IB Biology Year 1 Midterm

Over time, the hull of a sunken ship may become colonized by a wide range of marine organisms. What term is used to describe all of the organisms living in and on a sunken ship?

a) Community

b) Ecological niche

c) Population

d) Ecosystem

a) Community

Which organism would be classified as a saprotroph?

a) A single-celled eukaryote that obtains its carbon compounds by photosynthesis and ingestion of other single-celled organisms

b) A jellyfish that uses the stinging cells in its tentacles to paralyse its prey, which is passed to an internal gastric cavity through a single opening

c) A fungus that feeds by secretion of digestive enzymes onto its food and absorption of digested material

d) A dung beetle that feeds on the fecal material left behind by other animals

c) A fungus that feeds by secretion of digestive enzymes onto its food and absorption of digested material

Which level(s) of ecological complexity involve(s) biotic factors but not abiotic factors?

i. community ii. ecosystem iii.population

a) i only

b) ii only

c) i and ii only

d) i and iii only

d) i and iii only

How can a chi-squared test be used in ecological research?

a) To test the effect of an abiotic factor on one plant species

b) To test whether two species tend to live together

c) To test whether one population of plants is taller than another

d) To test whether one species is more tolerant to heavy metals than another

b) To test whether two species tend to live together

Hummingbirds eat flower nectar and small insects. To which nutritional group do they belong?

A. Autotrophs

B. Consumers

C. Detritivores

D. Saprotrophs

B. Consumers

In 1789 Gilbert White, a naturalist, observed eight breeding pairs of swifts (Apus apus) in the English village of Selborne. On average, each pair of swifts produces two offspring per year. This would allow the population to rise to1030 swifts over 200 years. A bird survey carried out in 1983 revealed only 12 breeding pairs in this village.What could have prevented the numbers rising to 1030?

l. The number of nesting sites remained the same.

II. The food supply of the swifts remained constant.

iii. Predatory birds in the area were exterminated.

A. i only

B. I and II only

C. II and Ill only

D. l, II and Ill

B. I and II only

Limpets are molluscs with conical shells that cling tightly to rocks on seashores. In a study of two species of limpets found on rocks along the Oregon coast, 30 randomly placed quadrats were used to determine how often the two species occurred together. The table shows the data that were collected.Which statistical method will determine whether these two species occur together by chance or by some kind of interaction?

A. Chi-squared test

B. t-test

C. Standard deviation

D. Means and ranges

A. Chi-squared test

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The image shows a food web.Which organism in the food web is assigned to its method of nutrition?A. A violet webcap fungus is both an autotroph and a heterotrophB. A pillbug is a secondary consumer.C. Bacteria are saprotrophs.D. Violet webcap fungus is a detritivore - //D. Violet webcap fungus is a detritivore

Which processes occur in an ecosystem?l. Biomass increases in each successive trophic level.II. Inorganic nutrients are recycled.Ill. Chemical energy is stored in carbon compounds.A. I and II onlyB. I and Ill onlyC. ll and Ill onlyD. I, II and Ill - //C. ll and Ill only

The image shows a transect through a stream and a field.Which calculation would test for the association between twospecies of plants from quadrat data from section A and sectionB of the field?A. Correlation coefficientB. Random numbers samplingC. Standard DeviationD. Chi-squared - //D. Chi-squared

Which are characteristics of a species?l. The potential to interbreed to produce fertile offspringII. The formation of a population with members of the same species within a communityIll. The overproduction of offspringA. I and II onlyB. I and Ill onlyC. II and Ill onlyD l, II and Ill - //D l, II and Ill

Compare and contrast the mode of nutrition of detritivores and saprotrophs. - //Detritivores are heterotrophs that obtain organic nutrients from detritus by internal digestion. Saprotrophs are heterotrophs that obtain organic nutrients from dead organisms by external digestion. Both groups constitute of heterotrophs. They contribute to recycling nutrients in the ecosystems.

Use Chi-Square to determine if there is a association between the size of the lioness and the weight of their cubs. - //Null Hypothesis is rejected, the cub;s weight is related to the size of its mother.

