Biology 110 midterm exam

Biology 110 midterm exam Name three levels of biological organization that refer to groups of organisms. - -population, community, ecosystem What is an organ? - -several types of tissues come together to form an organ to perform specific functions What is the difference between a population and a community? - -population: a group of the same species that lives together -community: all the populations of all the species that live in one area What are the most inclusive and least inclusive levels of taxonomic groups? - -most inclusive: domain -least inclusive: species List the differences between prokaryotes and eukaryotes. - -prokaryotes: No defined nucleus is cell No membrane bound organelles at all Simple cell structure Small size Asexual reproduction (binary fission) -eukaryotes Defined membrane bound nucleus and organelles Complex cell structure Capable of larger size Sexual reproduction (mitosis & meiosis) Some use asexual reproduction Explain binomial nomenclature and give an example of a scientific name. - -binomial nomenclature: unique scientific name consisting of genus and species Ex. African Lion - Panthera leo What is the difference between a hypothesis and a scientific theory? - -hypothesis: proposes and makes predictions about a specific question -theory: broad explanations of natural phenomenon supported by a large amount of data from different disciplines over a long period of time List the steps of the scientific method in order. - -make an observation -form a hypothesis -conduct experiment -analyze data -report results List the three subatomic particles and give the electrical charge of each. - -electron: negative -proton: positive -neutron: neutral Which electron shell can hold more electrons - the 1st shell or the 2nd shell? - -2nd shell For the element phosphorous, the atomic number is 15 and the atomic mass is 31. How many of the following subatomic particles does phosphorous have? - a. Protons = 15 b. Neutrons = 15 c. Electrons = 16 Oxygen has a total of 8 electrons. How many electrons are in the outer electron shell of oxygen? - -6 electrons Is the outer shell of oxygen full of electrons? - -no, there is room for 2 more electrons What is the octet rule? - -a chemical principle that states the main group of elements are most stable when 8 electrons are present in the valence electron shell What is the difference between a covalent and an ionic bond? - -the difference is that covalent bond shares electron while an ionic bond transfers electrons Are hydrogen bonds stronger or weaker than covalent bonds? - -hydrogen bonds are weaker What type of molecules are hydrophilic? - -polar and ionic molecules What property of water allows water to absorb large amounts of heat without changing temperature? - high specific heat and heat capacity Which of the following would be an acid - a substance with a pH of 3 or a pH of 9? - the substance with a pH of 9 would be an acid Do hydrolysis reactions form or break chemical bonds? - -hydrolysis breaks chemical bonds What is the difference between a monosaccharide and a disaccharide? - -monosaccharides make up disaccharides List two functions of carbohydrates - -energy source -structural support Are lipids hydrophilic or hydrophobic? - hydrophobic What is the difference between saturated and unsaturated fatty acids? - -saturated: Single covalent bonds Straight chains packed tightly together Solid at room temp -unsaturated: One or more double covalent bonds Double bonds create kinds Liquid at room temp Which part of a phospholipid is hydrophobic? - the tail Describe a peptide bond. - -covalent bonds that link together one carboxyl group of one amino acid to the amino group of a second amino acid What is the primary structure of proteins? - -liner sequence of amino acids (straight line) What is the tertiary structure of proteins? Is this structure cause by covalent or non-covalent interactions? - full folding of entire chain, noncovalent How are the two backbone strands of DNA held together? - -hydrogen bonds between bases of nucleotide monomers on each strand List the 4 basic tissue types, the function of each type and an example of each type. - -epithelial: function = lining internal and external of surfaces; makes glands Ex. Epidermis of skin, lining of intestine -connective: function = support and protection of tissues/organs; connect tissues to each other Ex. Bone, cartilage, blood, tendons, ligaments -muscle: function = strong contraction; body movement Ex. Skeletal muscles, cardiac muscles -nervous: function = transmission of nerve impulses Ex. Brain, spinal cord, nerves What is the extracellular matrix? - -fills the