Practice Paper 1 (DP IB Biology: SL)

Neonicotinoids are synthetic compounds similar to nicotine that are commonly found in pesticides. Neonicotinoids are considered to be especially suitable as pesticides because they're not toxic to humans and other mammals.

Which of statements I - IV are reasons for this?

I. A larger proportion of synapses in insects are cholinergic compared to mammals.

II. Neonicotinoids are more effective at preventing acetylcholinesterase from breaking down acetylcholine in insects compared to mammals.

III. Acetylcholinesterase in insects cannot break down neonicotinoids.

IV. Neonicotinoids bind more strongly to acetylcholine receptors in insects.

Where would myelin be found?

Membrane-bound sacs containing products of metabolism are produced by the endoplasmic reticulum.

Where are these products used?

In humans, cell division is regulated by several genes, one of which, p53, inhibits cell division at a particular checkpoint in the cell cycle through the following mechanism.

• p53 stimulates transcription of a gene to produce protein X
• Protein X combines with a cyclin-dependent kinase (CDK) protein
• The complex prevents initiation of mitosis

A heritable mutation in the p53 gene produces a dominant allele which inhibits the normal function of p53.

Which of the following explains the potential result of inheriting a mutant version of the p53 gene.

What is the benefit of collecting accurate, quantitative data on atmospheric carbon dioxide levels?

The Davson-Danielli model of cell membrane structure stated that cell membranes consisted of a phospholipid bilayer sandwiched between two layers of protein.

Which piece of evidence contributed to the falsification of the Davson-Danielli model and the acceptance of the Singer-Nicolson fluid mosaic model?

A study was conducted to investigate the effect of different fatty acids on the levels of low-density lipoprotein (LDL) and high-density lipoprotein (HDL) in the human bloodstream. An increase in LDL levels in the blood has been linked to an increase in the risk of developing coronary heart disease (CHD). The results are shown in the graphs below.

Which of the following conclusions would be the most valid concerning the data?

Which of the following causes fibrous polypeptides to be insoluble?

Lactase is an enzyme that is often immobilised and used in the food industry to produce lactose-free milk.

Which of the following would not be an advantage of using lactase?

The approximate angle of orientation ('twist') of one nucleotide in respect to its neighbouring nucleotide in a given strand of DNA is between 35 and 40 degrees. How many base pairs are required for the double-helix to twist by one whole turn? 

A polypeptide has the following amino acid sequence:

histidine - glutamine - lysine - alanine - valine - histidine - valine

The table below gives the tRNA anticodons for each amino acid.

A mutation causes the 18^th base in the DNA sequence to be deleted. 

Which of the following would represent the amino acid sequence after this deletion?

Which of the following statements about eukaryotic chromosomes are correct? 

1. Chromosomes are long, linear molecules that can be condensed for compact storage.
2. After DNA replication, the two strands of DNA are held together at the centromere.
3. DNA wraps around histone proteins to form chromatids.

Which of the following is not correct regarding online gene databases?

Which of the following statements best describes how Mendel eliminated any uncertainty from his experiments?

Two parents have an equal chance of having a child with blood groups A, B, AB, or O.

What are the genotypes of the parents?

Sea cucumbers are heterotrophic marine organisms that feed on dead or waste material from the seafloor and surrounding water.  They pick up and consume food particles using specialised tube feet that surround their mouths, as shown in the diagram below.

Which mode of nutrition and explanation is correct for sea cucumbers?

A company is advertising a peat-free compost with the statement below:

'Our peat-free compost is perfect for supporting growth in your plants whilst protecting the environment'

Which statement best justifies the use of this statement in the advertising of this peat-free compost?

The graph below shows the predicted effect on global warming of the continued draining of peat bogs.  Warming effect is measured on the kelvin (K) scale.

How does peat drainage lead to the effect on warming seen in the graph?

Which of the following must occur for speciation to take place?

1. Two populations of a species must be separated by a mountain range or body of water.
2. No gene exchange can take place between two populations of a species.
3. Two populations must develop differences in their physical characteristics.

The data below shows the number of DNA base sequence matches found between four species of marine mammal when a short section of their DNA is sequenced.

What can be concluded from the data?

Which of the following is not a feature of a clade? 

The activity of two types of protease enzymes was measured in two different species of fish; species X and species Y. The results of the research are shown in the graph.

The unit U denotes the enzyme required for the production of 1 μmol of product per minute. The bars represent standard deviation.

Which statement about protease enzymes is correct?

What is ‘X’ on the diagram?

The diagram below shows two cardiac cycles of a patient. The events of the cycle are placed next to a timescale.

What is the patient’s heart rate in beats per minute?

Which is a reason why fungi such as Penicillium have evolved to produce antibiotics?

Identify the set of images that correctly shows follicle development during the course of the menstrual cycle.

What is the function of pulmonary surfactant?

In which of the following scenarios would there be an increase in the breakdown of glycogen in the liver?