Cellular Processes and Molecular Biology, Exams of Biology

Download Cellular Processes and Molecular Biology and more Exams Biology in PDF only on Docsity!

Biology 200 Final Exam QUESTIONS &

SOLUTIONS 2024 LATEST UPDATE

Negative Feedback - ANSWER In which the response reduces the initial stimulus Positive Feedback - ANSWER In which an end product speeds up its own production Bacteria - ANSWER Single-celled organisms that lack a nucleus Archaea - ANSWER Single-celled microscopic organisms Eukarya - ANSWER Domain includes all eukaryotic organisms Plants, fungi, animals, protists Inductive reasoning - ANSWER Derives generalizations from a large number of specific observations Deductive reasoning - ANSWER Uses general premises to make specific predictions Data - ANSWER Recorded observations Theory - ANSWER Broader in scope than a hypothesis, General enough to lead to many new, testable hypothesis Technology - ANSWER The goal is to apply scientific knowledge for some specific purpose Element - ANSWER Substance that cannot be broken down to other substances by chemical reactions Compound - ANSWER Substance consisting of two or more elements in a fixed ratio

Atom - ANSWER Smallest unit of matter that still retains the properties of an element Atomic number - ANSWER Element's number of protons in its nucleus Acid - ANSWER Substance that increases the H+ concentration of a solution Base - ANSWER Substance that reduces the H+ concentration of a solution Buffer - ANSWER Substances that minimize changes in concentration of H+ and OH- in a solution Hydrocarbon - ANSWER Organic molecules consisting of only carbon and hydrogen Isomer - ANSWER Compounds with the same molecular formula but different structures and properties Structural isomer - ANSWER Have different covalent arrangements of their atoms Cis-trans isomer - ANSWER Have the same covalent bonds but differ in their spatial arrangements Enantiomer - ANSWER Are isomers that are mirror images of each other Functional group - ANSWER Are the components of organic molecules that are most commonly involved in chemical reactions ATP - ANSWER Is composed of ribose (a sugar), adenine (a nitrogenous base), and three phosphate groups; cell's energy shuttle Monomer - ANSWER The repeating units that serve as building blocks are called?

Polymer - ANSWER Long molecule consisting of many similar building blocks Dehydration reaction - ANSWER Occurs when two monomers bond together through the loss of a water molecule Hydrolysis reaction - ANSWER Polymers are disassembled to monomers by a reaction that is essentially the reverse of the dehydration reaction that is essentially the reverse of the dehydration reaction; water is added to break the bonds between atoms Monosaccharide - ANSWER Simplest carbohydrates; simple sugars Are usually multiples of CH2O Polysaccharide - ANSWER Polymers of sugars; have storage and structural roles Triacylglycerol - ANSWER Three fatty acids are joined to glycerol by an ester linkage, creating a? Steroid - ANSWER Lipids characterized by a carbon skeleton DNA - ANSWER provides directions for its own replication directs synthesis of messenger RNA (mRNA) and, through mRNA, controls protein synthesis RNA - ANSWER A molecule that interacts with the cell's protein -synthesizing machinery to direct production of a polypeptide single stranded Cell fractionation - ANSWER Takes cells apart and separates the major organelles from one another Plasma membrane - ANSWER Selective barrier that allows sufficient passage of oxygen, nutrients, and waste to service the volume of every cell

Prokaryotic cell - ANSWER No nucleus, DNA in an unbound region called the nucleoid, No membrane- bound organelles, Cytoplasm bound by the plasma membrane Eukaryotic cell - ANSWER DNA in a nucleus that is bounded by a double membrane, Membrane-bound organelles, Cytoplasm in the region between the plasma membrane and nucleus Atomic mass - ANSWER Atom's total mass; can be approximated by the mass number Isotopes - ANSWER Two atoms of an element that differ in the number of neutrons Polar covalent bond - ANSWER One atom is more electronegative, and the atoms do not share the electron equally Nonpolar covalent bond - ANSWER Atoms share the electron equally Ionic bond - ANSWER Attraction between an anion and a cation Hydrogen bond - ANSWER Forms when a hydrogen atom covalently bonded to one electronegative atom is also attracted to another electronegative atom Cohesion - ANSWER Collectively, hydrogen bonds hold water molecules together, a phenomenon called? Surface tension - ANSWER A measure of how difficult it is to stretch or break the surface of a liquid Specific heat - ANSWER Amount of heat that must be absorbed or lost for 1g of that substance to change its temperature by 1C Solvent - ANSWER Dissolving agent of a solution Hydrophilic - ANSWER Has an affinity for water

