A1.1 (Water) Flashcards
Why is water inorganic
Doesn’t have carbon. Organic stuff needs hydrogen AND carbon
Why can’t you drink ocean water while swimming?
It will make you dehydrated due to the high salt content
Why is water the medium of life?
We believe that life has originated in water.
- Where the cell membrane was formed
- Where the solutes dissolved
- Where the chemical reactions occurred
Implication: It gave way to prokaryotes. Life came from water
How much water is found in Earth? And where is most of them found? (edit percentage)
70%, most in oceans
Define covalent bond
Electron sharing
Why is water polar?
-
Unequal attraction/sharing of electrons oxygen has 8 electrons > the two hydrogen atoms have 1
-> due to oxygen’s stronger pull on the electrons
Outline the different bonds between water molecules (intermolecular + intramolecular)
If its just inside the molecule (i.e. between the oxygen and hydrogen atoms), it’s covalent (stronger),
if it’s between more than 1 molecule (intermolecular bond) it’s hydrogen bond
Explain what are hydrogen bonds
Definition: A type of bond between a hydrogen atom and an electronegatic (i.e. negatively-charged) atom such as oxygen
- This is due to the law of attraction as hydrogen is positively-charged.
Outline the biological properties of water
cohesion, adhesion, and solvent properties
Explain the cohesion of water and its effect on water
water-to-water molecule attraction (intramolecule — my own term)
- one hydrogen bond weak but many strong
Effect: More uniform motion — There would be surface tension when in contact with non-polar substances or — causing droplets (so they could have as less surface area/least “touching” with non-polar substances as possible). Because of the cohesive forces, the drop has a thin membrane.
Explain surface tension
tendency of liquid surfaces to be smallest VA when in contact with non-polar substances due to cohesion’s hydrogen bonding
(think of a drop of water on non-polar cloth for example)
How does cohesion affect the transport of water in plants?
Pulling forces caused by the evaporation of water from the leaves make the water moves upwards
-> And I think they’ll all go up in a somewhat uniform fashion because of the cohesive forces
Explain adhesion of water
- The attraction between water and polar surfaces (polar-polar attraction)
Adhesion and drinking from a straw
The water sticks to the polar surface (adhesion ) and make the capillary action to work
Describe capillary action relating to adhesion
(Adhesion): Water is attracted to polar surfaces, and the xylem vessel in the plants are polar.
- THEREFORE (implication): the water will follow the polar surface (xylem vessel) up and go to the parts of the plant that need water.
Side note: The law of attraction is not between non-polar and polar substances. It is only about polar and polar substances (because the law pertains to negative and positive charges)
Define “meniscus” (DOUBLE CHECK)
The shape of the “outer membrane” (or “outer layer of water”)
What determines the shape of the meniscus?
Convex: cohesive forces > adhesive forces (non-polar surface/substance)
(the molecules stick more together than on the surface)
Concave: cohesive forces < adhesive forces (polar)
(the molecules stick more to the surface than one another — most likely the surface will be wet bc its polar)
1 - OSC 1 - bs
Define tetrahedral
“4 heads”
How is tension created in the xylem when transporting water — aka what makes water go to the diff parts of the plant and why?
The water in the stomata are evaporating and creating different water potential (low water potential higher up the plant — near the stomata in the leaves)
- Therefore the water absorbed by the roots will travel along the water potential (high -> low) — transpiration pulling them
Why does water form a droplet when on non-polar molecules?
It’s averse to it and thus shrinks to smallest surface area possible -> droplet
How can water be attached to polar surfaces (like adhesion in capillary action in porous solids)
Because they can form a polar bond and thus attached to them.
Describe the solvent properties of water
It is a good solvent
- because it can be the place where metabolic and enzyme manipulated reactions
- due to their polarity
-> (assumption/memory, DOUBLE CHECK): Many molecules are polar and thus water can form polar bonds with them and dissolve substances through their bonds.
e.g.:
(w ->non-polar<- w ; w-non [break] polar-w)
Why is water needed in the cytoplasm
so catabolic reactions could occur (breaking down — but specifically to simplest solids)
Define “dissolve” (add photo of ppt)
When something is put in water, it will break down and “be attached to the other side of water”
Describe how glucose is dissolved by water
- Glucose is also polar
- The OH of the glucose will bond to the hydrogen molecules of water
- (and then describe dissolving..).
So this is a bit different because diff substance but
Why can polar substances dissolve better in the cytoplasm?
- cytoplasm is made up of water — a polar molecule
- Therefore, it can dissolve better (through the bonding)
Why can polar substances dissolve better in the cytoplasm?
- cytoplasm is made up of water (80%) — a polar molecule
- Therefore, it can dissolve better (through the bonding)
Describe how oxygen can be transported in blood
- Oxygen = nonpolar therefore dissolves poorly
- Heme grp (hemoglobin) will be highly attracted to oxygen (so non polar) and will carry it into the RBC so the RBC can transport the oxygen around the body
Describe how amino acids dissolve in water
- In the common 20 amino acids, they have different side-chains.
