Unit 1 - Wellness & Homeostasis Flashcards
What is homeostasis
Maintaining a stable internal environment.
What is a cell
the basic unit of the structure and function of living things.
What are the three main parts of cell theory
- all organisms are made up of one or more cells
- all the life functions of an organism occur within cells
- all cells come from preexisting cells.
Describe the role of the cell membrane
It protects and supports the cell and also controls everything that enters and leaves the cell
What is Semipermeability
the ability to allow only certain molecules in or out of the cell
Describe the composition of the cell membrane.
is composed mainly of phospholipids, which consist of fatty acids and alcohol. The phospholipids in the cell membrane are arranged in two layers, called a phospholipid bilayer.
Discuss the Fluid Mosaic Model.
proteins are embedded in the phospholipid bilayer forming a mosaic pattern
Explain how diffusion and facilitated diffusion differ.
Facilitated diffusion makes use of transport proteins
What is a transport protein? Give 2 examples.
transport protein completely spans the membrane, and allows certain molecules or ions to diffuse across the membrane. Channel proteins and carrier proteins
Explain how carrier proteins function?
“carry” the ion or molecule across the membrane by changing shape after the binding of the ion or molecule.
What is osmosis? What type of transport is it?
Diffusion of water → Passive transport
How does osmosis differ from diffusion?
It is a specific type of diffusion (water)
What happens to red blood cells when placed in a hypotonic solution?
They swell and may burst
What will happen to a salt water fish if placed in freshwater?
They will lose water and shrink or shrivel
What is diffusion?
When molecules move from a area of high concentration to low concentration
What is a concentration gradient?
difference in the concentrations of the molecules in the two areas
What is meant by passive transport?
a way that small molecules or ions move across the cell membrane without input of energy by the cell
What is active transport?
is the energy-requiring process of pumping molecules and ions across membranes “uphill” - against a concentration gradient.
Explain how cell transport helps an organism maintain homeostasis.
It helps to ensure that the cell has the right molecules it needs and wastes can be expelled
What is the difference between endocytosis and exocytosis?
Endo- moving substances in
Exo- moving substances out
Why is pinocytosis a form of endocytosis?
Because it’s bringing liquid molecules into the cell
Compare autotrophs to heterotrophs, and describe the relationship between these two groups of organisms.
Autotrophs store chemical energy in carbohydrate food molecules they build themselves.
Heterotrophs cannot make their own food, so they must eat or absorb it.
Heterotrophs consume autotrophs or other heterotrophs that have eaten autotrophs.
The fact that all organisms use similar energy-carrying molecules shows one aspect of the grand “Unity of Life.” Name two universal energy-carrying molecules, and explain why most organisms need both carriers rather than just one.
Glucose → can store a lot of energy; has just the right amount of energy for transport and uptake of cells
ATP → has just the right amount of energy for cells to use to do work
A single cell uses about 10 million ATP molecules per second. Explain how cells use the energy and recycle the materials in ATP.
An ATP molecule,, is like a rechargeable battery: its energy can be used by the cell when it breaks apart into ADP (adenosine diphosphate) and phosphate, and then the “worn-out battery” ADP can be recharged using new energy to attach a new phosphate and rebuild ATP. The materials are recyclable, but recall that energy is not!