Hydrophobic - ANSWER Does not have an affinity for water pH scale - ANSWER Measurement system to decide if a solution is acidic or basic Organelle - ANSWER The membrane-enclosed structures in eukaryotic cells Cytoskeleton - ANSWER Network of fibers extending throughout the cytoplasm Cilia - ANSWER Found in large numbers on a cell surface Microtubule containing extensions that project from some cells Flagella - ANSWER Are limited to one or a few per cell Microtubule containing extensions that project from cells Cell wall - ANSWER Extracellular structure that distinguishes plant cells from animal cells Extracellular matrix - ANSWER Animal cells lack cell walls but are covered by an elaborate Amphipathic - ANSWER Molecules containing hydrophobic and hydrophilic regions Selective permeability - ANSWER Some substances cross more easily than others Concentration gradient - ANSWER The region along which the density of a chemical substance increases or decreases Hypertonic - ANSWER Solute concentration is greater than that inside the cell; cell loses water Facilitated diffusion - ANSWER Transport proteins speed the passive movement of molecules across membrane; includes channel proteins and carrier proteins

Sodium potassium pump - ANSWER Energizes the transport of K+ into the cell and Na+ out of the cell Exocytosis - ANSWER Transport vesicles migrate to the membrane, fuse with it, and release their contents outside the cell Endocytosis - ANSWER Macromolecules are taken into the cell in vesicles Electron transport chain - ANSWER Consists of a series of molecules built into the inner membrane of the mitochondria Glycolysis - ANSWER Breaks down glycose into two molecules of pyruvate Citric acid cycle - ANSWER Completes the breakdown of glucose to CO Oxidative phosphorylation - ANSWER Electron transfer chain and chemiosmosis facilitate synthesis of most of the cell's ATP synthesis; powered by redox reactions Acetyl CoA - ANSWER The entry compound for the citric acid cycle in cellular respiration, formed from a two-carbon fragment of pyruvate attached to a coenzyme Proton-motive force - ANSWER The potential energy stored in the form of an electrochemical gradient, generated by the pumping of hydrogen ions across biological membranes during chemiosmosis. Chemiosmosis - ANSWER The use of energy in a H+ gradient to drive cellular work Autotrophs - ANSWER "Self-feeders" that sustain themselves without eating anything derived from other organisms; produce organic molecules from CO2 and other inorganic molecules; include plants, algae, some protists, and bacteria Chloroplasts - ANSWER Have an envelope of two membranes surrounding a dense fluid called the stroma

Thylakoids - ANSWER Connected sacs in the chloroplast that compose a third membrane system Photosynthesis - ANSWER Process that converts solar energy into chemical; nourishes entire living world Light reactions - ANSWER The first of two major stages in photosynthesis. These reactions, which occur on the thylakoid membranes of the chloroplast or on membranes of certain prokaryotes, convert solar energy to the chemical energy of ATP and NADPH, releasing oxygen in the process. NADPH - ANSWER An electron carrier involved in photosynthesis. Light drives electrons from chlorophyll to NADP+, forming NADPH, which provides the high-energy electrons for the reduction of carbon dioxide to sugar in the Calvin cycle. Stroma - ANSWER Chloroplasts have an envelope of two membranes surrounding a dense fluid called Visible light - ANSWER Wavelengths 380-740 nm drives photosynthesis and produces the colors we can see Wavelengths - ANSWER Measure of the distance between crests of electromagnetic waves Chlorophyll A - ANSWER The key light-capturing pigment that participates directly in light reactions Signal transduction pathway - ANSWER Series of steps by which a signal on a cell's surface is converted into a specific cellular response Local regulator - ANSWER Animal cells may communicate by direct contact or by using messenger molecules that travel only a short distance Hormones - ANSWER In long-distance signaling, plants and animals use molecules called Ligand - ANSWER The binding between a signal molecule