In a woodland ecosystem, each tree provides food for numerous aphids which feed on the sap of the tree. The aphids are eaten by carnivorous beetles, as shown in the food chain.Oak Tree + Aphids + BeetlesWhich pyramid of energy represents this relationship? - //c

The diagram shows the energy flow between five "sinks" in a terrestrial ecosystem.In a typical terrestrial ecosystem, which trophic level wouldhave the highest biomass?A. AutotrophsB. Primary consumersC. Secondary consumersD. Detritus feeders - //A. Autotrophs

Plankton are major producers in marine ecosystems. Only a small proportion of the energyharvested by plankton is passed to the primary consumers. Which process in phytoplankton results inthe largest loss of energy that could otherwise be utilized by consumers?A. ReproductionB. HomeostasisC. ExcretionD. Respiration - //D. Respiration

The diagram shows the food webfor an aquatic ecosystem in which letters R-Z represent individual species.Which organism is a tertiary consumer?A. organism TB. Organism UC. Organism WD. Organism Y - //C. Organism W

The Silver springs feed into the Silver River in Florida. The diagram shows a pyramid ofenergy for the Silver Springs ecosystem. The units are kJ m-2 y-1.What do level I and level Ill represent in the pyramid of energy?A. I. Sunlight III. Secondary ConsumerB. I. Producer III. Tertiary ConsumerC. I. Producer III. Secondary ConsumerD. I. Primary Consumer III. Tertiary Consumer - //C. I. Producer III. Secondary Consumer

The diagram shows interactionsbetween food chains in an ecosystem in the African savannah.Which arrowsindicate the flow ofchemical energy?A. I and II onlyB. I and Ill onlyC. II and Ill onlyD. 1, 11 and 111 - //C. II and Ill only

Animals in the highest trophic level of a food chain will often be the largest in body size but will be few in numbers.What accounts for the small numbers?A. Food eaten by animals at the highest trophic level has a lower energy content per gramB. Energy losses through the food chainC. Conversion of heat energy into chemical energyD. Biomass of producers is small - //B. Energy losses through the food chain

Which processes occur in an ecosystem?I. Biomass increases in each successive trophic level.II. Inorganic nutrients are recycled.Ill. Chemical energy is stored in carbon compounds.A. I and II onlyB. I and Ill onlyC. II and III onlyD. I, II and Ill only - //C. II and III only

What is lost between trophic levels in ecosystems and cannot be recycled?A. HeatB. NitrogenC Carbon compoundsD. Biomass - //A. Heat

What restricts the length of a food chain?A. Energy losses between the trophic levelsB. A greater biomass at the higher trophic levelsC. The number of species in the food webD. The consumption of waste by detritivores - //A. Energy losses between the trophic levels

Which category of organisms is correctly described by its method of nutrition and site of digestion?Category of organism, Method of Nutrition, site of digestionA. Consumer, heterotrophic, internalB. Saprotroph, Autotrophic, externalC. Producer, Autotrophic, InternalD. Detritivore, Heterotrophic, External - //A. Consumer, heterotrophic, internal

What limits the length of food chains in an ecosystem?A. The size of individual organismsB. Competition between organismsC. The loss of energy between trophic levelsD. Natural Selection - //D. Natural Selection

The Statement is about the roleof some bacteria inecosystems. What is themode of nutrition of thesebacteria?"Bacteria play an important role in recycling nutrients in ecosystems. They live on organic wastes and dead organisms and digest their molecules. They then absorb some of these molecules for their own metabolism, and the rest is used by other organisms."A. They are autotrophsB. They are consumersC. They are saprotrophsD. They are detritivores - //D. They are detritivores

The diagram represents a pyramid of energy.What level does the letter X represent?A. LightB. Primary consumersC. Abiotic environmentD. Producers - //D. Producers

The image shows an example of a soil food web.Draw a food chain from this food web, showing at least three organisms. - //plant roots -\> Nematodes -\> small soil arthropods -\> Robin

Explain the reasons for food chains rarely containing more than four or five trophic levels. - //according to the 10 per cent law, only 10 per cent of the available energy is transferred to the next trophic level. So, at the higher trophic levels, the amount of energy is reduced to such an extent that it becomes insufficient for an organism to sustain itself. So longer food chains are not encouraged by Nature.

