Question 1: Define the term 'organelles' as used in cell biology.

Answer: Organelles are specialised structures within a cell that perform specific functions necessary for cell survival and operation.

Question 2: Name three key components of an animal cell and briefly describe their functions.

Answer: Nucleus (controls cell activities), cytoplasm (site of chemical reactions), cell membrane (regulates entry and exit of substances).

Question 3: Explain why the nucleus is often referred to as the 'control centre' of the cell.

Answer: Because it contains the genetic material (DNA) that controls the activities and functions of the cell.

Question 4: What is the primary function of the cell membrane in animal cells?

Answer: To regulate the movement of substances in and out of the cell.

Question 5: Identify the organelle responsible for protein synthesis in animal cells.

Answer: Ribosome.

Question 1: A forensic scientist extracts a biological sample and finds that the sample contains 2.5 x 10^6 cells per millilitre. Calculate the total number of cells in a 2 millilitre sample.

Answer: Total cells = concentration (cells/mL) x volume (mL) = 2.5 x 10^6 x 2 = 5 x 10^6 cells.

Question 2: If a cell nucleus is 10 micrometres in diameter, what is its radius? Express your answer in micrometres.

Answer: Radius = Diameter / 2 = 10 μm / 2 = 5 μm.

Question 1: Describe a basic experimental procedure to extract animal cell nuclei from a biological sample in a forensic laboratory. Include safety precautions.

Answer: The procedure involves homogenising the sample in a cold isotonic solution to break cells open, then centrifuging to separate nuclei. Safety measures include wearing gloves, lab coat, eye protection, and working in a sterile environment to prevent contamination.

Question 2: Identify two variables that must be controlled during the microscopic examination of animal cells in forensic analysis and explain why.

Answer: Variables include temperature (to prevent cell damage) and staining concentration (to ensure clear visibility of cell components).

Question 1: A forensic report states that a biological sample contains 40% of cells with abnormal nuclear shapes. What might this indicate about the sample, and how could this information be useful in a forensic investigation?

Answer: It may indicate the presence of damaged or mutated cells, possibly pointing to disease or trauma. This information can help identify the tissue origin or suggest exposure to harmful agents relevant to the crime scene.

Question 1: Explain how understanding animal cell structure can assist forensic scientists in analysing biological evidence from crime scenes.

Answer: Knowledge of cell structure allows forensic scientists to identify tissue types, determine the origin of biological samples, and detect cellular abnormalities. This can aid in linking suspects or victims to crime scenes and understanding injury mechanisms.

Question 2: Which of the following is a true statement about animal cell components relevant to forensic analysis?

Answer: