Module 2: Organisation of Living Things Flashcards
What are unicellular organisms?
+ example
- Contain only one cell responsible for all life processes
- Simple structure
- Limits metabolic reactions
- Large surface area for all substances to diffuse across
- All prokaryotes are unicellular
- EXAMPLE: Bacteria (salmonella)
What are multicellular organisms?
+ example
- Made up of different types of cells
- Similar cells grouped together that communicate to perform specialised functions that combine together for efficient functioning
- Rely less on diffusion and are less efficient
- All cells have the same DNA
- Could not survive by themselves
- EXAMPLE: Animals and Plants
What are colonial organisms?
+ example
- Cells that form a cooperative group (colony) but can survive on their own
- Could be classed as a single celled organism
- More efficient as a colony
- EXAMPLE: Blue-bottle
Example of differentiated cells in humans:
Function:To carry oxygen to cells and remove carbon dioxide – RBCs travel through tiny capillaries to reach every single cell in our bodies
Nucleus-No – to limit size
Organelles-No – to limit size
Size- Red – 7-8um
What is the structure of organised life:
cell tissue organ organ system organism
cell function
smallest unit that can carry out lifes activities
tissue function
group of cells working together to perform specific job
organ
group of tissues working together to perform specific job
organ system function
group of organs working together to perform specific job
Example of organised life;
cell- Cardiomyocytes - These cells must be able to shorten and lengthen their fibres and the fibres must be flexible enough to stretch in order to create a ‘pumping’ motion in the heart.
tissue- Cardiac muscle tissue - Endocardium, Myocardium and Epicardium. This is a specialised form of muscle tissue
organ- heart
organ system- cardiovascular system
organism- humans
organelle summary:
Organelles are the subunit of a cell and consist of a group of functioning biomolecules. Organelles take part in the chemical reactions and interactions in the cellular processes of an organism. A few examples include nucleus and chloroplasts (plant cells), and Golgi bodies and mitochondria (animal cells).
tissue summary
tissue is combination of different types of cells which perform specialized functions. The group of cells that form a tissue are not necessarily identical, but they usually have the same origin i.e. cardiac muscle tissue consists of different types of muscle cells.
nervous tissue
Nervous tissues form organs like the brain and the spinal cord and are capable of sending and receiving electrochemical messages
muscle tissue
Muscle tissues are actively contractile, meaning they can contract and expand. These tissues are useful for producing force and motion.
connective tissue
Connective tissues are fibrous in nature, and they are made up of cells that are separated by an extracellular matrix.
epithelial tissue
- Epithelial tissues cover the surface of body organs.
what are the four types of tissue in the human body?
There are four types of tissue in the human body: nervous, muscle, connective, and epithelial tissues.
organ summary
An organ performs certain functions with the help of different tissues. The major organs of animals include the lungs, brain, liver and heart whereas roots, stem, and leaves are the different organs of plants.
how are organs classified?
on the basis of the functions they perform. For example, in case of animals, the tongue, ears, eyes, skin, and nose are sensory organs, and ovaries and testes are reproductive organs. These units are formed by tissues that serve a common function.
organ system summary
Organs working together to perform certain functions form organ systems. Examples are the circulatory system in animals, and the vascular system in plants. The organs in an organ system are interdependent, i.e. they work in harmony to carry out various body functions
organism summary
An organism could either be unicellular or multicellular. The ones that are closely related can be grouped together under a single genus. An organism can be defined as the fully functional form of a living being that can thrive in a particular environment.
What is a specialised cell?
Specialised cells make up tissues with different types of tissues forming organs that carry out particular function within an organ.
what are stem cells?
All specialised cells originate from cells that are known as stem cells. These stem cells are undifferentiated and are able to divide many times of a long period and become specialised.
What happens to cells once they have specialised?
Once cells have become specialised to form a particular type of cell, they lose their capacity to develop into other types of cells.
What is the relationship between cell structure and function?
The cells of those parts of the body include in exchanging substances with the environment have special structural features to increase their surface area to volume ratio allowing them to exchange the required materials more efficiently.
EXAMPLE – Alveoli
Cells may be flattened to increase their surface area to volume ratio that allow for the more efficient exchange of substances.
Skeletal muscle
Skeletal muscle – long and have striation which are caused by the arrangement of the actin and myosin in them. They are attached to the bones and they cause movement. They are voluntary muscles because they require conscious thought to function
cardiac muscle
fibres are present in the heart and also have striations, the individual cells have connection junctions that are necessary or the coordinated beating of the heart
smooth muscle
do not have striation and their contractions push substances through specialised organs such as the gastrointestinal tract, the blood vessels and the urethra which leads from the bladder.
What is the difference between voluntary and involuntry?
Muscles that are under your conscious control are called voluntary muscles. Muscles that are not under your conscious control are called involuntary muscles
Meristematic tissue:
(Plant cell)
• Found at the tips of roots and shoots
• In woody plants it can also be found in buds and in a ring around the stem
• Inside these tissues’ cells divide to produce new growth
• Cube shaped and very small
CHARACTERISTICS OF GAS EXCHANGE SYSTEMS:
surface area
thin moist surface
close proximity to transport system
greater concentration of gas on one side
CHARACTERISTICS OF GAS EXCHANGE SYSTEMS:
surface area
- Enhanced by folding, branching or flattening
* Allows for a higher rate of diffusion and remove carbon dioxide quicker
CHARACTERISTICS OF GAS EXCHANGE SYSTEMS:
thin moist surface
- Easier diffusion
* Decreases distance for gas to travel
CHARACTERISTICS OF GAS EXCHANGE SYSTEMS:
close proximity to transport system
• Efficient transport
CHARACTERISTICS OF GAS EXCHANGE SYSTEMS:
greater concentration of gas on one side
• To ensure the concentration gradient is upheld