The amount of food passing into food chains can be affected by the rate of photosynthesis.Explain the effect of one limiting factor on photosynthesis. - //Limiting factor on photosynthesis is the amount of sunlight, carbon, and loss of energy between trophic levels.

Identify the processes represented by the arrows labelled A and B in both diagrams. - //A= DecayB= Leaching

Dedice, with a reason, which ecosystem is representative of a tropical rainforest. - //Ecosystem 1 because the thicker the arrow the more nutrients which a tropical rainforest needs. Tropical rainforest=more nutrients.

Calculate the net production of the sutrophs. (NP=GP - R) - //43,510 - 23,930 = 19,580 kJm-2y-1

The total solar energy received by a grassland is 5 x 105 kJ m-2 year-1The gross production is 6.35 x 103 kJ rn-2 year-1.The net production of the grassland is 1.95 x 103 kJ m-2 year-I.A: Calculate the energy lost by plant respiration. (NP-GP -R) - //498,050 kJm-2y-1

Use the Letters in the pyramid to label the terms in the correct place. (will usesome letters more than once)/D\/ C \/ B \/ A \ - //

Use the Letters in the pyramid to label the terms in the correct about of energy found at each level./-\/ - \/ 9876 kcal \/ - \ - //98.76 kcal987.6 kcal9876 kcal98760 kcal

How do greenhouse gases contribute to global warming?A. They destroy the ozone layer, allowing radiation to reach the Earth's surface.B. They prevent radiation from the Earth escaping into space.C. They trap short wavelength radiation in the atmosphere.D. They are a product of combustion, which generates heat. - //B. They prevent radiation from the Earth escaping into space.

Which gases have made the most significant contributions to global warming?A. Water and carbon dioxideB. Carbon dioxide and methaneC. Methane and nitrous oxideD. Carbon dioxide and ozone - //A. Water and carbon dioxide

Under certain conditions, living organisms on Earth produce and release methane. What favours theproduction of methane?A. Forest firesB. High light intensityC. Anaerobic conditionsD. Dry conditions - //C. Anaerobic conditions

The oceans absorb much of the carbon dioxide in the atmosphere. The combustion of fossil fuels hasincreased carbon dioxide ocean concentrations. What adverse effect does this have on marine life?A. Heterotrophs consume more phytoplankton.B. Phytoplankton have increased rates of photosynthesis.C. Corals deposit less calcium carbonate to form skeletons.D. Increased pH reduces enzyme activity in marineorganisms. - //C. Corals deposit less calcium carbonate to form skeletons.

In the diagram, which of the processes labelledA to D transfers the largest mass of carbon per year in awoodland ecosystem? - //B

What material is formed when organic matter is not fully decomposed in acidic waterlogged soils?A. CoalB. HydrogenC. OilD. Peat - //D. Peat

Which organisms produce methane inanaerobic environments such as waterlogged soils?A. ArchaeaB. FungiC. EukaryotesD Eubacteria - //A. Archaea

The global carbon cycle involves sinks where carbon is stored, and fluxes where carbon is transferred. What are thelargest sink and flux?is stored, and fluxes where carbon is transferred. What are thelargest sink and flux?9.[2 mark] In addition to carbon dioxide, which of thesegreenhouse gases is the most significant?Sink, FluxA. Atmosphere, CombustionB. Oceans, RespirationC. Oceans, PhotosynthesisD. Limestone, Photosynthesis - //C. Oceans, Photosynthesis

In addition to carbon dioxide, which of these greenhouse gases is the most significant?A. MethaneB. OzoneC. Nitrogen oxidesD. Water vapour - //D. Water vapour

What describes a possible cause of a negative carbon flux in the atmosphere due to processes occurring in a forest ecosystem?A. The trees grew more so fixed more carbon dioxide.B. There was more respiration by soil organisms.C. There was more burning of forests.D. There was more decomposition of leaf litter. - //A. The trees grew more so fixed more carbon dioxide.