- Side-chains differ in charge (R grp)
-If polar: same as sodium chloride 🧂 and water
-if non-polar: ig simple diffusion>
Describe how fats can be dissolved in water (cytoplasm) (ADD FROM PPT)
- Through glycoproteins
Describe water’s physical property of buoyancy
Water is buoyant.
- Buoyancy - ability of a fluid to exert upwards force on an object placed in or on it.
- Conditions for floating: buoyancy >= weight of object, there’d be floating
Give an example of buoyancy
- Bony fish have gills which can control their density (so they can alter their density to go down or up)
Physical Property - Viscosity in relation to temperature
- viscosity = highly resistant to flow (i.e. cannot flow) /stickiness
-
Affected by forces of attraction between molecules
- If attracted ^ = ^ viscosity
- Affected by temp
- If temp ^ = & energy = v attracted = v viscosity
-> So I think, generally water is not that viscous. BUT! It’s viscosity can change according to the strength of the bond (e.g. when affected by temp)
- If temp ^ = & energy = v attracted = v viscosity
Physical Property - Specific heat capacity
- specific heat capacity - whats needed to increase obj’s temp by 1 degree
- For water: heat capacity is high.
- Due to it being liquid?
- Why is it good?: The sustainment of oceans, some evaporation (e.g. water) bad.
Physical properties - Thermal Conductivity (explain in accordance to water)
- Thermal conductivity = the rate at which heat goes thru materials
-
For water: thermal conductivity is relatively high due to the collision of particles and electrons (basically the closeness of particles [cohesion] and the closeness of it to electrons [covalent bond?])
[basically for heat transfer]:
-> electrons carry energy and therefore the particles must collide w/ it to gain energy
-> to pass it throughout the water/substance, atoms must collide with the atom that collided with the electron
Therefore, waters are good insulators
Why are gases poor conductors?
It is because less collisions occur due to the limited attraction between gas molecules thus less heat transfer occur less.
- *Unless dense — i.e. there’s more attraction/gas particles are nearer)
Why do we sweat while exercising
Due to metabolism — to decrease body temp
- food gets burned up when exercising and becomes enegy in the form of heat
- water will capture the heat and will rise to skin as sweat
- the (external) heat will add energy to hydrogen bonds of water and break the bonds — removing the energy from metabolism (heat)
- cooling sensation
Define insulators
things that don’t get easily hot — resist the transmission of heat
Define exoplanets
Planets outside the solar system
Explain the goldilocks zone
The temperature is within the range where a planet theoretically could have water
Define lysis (related to cell and water)
Cell bursting due to high intake of water
Define hypotonic solution
water potential > solute concentration of solution
or:
solute concentration of the cell > solute concentration of the solution
Define hypertonic solution
solution concentration > water potential of the environment (aka the solution)
Define turgid
Plant cells holds high amounts of water but will not burst
Define plasmolysis
The shrinking of the plant cell wall due to exposure to a hypertonic environment
Define isotonic environment
Balanced concentration
- solute cont of solution = solute cont. of cell :P
How will an isotonic, hypertonic and hypotonic the tonicity of the environment affect an animal cell
ISOTONIC
- no net movement
- rate of exit = rate of entering
- therefore, cell is stable
HYPERTONIC
- solute concentration of environment > solute concentration of cell [correct]
- Water exits > water enters cell (less water potential in the cell compared to out)
- Therefore the cell becomes crenated
HYPOTONIC
- Concentration of solution (env.) > concentration of the cell
- Therefore, the cell will burst — cytolysis
Differentiate between crenated cells and cytolyzed (?, cytolysis) cells
Crenated:
Animal cells that are dehydrated and shrunk due to hypertonic environments
Cytolysis:
Animal cells that burst because of high water intake and lack of cell wall (hypotonic environment)
How will an isotopic, hypertonic and hypotonic environment affect a plant cell / how water would move and affect the plant cell
ISOTOPIC:
- no net movement of water aka water will enter and exit the cell in the same rate
- so there’s stil movement of water it’s just the entering and exiting rate is equal
- Therefore, the cell is in a balanced state
HYPERTONIC
- More solute concon the outside compared to the cell
- the rate of water exiting the cell > the rate of water entering the cell
- Due to this, the plant cell will shrink (plasmolyze) due to the lack of water and the plant will be dehydrated (remember the vacuole in the plant cell is so large it makes up like.. 70% of the plant cell and thus their size)
HYPOTONIC
- Less concentration than cell
- the rate of water exiting < the rate of water entering the cell
- Due to this, the plant cell becomes turgid (lots of turgor pressure from water intake but not bursting due to cell wall)
How is sodium chloride dissolved and transported in the blood?
It’s polar so it can be transport easily without help
- additionally , it can also be dissolved in the plasma
How do carbohydrates get transported in the blood?
They are polar so they need no help to transport
- can be easily dissolved in plasma
How does protein get transported in the blood
Depends on the R-group (-> determines the polarity).
- if polar: same as carbs and sodium chloride
- if non-polar: can be through integral/transport proteins
How do lipids (triglycerides: fats, oils; steroids: cholesterol) get transported in the body?
Non-polar — so harder to transport
- carried by lipoproteins — made of proteins and fats — so a part of them can attract the lipids around for transport
