Characteristics and organization of
living organisms
1. Definition and terms of Mrs Gren
● Movement : A change of position
● Respiration : The chemical reactions that break down nutrient molecules in living cells to
release energy for metabolism
● Sensitivity : The ability to detect or sense stimuli in the internal or external environment
● Growth : A permanent increase in size and dry mass by an increase in cell number or cell size or
both
● Reproduction : The process that makes the same kind of that organisms
● Excretion : The removal from organisms of toxic materials, the waste products of metabolism
by poo poo and pee pee
● Nutrition : The taking in of materials for energy, growth and development
2. Cell structure
All living things are made of cells. New cells are produced by the division of existing cells.
Cell membrane
Very thin layer of protein
and fat
Controls movement in and out of cells
Cytoplasm
A clear jelly, nearly all
water (70%)
Where chemical reactions (metabolism) take
place
Nucleus
Mitochondria
Contains DNA, genetic information of the cell
In cytoplasm
Where aerobic respiration happens
Ribosome
Allows protein synthesis
Vacuole
Cell sap to keep cell turgid
Cell wall
Made mainly from
cellulose
Keep the shape of the cell and strengthens the
cell
Chloroplasts
Green
Contains chlorophyll, absorbs light energy for
photosynthesis
3. Levels of organization
The division of existing cells produce new cells
Cells : building blocks of life
Tissue : groups of cells (with similar structures working together to perform a shared function)
Organ : group of tissues (working together to perform a specific function)
Organ system : group of organs (related function working together to perform a specific function)
4. Specialized cells
Specialized cells have specific functions
Root hair cell :
-
Found in the plant’s root
-
Function : Absorb nutrients, water and mineral ions from the soils
-
Adaptations vs how it works
● Large surface area = more diffusion of water and mineral would happen
● No chloroplast = no sunlight = save place for energy
● Thin wall - large vacuole = Contains more water and nutrients = more absorption
● Extended membrane
Palisade mesophyll cell:
-
Found in the plant’s leaf
-
Function : photosynthesis
-
Adaptations vs how it works
●
●
●
●
Column shapes = maximize absorption of sunlight and increase photosynthesis
Many chloroplasts = maximize photosynthesis
Large vacuole = push chloroplasts to the edge
Thin cell wall = maximize photosynthesis
Red blood cell :
-
Found in the animal’s blood
-
Function : Transporting oxygen (O2)
-
Adaptations vs how it works
●
●
●
●
Biconcave disc shape = increase surface area for O2 to diffuse
Small and flexible = fit through blood vessels
Contains hemoglobin = blind O2
No nucleus = hold more O2
Sperm cell :
-
Found in the animal’s testes
-
Function : Contains the male genetic material for reproduction
-
Adaptations vs how it works
● Contains 50% amount of DNA (haploid) = fertilization
● Enzyme (acrosome in the head) = break down the ovum’s cell membrane
● Lots of mitochondria = release energy for movement
● Tail = for sperm to swim
Egg cell :
-
Found in the animal’s ovaries
-
Function : Contains the female genetic material for reproduction
-
Adaptations vs how it works
● Contains 50% amount of DNA (Haploid) = fertilization
● Cell membrane changes after fertilization = allow only one sperm to enter
● Lots of cytoplasm = nutrients for embryo development
Ciliated cell :
-
Found in the animal’s trachea
-
Function :Controls the movement of mucus in the trachea and bronchi
-
Adaptations vs how it works
● The extension of cell membrane = move mucus and trapped the particles from the respiratory
system
Prokaryotes (Bacteria)
Prokaryotes DO NOT have mitochondria and a true nucleus.
A bacterial cell only contains a cell
wall, cell membrane, cytoplasm,
ribosomes, circular DNA, and
plasmids.