cells

Question 1

Q: What is the function of the nucleus?

Answer 1

A: Contains DNA and controls the cell’s activities.

Question 2

Q: What is the function of the mitochondrion?

Answer 2

A: Site of aerobic respiration and ATP production.

Question 3

Q: What is the function of the rough endoplasmic reticulum?

Answer 3

A: Synthesises and transports proteins.

Question 4

Q: What is the function of the smooth endoplasmic reticulum?

Answer 4

A: Synthesises and processes lipids.

Question 5

Q: What is the function of the Golgi apparatus?

Answer 5

A: Modifies, sorts, and packages proteins and lipids.

Question 6

Q: What is the function of lysosomes?

Answer 6

A: Contains digestive enzymes to break down waste.

Question 7

Q: What is the function of ribosomes?

Answer 7

A: Site of protein synthesis.

Question 8

Q: What is the function of the cell surface membrane?

Answer 8

A: Regulates movement of substances into and out of the cell.

Question 9

Q: What is the function of the cell wall in plants?

Answer 9

A: Provides structural support and prevents osmotic lysis.

Question 10

Q: What is the function of the vacuole?

Answer 10

A: Maintains cell pressure and stores ions and molecules.

Question 11

Q: What is the function of the chloroplast?

Answer 11

A: Site of photosynthesis.

Question 12

Q: What are prokaryotic cells?

Answer 12

A: Cells without a nucleus or membrane-bound organelles.

Question 13

Q: What is the role of plasmids in prokaryotic cells?

Answer 13

A: Carry genes that may benefit survival, such as antibiotic resistance.

Question 14

Q: What is the structure of a virus?

Answer 14

A: Contains genetic material (DNA or RNA), a protein coat (capsid), and attachment proteins.

Question 15

Q: How do viruses replicate?

Answer 15

A: Attach to host cell, inject genetic material, and hijack host cell machinery.

Question 16

Q: What is the difference between magnification and resolution?

Answer 16

A: Magnification is how much bigger an image is, resolution is the clarity or detail.

Question 17

Q: What is the formula for magnification?

Answer 17

A: Image size / Actual size.

Question 18

Q: What is the purpose of cell fractionation?

Answer 18

A: To isolate different organelles.

Question 19

Q: What are the three steps of cell fractionation?

Answer 19

A: Homogenisation, filtration, ultracentrifugation.

Question 20

Q: What is the order of organelle separation in ultracentrifugation?

Answer 20

A: Nucleus → mitochondria → lysosomes → ER → ribosomes.

Question 21

Q: What is the difference between light and electron microscopes?

Answer 21

A: Electron microscopes have higher resolution and magnification.

Question 22

Q: What are the two types of electron microscopes?

Answer 22

A: Transmission (TEM) and Scanning (SEM).

Question 23

Q: What is the function of the plasma membrane?

Answer 23

A: Controls substance movement; site of cell signalling.

Question 24

Q: What are the main components of a plasma membrane?

Answer 24

A: Phospholipids, proteins, cholesterol, glycoproteins, glycolipids.

Question 25

Q: What is the fluid mosaic model?

Answer 25

A: Describes membrane as a flexible layer with proteins scattered throughout.

Question 26

Q: What factors affect membrane permeability?

Answer 26

A: Temperature, solvent concentration, pH.

Question 27

Q: What is simple diffusion?

Answer 27

A: Passive movement of molecules from high to low concentration.

Question 28

Q: What is facilitated diffusion?

Answer 28

A: Passive movement via channel or carrier proteins.

Question 29

Q: What is osmosis?

Answer 29

A: Movement of water across a semi-permeable membrane from high to low water potential.

Question 30

Q: What is active transport?

Answer 30

A: Movement of substances against the concentration gradient using ATP.

Question 31

Q: What is co-transport?

Answer 31

A: When one substance helps move another across the membrane.

Question 32

Q: How is glucose absorbed in the ileum?

Answer 32

A: Sodium-glucose co-transport via active transport.

Question 33

Q: What is an antigen?

Answer 33

A: A molecule on the surface of a cell that triggers an immune response.

Question 34

Q: What is phagocytosis?

Answer 34

A: Ingestion of pathogens by phagocytes.

Question 35

Q: What is the role of T cells?

Answer 35

A: Recognise antigens and activate other immune cells.

Question 36

Q: What is the role of B cells?

Answer 36

A: Produce antibodies specific to an antigen.

Question 37

Q: What is the difference between the primary and secondary immune response?

Answer 37

A: Secondary is faster and stronger due to memory cells.

Question 38

Q: What are monoclonal antibodies?

Answer 38

A: Identical antibodies produced from a single B cell clone.

Question 39

Q: What are monoclonal antibodies used for?

Answer 39

A: Cancer treatment, pregnancy testing, targeted drug delivery.

Question 40

Q: What is a vaccine?

Answer 40

A: Contains antigens that stimulate the production of memory cells.

Question 41

Q: What is herd immunity?

Answer 41

A: When enough of a population is immune, reducing disease spread.

Question 42

Q: What is the difference between active and passive immunity?

Answer 42

A: Active involves memory cells; passive is temporary with no memory cells.

Question 43

Q: Why is antigenic variation a problem for immunity?

Answer 43

A: It allows pathogens to evade the immune system and vaccines.

Question 44

Q: How does HIV infect the body?

Answer 44

A: Attaches to T helper cells and uses them to replicate.

Question 45

Q: Why do antibiotics not work against viruses?

Answer 45

A: Viruses replicate inside host cells and lack metabolic pathways targeted by antibiotics.

Question 46

why might a babies whose mother is HIV positive, test positive for it too, without having HIV? (2)

Answer 46

- child receives antibodies from mother - so solution will test positive (before 18 months)

Question 47

suggest two purposes of the control well in ELISA tests? (2)

Answer 47

- shows that only the enzyme is causing the colour change - shows that all unbound antibody is washed away