Untitled Deck Flashcards
(38 cards)
What are the visible signs we often use to determine if something is alive?
Breathing, movement, growth
These signs can include breathing or visible movement, but are not definitive indicators of life.
Why is visible movement not a sufficient criterion for determining life?
Invisible molecular movements also indicate life
Some living organisms show little to no visible movement yet are still alive.
What do professional biologists say about molecular movement?
It is necessary for life
Viruses are a controversial case as they do not show molecular movement until they infect a host.
What must living organisms do to maintain their structures?
Repair and maintain their structures
This is necessary to prevent breakdown due to environmental effects.
What are life processes?
Processes that perform maintenance in living organisms
These processes continue even during inactivity, like sleeping.
What is the source of energy needed for maintenance processes in organisms?
Food
Food provides energy and raw materials necessary for growth and maintenance.
What are the two types of nutritional processes based on the source of food?
- Autotrophic
- Heterotrophic
What is autotrophic nutrition?
Nutrition where organisms produce their food from inorganic sources
Autotrophs, like green plants, utilize sunlight for this process.
What is photosynthesis?
The process by which autotrophs convert carbon dioxide and water into carbohydrates using sunlight
This process is essential for energy storage in plants.
What do chloroplasts contain that is essential for photosynthesis?
Chlorophyll
Chlorophyll captures light energy necessary for the photosynthesis process.
What role do stomata play in photosynthesis?
They allow gas exchange for carbon dioxide uptake
Stomata open and close to regulate water loss and gas exchange.
What is the difference between autotrophs and heterotrophs?
- Autotrophs produce their own food
- Heterotrophs consume other organisms for food
What is heterotrophic nutrition?
Nutrition where organisms depend on other organisms for food
Heterotrophs include animals and fungi that cannot produce their own food.
How do single-celled organisms obtain food?
Through their entire surface
In contrast, multicellular organisms have specialized structures for food intake.
What is the alimentary canal?
A long tube from the mouth to the anus in humans
It consists of various regions, each specialized for different functions.
What are the essential processes for maintaining life?
- Nutrition
- Respiration
- Excretion
Fill in the blank: The process of acquiring oxygen and breaking down food for energy is called _______.
Respiration
Why is diffusion insufficient for oxygen transport in multicellular organisms?
Not all cells are in direct contact with the environment
As organisms grow larger and more complex, specialized transport systems are needed.
What is excretion?
The process of removing waste products from the body
Excretion is crucial to prevent the accumulation of harmful by-products.
What is the structure that has a definite shape and takes in food at a specific spot?
Amoeba
The food is moved to this spot by the movement of cilia covering the cell surface.
What is the alimentary canal?
A long tube extending from the mouth to the anus
It has different parts that are specialised to perform different functions.
What role does saliva play in digestion?
It contains the enzyme salivary amylase that breaks down starch into sugar.
What is the function of the muscular tongue during chewing?
To mix food thoroughly with saliva and move it around the mouth.
What are peristaltic movements?
Rhythmic contractions of muscles in the lining of the canal to push food forward.
