Characteristics of Life
What is biogenesis?
Life comes from life
Define homeostasis
Maintaining internal balance
The gel-like substance that fills up a cell
Cytoplasm
What is diffusion?
Passive movement of particles from high to low concentration (stuff spreading out over time)
The smallest living unit in all organisms
What are at least 2 things that need to be kept in balance in your body?
Eg. O2, salt, sugar, CO2, temperature, pH...
Works like the control center of the cell. Contains the DNA
Nucleus
Which way will water flow in the diagram on the board?
See board
Stimuli
What type of feedback loop is this: I am driving too fast and see a digital speed sign that says "slow down". That causes me to slow back down to the speed limit.
Negative feedback. Stabilizing toward set point.
Describe the function of the golgi apparatus.
Some things can pass through, other things can't.
List at least 4 of the characteristics of life from class
Growth, reproduction, heredity, responds to stimuli, uses energy, made of cells, homeostasis
What feedback loop is this: Students are trying to converse in a noisy classroom. The louder the room gets, the louder they must talk, which makes the room even noisier, meaning they need to talk even louder.
Positive feedback. Amplifying away from set point.
What are two features that can be used to distinguish a plant cell from an animal cell?
When might a cell use active transport?
When it needs to move something against its concentration gradient.
A seed from my apple does not move, does not react when I shout at it, and if I leave it in a dry plastic bag it will not change in any way. However, it is made of cells and if i put it in the ground, it may sprout.
Is the apple seed alive? Give at least 3 reasons why or why not.
Yes, it's alive. Made of cells, responds to stimulus (being in ground vs. not), grows, will have DNA from parent tree (heredity)
Give an example of how negative feedback is used by our bodies to maintain homeostasis.
Eg. sweating, insulin for blood sugar regulation, heart beats faster with exercise, breathing faster
What are two important differences between prokaryotes and eukaryotes?
Prokaryotes are always unicellular and have no membrane-bound organelles. Eukaryotes are larger, contain DNA in nucleus, and can be multicellular or unicellular.
Why can high salt diets lead to high blood pressure?
The salt draws water into blood vessels, which increases the volume of blood and therefore the pressure.