Unit 2 Part 1: Organelles Flashcards
Why are Cells so small?
The higher the difference between SA:V ratio, the more amount of diffusion takes place
What could a cell do in response to a shrinking SA/V ratio?
the cell could slow down its processes in response to shrinking SA:V because a smaller ratio of Sa:V could mean more space available inside the cell. The cell could also start to divide or evolve.
Justify “Numerous small cells are evolutionarily advantageous in regard to maintaining homeostasis in multicellular organisms”
This is true because having smaller cells maximize the surface are to volume ration, helping the diffusion rate go up.
As the mitochondria metabolize the glucose, they produce carbon dioxide waste. Would the CO2 be able to leave the cell faster if the cell had a smaller volume or larger volume?
CO2 would be able to leave the cell with a smaller volume faster than a cell with a larger volume due to there being less surface area to journey.
Is bigger always better for a cell
Bigger is not always better for the cell because cells with a larger surface area would have waste and other unwanted objects in their cell for a longer time. This additional time traveling could also create more time objects to travel that a cell might need immediately.
Is it more desirable for a cell to have a small SA:V ratio or a large SA:V function of a cell
It would not be desirable for cells to have a small SA:V because a lower SA:V ratio would guarantee a larger cell that has more processes occurring and a lower rate of diffusion (so water would leave the cell slower)
What might be some reasons why these unicellular organisms have larger cells than cells with similar traits (heterotrophic, lacking cell walls) that are found in multicellular organisms?
Unicellular organisms have larger cells because they depend on only themselves for protection and nutrients. That one cell has to be specialized in different jobs, unlike multicellular cells that can work with each other.
How are phospholipids arranged in the cell membrane?
Heads facing out toward the water and the tail face each other.
Remembering the characteristics of a lipid, why must one of the fatty acid chains be replaced with a phosphate group?
So the lipid can become hydrophilic. Lipids are naturally hydrophobic, so adding a phosphate group will change the lipid and give it a hydrophilic part.
What do you have to put into the membrane to help stabilize it?
Cholesterol will help stabilize the membrane.
What does Cholesterol do for the membrane?
Cholesterol acts as a Buffer for the membrane, it will dampen the effects of temperature
What is selectively permeable?
That the membrane allows some substance to pass through, but not others.
What 2 molecules easily pass through the membrane?
Simple Diffusion - O2 moves high concentration (outside the cell) to lower concentration (inside the cell) and Simple Diffusion - CO2 moves high concentration (outside the cell) to lower concentration (inside the cell
What does polar mean?
Molecules that have areas where there is a partial positive or negative charge.
Why are CHANNEL PROTEINS part of the cell membrane?
TO help transportation of substances that couldn’t pass easily through the membrane
Compare and contrast diffusion and facilitated diffusion.
DIffusion happens naturally, but facilitated diffusion happens with help from channel proteins. Both do not require energy.
Why is energy (ATP) sometimes required for the transport of materials?
ATP is needed for active transport, this is when the substance needs to go against its concentration gradient. This type of transport is called active transport. What type of materials are moved via this transport mechanism? Negative charges substances
What do Carbohydrates do in plasma membranes?
Carbohydrates are like identification badges. Cells that have different membrane carbohydrates do different jobs/functions. The immune system uses the carbohydrates to recognize that your cells belong to you and are not viruses, bacteria, or other foreign cells.
What is dynamic equilibrium?
Dynamic equilibrium is a state where no change is occurring but individual molecules still react continuously.
Why can’t sugar diffuse across the membrane?
Because it is polar and too large.
Why did diffusion stop after a certain period of time? .
Because there was nothing left to diffuse
What is Osmosis?
Water moves into and out of the cell by osmosis. This is when the diffusion of water across the membrane from an area of high concentration to an area of low concentration.
What are solutes?
Solutes are the substances that are dissolved in water.
What is Hypotonic?
When there is a low amount of solutes in water.
What is Hypertonic?
When there is a high amount of solutes in water.
What is Isotonic?
When there is an equal amount of solutes in water