Euglena is a unicellular organism that feeds on bacteria and uses C02 as a carbon source. Whichdescribes the nutrition of this organism?A. Autotrophic onlyB. Heterotrophic onlyC. Saprotrophic onlyD. Autotrophic and heterotrophic - //D. Autotrophic and heterotrophic

The diagram shows a version of the carbon cycle. What is indicated by the numbers?A. Death of consumers, Cell respiration in saprotrophs, Cell respiration in producersB. Death of consumers, Incomplete decomposition, Photosynthesis in producersC. Cell respiration in saprotrophs, Incomplete decomposition, Photosynthesis in producersD. Cell respiration in consumers, Cell respiration in saprotrophs, Cell respiration in producers - //C. Cell respiration in saprotrophs, Incomplete decomposition, Photosynthesis in producers

How is peat formed?A. From methanogenic archaeans under anaerobic and acidic conditions in deep sea ventsB. From partially decomposed organic matter under anaerobic and acidic conditions in waterlogged soilsC. From porous limestone under high pressure, aerobic and alkaline conditions in ocean bedsD. From bituminous coal under high pressure, anaerobic and acidic conditions below ground - //B. From partially decomposed organic matter under anaerobic and acidic conditions in waterlogged soils

Increasing carbon dioxideconcentration in the atmosphere leads to acidification of the ocean. This in turn reduces the amount of dissolved calcium carbonate. A study was undertaken to investigate the effect ofincreasing the concentration ofatmospheric carbon dioxide on the calcification rate of marine organisms. Calcification is the uptake of calcium into the bodies and shells of marine organisms. The study was undertakeninside Biosphere-2, a large-scale closed mesocosm. The graph shows the results of the data collection. State the relationship between atmospheric carbon dioxide and calcification rates. - //Atmospheric carbon dioxide: increaseCalcification rates: decreases

A cell contains chloroplasts, plasma membrane and 80S ribosomes. What type of cell could it be?A. FernB. LymphocyteC. ProkaryoteD. Neuron - //A. Fern

Two cells have the following characteristics. Which deduction is supported by this information?A. Both cells are from plants.B. Cell I is more complex than cell II.C Cell II is an animal cell.D. Cell I is prokaryotic. - //D. Cell I is prokaryotic.

In mammals, mature red blood cells are specialized inthat they lack nuclei, mitochondria or ribosomes. Which statementapplies to red blood cells?A. No chemical reactions take place within their cytoplasm.B. They cannot produce new enzymes.C. Materials cannot enter red blood cells.D. Materials cannot exit red blood cells. - //B. They cannot produce new enzymes.

What organelle's function is to make proteins?A. VacuoleB. Smooth endoplasmic reticulumC RibosomesD. Nucleus - //C Ribosomes

The electron micrograph shows a section through a cell.What is the name of the cell component labelled Y?A. Golgi apparatusB. nucleusC. CytoplasmD. Vacuole - //B. nucleus

What is the function of this organelle pictured to the right?A. It creates lipids and membranesB. It modifies, sorts, and ships proteinsC. It is the site of photosynthesisD. It stores food and water - //B. It modifies, sorts, and ships proteins

Which structures are found only in prokaryotic cells?A.RibosomesB PiliC. Cell wallsD. Flagella - //B Pili

Which of the following organelles is found in ALL cells, including eukaryotes and prokaryotes?A. MitochondriaB. CytoplasmC. LysosomesD. Chloroplasts - //B. Cytoplasm

Which of the following organelles is only found in PLANT cells?A. LysosomeB. MitochondriaC.NucleusD. Chloroplast - //D. Chloroplast

What is the function of the mitochondria?A. Contains all of the DNA of the cellB. It provides structure to the cellC. creates energy in the form of ATPD. It makes lipids - //C. creates energy in the form of ATP

What organelle maintains homeostasis by controlling which substances enter and exit the cell?A. Cell membraneB.Rough endoplasmic reticulumC. Golgi bodiesD. Centrosome - //A. Cell membrane

The image shows an electron micrograph of a cell.Which organelles correspond to the labels in the electronmicrograph of this cell? - //c

The image is of a Paramecium.What evidence from the image of Paramecium indicates whetherthe organism is a prokaryote or a eukaryote?A. compartments in the cell indicate that it is a eukaryote.B. No nucleus indicates that the cell is a prokaryote.C. Lack of a cell wall indicates that the cell is a eukaryote.D. It is a unicellular organism, so it must be a prokaryote. - //A. compartments in the cell indicate that it is a eukaryote.

