IBDP Biology-Core Revision Mixed

Which processes occur in an ecosystem?

I. Biomass increases in each successive trophic level.

II. Inorganic nutrients are recycled.

III. Chemical energy is stored in carbon compounds.

• I and II only

• I and III only

• II and III only

• I, II and III

Which of the adaptations of flowers would be most successful for the survival of a species?

• Spiny seeds for better wind dispersal

• Different flowering times for better seed dispersal

• Sticky pollen for better water dispersal

• Specific odours for better insect pollination

Prickly pear cactus plants are well adapted to desert conditions. The stems are the flattened structures visible in the image and the leaves are reduced to spines. The white spots in the image are groups of spines. Which characteristic describes the advantage of one of their adaptations?

• Leaves are reduced to spines to lose less carbon dioxide.

• Spines increase surface area for more photosynthesis.

• Stems are flattened to allow more water to be stored between periods of rain

• Waxy cuticle on the stems is very thin to allow rapid absorption of rain.

The diagram shows the human digestive system. Where are lipids digested?

• A

• B

• C

• D

Neurons transmit electrical impulses. Which statement describes part of this process?

• K ions are pumped out of the cell to depolarize the membrane.

• Ion channels let K diffuse into the cell to depolarize the membrane.

• Na ions are pumped into the cell to repolarize the membrane.

• Ion channels let Na diffuse into the cell to depolarize the membrane.

Which type of transportation happens in the sodium–potassium pump?

• Facilitated diffusion

• Osmosis

• Simple diffusion

• Active transport

What is a requirement for accurate measurements of the rate of respiration using a respirometer?

• CO must be absorbed by water so that only O production is measured.

• Temperature must be kept constant so the volume changes are only due to O use

• Anaerobic organisms are better to use than aerobic ones as they will produce larger volume changes

• Warm-blooded animals are better to use than cold-blooded animals as they do not change the temperature of the container

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?

• The cell will lose salt to the medium.

• The contractile vacuole will expel more water

• The cell will swell and eventually burst.

• The membrane will become more permeable to salt

The image shows a karyogram. What information can be determined from this karyogram?

• The sex is female.

• The haploid number is 54

• Disjunction occurred during meiosis

• The species is not human.

A dominant autosomal allele for lactase persistence allows humans to digest milk as adults. People who lack this allele are lactose intolerant in adulthood. If J and K have a child L, what is the probability that L will be lactase persistent?

• 25 %

• 50 %

• 75 %

• 100 %