WATER Flashcards
How were the first cells evolved? And how is water the medium for life?
The first cells were evolved in a watery environment. It is believed that this occurred in deep oceans, nearby hydrothermal vents. Solutes and water were trapped in a membrane. Chemical reactions began to occur in the membrane. This is how the first cells evolved. All life process occur in water. The link between water and life is so strong that scientists looking for life on other planets and moons look for evidence of water to suggest that life could have occurred there.
What are the key functions of hydrogen bonding?
1) The cohesion and adhesion of water molecules
2) Base-pairing between the two strands of DNA
Structure:
3) Hydrogen bonds help to form part of the secondary and tertiary levels of structure in proteins
4) The hydrogen bonds found between strands of cellulose and collagen give those molecules their tensile strength
5) Interactions between mRNA and tRNA during protein synthesis
What are hydrothermal vents?
Hydrothermal vents are fissures or cracks in the sea bed, which allow water that is heated through geothermal activity, to pass through. This helps give energy to organisms that are too deep under water to recieve energy from the sunlight.
Describe a water molecule
1) It is made up of 2 oxygens and 1 hydrogen. Oxygen is more electronegative.
2)It is a polar molecule
3) It is a dipole covalent bond.
4)It has an asymmetrical shape.
Define Cohesion and give an example of cohesion.
Hydrogen bonds between water molecules. Mass transport of water is an example of cohesion.
Define Adhesion and give an example
between water and other molecules that are charge or polar. An example of Adhesion is during transpiration (loss of water from a plant through stomata through evaporation) … Adhesion allows for the water to move up the Xylem.
Hydrophilic and Hydrophobic and Polarity
Hydrophilic = “water-loving”
Hydrophobic = “water-hating”
Polar molecules or molecules with positive or negative charge can form hydrogen bonds with water therefore making polar molecules hydrophilic.
Non-Polar molecules (without negative or positive charge) can’t form hydrogen bonds with water therefore making them hydrophobic
Name
1) Highly Soluble molecules
2) Less soluble molecules
3)Insoluble molecules
1) Sodium chloride (salt) , Urea, amino acids, glucose
2) Oxygen
3) Fats
Name 4 physical properties of water
1) Specific heat capacity
2) Thermal conductivity
3) Buoyancy
4) Viscosity
What is specific heat capacity?
Specific heat capacity is the measure of energy required to raise temperature of 1kg of a substance by 1 degree celcious…
Describe Specific heat capacity and its relation to water and give a brief example.
Water has a high specific heat capacity. It is 4200 joules. This is because it takes a lot of thermal energy to break and build hydrogen bonds. This is advantages as it allows for a stable aquatic habitat and allows large bodies of water to keep their temperatures remaining constant. The ringed seal is able to survive throughout the year throughout the year due to stable sea temperatures. The density of ice is lower than the density of liquid water, which means that ice floats on water
This forms a habitat for the seals both on the floating ice sheets, as well as below the ice.
What is Thermal Conductivity?
Thermal conductivity is the ability for a substance to conduct heat.
Thermal conductivity and its relationship with water.
Water has a high thermal conductivity making it a good insulator for organisms living in colder climates. The black- throated loon is a species that spends much of its time catching prey underwater. Their feathers trap an insulating layer of air, which assists them with regulating their body temperature.
What is Buoyancy?
Buoyancy is the ability of an object to float in water.
What is viscosity?
Viscosity refers to a resistance of a fluid to flow.
