IB Biology Unit 1-4 Question Bank

What is a role of cholesterol in animal cells? A. It increases body fat. B. It controls membrane fluidity. C. It lines the inner wall of capillaries. D. It is a constituent of bile.

B

What is decreased when lactase is added to milk? A. Sweetness B. Disaccharides C. Calcium D. Monosaccharides

B

What is the cell theory?

- the cell is the most basic unit of structure and function - all cells come from pre-existing cells - all living things are made up of cells

A parent organism of unknown genotype is mated in a test cross. Half of the offspring have the same phenotype as the parent. What can be concluded from this result? A. The parent of unknown genotype is heterozygous. B. The parent of unknown genotype is homozygous dominant. C. The parent of unknown genotype is homozygous recessive. D. The parent of known genotype is heterozygous.

A

For what purpose is the enzyme lactase useful? A. Production of lactose-free milk so that more people can consume dairy products B. As a dietary supplement to aid in protein digestion of milk C. For use in coagulating milk protein to make cheese D. To improve protein consumption in developing countries that lack milk

A

What feature of cell membranes allows endocytosis to occur? A. Fluidity of phospholipid bilayer B. Presence of protein pumps C. Presence of carrier proteins D. Glycoprotein binding sites

A

What is denaturation? A. A structural change of a protein that results in the loss of its biological properties B. A change in the genetic code of an organism C. A change in the amino acid sequence of a protein causing a disruption of its 3D shape D. The process by which amino acids are broken down and ammonia is released

A

What is osmosis? A. The movement of water through a membrane from a low to a high solute concentration B. The movement of solutes through a membrane from a high to a low water concentration C. The movement of water through a membrane from a high to a low solute concentration D. The movement of solutes through a membrane from a low to a high water concentration

A

What is produced when the enzyme lactase is added to milk? A. Glucose and galactose B. Lactose C. Glucose and fructose D. Lactic acid

A

What is the approximate thickness of the plasma membrane of a cell? A. 10 nm B. 50 nm C. 10 µm D. 50 µm

A

Which process is possible due to the fluidity of cell membranes? A. Endocytosis B. Osmosis C. ATP production D. Cell recognition

A

Why does the amount of CO fall between April and August? A. Seasonal increase in the rate of photosynthesis in northern hemisphere forests B. Seasonal decrease in the rate of photosynthesis in northern hemisphere forests C. Seasonal decrease in the rate of fossil fuel consumption D. Seasonal increase in the amount of CO taken up by the oceans

A

What happens as an enzyme becomes denatured? A. The enzyme works faster. B. The enzyme works slower. C. The enzyme can perform a new role. D. The enzyme can make the reverse reaction proceed faster.

B

A man of blood group A and a woman of blood group B have a child. If both are heterozygous for the gene, what are the chances of them having a child with blood group B? A. 0% B. 25% C. 50% D. 75%

B

How can the rate of photosynthesis be measured? I. By the amount of oxygen produced II. By the increase in biomass III. By the amount of carbon dioxide produced A. I only B. I and II only C. I and III only D. I, II and III

B

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

B

If a father with A-type blood and a mother with B-type blood have a child, what is the probability that the child will have O-type blood? A. 50 % chance if both parents have the recessive allele. B. 25 % chance if both parents have the recessive allele. C. 0 % chance because neither parent has the allele. D. 50 % chance if either parent has the recessive allele.