space between cells and supports and keeps the cells arranged in the proper positions and orientation What are the components of the extracellular matrix? - -water, proteins, and polysaccharides What type of protein is most common in the extracellular matrix? - collagen What is the function of Type I collagen? - -it forms large fibers and has high tensile strength Give one location of Type I collagen - skin, bones, cartilage What are glycosaminoglycans? - most common polysaccharides in ECM give an example of a glycosaminoglycan. - hyaluronic acid What is the function of anchoring junctions? - -binds cells strongly to each other and/or extracellular fluid List the types of anchoring junctions and indicate what cell adhesion molecule each type uses. - -Adherens junctions: cadherins -Desmosomes: cadherins -Hemidesmosomes: integrins -Focal adhesions: integrins Why are tight junctions necessary in the urinary bladder? - Neither water, nor other material, can leak between the cells. Give a location of a gap junction. - cardiac muscle List two tenets of cell theory - -cells are the smallest unit of life. -all living organisms are composed of one or more cells How does the available surface area of the cell membrane affect how large a cell can grow? - -the cell has to be able to transport things quickly in and out, so a bigger cell would have more things to transport, so it would need a bigger membrane (with a higher surface area) What are the 3 functions of microtubules? - -cell organization: position organelles within the cells -movement of chromosomes during cell division: make up the miotic spindle that pulls the chromosomes apart -cell movement: cilia and flagella create movement is the difference between cilia and flagella? - -cilia: -usually found in large numbers covering the surface of a cell -can be used to move a cell (paramecium) or to move substances across the surface of a cell (respiratory tract) -flagella: -long and occur singly or in pairs -used to move a cell (sperm) Nucleus - location of DNA Nucleolus - ribosomes made here; RNA; droplet organelle Endoplasmic Reticulum (rough) - studded with ribosomes that can be released into the lumen to be folded into their final shape and have things added to them; then packaged in membrane vesicles and sent to the golgi apparatus ribosomes - make proteins Smooth Endoplasmic Reticulum - detoxify many organic molecules (including alcohol and drugs); makes lipids; carbohydrate metabolism (breakdown glycogen in liver cells to release the glucose monomers into blood for energy); store calcium ions golgi apparatus - processes and secretes proteins and lipids lysosomes - breakdown old cell molecules so the pieces can be recycled; digest and breakdown foreign matter brought into the cell through phagocytosis peroxisomes - contains enzymes that can breakdown organic molecules and detoxify certain molecules; particularly involved in breaking down the toxic waste product hydrogen peroxide mitochondria/chloroplasts - animal cells: makes ATP to be used by cell for energy Plant cells: very similar, but carry out photosynthesis How does the endosymbiosis theory explain the DNA present in mitochondria? - -it's thought that mitochondria and chloroplasts were once bacteria that were engulfed by and lived in ancestral eukaryotic host cells, so they formed a beneficial relationship (endosymbiotic) where the bacteria that evolved into mitochondria gave the host cell increased ability to make ATP and the bacteria that evolved into chloroplasts gave the host cell ability to photosynthesize, this explains why mitochondria has its own small amount of DNA Describe the structure of the cell (plasma) membrane. - phospholipid bilayers where the hydrophilic heads are on the inner and outer surfaces of the membrane, and the hydrophobic tails are hidden on the inside of the membrane (each layer is called leaflet). How does the amount of saturated vs. unsaturated fatty acids affect the cell membrane? - -unsaturated fatty acids increase membrane fluidity because the double bonds make it too hard for lipids to be close together) -saturated fatty acids decrease membrane fluidity 1. Photosynthesis is an endergonic reaction. What is the source of energy that allows photosynthesis to occur? - light energy is converted to chemical energy in the form of glucose 1. What is the difference between autotrophs and heterotrophs? - -Autotroph: organisms that can make organic molecules from inorganic ones; makes their own food - sustain themselves without consuming anything derived from other organisms. -Heterotrophs: must get organic molecules from outside sources; can't make own food, has to eat. a. Are humans autotrophs or heterotrophs? - heterotrophs 1. What structures allow gas exchange in leaves (CO2 in, O2 out)? - -The inside of the leaf is a tissue called mesophyll. Holes on the surface of the leaf, called stomata, open into the mesophyll. The holes allow CO2 to enter and O2 to leave. 