IB Biology HL Exam Questions with correct Answers

What are the characteristics common to all forms of life? - THE CORRECT ANSWER IS reproduction, carbon, responds to surroundings, Growth and Development, cellular organization, and energy What are the levels of biological organization from simple to most complex? - THE CORRECT ANSWER IS Molecules, cell, tissue, organ, organism, population, community, ecosystem, biosphere What are the 4 most common types of biological molecules? - THE CORRECT ANSWER IS Proteins, nucleic acids, carbohydrates, and lipids Organelle - THE CORRECT ANSWER IS any of a number of organized or specialized structures in a living cell Cell - THE CORRECT ANSWER IS The smallest structure and functional unit of an organism. Tissue - THE CORRECT ANSWER IS The material of specialized cells and their products that make a wall of cells and their products Organ - THE CORRECT ANSWER IS a part of an organism that is self-contained and serves a function Organism - THE CORRECT ANSWER IS an individual animal, plant, or single-celled life form What are the similarities and differences of a population and an ecosystem? - THE CORRECT ANSWER IS a population and ecosystem both include organisms, however a population is one type of species while an ecosystem is both biotic and abiotic things. What is the definition of emergent properties? - THE CORRECT ANSWER IS the feature that can't be directly from the features of its simpler parts eg. the taste of salt w/ the combination of Na+Cl What are the 4 shared characteristics of cells? - THE CORRECT ANSWER IS DNA, cytoplasm, ribosome, and plasma membranes What is the definition of unicellular organisms? - THE CORRECT ANSWER IS an organism that consists only of 1 cell eg. bacteria/microorganisms What is the definition of multicellular organisms? - THE CORRECT ANSWER IS an organism that consists of multiple cells eg. human What are the similarities and differences between prokaryotic and - THE CORRECT ANSWER IS eukaryotic cells? Prokaryotic cells have no nuclei, unlike Eukaryotic cells. Both are enclosed by membranes and have DNA. Prokaryotic cells have no independent organelles, except for the organelle of ribosome How do the cells in multicellular organisms become specialized? - THE CORRECT ANSWER IS By controlling what DNA is expressed in one cell, because all of the cells in an organism have the same DNA, but only express some. This might include how tight the bindings of the protein are, and if protein is made what the microRNAs do What is sexual reproduction? - THE CORRECT ANSWER IS the production of a new living organism by combining genetics of 2 different sexes/fusion of 2 gametes What is asexual reproduction? - THE CORRECT ANSWER IS the reproduction of offspring without the fusion of gametes. How do Growth and Development differ? - THE CORRECT ANSWER IS Growth is the process of Development, which is getting bigger/stronger/smarter When consumers die, what gets nutrients and energy from the dead? - THE CORRECT ANSWER IS The saprotrophs and detritivores What is the definition of homeostasis and an example? - THE CORRECT ANSWER IS The ability or tendency of an organism or cell to maintain internal equilibrium by adjusting its physical processes. eg. body temperature in mammals What is the definition of metabolism? - THE CORRECT ANSWER IS The chemical processes in living organisms in order to maintain life. eg. the mammal's body metabolism can change the need and absorption of energy, depending on environment How does "response to environment" differ from "adaptation to environment?" - THE CORRECT ANSWER IS Response involves the behavior that results from the environment, while adaptation is how structures or functions of an organism change in order to better survive in the environment. What is the definition of adapt? - THE CORRECT ANSWER IS to adjust to the environment What is the definition of anabolism? - THE CORRECT ANSWER IS constructive metabolism that synthesizes more complex substances from simple substances What is the definition of an atom? - THE CORRECT ANSWER IS The smallest unit of matter What is the definition of autotroph? - THE CORRECT ANSWER IS any organism capable of self nourishment to get energy What is the definition of Biome? - THE CORRECT ANSWER IS a large naturally occuring community of fauna and flora occupying that habitat What is the definition of biosphere? - THE CORRECT ANSWER IS it is the part of the earth's crust, waters, and atmosphere that support life What is the definition of catabolism? - THE CORRECT ANSWER IS the metabolism breaking down complex into simple substances with the release of energy What is the definition of cell? - THE CORRECT ANSWER IS the smallest functioning structure of living matter What is the definition of cell membrane? - THE CORRECT ANSWER IS The semipermeable membrane enclosing the cytoplasm of a cell What is the definition of community? - THE CORRECT ANSWER IS a set of species found in the same place at the same time What is the definition of cytoplasm? - THE CORRECT ANSWER IS The cell substance between cell membrane and nucleus What is the definition of detritivore? - THE CORRECT ANSWER IS an organism that uses organic waste as a food source What is the definition of differentiation? - THE CORRECT ANSWER IS process by which cells or tissues change/specialize in development What is an electron? - THE CORRECT ANSWER IS an elementary particle