B

If a man with blood group O and a woman with blood group AB have children, which blood group(s) could the children have? A. Group O only B. Groups A and B only C. Group AB only D. Groups O, A, B and AB

B

In an experiment the effect of changing pH on an enzymatic reaction is tested. Which could be a dependent variable in this kind of experiment? A. Changing substrate concentration B. Rate of formation of product C. Variation in temperature D. Change in pH

B

It is possible to attach β-galactosidase to alginate beads for use in the production of lactose-free milk. What are enzymes that have been attached in this way called? A. Inhibited B. Immobilized C. Catalysed D. Activated

B

The following statements refer to a pyramid of energy. I. Some material is not assimilated by each trophic level. II. Energy transformations are never 100 % efficient. III. Heat is lost during photosynthesis. Which of the statements give the reason why a pyramid of energy is narrower at the top than at the bottom? A. I only B. I and II only C. II and III only D. I, II and III

B

The presence of freckles is a characteristic controlled by a dominant gene. Two parents who are heterozygous for the characteristic have three children, all of whom have freckles. Which statement is true if they have a fourth child? A. There is a 100 % chance that their next child will have freckles. B. There is a 75 % chance that their next child will have freckles. C. There is a 50 % chance that their next child will have freckles. D. The next child will have no freckles as the ratio is 3 with freckles to 1 without freckles

B

The salt concentration inside the Paramecium is 1.8 %. The salt concentration in the surrounding medium suddenly drops to 0.2 %. What will be the likely response? A. The cell will lose salt to the medium. B. The contractile vacuole will expel more water. C. The cell will swell and eventually burst. D. The membrane will become more permeable to salt.

B

What is recycled in an ecosystem? A. Nitrogen, carbon and energy are all recycled. B. Nitrogen and carbon are recycled but not energy. C. Nitrogen is recycled but not carbon or energy. D. Nitrogen, carbon and energy are not recycled.

B

What is the best definition of the greenhouse effect in the Earth's atmosphere? A. A naturally occurring effect by which shorter wavelength radiation is trapped B. A naturally occurring effect by which longer wavelength radiation is trapped C. An effect of pollution by which shorter wavelength radiation is trapped D. An effect of pollution by which longer wavelength radiation is trapped

B

What route is used to export proteins from the cell? A. Golgi apparatus → rough endoplasmic reticulum → plasma membrane B. Rough endoplasmic reticulum → Golgi apparatus → plasma membrane C. Golgi apparatus → lysosome → rough endoplasmic reticulum D. Rough endoplasmic reticulum → lysosome → Golgi apparatus

B

Which evidence falsifies the Davson-Danielli model? I. The presence of globular proteins within the phospholipid bilayer II. Non-polar amino acids cause proteins to remain embedded in membranes III. Membrane proteins remain in a fixed position inside a membrane A. I only B. I and II only C. II and III only D. I, II and III

B

Which gas will enhance the greenhouse effect if released into the atmosphere? A. Hydrogen B. Oxide of nitrogen C. Oxygen D. Nitrogen

B

Which of the following is the best definition of a population? A. A group of individuals that can interbreed and produce fertile offspring B. The number of individuals of the same species in a given area C. A group of species living and interacting with each other in a given area D. The total number of individuals in a given area

B

Which pair of statements is correct? A. autotroph-obtains organic molecules from other organisms, heterotroph-synthesizes organic molecules from inorganic molecules B. autotroph-synthesizes organic molecules from inorganic molecules, heterotroph-obtains organic molecules from other organisms C. autotroph-synthesizes inorganic molecules from organic molecules, heterotroph-synthesizes organic molecules from inorganic molecules D. autotroph-obtains inorganic molecules from other organisms, heterotroph-obtains inorganic molecules from other organisms

B

Which statement describes the term species? A. Members of the same ecological community B. Organisms that reproduce together to produce fertile offspring C. Organisms of the same type in a population D. The first word in the binomial name of an organism

B

Which variable has the least effect on enzyme activity? A. Temperature B. Light intensity C. pH D. Substrate concentration

B

Why does exposure to high temperatures cause an enzyme to lose its biological properties? A. The substrate blocks the active site at high temperatures. B. The three dimensional structure of the enzyme becomes changed. C. Chemical reactions cannot take place at high temperatures. D. High temperatures increase the activation energy of reactions.

