Characteristics of Organisms and Levels of Organisms

Processes which all organisms need to do in order to be considered as alive

Movement: all or part of themeselves. For example: Plants demonstrate movement by growing in the direction or away from stimula such as light or gravuty.
Respiration: Releasing energy from glucose
Sensitivity: Detecting and responding to changes in the enviroment.
Control: of internal enviroment; keeping parameters withen strict limits such as temperature.
Nutrition: Taking in certain substances to help carry out reactions
Excretion: Removal of metabollic waste, e.g: Urea which is released from kidneys, or Carbon Dioxide which is released from lungs.
Reproduction: Either by themeselves or with others of their species.
Growth: Increasing in size and/or the number of cells.

Why are viruses not considered living organisms

Viruses cannot reproduce independently, they must infect a host cell to make copies of themselves. Viruses do not carry out metabolism (they don’t perform chemical reactions to maintain life). They do not respire, grow or use their own energy like living cells.

Homeostasis and ATP

Maintenance of a constant internal enviroment, such as temperature, water, and glucose.

ATP: Energy molecule which is released through respiration.

Sensitivity

Means detecting and responding to changes in the enviroment (stimula)

Receptors

Cells that detect stimuli are called receptorss found in eyes, toungue, nose, ears and skin. Eyes detect light, tougue detects chemicals in food and drink, noses detect chemicals in the air. Ears detect sound and positions of head, skin detects touch, temperature, pressure and pain.

Stimulas: Change in enviroment.

Excretion vs Egestion

Excretion is the remocal of metabollic waste, however egestion is the removal of undigested food from the body through the anus.

Anerobic Respiration vs Aerobic Respiration

Anerobic Respiration takes place when there isnt enough oxygen, and it takes place in the cytoplasm. Glucose—> Lactic acid (energy). The energyy that is produced is less energy compared to the energy produced in Aerobic Respiration but it can be produced with only glucose.

Aerobic Respiration takes place in the mitochondria.

Glucose+Oxygen—>Carbon Dioxide+Water (energy)

Levels of Organisms

Organelles—>Cells—>Tissues—>Organs—>Organ systems—>Organism

Organelles and Cells

Organelles: Sub-cellular structures that have particular functions inside a cell. For example, mitochondria or ribosomes.

Cells: Made up of organelles which work together to perform a function. For example, muscle cell.

Tissues and Organs and Organ Systems

Tissue: This is a group of cells which have similar structures to perform a funtion. For example, cardiac muscle tissue

Organs: These are structures made up of tissues which work together to perform specific functions. For example, the heart which pumps blood around the body.

Organ Systems These are groups of organs with related functions which work together to perform body functions. For example, the cardiovascular system.