Cell Types and Requirements Flashcards
What is a cell?
- The basic structural unit of all forms of life on Earth.
- All living things are made up of one or more cells.
What is a heterotroph?
An organism that can obtain energy by consuming organic substances (animal or plant tissue).
What is an autotroph?
An organism that can use light or chemical energy to synthesise food from simple inorganic substances (photosynthesis).
What is a chemotroph?
A small group of bacteria that are able to create sugars (organic molecules) from inorganic compounds without sunlight (chemosynthesis).
What is the cell theory?
1.The cell is the most basic unit of life.
2. All cells arise from pre-existing cells.
3. Every living organism is made up of one or more cells.
What are chemical reactions?
Cellular processes build and break down complex molecules through chemical reactions. Chemical reactions are occuring in your body at all times.
What are the 2 types of chemical reactions?
- Exothermic
- Endothermic
What are exothermic reactions?
Reactions that release energy.
What are endothermic reactions?
Reactions that absorb energy.
What do exothermic and endothermic reactions require?
The require energy to proceed.
What is metabolism?
Metabolism is the sum of all of the chemical reactions occuring in a body.
What types of energy enter/exit cells?
- Light from the sun
AND/OR - Chemical energy stored in complex molecules
What types of matter enter/exit cells?
- Gases such as oxygen and carbon dioxide
- Simple nutrients, ions and water
- Wastes
Describe prokaryotic cells.
- Simplest type of cell
- Small in size 1 -10μm long 0.2 - 2μm diameter
- Have difficultly in performing multiple functions at the same time
- Lack membrane bound organelles, including a nucleus
- Belong to the Domains - Bacteria and Archaea
- Exist as single cells
Describe the cytoplasm in prokaryotic cells.
- Makes up the bulk of the cell and contains ribosomes, cytosol, plasmids and circular chromosomes.
- Cytosol is the semi fluid component of the cytoplasm, it contains many dissolved substances.
- Chemical reactions that enable the cell to live are carried out here.
Describe the ribosomes in prokaryotic cells.
- Scattered freely throughout the cytosol.
- Only distinguishable organelles in a prokaryotic cell.
- Not bound by a membrane.
- Site of protein synthesis (joining of amino acids to form proteins).
- Proteins are required for cell growth, repair and general cell functioning.
Describe the genetic material in prokaryotic cells.
- The genetic code in DNA differs between different species of bacteria.
- Most contain a single circular chromosome (not visible by light microscope) which is in direct contact with the cytoplasm.
- Chromosome contain the instructions for making different proteins.
- Numerous small rings of DNA (plasmids) may also be present. These can reproduce independently of the main chromosome.