having negative charge and exists outside of the nucleus (electron cloud) What is evolution? - THE CORRECT ANSWER IS process how different living organisms developed and diversified What is growth? - THE CORRECT ANSWER IS increasing in amount or complexity What is a heterotroph? - THE CORRECT ANSWER IS organism deriving nutrients from complex organic substances What is a molecule? - THE CORRECT ANSWER IS a group of atoms bonded together What is a neutron? - THE CORRECT ANSWER IS a neutrally charged ion inside the nucleus with proton What is organization? - THE CORRECT ANSWER IS organic structure or compositions What is a proton? - THE CORRECT ANSWER IS A positive ion in the nucleus with a neutron What are ribosomes? - THE CORRECT ANSWER IS tiny mitten-shaped organelles that manufacture proteins What is a saprotroph? - THE CORRECT ANSWER IS organism that live and feeds on dead organic matter What is tissue? - THE CORRECT ANSWER IS An aggregate of similar cells and cell products What happens to the SA:V ratio when the size of the cell increases? - THE CORRECT ANSWER IS the ratio is becoming smaller ad smaller, giving a cell less surface area for the transport of nutrients for given unit volume What does the amount of surface area for a cell dictate? - THE CORRECT ANSWER IS the larger the SA is, the rate of diffusion halves each time cell doubles size, and the cell has a limit before it is too large to metabolize What does the amount of volume dictate in a cell? - THE CORRECT ANSWER IS the number of reactions increase in a cell the larger the volume What are some adaptations by cells to maximize their SA:V ratio? - THE CORRECT ANSWER IS Creating many more cell folds (Crista) in their cell membranes to maximize the SA which speeds up the processes of cellular metabolism What is the function of a cell membrane? - THE CORRECT ANSWER IS To protect the nucleus and filter particles What is the structure of a phospholipid? - THE CORRECT ANSWER IS made up of 2 hydrophobic tails for each hydrophilic head. Structure is flexible and changes shape easily due to fluidity. Structure is strong due to attraction between hydrophobic tails How are integral proteins different from peripheral proteins? - THE CORRECT ANSWER IS integral protein is inside the lipid bilayer, where peripheral protein are attached to the hydrophilic heads of the bilayer What are the 4 functions of membrane bound proteins? - THE CORRECT ANSWER IS a) Immune system receptors (b) act as carrier proteins to transport molecules across cell membranes (c) signal transduction (d) cell-cell adhesion Why are carrier proteins and channel proteins different types of transport proteins? - THE CORRECT ANSWER IS both are integral membrane proteins involved in moving things across the membrane and both have specific targets, but carrier proteins transport molecules by changing shape while channel proteins are like tubes to transport. Carrier proteins are saturated, while channel proteins are unsaturated Why are phospholipids in the membrane fluid? - THE CORRECT ANSWER IS fluid membranes allow cells to be dynamic and responsive in their environment Why are some fatty acids considered saturated while others are unsaturated? - THE CORRECT ANSWER IS saturated fatty acids are evenly filled with hydrogen, while double bonds in the hydrocarbon chain create unsaturated fatty acids What is the effect on the fluidity of being saturated or unsaturated? - THE CORRECT ANSWER IS That the double bonds in the unsaturated require more room, so unsaturated is more fluid than saturated What is the function of the cholesterol molecules in the membrane? - THE CORRECT ANSWER IS to provide protection from some water soluble molecules and provide structure in the cell membrane. Cholesterol also contains both a hydrophilic and hydrophobic What is adhesion? - THE CORRECT ANSWER IS water is attracted to other substances (like how water sticks together) What is a carrier transport protein? - THE CORRECT ANSWER IS can carry non charged substances across the membrane What is a channel carrier protein? - THE CORRECT ANSWER IS can carry charged substances across the membrane What is cholesterol in the membrane? - THE CORRECT ANSWER IS used to build and maintain the membrane, and modulates membrane fluidity What is an enzyme? - THE CORRECT ANSWER IS a substance produced by a living organism that acts as a catalyst in reactions What is a fatty acid? - THE CORRECT ANSWER IS carboxylic acid consists of hydrocarbon chain and terminal carboxyl groups What is a fluid mosaic? - THE CORRECT ANSWER IS widely accepted idea: in plasma membranes proteins are embedded in lipids What is an integral protein? - THE CORRECT ANSWER IS protein molecule is permanently attached to biological membrane What is a peripheral protein? - THE CORRECT ANSWER IS adheres only temporarily to biological membrane that they're associated What is the phospholipid bilayer? - THE CORRECT ANSWER IS thin membrane made of 2 layers of lipid molecules What is the plasma membrane? - THE CORRECT ANSWER IS external fatty layer surrounding molecules of a cell What is a receptor? - THE CORRECT ANSWER IS an organ or cell able to respond to stimuli and transmit signal What is saturated? - THE CORRECT ANSWER IS containing no double or triple bonds 2.1.1 Outline Cell Theory - THE CORRECT ANSWER IS Cell theory states that: all living organisms are composed of cells. Multicellular organisms are composed