B

A fever in a normally healthy adult during an illness is not usually a problem and can be regarded as a defence mechanism. However, a fever higher than 41°C might be dangerous. What is the cause of the possible damage due to a high fever? A. Loss of body mass B. Muscle damage due to shivering C. Overactive metabolic enzymes D. Spread of infection

C

A number of different proteins are involved in nerve function. Which of the following does not require a membrane protein? A. Active transport of sodium B. Diffusion of K+ into the cell C. Diffusion of the neurotransmitter across the synapse D. Binding of the neurotransmitter to the post-synaptic membrane

C

At each trophic level energy is lost. How is this energy regained by the ecosystem? A. Heat B. Nutrients C. Photosynthesis D. Recycling

C

Cladograms can be created by comparing DNA or protein sequences. The cladogram on the left is based on DNA sequences and the cladogram on the right is based on comparing protein sequences. What is the reason that cladograms based on DNA sequences are more reliable predictors of the phylogenetic relationship of species than cladograms based on protein sequences? A. Amino acids are not as chemically stable as DNA nucleotides. B. DNA mutates but amino acids do not. C. Several different triplets of bases can code for the same amino acid. D. There are 20 different amino acids but only 4 nucleotides.

C

Global warming caused by the enhanced greenhouse effect is likely to have major consequences for arctic ecosystems. Which of the following are likely to occur in the arctic if the Earth's surface temperature rises? I. Decreased rates of decomposition of detritus II. Increased range of predators from temperate regions III. Increase in numbers of pest species and pathogens A. I and II only B. I and III only C. II and III only D. I, II and III

C

How can the activity of a human amylase enzyme be increased during a laboratory experiment? A. Adding sugar to the mixture B. Decreasing the pH from 7 to 3 C. Increasing the temperature from 20 °C to 37 °C D. Adding water to the mixture

C

The cell membrane model proposed by Davson-Danielli was a phospholipid bilayer sandwiched between two layers of globular protein. Which evidence led to the acceptance of the Singer-Nicolson model? A. The orientation of the hydrophilic phospholipid heads towards the proteins B. The formation of a hydrophobic region on the surface of the membrane C. The placement of integral and peripheral proteins in the membrane D. The interactions due to amphipathic properties of phospholipids

C

What are examples of greenhouse gases? A. Ethane and ozone B. Methane and nitrogen C. Methane and carbon dioxide D. Ethane and oxygen

C

What contributes to rising atmospheric concentrations of carbon dioxide and increases in average global temperature? A. An increase in the shorter wavelength radiation emitted by Earth B. An increase in longer wavelength radiation emitted by Earth C. An increase in the combustion of fossilized organic matter D. The depletion of ozone in the stratosphere

C

What contributes to the structure of an enzyme? A. Sequence of bases linked by hydrogen bonds B. Sequence of substrates linked by condensation reactions C. Sequence of amino acids linked by peptide bonds D. Sequence of polypeptides linked by hydrolysis reactions

C

What is the mode of nutrition of midge larva? A. Autotroph B. Detritivore C. Heterotroph D. Saprotroph

C

What term describes the failure of sister chromatids to separate during anaphase II? A. Sex linkage B. Karyotyping C. Non-disjunction D. Semi-conservative replication

C

Which are functions of membrane proteins? A. Hormone binding sites and DNA replication B. Cell adhesion and translation C. Cell to cell communication and protein pumps D. Passive transport and glycosis

C

Which movement occurs by osmosis? A. Oxygen from alveoli into the blood B. Water from a leaf into the atmosphere C. Water from soil to root D. Nitrate ions from soil to root

C

Which of the following is not a function performed by a membrane protein? A. Hormone binding sites B. Cell adhesion C. Enzyme synthesis D. Pumps for active transport

C

Which of the following statements is true about enzymes? A. They are used up in the reactions they catalyse. B. Allosteric inhibitors bind to the active site. C. They lower the energy of activation for a reaction. D. They supply the energy of activation for a reaction.