What organelle found only in eukaryotic cells stores DNA?A. NucleusB. RibosomeC. CytoskeletonD. Lysosome - //A. Nucleus

Look at the image.What type of cell is this?A. Bacteria cellB. Plant cellC. Animal CellD. Protista - //C. Animal Cell

Look at the image.What type of cell is this?A. Bacteria cellB. Plant cellC. Animal CellD. Protista - //B. Plant cell

What is the primary function of a vacuole in a cell?A. enzyme productionB. protein synthesisC. storageD. reproduction - //C. storage

Which of the following is found in a eukaryotic cell, but is not found in a prokaryotic cell?A. CytoplasmB. Cell membraneC NucleusD. Flagella - //C Nucleus

Where you can find ribosomes in the cell?A. cytoplasmB. rough ERC. smooth ERD. Both A and B - //D. Both A and B

Bacteria perform a specific type of asexual reproduction calledA. buddingB. sporulationC. fragmentationD. binary fission - //D. binary fission

More than 90 % of cellular cholesterol is located in the cell's plasma membrane. Whatis the main role of cholesterol in the plasma membranes of mammalian cells?A. To regulate membrane fluidityB. To increase membrane solubilityC. To increase membrane permeabilityD. To regulate membrane temperature - //A. To regulate membrane fluidity

Which plasma membrane is the least fluid at high temperatures? - //B

Which features of phospholipidsgive them their amphipathic properties?A. Basic phosphate groups and acidic lipidsB. Acidic phosphate groups and basic lipidsC. Hydrophobic phosphate groups and hydrophilic fattyacidsD. Hydrophilic phosphate groups and hydrophobic fatty acids - //D. Hydrophilic phosphate groups and hydrophobic fatty acids

What special property ofphospholipid molecules explains their ability to spontaneously assemble into a lipid bilayer?A. They are hydrophobic.B. They are amphipathic.C. They are saturated.D. They are hydrophilic - //B. They are amphipathic.

Which is an essential feature of the Davson-Danielli model of membrane structure?A. A phospholipid monolayer with intrinsic and extrinsic proteinsB. A layer of protein sandwiched between two layers of lipidC. A phospholipid bilayer with intrinsic and extrinsic proteinsD. A layer of lipid sandwiched between two layers of protein - //D. A layer of lipid sandwiched between two layers of protein

What part of the plasma membrane is fluid, allowing the movement of proteins in accordance with the fluid mosaic model? - //b

Which molecule regulates the fluidity of cell membranes?A. PhospholipidB. CholesterolC. GlycoproteinD. Peripheral protein - //B. Cholesterol

A diagram of amembrane. In the diagram, whichstructure is an intrinsic or integralprotein? - //B

The cell membrane model proposed byDavson-Danielli was a phospholipidbilayer sandwiched between twolayers of globular protein. Which evidence led to the acceptance of the Singer-Nicolson model?A. The orientation of the hydrophilic phospholipid heads towards the proteinsB. The formation of a hydrophobic region on the surface of the membraneC The placement of integral and peripheral proteins in the membraneD. The interactions due to amphipathic properties of phospholipids - //C. The placement of integral and peripheral proteins in the membrane

Membrane structure can beinvestigated using atechnique known as freezefracture.Cells are frozen and thensplit. Fracturing oftenoccurs between the twophospholipid layers ofmembranes in the cell. Anelectron micrograph ofsuch a fractured membraneis shown.Using the scale bar,calculate the magnificationof the image. - //

Explain how electronmicrographs such as thishelped to falsify theDavson-Danielli model ofmembrane structure. - //It helps falsify this because of how it is placed. They discovered that they are proteins embedded in the cell.

Explain how the amphipathic nature of phospholipids allows them to form bilayers. - //The amphipathic nature of phospholipids allowed them to form bilayer because of the hydrophilic head being made up of phosphate and hydrophobic being made up of fatty acids.

