Characteristics of Life and Cell Theory Flashcards
(20 cards)
Name 10 basic characteristics of living things
- Organised structures
- Reproduction
- Grow and develop
- Feed
- Respire
- Excrete waste
- Respond to their surroundings
- Move
- Control their internal conditions
- Able to evolve
Organisation
Living things are made up of cells, which are the basic units of life.
Cells are organized into tissues, organs, and systems to carry out specific functions.
Reproduction
Living things can reproduce to create offspring.
Asexual (one parent, identical offspring).
Sexual (two parents, genetically diverse offspring)
Growth and development
Living organisms grow in size and undergo changes throughout their life cycle.
Growth can be cell division or increase in cell size.
Feeding
The process by which organisms obtain food to provide energy for growth, repair, and maintaining body functions.
Organisms can be herbivores, carnivores, or omnivores depending on their diet.
Respiration
The process of converting food (glucose) and oxygen into energy (ATP), carbon dioxide, and water.
Happens in mitochondria in eukaryotic cells.
Can be aerobic (with oxygen) or anaerobic (without oxygen).
Excretion
The removal of waste products produced by metabolic processes.
Examples include urine in animals, oxygen in plants, and carbon dioxide from cellular respiration.
Responsiveness
Living organisms can respond to changes in their environment.
This can include responding to light, temperature, sound, or touch.
Example: A plant bending towards light (phototropism).
Movement
Living things can move, either as a whole or in parts.
Movement may be voluntary (animals moving) or involuntary (plants growing towards light).
Helps organisms find food, escape danger, or adapt to their environment.
Homeostasis
The ability of organisms to maintain a stable internal environment, despite changes in the external environment.
Examples include regulating body temperature, pH balance, and water levels.
Evolution
The gradual change in species over time due to changes in their genetic material.
Driven by natural selection, where advantageous traits increase in frequency within a population.
Leads to adaptation to the environment and new species over generations.
What is cell theory
One of the basic principles of biology
Who formulated this theory
Theodor Schwann, Mathias Schleiden, Rudolph Virchow, Jan Evangelista Purkyňe
Cell theory states…
All living organisms are made of one or more cells.
The cell is the basic unit of structure and function in living organisms.
All cells come from pre-existing cells through cell division.
Hereditary information is passed on from one cell to another
All cells have the same basic chemical composition, functional units of life, metabolism
Capable of independent existence
Two types of cells
Prokaryotic cells: Simple, no nucleus (archaeans, bacteria).
Eukaryotic cells: More complex, with a nucleus (animal, plant, fungal, Protozoan cells).
Reproduction: eukaryotic cell
Somatic cells:
All body cells (e.g., skin, muscle, nerve cells).
Diploid (2 sets of chromosomes, one from each parent).
Undergo mitosis for growth and repair.
Sex cells (Gametes):
Egg and sperm in animals, pollen and ovules in plants.
Haploid (1 set of chromosomes).
Undergo meiosis to produce gametes for sexual reproduction.
Reproduction: prokaryotic cell
Binary fission: The cell duplicates its DNA, then splits into two identical cells.
No mitosis or meiosis because prokaryotes lack a nucleus.
Asexual reproduction
Budding: New organism grows from a bud on the parent (e.g., Hydra).
Fragmentation: Parent breaks into pieces, each grows into a new organism (e.g., Starfish).
Regeneration: Lost body parts regrow, and sometimes the part grows into a new organism (e.g., Planarians).
Parthenogenesis: Egg develops into a new organism without fertilization (e.g., Bees).
Cell Processes: Endocytosis and Exocytosis
Endocytosis: The process where the cell engulfs substances from outside by folding its membrane around them to form a vesicle.
Example: White blood cells engulfing pathogens.
Exocytosis: The process where the cell releases substances by fusing a vesicle with the cell membrane, expelling its contents outside.
Example: Secretion of hormones from cells.
Cell migration
Vital for the development of tissues and organs. Cell movement is required for mitosis and cytokinesis.
it is possible by interactions between enzymes and cytoskeleton microtubules
