Cell Biology Quiz: Ribosomes and Microscopes

Living Beings and Their Structures

• This topic includes: the cell, classification of living organisms, microorganisms, and food preservation methods.

1. The Cell

• Objectives: Identify and describe the structure of animal and plant cells, explain characteristics and functions of cell organelles, and compare/contrast plant and animal cells.
• Basic Terms:
  • Cell: The basic structural and functional unit of life.
  • Cytology: The branch of biology that studies cells.
  • All life processes (digestion, respiration, reproduction, etc.) are carried out inside cells via biochemical reactions.
• Discovery: Robert Hooke discovered cells in 1665, using cork. He called them "tiny rooms." Later, scientists like Theodor Schwann, Matthias Jakob Schleiden, and Rudolf Virchow established that all living organisms are composed of cells.

2. Shape and Size of Cells

• General cell shapes: oval, spherical, rod-like, elongated, cubical, or columnar (animal cells); hexagonal (plant cells); various in other forms.
• Cell sizes: Most cells are too small to see with the naked eye. Examples of bigger cells include ostrich eggs. The cell of Mycoplasma is the smallest.

3. Structure of Cell

• Diagram: Includes labels of different organelles in animal and plant cells. This section includes diagrams showing various organelles in animal and plant cells.

4. Basic Terms Continued

• Cell organelles: Living sites in the cell responsible for specific metabolic processes.
• Cell inclusions: Non-living components (e.g., water, salts, minerals, enzymes, vitamins, waste materials) that serve as raw materials and energy.
• The cell wall: An outer protective layer surrounding plant cells, composed of cellulose (generally tough, rough, semi-elastic, and non-living).

5. Functions of Cell Wall

• Provides mechanical support and shape to plant cells.
• Protects the cell from fungi, viruses, and bacteria.
• Enables the absorption of minerals from the soil and water by root hairs.
• Allows substances to pass through due to its permeable nature.

6. Cell Membrane

• The outer layer of most cells (called plasma membrane) that regulates what enters and leaves the cell; relatively smoother and elastic than the cell wall.
• Its composition: Phospholipid bilayer with embedded proteins, cholesterol, and carbohydrates.

7. Functions of Cell Membrane

• Provides a protective boundary to animal cells.
• Controls and coordinates intercellular fluid transport.
• Facilitates food capture, locomotion, and waste excretion in unicellular organisms (e.g., amoeba).

8. Cytoplasm

• A viscous, clear, semi-liquid substance between the cell membrane and the nucleus.
• Composed of water, soluble salts, minerals, and cell components like ribosomes, plastids, and Golgi bodies. The cytoplasm supports life processes.

9. Mitochondria

• Cellular energy-generating organelles.
• Use glucose and oxygen to produce energy (ATP).
• Found in most eukaryotic cells.

10. Functions of Mitochondria

• Generate energy (ATP) via cellular respiration.
• Crucial for the survival and functioning of the cell by providing energy.

11. Plastids

• Organelles found in plant cells.
• Types: chloroplasts, chromoplasts, and leucoplasts.
  • Chloroplasts: Green in color and conduct photosynthesis.
  • Chromoplasts: Colored (e.g., red, yellow) and involved in pigment production and flower/fruit color.
  • Leucoplasts: Colorless and store starch, protein, and lipids.

12. Functions of Plastids

• Chloroplasts: Photosynthesis, production of carbohydrates, fatty acids, and amino acids.
• Chromoplasts: Attract pollinators and aid in seed dispersal.
• Leucoplasts: Store starch, proteins, and lipids.

13. Ribosomes

• Small organelles, not enclosed by an outer membrane.
• Sites of protein synthesis (protein factories)
• Found freely in the cytoplasm, attached to ER, or within mitochondria/chloroplasts.

14. Functions of Ribosomes

• Synthesizes proteins from amino acids.
• Involved in gene expression (DNA activity for protein/RNA creation).

15. Endoplasmic Reticulum (ER)

• Highly folded membranous organelle.
• Types: Rough ER (with ribosomes) and smooth ER (without ribosomes).
  • Rough ER: involved in protein synthesis and modification, transport, and construction of Golgi body.
  • Smooth ER: involved in lipid synthesis, carbohydrate metabolism, and detoxification.

16. Golgi Body/Apparatus

• Organelle consisting of flattened sacs and vesicles.
• Involved in secretion, new cell membrane synthesis, and protein transport/sorting.

17. Functions of Golgi Body

• Secretes substances from the cells (mucus, sweat, saliva, tears, etc.).
• Contributes to cell membranes/cell plates during cell division.
• Transports/sorts proteins within the cells.

18. Lysosomes

• Small, round organelles with single-layered membranes.
• Contain digestive enzymes.
• Primarily involved in the digestion of macromolecules.

19. Functions of Lysosomes

• Digest protein, lipids, and glycogen; generate energy for the cells.
• Digest dead or fragments of cells.
• Provide nutrients to germinating seeds during their development.

20. Vacuoles

• Spaces within the cell bounded by a membrane (tonoplast).
• Filled with water, mineral salts, enzymes, and other substances ('cell sap').
• Types: Food vacuoles, contractile vacuoles (especially in protozoans) and large central vacuoles in plant cells.

21. Functions of Vacuoles

• Balance the amount of water and salts in the cytoplasm.
• Collect and store metabolic wastes before excretion.

22. Nucleus

• Central part of the cell.
• Enclosed by a double-layered, perforated membrane.
• Contains genetic material (DNA).
• Types: Eukaryotic organisms have a true nucleus, while prokaryotic organisms do not have one.

23. Parts of the Nucleus

• Nuclear membrane: Protects the nucleus, composed of a lipid and protein bilayer.
• Nucleolus: Non-membrane bound, involved in ribosome formation.
• Nucleoplasm: Liquid solution that contains water, amino acids, minerals, and enzymes.
• Chromatin fibers/Chromosomes: DNA and protein molecules; carry genetic information.

24. Functions of the Nucleus

• Controls and coordinates cell activities.
• Inherits and transfers genetic characteristics between generations via reproduction.
• Actively involved in cellular division.

25. Types of Cells based on the Nucleus

• Prokaryotic Cells: Lack a well-defined nucleus and organelles; examples include bacteria.
• Eukaryotic Cells: Contain a well-defined nucleus and other membrane-bound organelles; examples include plant and animal cells.

26. Food Preservation

• Techniques to prevent food spoilage, food poisoning, and microbial contamination.
  • Methods: Drying/dehydrating; refrigeration/freezing; canning; vacuum packing; salting; sugaring; and fermentation.
  • Preservatives: Chemicals or natural substances added to food materials to prevent spoilage/contamination.

27. Microorganisms

• Organisms too small to see with the naked eye; found in air, water, soil, food, living bodies.
• Examples: Bacteria, fungi (yeast, molds), algae (Chlamydomonas, Chlorella), protozoa (Amoeba, Paramecium, Plasmodium), viruses.

Test your knowledge about the functions of ribosomes, the endoplasmic reticulum, Golgi body, and the parts of a compound microscope. This quiz covers essential concepts in cell biology and the functioning of microscopes. Perfect for students learning about these critical biological structures.