C

A certain breed of mouse can have fur that is either black or brown. A mouse breeder performs a test cross using a brown mouse to determine the unknown genotype of a black mouse. There are four offspring produced by the cross. What conclusions can be drawn? A. If the black mouse is homozygous, one of the four offspring must be brown. B. If the black mouse is heterozygous, three of the four offspring must be black. C. The black mouse must be homozygous if all four offspring are black. D. The black mouse must be heterozygous if any of the offspring are brown.

D

A child has blood group A. The father of the child has blood group B. What are the possible genotypes of the mother? I. IAIA II. IAIB III. IAi A. I only B. I and II only C. II and III only D. I, II and III

D

Euglena is a unicellular organism that feeds on bacteria and uses CO2 as a carbon source. Which describes the nutrition of this organism? A. Autotrophic only B. Heterotrophic only C. Saprotrophic only D. Autotrophic and heterotrophic

D

In enzyme experiments, the rate of enzyme activity often gradually decreases. What is most likely to cause this decrease? A. The temperature decreasing B. The enzyme concentration decreasing C. The pH decreasing D. The substrate concentration decreasing

D

In humans the ABO blood groups are an example of inheritance involving multiple alleles. In a family the parents have blood group A and blood group B respectively. Their first child has blood group O. What is the probability that their next child will have blood group B? A. 100 % B. 75 % C. 50 % D. 25 %

D

Methanogens produce methane gas. What is this gas converted to in the atmosphere? A. Carbon dioxide and oxygen B. Ethanol and carbon dioxide C. Carbon monoxide and ozone D. Carbon dioxide and water

D

Red-green colour blindness is a sex-linked condition. Which of the following always shows normal vision? A. A homozygous male B. A homozygous female C. A heterozygous male D. A heterozygous female

D

The feather colour of a certain breed of chicken is controlled by codominant alleles. A cross between a homozygous black-feathered chicken and a homozygous white-feathered chicken produces all speckled chickens. What phenotypic ratios would be expected from a cross between two speckled chickens? A. All speckled B. 1 black feathers : 1 white feathers C. Speckled, black feathers and white feathers in equal numbers D. 1 black feathers : 2 speckled feathers : 1 white feathers

D

The giant marine alga Halicystis ovalis is able to move sodium ions from vacuoles to the surrounding seawater through active transport. Which condition or feature is required for this mode of transport? A. Movement from a region of higher sodium concentration to a region of lower sodium concentration B. A partially permeable surface C. Membrane fluidity D. Transmembrane proteins

D

The salt concentration inside an animal cell is 1.8 %. The salt concentration in the surrounding medium becomes 5 %. What will be the likely response? A. The cell will gain water from the medium. B. The cell will lose salt to the medium. C. The cell will remain unchanged. D. The cell will shrink from loss of water.

D

What favours the production of peat? I. Presence of organic matter II. Anaerobic conditions III. Acidic conditions A. I and II only B. I and III only C. II and III only D. I, II and III

D

Which disease is an example of sex-linked (X-linked) inheritance? A. AIDS B. Down syndrome C. Sickle-cell anemia D. Hemophilia

D

Which group of organisms in the carbon cycle converts carbon into a form that is available to primary consumers? A. Decomposers B. Saprotrophs C. Detritus feeders D. Producers

D

Which hypothesis is supported by evidence from ecological research? A. Decomposers are the final stage in the food chain. B. Producers depend upon consumers more than on decomposers. C. Decomposers help to recycle energy from food chains. D. Producers use nutrients that decomposers help to recycle.

D

Which is a feature of sex-linked genes in humans? A. Males can only be heterozygous for the gene. B. Females can only be homozygous for the gene. C. Males can be either heterozygous or homozygous for the gene. D. Females can be either heterozygous or homozygous for the gene.

D

Which of the following are greenhouse gases? I. Oxides of nitrogen II. Carbon dioxide III. Methane A. I and II only B. I and III only C. II and III only D. I, II and III

D