What are the three tenets of cell theory?
- All living organisms are composed on of one or more cells
- The cell is the basic unit of structure & organization in organisms
- All cells come from pre-existing cells
When were cells first discovered?
17th Century
What are the two types of cells and their characteristics?
Prokaryotic Cells
- No nucleus or membrane bound organelles
- Smaller cells
- Unicellular
- Binary Fission
- Asexual
- Bacteria
Eukaryotic Cells
- Has a nucleus and membrane bound organelles
- Large Cells
- Multicellular
- Mitosis/Meiosis
- Sexual or Asexual
- Plant or Animal
Describe Epithelial cells function
Form protective barriers in tissues and may be specialized to absorb or secrete specific compounds
Describe Muscle cells function
Responsible for the movement of the skeleton, heart, and many internal organs
Describe Nerve Cells function
Conduct electrical signals throughout the body. Control contraction of muscles. Responsible for 5 senses (sight, hearing, smell, touch, taste)
Describe Connective tissue Cell function
Create extracellular material that holds cells together in tissue. Maybe specialized to absorb or resist external forces
Describe Bone Cell function
Form the bones of the skeletal system and to give strength and support to the body - very tough cells
Describe Secretory Cell function
These cells form gland and are for secretion.
Describe Adipose Cell function
Fat cells located throughout the body to store fat cells
Describe RBC function
Formed in the bone marrow, released into circulation and move throughout the body, carry oxygen to different organs, have limited life spans and must be replaced continuously.
Define Hydrophilic
Literally means “water-liking”. Hydrophilic molecules are attracted to water. Hydrophilic molecules are attracted to hydrophilic molecules but repel hydrophobic molecules.
Define Hydrophobic
Literally means “water-fearing”. Hydrophobic molecules tend to try and keep away from water.
What are cells mainly composed of?
Carbon and Water
Give some examples of carbon based molecules
Lipids
Carbohydrates
Amino Acids
Nucleotidea
What are the 5 characteristics of water that make it ideal for supporting life?
- Water is liquid at room temperature unlike other molecules of the same size which are gasses at room temperature
- Water is a polar molecule - Oxygen has a slightly (-) charge and hydrogens atoms have a (+) charge. Therefore H2O molecules form weak but significant bonds known as Hydrogen bonds.
- Water is more dense as a liquid, not as a solid. (i.e. ice floats about water).
- Water has high specific heat capacity. (The amount of heat needed to change the temperature of one gram of a substance by one degree Celsius)
- Water has a high heat of vaporization. i.e. heat of vaporization is the quantity of heat that must be absorbed for a liquid to vaporize to a gas.
What are the two most important properties of Water that support life?
The polar properties of water make it an excellent solvent. This facilitates the delivery of nutrients and removal of wastes, and provides an environment that allows cells to exist within a network by facilitating the movement of chemical messengers within and between cells.)
The high specific heat capacity of water allows for thermoregulation by acting as a heat sink for the many chemical reactions that occur within cells, as well as the exchange of heat between liquid and air. This is critical for warm-blooded organisms, such as humans, that must regulate their body temperature.
What are Lipids?
- Oils and Fats, made up of hydrocarbon chains
- Lipids are commonly amphipathic - a term that describes a molecule which is both hydrophilic and hydrophobic in certain sections.
Give 3 Main examples of Lipids
- Cholesterol -regulates cell membrane fluidity
- Phospholipids an amphipathic lipid that forms cell membranes. Hydrophilic head and hydrophobic tail
- Triglycerides - main component of body fat and how we store energy
What are carbohydrates?
Hydrated carbon. Composed of H2O and Carbon
What are the 3 types of Carbohydrates?
- Monosaccharides are single carbohydrate molecules containing only carbon, hydrogen and oxygen.
- Disaccharides are two monosaccharides bonded together with a type of bond called a glycosidic bond.
- Oligosaccharides are composed of 3 to 10 monosaccharides linked together, while polysaccharides are much longer chains.
What are Amino Acids?
Monomers composed of carboxylic acid and an amino group with a side group that varies between the types of amino acids (this is known as the R group). When amino acids are linked together they form proteins.
The side chains of an amino acids determine the structure of the protein. The 20 most common amino acids are grouped into categories based on the chemical properties of the side chains.
Two amino acids linked together by a peptide bond. Multiple amino acids linked together, form a polypeptide.
What are proteins?
Proteins are made up of long chains of amino acids held together by peptide bonds. These polypeptides fold into a 3D structure that is required for protein function.
What are Nucleotides?
Nucleotides are the building blocks of nucleic acids like deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). They also form adenosine triphosphate (A T P), the main form of cellular energy used to power reactions within an organism.
They are made up of three components:
- A base
- A five carbon (pentose) sugar
- At least one phosphate group
