AS & A Level Biology - 9700 Paper 1 2019 Summer Zone 2

The actual length of a cell structure is 8 µm.
Which steps are used to calculate the magnification of an electron micrograph of this cell structure?
step 1 measure the length of the cell structure image on the micrograph in centimetres
step 2 measure the length of the cell structure image on the micrograph in millimetres
step 3 divide the image length by 1000
step 4 multiply the image length by 1000
step 5 divide by 8
step 6 multiply by 8

What is the typical resolution of a microscope using daylight as a light source with a ×10 eyepiece lens and a ×40 objective lens?

Two different types of cell, P and Q, were broken up using ultrasound and their contents analysed. Both types of cell contained small circular DNA. The circular DNA from P all carried the same base sequence, but those from Q were of two types, with different base sequences.
What may be concluded about the identity of cell types P and Q? [Table_1]

Which features shown in the diagram can be present in viruses?

After boiling a sample of milk with Benedict’s solution, a yellow colour is observed. Which conclusion about the sample of milk is correct?

Which of the statements about polysaccharides can be used to describe amylose and cellulose?
1. contains 1,4 glycosidic bonds
2. contains 1,6 glycosidic bonds
3. polymer of glucose

Which diagram shows the formation of a peptide bond?

In enzyme-catalysed reactions, the position of the amino acids found at the active site is important. During the synthesis of enzymes, amino acids are brought together in the correct position to form the active site. Which levels of protein structure must be involved in forming the active site? [Table_1]

Which features affect the tensile strength of collagen?
1 the helical structure of collagen chains
2 the small R group of the amino acids in collagen
3 the insoluble nature of collagen
4 the bonds between collagen molecules

A fixed volume of the enzyme catalase was added to a fixed volume of hydrogen peroxide solution. The diagram shows how the concentration of product changed over the course of the reaction.
What explains the shape of this graph?

A fixed volume and concentration of substrate and enzyme were mixed. All other variables were kept constant. The enzyme-catalysed reaction was left until it was complete. Which graph shows how the rate of reaction changes with time?

The fatty acids elaidic acid and oleic acid have exactly the same structural formulae, with one double bond in the chain. However, the shapes of the chains are different, as shown in the diagram.



Which row shows the effect of the presence of these fatty acids on the structure and behaviour of a cell surface membrane?

The diagram shows a cell surface membrane.

Which is a correct role for a labelled molecule?

The diagram shows a simple cell signalling pathway in which a signal molecule leads to a response, such as a secretion.

Which row identifies P and Q?

Three parts of a chromosome and their functions are listed.

[Table_1]

Which part is matched with its correct function?

The enzyme telomerase prevents loss of telomeres after many mitotic cell cycles.
Which cells need to transcribe telomerase enzyme?
1. cancer cells
2. stem cells
3. activated memory B-lymphocytes

The diagram shows some of the stages which take place during the cell cycle.

Which two stages take place during interphase?

Which statement correctly describes the base pairing in a molecule of DNA?

Which statements about complementary base pairing are correct?
1. It allows translation to occur.
2. Purines and pyrimidines are the same size.
3. The base pairs are of equal length.
4. Uracil forms two hydrogen bonds with adenine.

The diagram shows the possible organisation of DNA molecules after one replication. Which organisation is correct?

The diagram shows part of the DNA sequence of a gene and a mutated sequence of the same gene.

normal DNA sequence   ...CCG GAT TAT TGC GAG AAA TGG CAT TCT AGG...
mutated DNA sequence   ...CCG GAT GTA TTG CGA GAA ATG CAT TCT AGG...

What are possible effects of the mutated sequence?

What is correct for phloem sieve tube elements?

The diagrams show transverse sections of parts of a plant.

Transport tissues are labelled 1 to 6.



Which combination shows the tissues that have a main function of transporting water?

The statements are descriptions of how water moves across the root to the xylem vessel elements.
1. Water enters cell walls.
2. Water enters cytoplasm by osmosis.
3. Water moves from cell to cell through plasmodesmata.
4. Water moves through cell walls.

Which statements describe the apoplast pathway?

Four plants, A, B, C and D, were grown in the same conditions and their transpiration rates measured.
Which plant is most likely to be a xerophyte?

Sucrose moves from a mesophyll cell in a leaf into a phloem sieve tube element.
Which changes to the water potential and the volume of liquid in the phloem sieve tube element are correct?
[Table_1]

The diagram shows a cross-section through a mammalian heart. Which chambers of the heart are represented by W and X?

At a certain point in a cardiac cycle, the pressure in the right ventricle is lower than that in the right atrium and lower than that in the pulmonary artery.
Which row is correct?
[Table_1]

The diagram shows the pathway for the transport of carbon dioxide that occurs in red blood cells.
Which row is correct?

The diagram shows a transverse section through an artery.

Which statement describes the tissues present in layer X?

The large arteries close to the heart have a thick elastic layer in their walls. Which statements about this layer are correct?
1 helps to maintain the blood pressure in arteries
2 reduces friction within the arteries
3 prevents too much pressure bursting the artery wall

Which tissues are present in the walls of a trachea and an alveolus?
[Table_1: The table shows epithelium with goblet cells and smooth muscle present or absent in trachea and alveolus.]

The surface tension of the layer of liquid lining the alveoli tends to pull the walls inwards so alveoli could collapse.
Which statements could explain how this is prevented?
1. Alveolar fluid is moved around by cilia.
2. Elastic fibres keep the alveoli open.
3. Epithelial cells secrete a chemical that reduces the cohesion in water.

The diagram shows some of the effects of nicotine and carbon monoxide in cigarette smoke.

Which row is correct?

Which row correctly identifies the causative organism of each disease? [Table_1]

The following advice was given to a person travelling to a country where there had been an outbreak of an infectious disease.
• cook food well and eat it hot
• peel fruit and vegetables
• drink only cool, boiled water
• wash hands often with soap and cool, boiled water

Which infectious disease would this advice help to protect against?

What is a \textit{social} factor that affects the spread of malaria?

Which are specific immune responses?
1 phagocytosis
2 production of antibodies
3 production of memory cells

Newborn babies have natural passive immunity. What is correct for this type of immunity?
[Table_1]

The diagrams show three different types of antibody structure.
[Image_1: Diagram of IgG, IgA, IgM]
Which row is correct?