Homeostasis, Cell Struc. & Function Flashcards
What is a cell?
Cells are the smallest living units; they are dubbed “the building blocks of life” because they makes up all living organisms.
Who first used the term “cell”?
Robert Hooke
Cells are so small that their existence was unknown before what?
The invention of microscopes.
What is the significance of cell theory?
It is one of the fundamental ideas of modern biology.
What are the three principles of cell theory?
All living organisms are composed of one of more cells.
Cells are the basic unit of structure and organization of all living organisms.
Cells arise only from previously existing cells, with cells passing copies of their genetic material on to their daughter cells.
What do all cells have in common?
A plasma membrane.
What do most cells have in common?
Most cells contain genetic material in some form.
Most cells break down molecules to generate energy.
What are Eukaryotic cells?
Eukaryotic cells contain a nucleus and other organelles.
What are organelles?
Specialized structures that perform specific cell functions.
What is the distinct central organelle that contains the cell’s genetic material?
The nucleus.
What is the size of eukaryotic cells relative to prokaryotic cells?
Eukaryotic cells are generally much larger than prokaryotic cells.
What are Prokaryotic cells?
They are cells without a nucleus or other membrane-bound organelles.
What are cells without a nucleus or other membrane-bound organelles?
Prokaryotic cells.
What cells are believed to be similar to the first organisms that lived on earth?
Prokaryotic cells.
What does the endosymbiont theory propose?
That a symbiotic relationship formed between two prokaryotic cells, one of which lived inside the other.
Eventually the symbiotic relationship led to the two cells becoming one.
Because eukaryotic cells are larger and more complex, they developed specific functions.
These specific functions led to cell diversity, and thus organismal diversity.
What is homeostasis?
The process of keeping balance in a living thing.
What is the plasma membrane?
It is a thin, flexible boundary between a cell and its environment that helps control what enters and leaves the cell. One of the structures responsible for homeostasis.
What is selective permeability?
It is a trait that plasma membranes have which allows some substances to pass through while keeping others out.
What is the function of the Plasma Membrane?
It controls how, when, and how much of various substances enter and leave a cell depending on its structure.
What is the phospholipid bilayer?
It is what the plasma membrane is made of–two layers of phospholipids arranged tails to tails.
How do polar and non-polar substances dissolve?
Polar substances dissolve in polar substances.
Non-polar substances dissolve in non-polar substances.
What is the structure of a phospholipid?
Phospholipids are made of glycerol, two fatty acids, and a
phosphate group. Each phospholipid has a polar head and two nonpolar tails.
Where are proteins found on the plasma membrane?
Proteins are found on both the inner surface and the outer surface of the plasma membrane.
What three substances move among the phospholipids in the plasma membrane?
Cholesterol, proteins, and carbohydrates.
What are proteins on the outer and inner surfaces?
Proteins on the outer surface are called receptors because they send signals to the inside of the cell. Proteins on the inner surface anchor the plasma membrane to the cell’s internal support structure and give the cell its shape.
What are transport proteins?
Proteins that create tunnels through the plasma membrane and move needed substances or waste materials through it.
How does cholesterol help cells?
Cholesterol helps prevent the fatty-acid tails
from sticking together, keeping the plasma membrane fluid.
What is the charge of cholesterol molecules and where are they located?
Cholesterol molecules are nonpolar. They are among the tails of phospholipids.
What molecules are nonpolar and move among the tails
of the phospholipids?
Cholesterol.
What substances help identify chemical signals from the environment?
Carbohydrates and proteins.
What is the fluid mosaic model?
A model of the organization of the plasma membrane.
The basic structural and functional unit of all living organisms.
What is a cell?
Robert Hooke
Who first used the term “cell”?
What happened after the invention of microscopes?
The discovery of cells.
What is one of the fundamental ideas of modern biology?
Cell theory.
The following are the principles of what theory?
All living organisms are composed of one of more cells.
Cells are the basic unit of structure and organization of all living organisms.
Cells arise only from previously existing cells, with cells passing copies of their genetic material on to their daughter cells.
The cell theory.
What is a special boundary that helps control what enters and leaves the cell?
Plasma membrane.
What is the significance of plasma membrane?
All cells have it.
How many cells contain genetic material in some form and break down molecules to generate energy?
Most of them.
What cells contain a nucleus and other organelles?
Eukaryotic cells.
What are specialized structures that perform specific cell functions?
Organelles.
What is the nucleus?
It is the distinct central organelle that contains the cell’s genetic material.
What cells are generally much larger than what cells?
Eukaryotic cells are generally much larger than prokaryotic cells.
What are Prokaryotic cells believed to be similar to?
The first organisms that lived on earth.
What does the following describe?
A symbiotic relationship formed between two prokaryotic cells, one of which lived inside the other.
Eventually the symbiotic relationship led to the two cells becoming one.
Because eukaryotic cells are larger and more complex, they developed specific functions.
These specific functions led to cell diversity, and thus organismal diversity.
The endosymbiont theory.
What is the process of maintaining balance in living things?
Homeostasis
Which one of the structures responsible for homeostasis forms a thin, flexible boundary between a cell and its environment?
The plasma membrane.
What is the trait that plasma membranes have which allows some substances to pass through while keeping others out?
selective permeability.
What part of the cell controls how, when, and how much of various substances enter and leave a cell depending on its structure?
The plasma memberane.
What is the plasma membrane is made of?
The phospholipid bilayer, which is two layers of phospholipids arranged tails to tails with some protein, carbohydrates, and cholesterol mixed in.
What structure has polar heads facing outside and nonpolar tails facing inside, and what is the function of its structure?
The phospholipid bilayer.
Substances that can dissolve
in water will not pass through the plasma membrane because
they are stopped by the nonpolar middle.
In what ways can molecules pass through the plasma membrane?
Small, uncharged molecules pass through the cell membrane easier than larger, charged molecules.
What molecule is made of glycerol, two fatty acids, a
phosphate group, and has a polar head and two nonpolar tails?
Phospholipids.
What three substances move among the phospholipids in the plasma membrane?
Cholesterol, proteins, and carbohydrates.
What molecule is found on both the inner surface and the outer surface of the plasma membrane?
Protein.
What are receptors, and what do proteins on the inner surfaces do?
Proteins on the outer surface are called receptors because they send signals to the inside of the cell. Proteins on the inner surface anchor the plasma membrane to the cell’s internal support structure and give the cell its shape.
What are proteins that create tunnels through the plasma membrane and move needed
substances or waste materials through the plasma membrane called?
Transport proteins.
What helps keep the plasma membrane fluid by preventing the fatty-acid tails
from sticking together, and also helps maintain homeostasis in a cell?
Cholesterol.
What substances help identify chemical signals from the environment?
Carbohydrates and proteins.
What is the model of the organization of the plasma membrane?
The fluid mosaic model.
Why is the fluid mosaic model fluid?
It is fluid because the molecules are moving
and being rearranged.
Why is the fluid mosaic model mosaic?
It is called a mosaic because scientists can
observe clear patterns on the surface of the plasma membrane.
What goes in and out of the cell?
Water.
What two substances go into the cell?
Oxygen and glucose.
What goes out of the cell, and can be rejected from entering back into the cell?
Wastes.
What substance goes out of the cell?
Carbon dioxide.
