Chapter 3 Flashcards
What are 3 important things for understanding cells?
The workings of the human body
Mechanisms of disease
Rationale of therapy
Robert Hooke…
Coined the word cellulae to describe empty cell walls of cork in the early 17th century.
Theodor Schwann concluded…
That all animals are made of cells.
Louis Pasteur demonstrated in 1859 that…
Cells arise only from other cells.
What are the 5 points of cell theory?
All organisms composed of cells and cell products.
Cell is the simplest structural and functional unit of life.
An organism’s structure and functions are due to activities of cells.
Cells come only from preexisting cells.
Cells of all species exhibit biochemical similarities.
How many types of cells are in the human body?
200
Squamous cell
Thin, flat, scaly
Cuboidal cell
Squarish-looking
Columnar
Taller than wide
Polygonal cell
Irregularly angular shapes, multiple sides
Stellate cell
Star-like
Spheroid to ovoid
Round to oval
Discoidal
Disc-shaped
Fusiform
Thick in middle, tapered toward the ends.
Fibrous
Thread-like
A cell’s shape can appear…
Different if viewed in a different type of section (longitudinal VS cross section)
Most human cells are what length in diameter?
10-15 micrometers
What are 3 human cells you can see without a microscope?
Egg cells, some nerve cells, and osteoclast cells.
Why is there a limit on cell size?
An overly large cell cannot support itself; it may rupture.
For a given increase in diameter, volume…
Increases more than surface area
Volume of cell is proportional to…
Cube of diameter
Surface area of cell is proportional to…
Square of diameter
Light microscope (LM) revealed…
The plasma membrane, nucleus, and cytoplasm
Transmission electron microscope (TEM) improved…
Resolution (ability to reveal detail)
Scanning electron microscope (SEM) improved…
Resolution further, but only for surface features
H & E stain turns the cytoplasm ____ and the nucleus _____.
Cytoplasm = Pink
Nucleus = blue/purple
What is the plasma (cell) membrane?
The outer limiting layer of the cell. It surrounds the cell and defines the boundaries.
What is the plasma (cell) membrane made of?
Proteins and lipids
What is cytoplasm?
Gelatinous liquid that fills the inside of a cell.
What is extracellular fluid (ECF)?
Includes any fluid outside of cells.
What are some examples of extracellular fluid (ECF)?
Tissue (interstitial) fluid, blood plasma, lymph, and cerebrospinal fluid. Blood is also an ECF.
Why are the basic parts of a cell?
The plasma (cell membrane), the nucleus, and the cytoplasm.
Describe the plasma (cell) membrane.
It is flexible, thin, 7-10nm in thickness, and a sturdy barrier between the inside and the outside of a cell.
What 2 things do you ALWAYS have to remember about plasma (cell) membrane?
Semipermeable, and fluid mosaic model
Cell membranes are semipermeable, meaning…
Molecules can move through them.
What is fluid mosaic model?
It describes the structure of the plasma membrane as a mosaic of components - including phospholipids, cholesterol, proteins, and carbohydrates - that gives the membrane a fluid character
What is the nucleus?
It is the command/control center of a cell
All cells have a…
Nucleus with a few exceptions
Cells usually have 1 nuclei so they are…
Uninucleate
A cell with no nucleus is called…
Anucleate. Examples are RBC (red blood cells) and platelets.
What is cytosol?
It is the solution part of the cell. Also called the intercellular fluid.
How much of the cells is made up of cytosol?
60%
What is cytoplasm composed of?
Cytosol and organelles
What are organelles and what do they look like?
Organelles are itsy bitsy structures that look like mini factories. They look like little organs.
What are the 10 different organelles?
Mitochondria
Ribosomes
Golgi apparatus
Rough endoplasmic reticulum
Smooth endoplasmic reticulum
Lysosomes, peroxisomes, proteosomes
Centrioles
Cytoskeleton
When viewed with an electron microscope, plasma (cell) membrane appears as…
A pair of dark parallel lines
Plasma (cell) membrane has ______ faces and _______ faces.
Intercellular faces and extracellular faces.
What are the 3 functions of the plasma membrane?
Defines cell boundaries
Governs interactions with other cells
Controls passage of materials in and out of cell.
98% of the plasma (cell) membrane molecules are…
Lipids
What are lipids?
Fats
75% plasma (cell) membrane lipids are…
Phospholipids
A plasma membrane is made up of ___ layers of _____ called the _____.
2 layers of phospholipids called the bilayer
Amphipathic molecules arranged in a bilayer means…
There is a water loving and water hating phospholipid in the same layer.
The heads on phospholipids are…
Hydrophilic
Hydrophilic means…
Water loving
The tails on phospholipids are…
Hydrophobic
Hydrophobic means…
Water hating
Phospholipids drift _____, keeping the membrane _____.
Laterally, fluid
What are the 3 lipids?
Phospholipids, cholesterol, and glycolipids
Phospholipids make up ___ of the membrane layer.
75%
Cholesterol makes up ___ of the membrane layer.
20%
Glycolipids make up ___ of the membrane layer.
5%
What does cholesterol do?
They hold phospholipids still and can stiffen the membrane.
Cholesterol looks like…
4 ring-like structures linked.
Cholesterol are _____ in between the ________.
Wedged, fatty acid tails
____ of cholesterol needed for all cells is created by the _____.
85%, liver
Glycolipids are only found on…
The extracellular surface of a cell
Glycolipids are…
Nothing but sugars attached to liquid.
Glycolipids are attached to…
The fatty acid tails
Glycolipids look like…
Tree branches. 8 ring-like structures linked.
Glycolipids + glycoproteins =
Glycocalyx
What is glycocalyx?
Carbohydrate coating on cell surface. It helps with understanding.
What is the body structure of lipids (fats)?
Glycerol with 3 fatty acid tails
Phospholipids have ___ fatty acid tails and a ______
2, phosphate
2% of cells are made of…
Proteins
Proteins are the ________ of any cell.
Functioning units
What are glycoproteins?
Integral or transmembrane proteins
What do glycoproteins do?
Penetrate the membrane.
What is the main job of peripheral proteins?
Structural support
Function of the membrane proteins include:
Receptors, enzymes, channels, carriers, cell-identity markers, and cell-adhesion molecules.
What are the function of receptors?
They bind chemical signals. Allows chemical to sit.
What are the functions of the enzymes?
They speed up a chemical reaction. They are not destroyed in the process.
What are the functions of channel proteins?
They allow hydrophilic particles and water to come in and out of the membrane.