of many cells, while unicellular are of one cell. Cells are the basic unit of structure in all organisms. Cells are the smallest units of life capable of surviving on their own. Cells come from pre-existing cells and never non-living material 2.1.2 Discuss the evidence for the Cell Theory - THE CORRECT ANSWER IS Scientists had experimented and found the cell was the smallest piece of living matter that could live on its own, and because of these units were so small, they were named cells. Cells could only reproduce from living matter, because cells cannot reproduce unless the cells can perform cell reproduction, which is impossible with a dead cell 2.1.3 State that unicellular organisms carry out all functions of life. - THE CORRECT ANSWER IS Unicellular organisms carry out al the functions of life including: metabolism, response, homeostasis, growth, reproduction, and nutrition. 2.1.7 State that multicellular organisms show emergent properties - THE CORRECT ANSWER IS multicellular organisms show emergent properties. cells can form different substances by specializing. Being one cell on its own is useless because of cells working together to function 2.1.8 Explain that cells in multicellular organisms differentiate to carry out specialized functions by expressing some of their genes but not others - THE CORRECT ANSWER IS Each cell in a multicellular organism contains all of the genes of that organism. The genes that are activated are different for each cell in our body to have its own function. Cells will develop in their own ways by differentiation which depends on the gene expression 5.1.1 Define species, habitat, population, community, ecosystem, and ecology - THE CORRECT ANSWER IS Species are a group of organisms which can interbreed and produce fertile offspring. Habitat is environment in which a species normally lives. Population is a group of organisms of same species. Community is a group of populations living and interacting in an area. Ecosystem is system of organisms and abiotics in area. Ecology is the study of relationships between biotic and abiotic and the environment they're in 5.1.2 Distinguish between autotroph and heterotroph - THE CORRECT ANSWER IS autotrophs are organisms that synthesize their organic molecules from simple inorganic substances where areas heterotrophs are organisms that obtain organic molecules from other organisms 5.1.3 Distinguish between consumers, detritivores, and saprotrophs - THE CORRECT ANSWER IS consumer is an organism that ingests other organic material that is living or recently killed. Detritivore is an organism that ingests nonliving organic matter. Saprotroph is an organism that lives on nonliving organic matter, secreting digestive enzymes into it an absorbing the products of digestion 2.1.6 Explain the importance of the surface area to volume ratio as a factor limiting cell size. - THE CORRECT ANSWER IS A large number of chemical reactions take place in the cytoplasm of cells. To be able to use this space effectively (like metabolizing) the surface area to volume ratio is very important. If it is too small, cells will overheat because metabolism is too fast. If the ratio is too big, the cell will die because metabolism is too slow 2.4.1 Explain how the hydrophobic and hydrophilic properties of phospholipids help to maintain the structure of cell membranes. - THE CORRECT ANSWER IS the phospholipid is both hydrophilic and hydrophobic. With a hydrophilic head pointed pointed out hydrophobic tailspointed in when the lipid is in water, the phospholipid can be flexible but strong. This is also in part that the hydrophobic tails like to be by each other. This is a stable structure with fluidity that allows the cell to change shape easily and maintain the structure of cell membranes 2.4.3 List the functions of membrane proteins. - THE CORRECT ANSWER IS Membrane proteins can act as hormone binding sites, electron carriers, pumps for active transport, channels for passive transport, and enzymes. Also, they can be used for cell to cell communication and cell adhesion. 2.4.8 Describe how the fluidity of the membrane allows it to change shape, break and reform during endocytosis and exocytosis. - THE CORRECT ANSWER IS the phospholipids int he cell membrane are not solid but are in a fluid state allowing the membrane to change its shape and also vesicles to fuse with. This means substances can enter the cell via endocytosis and exit via exocytosis. The membrane then returns to its original states. In exocytosis, the vesicles fuse with the membrane expelling their content outside the cell. The membrane then goes back to its original state. Endocytosis is a similar process which involves the pulling of the plasma membrane inwards so that a vesicle is pinched off and then this vesicle can carry its content to anywhere in the cell 3.1.1 - State that the most frequently occurring elements in living things are carbon, hydrogen, oxygen and nitrogen. - THE CORRECT ANSWER IS Carbon, hydrogen, oxygen and nitrogen are the most frequently occurring chemical elements in living things. All of these elements form macromolecules essential to life, and are macronutrients/important components in all biochemical molecules.This is why all organisms are carbon-based life-forms. 