GCSE Combined Science Foundation Short Paper A
Covers Cell Biology, Organisation, Infection and Response and 3 more.
Questions
Question 1 [2 marks]
Bonding, Structure and the Properties of Matter
Sodium chloride is an ionic compound.
State the type of bonding found in sodium chloride, and name the particles held together by this bonding.
Question 2 [2 marks]
Bioenergetics
Photosynthesis is the process by which plants make glucose.
Write the word equation for photosynthesis.
Question 3 [2 marks]
Organisation
The small intestine is the main site of absorption of digested food in the human digestive system.
State two ways the small intestine is adapted for the efficient absorption of digested food.
Question 4 [2 marks]
Cell Biology
Prokaryotic cells and eukaryotic cells are the two basic types of cell.
State two differences between a prokaryotic cell and a eukaryotic cell.
Question 5 [2 marks]
Bonding, Structure and the Properties of Matter
Sodium chloride is an ionic compound with a giant ionic lattice structure.
State two properties typical of ionic compounds such as sodium chloride.
Question 6 [3 marks]
Infection and Response
The skin is part of the body's non-specific defence system against pathogens.
Describe how the skin acts as a barrier to prevent pathogens entering the body.
Question 7 [3 marks]
Atomic Structure and the Periodic Table
An atom is made up of protons, neutrons and electrons.
State the relative charge and relative mass of an electron, and state the relative charge of a neutron.
Question 8 [4 marks]
Bonding, Structure and the Properties of Matter
A polymer chain is made from 250 repeating ethene monomer units.
Each monomer unit has a length of 0.25 nm when incorporated into the polymer chain.
Calculate the total length of the polymer chain, in nm.
Question 9 [5 marks]
Infection and Response
The human body has non-specific and specific defences against pathogens.
Describe three ways white blood cells help to defend the body against pathogens, and state the name of the process by which a phagocyte destroys a pathogen.
Question 10 [5 marks]
Organisation
A sample of blood has a total volume of 5.0 cm^3.
The sample contains 2.2 cm^3 of red blood cells, white blood cells and platelets, and the rest of the sample is plasma.
Calculate the percentage of the blood sample's volume that is plasma.
Question 11 [5 marks]
Infection and Response
A student wants to grow a culture of bacteria on an agar plate to investigate the effect of an antibiotic.
Describe the aseptic techniques the student should use to prevent contamination of the culture by unwanted microorganisms.
Question 12 [5 marks]
Bonding, Structure and the Properties of Matter
Metals consist of giant structures held together by metallic bonding.
Describe the structure of a metal in terms of metallic bonding, and explain why metals conduct heat well.
Model solutions
| Question 1[2 marks] | |
|---|---|
| Answer or working | Marks |
| ionic bonding | B1 |
| ions (Na+ and Cl- ions) | B1 |
| Final answer: Ionic bonding between Na+ and Cl- ions | |
| Question 2[2 marks] | |
|---|---|
| Answer or working | Marks |
| carbon dioxide + water as the reactants | B1 |
| glucose + oxygen as the products (using light energy) | B1 |
| Final answer: carbon dioxide + water -> glucose + oxygen | |
| Question 3[2 marks] | |
|---|---|
| Answer or working | Marks |
| villi, which increase the surface area for absorption | B1 |
| a good blood supply / capillaries (or a thin wall), which maintains a steep concentration gradient | B1 |
| Final answer: Villi and a good blood supply (or thin walls) | |
| Question 4[2 marks] | |
|---|---|
| Answer or working | Marks |
| a eukaryotic cell having a nucleus, while a prokaryotic cell has no nucleus (genetic material free in the cytoplasm) | B1 |
| a eukaryotic cell being much larger than a prokaryotic cell | B1 |
| Final answer: Eukaryotic cells have a nucleus and are larger; prokaryotic cells have no nucleus and are much smaller | |
| Question 5[2 marks] | |
|---|---|
| Answer or working | Marks |
| ionic compounds having high melting and boiling points | B1 |
| ionic compounds conducting electricity when molten or dissolved in water, but not when solid | B1 |
| Final answer: High melting/boiling points; conduct electricity only when molten or dissolved | |
| Question 6[3 marks] | |
|---|---|
| Answer or working | Marks |
| the skin forming a physical barrier covering the body | B1 |
| the skin producing antimicrobial secretions that kill pathogens | B1 |
| clotting/scab formation sealing a wound to prevent pathogens entering | B1 |
| Final answer: Physical barrier, antimicrobial secretions, clotting/scabs | |
| Question 7[3 marks] | |
|---|---|
| Answer or working | Marks |
| the electron having a relative charge of -1 | B1 |
| the electron having a very small (negligible) relative mass | B1 |
| the neutron having a relative charge of 0 | B1 |
| Final answer: Electron: charge -1, very small (negligible) mass; neutron: charge 0 | |
| Question 8[4 marks] | |
|---|---|
| Answer or working | Marks |
| using total length = number of units x length per unit | M1 |
| substituting 250 x 0.25 | M1 |
| 62.5 | A1 |
| the unit nm | B1 |
| Final answer: 62.5 nm | |
| Question 9[5 marks] | |
|---|---|
| Answer or working | Marks |
| phagocytes engulfing and digesting pathogens | B1 |
| lymphocytes producing antibodies that are specific to antigens on the pathogen | B1 |
| lymphocytes producing antitoxins that neutralise toxins produced by the pathogen | B1 |
| stating the process is called phagocytosis | B1 |
| memory cells remaining after an infection, allowing a faster response if the same pathogen returns | B1 |
| Final answer: Phagocytosis, antibody production and antitoxin production; the phagocyte process is called phagocytosis | |
| Question 10[5 marks] | |
|---|---|
| Answer or working | Marks |
| plasma volume = 5.0 - 2.2 | M1 |
| 2.8 cm^3 | A1 |
| using percentage = (plasma volume / total volume) | M1 |
| substituting (2.8 / 5.0) x 100 | M1 |
| 56% | A1 |
| Final answer: 56% of the blood sample's volume is plasma | |
| Question 11[5 marks] | |
|---|---|
| Answer or working | Marks |
| sterilising the agar plates and culture media before use, to kill unwanted microorganisms | B1 |
| sterilising the inoculating loop by passing it through a flame before and after use | B1 |
| briefly lifting (rather than fully removing) the lid of the petri dish when inoculating, to reduce contamination from the air | B1 |
| taping the lid of the petri dish closed after inoculating | B1 |
| incubating the plate at a suitable temperature, below 25 degrees C in a school laboratory, to reduce the growth of harmful pathogens | B1 |
| Final answer: Sterilise the plates, media and inoculating loop, briefly lift (not remove) the lid when inoculating, tape the lid shut, and incubate below 25 degrees C in a school lab | |
| Question 12[5 marks] | |
|---|---|
| Answer or working | Marks |
| metal atoms losing their outer shell electrons to form positive ions | B1 |
| these electrons becoming delocalised (free to move) throughout the structure | B1 |
| the positive metal ions being arranged in a regular, giant structure | B1 |
| there being strong electrostatic attraction between the positive ions and the delocalised electrons throughout the structure | B1 |
| metals conducting heat well because the delocalised electrons can move and transfer energy quickly throughout the structure | B1 |
| Final answer: Metal ions are held in a giant structure by strong attraction to a sea of delocalised electrons, which also lets metals conduct heat and electricity well | |