Topic 1: Cell Structure Flashcards
Definitions I:
(a) Magnification
(b) Resolution
(a) Magnification: Increase in size via microscope lenses. (1 mark)
(b) Resolution: Ability to distinguish two close points. (1 mark)
Describe the structure and function of:
(a) Cell surface membrane [1 Mark]
(b) Nucleus [1 Mark]
(c) Nucleolus [1 Mark]
(a) Cell surface membrane: Phospholipid bilayer, regulates transport. (1 mark)
(b) Nucleus: Double envelope, DNA, controls activity. (1 mark)
(c) Nucleolus: Dense region, synthesises rRNA. (1 mark)
Outline the structure and role of:
(a) Rough endoplasmic reticulum [1 Mark]
(b) Smooth endoplasmic reticulum [1 Mark]
(c) Golgi body [1 Mark]
(a) RER: Ribosomes, folds, protein synthesis. (1 mark)
(b) SER: Tubular, lipid synthesis. (1 mark)
(c) Golgi body: Stacked sacs, modifies/packages proteins. (1 mark)
State the features and functions of:
(a) Mitochondria [1 Mark]
(b) Ribosomes [1 Mark]
(c) Lysosomes [1 Mark]
(d) Centrioles [1 Mark]
(a) Mitochondria: Double membrane, cristae, ATP production. (1 mark)
(b) Ribosomes: 80S/70S, protein synthesis. (1 mark)
(c) Lysosomes: Single membrane, digests waste. (1 mark)
(d) Centrioles: Microtubule pairs, spindle in mitosis. (1 mark)
Describe the structure and purpose of:
(a) Cilia [1 Mark]
(b) Microvilli [1 Mark]
(c) Microtubules [1 Mark]
(a) Cilia: Hair-like, move mucus, e.g., trachea. (1 mark)
(b) Microvilli: Folds, increase absorption, e.g., gut. (1 mark)
(c) Microtubules: Tubes, support, transport. (1 mark)
Outline the structure and function of:
(a) Chloroplasts [1 Mark]
(b) Cell wall [1 Mark]
(c) Plasmodesmata [1 Mark]
(a) Chloroplasts: Thylakoids, stroma, photosynthesis, DNA. (1 mark)
(b) Cell wall: Cellulose, rigid support. (1 mark)
(c) Plasmodesmata: Channels, cell communication. (1 mark)
Describe the features of:
(a) Large permanent vacuole [1 Mark]
(b) Tonoplast [1 Mark]
(a) Large permanent vacuole: Sap-filled, turgor pressure. (1 mark)
(b) Tonoplast: Vacuole membrane, regulates ions. (1 mark)
In a biology lab, describe three steps to prepare a temporary slide of onion epidermal cells for light microscopy. [3 Marks]
Peel onion epidermis, stain with iodine (1 mark)
Mount on slide with water (1 mark)
Add coverslip, blot excess (1 mark). (3 marks)
Calculate the magnification if a 5 µm mitochondrion from a muscle cell image is 25 mm wide. [2 Marks]
Magnification = 25 mm / 0.005 mm (1 mark) = 5000x (1 mark). (2 marks)
After observing a TEM, draw and label a plant cell from a leaf and an animal cell from muscle with key organelles. [2 Marks]
Plant: Box, chloroplasts, vacuole (1 mark); Animal: Oval, nucleus, mitochondria; Labels (1 mark). (2 marks)
Explain the differences between light and electron microscopy in studying cell ultrastructure. [3 Marks]
Light: 2000x, 200 nm resolution (1 mark); Electron: >2000x, 0.5 nm (1 mark); Electron reveals ultrastructure, e.g., RER (1 mark). (3 marks)
In a plant root and animal intestine, compare the structure of typical plant and animal cells. [2 Marks]
Plant root: Wall, chloroplasts (1 mark); Animal intestine: No wall, no chloroplasts (1 mark). (2 marks)
State how muscle cells use ATP from respiration, with two specific examples. [2 Marks]
ATP powers contraction, e.g., actin movement (1 mark); Ion pumps, e.g., calcium regulation (1 mark). (2 marks)
Outline four key structural features of a prokaryotic cell, like E. coli, from a bacterial culture. [4 Marks]
E. coli: Unicellular, 1-5 µm, peptidoglycan (1 mark); Circular DNA (1 mark); 70S ribosomes (1 mark); No organelles (1 mark). (4 marks)
In a study of bacteria and human cells, compare prokaryotic and eukaryotic cell structures with three differences. [3 Marks]
Bacteria: No nucleus, 70S (1 mark); Human: Nucleus, 80S (1 mark); Bacteria simpler, no organelles (1 mark). (3 marks)
Define the structure of viruses like influenza and explain their dependency on host cells, measurable in µm. [4 Marks]
Influenza: Nucleic acid, capsid (1 mark); Some have envelope (1 mark); Non-cellular, no metabolism (1 mark); Replicates in host, measurable in µm (1 mark). (4 marks)