What is the benefit to living organisms that water has a high specific heat capacity?a. Heat can be lost from the skin when sweat evaporates.b. Aquatic environments do not have a great fluctuation in their temperature.c. The amount of heat stored by water is highly predictable.d. It allows water to be a solvent for chemical reactions at body temperature. - //a. Heat can be lost from the skin when sweat evaporates.

What is the term for the attraction of water molecules to other water molecules?a. surface tensionb. capillary actionc Cohesiond adhesion - //c Cohesion

What is a property of water?a. Water has a low specific heat capacity so large increases in heat energy cause asmall temperature change.b. Water is an excellent solvent for nonpolar substances.c. Covalent bonds between adjacent water molecules are responsible for its uniqueproperties.d. Water molecules are highly•cohesive which is important for transport in xylem. - //d. Water molecules are highly•cohesive which is important for transport in xylem.

Which substance must be transported in the blood by lipoprotein complexes?a. cholesterolb. oxygenc. sodium chlorided. amino acids - //a. cholesterol

Where do hydrogen bonds form?a. Between the slight negative charge of hydrogen and slight positive charge of oxygen.b. Between the slight positive charge of hydrogen and the slight negative charge of oxygen. - //b. Between the slight positive charge of hydrogen and the slight negative charge of oxygen.

What feature of carbon makes it most suitable as a basic for life?a. Its abundance in natureb. Its bonding propertiesc.Its reactivity to lightd. Its presence in the early atmosphere of the Earth - //b. Its bonding properties

Researchers have developed a skin patch which can detect a measure very smallconcentrations of ions, sugars, amino acids, proteins, and hormones which remain whensweat evaporates. What allows the presence of these substances in sweat?a. cohesionb. hydrophobic interactionsc. solvent propertiesd. thermal properties - //c. solvent properties

Glucose is absorbed through protein channels in the plasma membrane of epitheliumcells in the small intestine. Which characteristic of glucose prevents its diffusion throughthe phospholipid bilayer?a. It is non-polar and therefore hydrophobic.b. Its hydrogen bonds link with b. amino acids in the protein channel.c. It is polar and therefore hydrophilic.d. Its covalent bonds interact with the phospholipids. - //c. It is polar and therefore hydrophilic.

The diagram shows the structure of palmitic acid. What type of fatty acid is palmitic acid?a. It is monounsaturatedb. It is polyunsaturatedc. it is saturatedd. It is a trans-fatty acid - //c. it is saturated

Which properties explain the ability of water to dissolve solutes?i. Polarity of water moleculesii. High specific heat capacity of wateriii. Hydrogen bondinga. i and ii onlyb. i and iii onlyc ii and iii onlyd. i, ii, and iii - //b. i and iii only

The figure represents a water molecule. Draw a second water molecule to show howbonds can form between water molecules, including the name of the bond. - //o-h| hydrogen bondh

The figure shows a tripeptide. Label one peptide bond in this molecule. - //

Draw a diagram of alpha-glucose. - //

The graph shows enzyme activity plotted against temperature.What is the reason for the drop in enzyme activity above 40 C?A. A decrease in the enzyme concentrationB. Reaction is saturated because active sites areoccupiedC. Insufficient activation energy for the reaction to proceedD. changes to the conformation of the enzyme - //D. changes to the conformation of the enzyme

Lactose can be removed from milk by passing the milk through a column of alginate beads towhich immobilized lactase is bound. What is an advantage of immobilizing the enzyme?A. It creates more active sites.B. The alginate beads act as a coenzyme.C. It lowers the activation energy of the reaction.D. It allows the product to be separated easily from the enzyme. - //D. It allows the product to be separated easily from the enzyme.

The table shows the rangeand classification of body mass index (BMI) values, as shown in thenomogram.What is the approximate reduction in body mass that a person of height 155 cm and mass 95kg would have to lose to reach normal body mass?A. 10kgB. 22kgC. 36kgD. 54kg - //C. 36kg

Which statement applies toenzymes?A. enzyme function depends on collisions between substrate and active sites.B. One active site typically binds to a broad range of substrates.C. The active site on the substrate is specific to one enzyme.D. When enzymes are immobilized they stop working. - //A. enzyme function depends on collisions between substrate and active sites.

Which enzyme is matched to its function? - //b