G protein - ANSWER Acts as on/off switch Protein kinase - ANSWER Transfer phosphates from ATP to protein, a process called phosphorylation Protein phosphatase - ANSWER Remove the phosphates from proteins, a process called dephosphorylation Second messenger - ANSWER Small, nonprotein, water-soluble molecules or ions that spread throughout a cell by diffusion Apoptosis - ANSWER Prevents enzymes from leaking out of a dying cell and damaging neighboring cells Chromosomes - ANSWER DNA molecules in a cell are packaged into Carries several hundred to a few thousand genes Somatic cells - ANSWER Have two sets of chromosomes non-reproductive Sister chromatids - ANSWER Each duplicated chromosome has two They separate during cell division Centromeres - ANSWER Narrow "waist" of the duplicated chromosome, where the two chromatids are most closely attached Mitosis - ANSWER Division of the genetic material in the nucleus, process of creating new somatic cells Cytokinesis - ANSWER Division of the cytoplasm Cleavage - ANSWER In animal cells, cytokinesis occurs by a process known as

Cell plate - ANSWER In plant cells, a ____ _____ forms during cytokinesis Binary fission - ANSWER A method of asexual reproduction in single-celled organisms in which the cell grows to roughly double its size and then divides into two cells Metastasis - ANSWER The spread of cancer cells to other parts of the body, where they may form additional tumors Locus - ANSWER A gene's specific position along a chromosome is called Karyotype - ANSWER Ordered display of the pairs of chromosomes from a cell Diploid - ANSWER Has two sets of chromosomes Homologous - ANSWER term used to refer to chromosomes that each have a corresponding chromosome from the opposite-sex parent Autosomes - ANSWER Remaining 22 pairs of chromosomes Sex chromosomes - ANSWER Determine the sex of the individual; are called X and Y Gametes - ANSWER Genes are passed to the next generation via reproductive cells called Haploid - ANSWER One gamete contains a single set of chromosomes and is a Meiosis - ANSWER Gametes are only human cells produced by Results in 1 set of chromosomes in each gamete Crossing over - ANSWER Exchange of DNA segments between non-sister chromatids

Heterozygotes - ANSWER An organism with two different alleles for a gene is Dominant allele - ANSWER If the two alleles at a locus differ then one is Catabolic - ANSWER Release energy by breaking down complex molecules into simpler compounds Anabolic - ANSWER Consume energy to build complex molecules from simpler ones Entropy - ANSWER disorder in the universe Free energy - ANSWER The portion of a system's energy that can do work when temperature and pressure are uniform throughout the system, as in a living cell Exergonic - ANSWER Proceeds with a net release of free energy to the surroundings and is spontaneous Endergonic - ANSWER Absorbs free energy from the surroundings and is nonspontaneous Energy coupling - ANSWER The use of an exergonic process to drive and endergonic one Active site - ANSWER Region on the enzyme, often a pocket or groove, that binds to the substrate Substrate - ANSWER The reactant that an enzyme acts on is called the enzyme's Competitive inhibitor - ANSWER Closely resemble the substrate and can bind to the enzyme's active site Oxidation - ANSWER Substance loses electrons Fermentation - ANSWER Partial degradation of sugars that occurs without oxygen

