Master GCSE Biology

MS1 (1 mark)

- A prokaryote is a type of cell that lacks a membrane-bound nucleus or other membrane-bound organelles.

MS2 (2 marks)

>1. The cell membrane controls what enters and exits the cell (1)

>2. It protects the cell from its surroundings (1)

MS3 (3 marks)

>1. Plant cells have a chloroplast, while animal cells do not (1)

>2. Plant cells have a cell wall, while animal cells do not (1)

>3. Plant cells have a larger central vacuole, while animal cells have smaller ones (1)

MS4 (2 marks)

- Ribosomes are cell organelles that are responsible for protein synthesis (2)

MS5 (3 marks)

>1. Binary fission produces two identical daughter cells (1)

>2. Mitosis produces two daughter cells that may be genetically different (1)

>3. Mitosis occurs in eukaryotes, while binary fission occurs in prokaryotes (1)

MS6 (4 marks)

>1. Aseptic technique prevents contamination of the cell culture with microorganisms (1)

>2. This ensures that the cells remain viable and uncontaminated (1)

>3. Contamination can lead to incorrect results or even the loss of the cell culture (1)

>4. Aseptic technique involves using sterile equipment, working in a sterile environment, and avoiding contact with microorganisms (1)

MS7 (1 mark)

- Mitosis

MS8 (2 marks)

>1. The nucleus contains the cell's genetic material (DNA) (1)

>2. DNA directs the production of proteins, which control cellular activities (1)

MS9 (3 marks)

>1. Diffusion is the movement of molecules from an area of high concentration to an area of low concentration (1)

>2. Molecules diffuse through the cell membrane down a concentration gradient (1)

>3. Diffusion is a passive process, meaning that it does not require energy input (1)

MS10 (2 marks)

- Cytoplasm