1. What are thylakoids, where are they located, and what stage of photosynthesis occurs in them? - -Within the stroma is a series of interconnected, flattened membrane discs called thylakoids. Light reactions occurs in them. what is a pigment? - molecule that can absorb specific wavelengths of light why do plants look green? - -They are high in Chlorophyll a and b. Leaves absorb red and violet light, and they reflect green light. 1. Flowers and fruits that are orange or red in color are high in what pigment? - Carotenoids which stage of photosynthesis releases oxygen into the air? - light reactions what stage of photosynthesis uses carbon dioxide absorbed from the air? - calvin cycle 1. What is the purpose of the electron chain used in the light reactions of photosynthesis? - -The energy created in the electron chain is used to pump H+ into the thylakoid lumen 1. What are the three products of the light reaction stage of photosynthesis? - -Oxygen, ATP, NADPH 1. What is the end product of the Calvin cycle in photosynthesis? - carbohydrates (glucose) 1. What stage of the Calvin cycle uses carbon dioxide? - carbon fixation 1. What is the G3P (glyceraldehyde-3-phosphate) made in the Calvin cycle used for? - -it is a sugar phosphate molecule that can be used to make glucose/starch 1. How do plants, by conducting photosynthesis, benefit humans? - -Humans receive Oxygen from photosynthesis 1. How does the membrane of the cell allow for different environments inside and outside the cell? - -Because the membrane is selectively permeable, the internal cell conditions can be regulated and designed for the best functioning of the cell. 1. Molecules diffuse down their concentration gradients. What does this mean? - from High concentration to Low concentration a. Does diffusion require energy input? - -No, it is a passive process and requires no input of energy. a. When will diffusion of a molecule across a membrane stop? - -It will continue to diffuse until there is the same concentration of solute on both sides of the membrane. (equilibrium) 1. For each example, circle the type of molecule that would diffuse across a membrane the fastest. - -small molecule* or large molecule -nonpolar (hydrophobic)* or polar (hydrophilic) -Ion (charged) or non charged molecule* what is osmosis? - -diffusion of water across a semipermeable membrane 1. Why do cells shrink (crenate) if placed in a hypertonic solution? - -water moves out of the cell in order to balance the concentration. The cell shrinks due to the loss of water. 1. If cells are placed in a hypotonic solution, will water move into or out of the cell? - -water will move into the cell 1. What is the function of channel proteins in the cell membrane? - -create open pores in a membrane, allows for rapid transport, used to transport ions and water a. What are three ways channel proteins can be "opened"? - -Binding of a small molecule, called a ligand, to the channel protein -Changes in electrical charge on one side of the channel -Mechanical pressure on the membrane and channel protein 1. What is the difference between channel proteins and transporter proteins? - -Channel proteins: transports ions and water -Transport proteins: moves organic molecules into the cell, moves some waste products out of cell 1. Why does active transport require an input of energy? - -because it's the movement of a solute across a membrane against its concentration gradient, so energy is needed 1. What is the function of Na+/K+ ATP-ase? (include the ions and charges present inside and outside the cell) - It is a primary transport; it maintains the correct amounts of sodium and potassium, and the correct charge difference, inside and outside of cell. Outside of the cell is positive (Na+ high), Inside of cell is negative (K+ high). 1. Does Na+/K+ ATP-ase use active or passive transport? - active transport 1. How is secondary active transport different from primary active transport? - -primary: gradients store energy, when is then released as the transported molecules are allowed to move back down their gradients. -secondary: uses stored energy to move other substances against their own gradients. 