Reduction - ANSWER Substance gains electrons Recessive allele - ANSWER Mutated genetic variation not always less common Homozygotes - ANSWER An organism with two identical alleles for a gene is Law of segregation - ANSWER The two alleles for a heritable character separate during gamete formation and end up in different gametes Law of independent assortment - ANSWER Each pair of alleles segregates independently of any other pair of alleles during gamete formation Incomplete dominance - ANSWER Phenotypes of F1 hybrids are somewhere between the phenotypes of the two parental varieties Codominance - ANSWER Two dominant alleles affect the phenotype in separate distinguishable ways Pleiotropy - ANSWER Most genes have multiple phenotypic effects, a property called Multifactorial - ANSWER Traits that depend on multiple genes combined with environmental influences are called X-linked - ANSWER Genes on the X chromosome Barr body - ANSWER The inactive X condense into a? Linkage map - ANSWER Genetic map of a chromosome based on recombination frequency Aneuploidy - ANSWER Results from the fertilization of gametes in which nondisjunction occurred

Nondisjunction - ANSWER Pairs of homologous chromosomes do not separate normally during meiosis Polyploidy - ANSWER Condition in which an organism has more than two complete sets of chromosomes Deletion - ANSWER Removes a chromosomal fragment Duplication - ANSWER Repeats a chromosomal segment Inversion - ANSWER Reverses orientation of a segment within a chromosome Translocation - ANSWER Moves a segment from one chromosome to another Double helix - ANSWER Pattern in photo suggested that the DNA molecule was made up of two strands forming a? Antiparallel - ANSWER Subunits run in opposite directions Semiconservative - ANSWER Predicts that when a double helix replicates, each daughter molecule will have one old strand and one newly made strand Replication fork - ANSWER At the end of each replication bubble is a A Y-shaped region where parental DNA strands are being unwound Leading strand - ANSWER Along one template strand of DNA, the DNA polymerase synthesizes a Lagging strand - ANSWER To elongate the other new strand DNA polymerase must work in the direction away from the replication fork Telomeres - ANSWER Eukaryotic chromosomal DNA molecules have special nucleotide sequences at their ends called

Histones - ANSWER Are responsible for the main level of DNA packing in interphase chromatin Nucleosomes - ANSWER In a 10-nm chromatin fiber, the unfolded chromatin resembles beads on a string, with each "bead" being a Euchromatin - ANSWER Loosely packed chromatin Transcription - ANSWER Synthesis of RNA using information in DNA; produces messenger RNA (mRNA) Translation - ANSWER Synthesis of a polypeptide, using information in the mRNA; takes place at ribosomes mRNA - ANSWER messenger RNA; type of RNA that carries instructions from DNA in the nucleus to the ribosome Codons - ANSWER During translation the mRNA base triplets called Are read in the 5' -> 3' direction RNA polymerase - ANSWER RNA sythesis is catalyzed by Which pries the DNA strands apart and joins together the RNA nucleotides RNA processing - ANSWER Enzymes in the eukaryotic nucleus modify pre-mRNA Exon - ANSWER Eventually expressed, usually translated into amino acid sequences Spliceosomes - ANSWER Variety of proteins and several small RNAs that recognize the splice sites tRNA - ANSWER transfer RNA; type of RNA that carries amino acids to the ribosome

rRNA - ANSWER ribosomal RNA; type of RNA that makes up part of the ribosome Operon - ANSWER Entire stretch of DNA that includes the operator, the promoter, and genes that they control Repressor - ANSWER Operon can be switched off by a protein Prevents gene transcription by binding to the operator and blocking RNA polymerase Inducer - ANSWER Inactivates the repressor and turns on transcription Activator - ANSWER Protein that binds to and enhancer and stimulates transcription of a gene Enhancer - ANSWER Distal control elements, groupings of which are called May be far away from a gene or even located in an intron Alternative RNA splicing - ANSWER Different mRNA molecules are produced from the same primary transcript, depending on which RNA segments are treated as exons and which as introns Differentiation - ANSWER Process by which cells become specialized in structure and function Morphogenesis - ANSWER The physical processes that give an organism its shape constitute Pattern formation - ANSWER Development of a spatial organization of tissues and organs In animals it begins with the establishment of the major axes Oncogene - ANSWER Cancer causing genes