Characteristics of living organisms, cell structure, levels of organisation and variety of life

CHECKLIST:

  • Understand that living organisms share certain characteristics (MRS C. GREN)

  • Describe levels of organisation in organisms: organelles, cells, tissues, organs, and systems

  • Describing cell structures and their functions: nucleus, cytoplasm, cell membrane, cell wall, mitochondria, chloroplasts, ribosomes and vacuole

  • Know the similarities and differences in the structure of animal and plant cells

  • Explain the importance of cell differentiation in the development of specialised cells

  • Understand the pros and cons of using stem cells in medicine

  • Describe the common features shown by eukaryotic organisms: plants, animal, fungi and protoctists

  • Describe the common features shown by prokaryotic organisms, such as bacteria

  • Understand the term pathogens and know that pathogens may include fungi, bacteria, protoctists or viruses

Characteristics of Living Organisms

To be classified as a living organism, you must carry out all 8 characteristics

If not, you are considered dead or non-living

MRS C. GREN

  • Movement —> An action by an organism or part of an organism causing a change in position/place

  • Respiration —> The chemical reaction that releases energy from glucose

  • Sensitivity —> The ability to detect or sense stimuli and make appropriate responses

  • Control —> The ability to keep internal conditions constant within narrow limits (EG: control of body temp, control of blood, glucose)

  • Growth —> An increase in cell number, cell size or both

  • Reproduction —> The process that makes offspring/more of the same species

  • Excretion —> The removal of metabolic waste (EG: CO2 from lungs, urea from kidney)

  • Nutrition —> Obtaining food, either by making it or consuming it

Note: Common mistake! Confusion w Excretion and Egestion

Egestion —> removal of undigested material (EG: faeces from anus)

Excretion —> removal of metabolic waste (EG: urea from kidney)

Variety of life

Five kingdoms:

  • Animals

  • Plants

  • Fungi

  • Protoctists

  • Prokaryotes (bacteria)

Animals

Animal Cell Structure

Below is a concise overview of the main components of an animal cell:

  1. Nucleus: Control center containing DNA.

  2. Cytoplasm: Jelly-like substance where organelles are located.

  3. Cell Membrane: Outer layer that regulates what enters and exits the cell.

  4. Mitochondria: Powerhouse of the cell that produces energy.

  5. Ribosomes: Synthesize proteins.

  6. Endoplasmic Reticulum (ER): Network of membranes involved in protein and lipid synthesis.

  7. Golgi Apparatus: Modifies, sorts, and packages proteins and lipids.

  8. Lysosomes: Contain enzymes for digestion of waste.

  9. Vacuole: Storage of substances.

For labeled diagrams or images of animal cells, please refer to educational resources or biology textbooks, as I currently cannot provide images.