pathways
- Small molecules are synthesized into molecules having higher bond energies, such as complex carbohydrates, lipids, and proteins. (requires energy inputs)
- Mutation Rate
- The probability of a gene mutating during or between DNA replications
- Morphological Divergence
- Chance in the body form from a common ancestor
- Theory of Segregation
- Diploid cells have pairs of genes, on pairs of homologous chromosomes. The two genes of each pair are separated from each other during meiosis, so they end up in different gametes.
- Fitness
- An adaptation to an environment.
- Lytic Pathway
- Steps 1-4 of the viral multiplication proceed rapidly and new particles are released when a cell undergoes lysis.
- Calcium Pump
- Helps keep the calcium concentration in a cell at least a thousand times lower than the outside.
- Exons
- Parts that remain in the mDNA when it gets translated into a protein.
- Non-polar
- Participating atoms exert the same pull on the electrons and both share them equally
- Telophase
- there are now two clusters of chromosomes which decondense. Patches of new membrane fuse to form a new nuclear envelope.
- Founder Effect
- When a few individuals leave a population and establish a new one elsewhere.
- Cytokinesis
- Membrane pinches together to form two separate cells.
- Chargaff
- Found that the amount of adenine relative to guanine differs from one species to the next; A = T; G = C
- Interphase
- G1, S, G2; leads to the rest of mitosis
- Nondisjunction
- when one or more chromosomes fail to separate in mitosis or meiosis. The forthcoming cells will have too many or too few chromosomes.
- First Law of Thermodynamics
- The total number of energy in the universe remains constant. it can only be converted from one form to another; it can not be created or destroyed.
- Receptor Proteins
- Bind extracellular substances that trigger changes in cell activities (ex. hormones).
- Scanning Electron Microscope
- A narrow beam of electrons moves back and forth across a specimen to which a thin coat of metal was applied. The metal responds by emitting some of its own electrons and a detector ties into electronic circuitry transforms the energy of electrons into an image of the specimen's surface on a television screen.
- Solute
- Any dissolved substance
- Hydrogen Bonding
- A weak attraction between electronegative atom and a hydrogen atom taking part in a second polar covalent bond.
- Genetic Equilibrium
- These conditions are met: 1. There have been no gene mutations 2. The population is large 3. It is isolated from other populations of the same species 4. The gene has no effect on survival or reproduction 5. Mating is random.
- Metaphase
- All chromosomes line up at the spindle equator. Chromosomes are in most tightly condensed form.
- Cell Theory
- 1.Every organism is composed of one or more cells. 2. The cell is the smalled unit having the properties of life 3. The continuity of life arises directly from the growth and division of single cells.
- Functional Groups
- Various kinds of atoms or clusters of them covalently bonded to the backbone.
- Surface-to-Volume Ratio
- An object's volume increases with the cube of the diameter, but its surface area increases only with the square.
- Transcription
- DNA to RNA
- Crossing Over
- A molecular interaction between two of the nonsister chromatids of a pair of homologous chromosomes.
- Genetic Drift
- A random change in allele frequencies over the generations brought about by chance alone.
- Chemoheterotrophic
- parasites and saprobes
- Codominance
- Blood type
- Somatic Cells
- Body Cells
- Comparative Morphology
- Comparing body forms and structures of major lineages.
- Polypeptide Chain
- When three or more amino acids are joined by peptide bonds.
- Adhesion Proteins
- Help cells of the same type locate and stick to one another and stay positioned in the proper tissues.
- Levels of Protein Structure
- Primary (polypeptide chain), secondary (coiled or extended/sheet), tertiary (loop out), quaternary (globular or fibrous)
- Haploid
- n; cells that contain only one of each type of chromosome characteristic of the species.
- Transport Proteins
- Allow water-soluble substances to move through their interior.
- Diploid
- 2n; when a cell has two of each type of chromosome characteristic of that species.
- Ionic Bonding
- An association of two ions that have opposing charges
- Anaphase
- Attachments between the two sister chromatids break. Now the two are separated and microtubules move them to opposite poles.
- Homologous Chromosomes
- Diploid chromosomes that have the same length and shape. Their genes line up with the same traits and they line up with each other during meiosis.
- Phosphorylation
- any transfer of a phosphate group to a molecule
- Photoautotrophic Bacteria
- Build organic compounds by photosynthesis; use CO2 for carbon source
- Entropy
- A measure of the degree of a system's disorder
- Balanced Polymorphism
- When two or more alleles for a trait persist over time in a popilation. Nonidentical alleles for a trait are being maintained at frequencies greater than 1%.
- Condensation
- When enzymes remove a hydroxyl group from one molecule and a hydrogen atom from another, then speed the formation of a covalent bond between the two molecules at their exposed sites; discarded atoms form a molecule of water
- Reduction
- The addition of electrons to substances
- Chromosome
- Each DNA molecule with its attached proteins.
- Cohesion
- The capacity to resist rupturing when placed under tension
- Theory of Independent Assortment
- By the end of meiosis, genes on pairs of homologous chromosomes have been sorted out for distribution into one gamete or another independently of gene pairs of other chromosomes.
- Oxidation
- The removal of electrons from substances
- Hydrophilic
- Water-loving, readily hydrogen bonds with water, polar molecules, sugars
- Lysogenic Pathway
- A latent period extends the cycle; the virus cuts the host chromosome and integrates the viral genes into it; when host cell divides, it replicates the viral DNA with it.
- Cell Cycle
- Interphase, Prophase, Metaphase, Anaphase, Telophase.
- Hershey and Chase
- Used viruses as experimental subjects called bacteriophages to infect E. coli and other bacteria.
- S
- Synthesis (DNA replication)
- Second Law of Thermodynamics
- Everything in the universe is slowly headed towards entropy.
- Gene Pool
- A pool of genetic resources that is sheared by all members of a population and is passed on to the next generation.
- Transmission Electron Microscope
- A magnetic field is the "lens"; accelerated electrons are directed through a specimen, focused into and image and magnified.
- G1
- A gap of cell growth and functioning before the onset of DNA replication
- Morphological Convergence
- When two or more separate lineages evolve in similar ways because of similar environmental pressures.
- Germ Cells
- A cell lineage set aside for the formation of gametes (such as sperm and egg) and sexual reproduction.
- Catabolism
- When the cell degrades energy-rich compounds to smaller simpler molecules to release usable energy for cellular work (anaerobic respiration)
- Scanning Tunneling Microscope
- Magnifies up to 100 million times; gave the picture of DNA; has a needle-like probe that has a single atom at its tip and when voltage is applied between the tip and an atom at the specimen's surface, it tunnels into the electron orbitals giving a three-dimensional view of surface atoms.