3.1.2 - State that a variety of other elements are needed by living organisms, including sulfur, calcium, phosphorus, iron and sodium. - THE CORRECT ANSWER IS A variety of other elements are needed by living organisms including sulfur, calcium, phosphorus, iron and sodium to maintain homeostasis in living organisms with the most significant function being bonding to oxygen. 3.1.3 - State one role for each of the elements mentioned in 3.1.2 - THE CORRECT ANSWER IS Sulfur is needed for the synthesis of two amino acids. Calcium acts as a messenger by binding to calmodulin and a few other proteins that regulate transcription and other processes in the cell. Phosphorus is a part of DNA molecules and is also part of the phosphate groups in ATP. Iron is needed for the synthesis of cytochromes that are proteins used during electron transport for aerobic cell respiration. Sodium upon entering the cytoplasm raises the solute concentration, which allows water to enter by osmosis. 3.1.4 - Draw and label a diagram showing the structure of water molecules to show their polarity and hydrogen bond formation. - THE CORRECT ANSWER IS The Hydrogen in this diagram are positive and the oxygen carries a -2 polarity. To let the Oxygen form bonds with other Hydrogen after becoming neutral, it must connect by a covalent bond to the Hydrogen of another neutral water molecule. 3.1.5 - Outline the thermal, cohesive and solvent properties of water. - THE CORRECT ANSWER IS Thermal properties of water include heat capacity, boiling and freezing points and the cooling effect of evaporation. Due to water's substantial heat capacity, a significant amount of energy is needed to increase its temperature and break the many sturdy Hydrogen bonds included in its structure. This is why the temperature of water maintains homeostasis easily. Water has a high boiling and freezing point. It boils at 100 C due to strong hydrogen bonds that need to break before liquid can change to gas. Due to low density in the water as it reaches its freezing point, ice will float. To evaporate water below the boiling temperature, Hydrogen bonds need to break. Cohesion is the effect of hydrogen bonds holding the water molecules together. Capillary Action is due to cohesion. The polarity of water creates a magnetism in water, allowing for strong adhesion between water molecules. The solvent properties of water helps the many different molecules can adhere to it due to its polarity. 3.1.6 - Explain the relationship between the properties of water and its uses in living organisms as a coolant, medium for metabolic reactions and transport medium. - THE CORRECT ANSWER IS Water can evaporate at temperatures below the boiling point with breaking Hydrogen bonds. Evaporation of water cools mammalian bodies by sweat and plant leafs by transpiration. This is from using the heat energy to to break the hydrogen bonds. The solvent properties of water allow many different substances to attach to it due to its polarity and so substances can be carried in the blood and sap of plants as they dissolve in water. By doing these processes and having strong homeostasis, water can produce good metabolic reactions. 3.2.1 - Distinguish between organic and inorganic compounds. - THE CORRECT ANSWER IS Organic compounds are compounds that contain carbon. Inorganic compounds are the ones that don't contain carbon. There are few compounds found in living organisms that do not contain carbon, but are considered as inorganic compounds. These include carbon dioxide, carbonates and hydrogen carbonates. 3.2.2 - Identify glucose, ribose and fatty acids from diagrams showing their structures. - THE CORRECT ANSWER IS Glucose is a monosaccharide and is the easiest sugar to digest because it can be easily made into blood sugar. The glucose has a structure of five OH molecules, with the fifth hanging off of an Oxygen molecule. Glucose is a carbohydrate macromolecule. Ribose is a Pentose molecule, and has all of its hydroxyl groups on the same side. Ribose is a Nucleic Acid macromolecule. When mutated into deoxyribose, ribose can be part of a DNA strand. Fatty Acids are a macromolecule broken up into: triglycerides, phospholipids, and steroids. This group needs more oxygen to release energy. 3.2.3 - List three examples each of monosaccharides, disaccharides and polysaccharides. - THE CORRECT ANSWER IS Glucose, galactose and fructose are all monosaccharides. Maltose, lactose and sucrose are all disaccharides. Starch, glycogen and cellulose are all polysaccharides. 3.2.4 - State one function of glucose, lactose and glycogen in animals, and of fructose, sucrose and cellulose in plants. - THE CORRECT ANSWER IS In animals, glucose is used as an energy source for the body and lactose is the sugar found in milk which provides energy to new borns until they are weaned. Finally, glycogen is used as an energy source (short term only) and is stored in muscles and the liver. In plants, fructose is what makes fruits taste sweet that attracts animals that then eat the fruits and disperse the seeds found in the fruits. Sucrose is used as an energy source for the plant whereas cellulose fibers are what make the plant cell wall strong. 3.2.5 - Outline the role of condensation and hydrolysis in the relationships between monosaccharides, disaccharides and polysaccharides; between fatty acids, glycerol and triglycerides; and between amino acids and polypeptides. - THE CORRECT ANSWER IS Condensation reactions occur when molecules are covalently joined together and water is formed as a by-product. In carbohydrates, that bond is called g