1. What type of transport would be used to take large particles, like bacteria, into the cell? - phagocytosis what type of energy is present in chemical bonds? - potential energy 1. When energy is converted from one form to another, for example: chemical energy (breaking chemical bonds) to mechanical energy (muscle contraction), most of the that energy is used to do work. What happens to the energy not used to do work? - -Some energy released is unusable. This unusable portion is usually in the form of heat, so most chemical reactions release heat as a by-product. 1. If a chemical reaction needs energy to happen, will it occur spontaneously? - -If there is enough free energy produced by a reaction, then the reaction will occur spontaneously. If not, then more energy will have to be added to the reaction for it to occur. a. What is the name for this type of reaction? - exergonic reaction a. Is the breaking of ATP to release a phosphate endergonic or exergonic? - exergonic reaction 1. Enzymes are types of catalysts. What does this mean? - -They speed up the rate of chemical reaction. 1. Why can only specific substrates bind to specific enzymes (how do enzymes make sure only the correct substrate can bind)? - -Lock and key model of enzyme binding. Only the correct substrate will fit into the enzyme active site. 1. In general, do enzymes work faster or slower at higher temperatures? - -Higher temperatures make enzymes work faster, however, enzymes are designed to function within a certain temperature range. If the temperature is higher or lower than the optimal range, the enzyme function will decrease or the enzyme may receive damage. 1. What type of metabolic reaction breaks down molecules? - catabolic reaction 1. Do anabolic reactions require energy or release energy? - requires energy 1. How does feedback inhibition regulate metabolic pathways? - -prevents overproduction of products 1. What is the main purpose of cellular respiration in eukaryotic cells? - -it is the process used by a cell to convert the energy in food molecules to a useable form of energy that can be used to power metabolic reactions 1. What is the function of kinase enzymes in phosphorylation reactions? - -the kinase enzymes move phosphates 1. What type of reactions transfer electrons from one molecule to another? - redox reactions 1. During what stage of glycolysis is ATP used (broken down to release phosphates)? - during the energy investment phase 1. How many pyruvate molecules are produced during glycolysis? - two molecules are produced 1. What happens to the pyruvate molecules made during glycolysis? - -they are transported to the mitochondrial matrix and each other are broken down (oxidized) into an acetyl group and a carbon dioxide 1. What is the first step of the citric acid cycle? - -the acetyl group is removed from acetyl CoA and attached to the 4-carbon molecule, oxaloacetate 1. What molecules are produced through the redox reactions of the citric acid cycle? - -NAD+ and FAD2 get reduced to form molecules of NADH and FADH a. What are these molecules used for? - -electron carriers pick up electrons from one molecule and transport them to another, so when they drop off the electron they go back to their original forms (NAD+ and FAD) and can be used again in more redox reaction 1. What happens to the carbon dioxide (CO2) produced during cellular respiration? - it is released as a waste product 1. Which step of cellular respiration requires oxygen? - -oxidative phosphorylation a. What is the function of oxygen in this step? - it is the final electron acceptor in the electron transport chain 1. How does energy released by electrons moving through the electron transport chain produce ATP? - -some of energy released during the electron transport chain is used to pump H+ out of the mitochondrial matrix and into the inner membrane space of the mitochondria, When H+ are allowed to flow passively back down that gradient, they pass through, and power, an enzyme called ATP Synthase a. What is the name of the enzyme used to make the ATP? - ATP synthase 1. Which step of cellular respiration is the only step used in fermentation? - glycolysis a. What happens to the NADH molecules produced during fermentation? - -the NADH go to the electron transport chain, drop off its' electrons and convert back to NAD+ 1. What is the difference between lactic acid fermentation and alcohol fermentation? - -lactic acid fermentation is used by many typed of eukaryotic cells and bacteria and alcohol fermentation is used by yeast and some bacteria how many ATP are produced through fermentation? - 2 Where does glycolysis happen? - cytosol (2 atp) where does pyruvate breakdown happen? - mitochondrial matrix (0 atp) Where does citric acid cycle happen? - mitochondrial matrix (2 ATP) Where does oxidative phosphorylation happen? - Cristae of inner mitochondrial matrix (30-34 ATP)