cytology intro Flashcards
Spontaneous generation
The formation of living organisms from non-living matter
Who set out to prove that spontaneous generation does not occur? When did this happen?
Louis Pasteur in 1880’s
What famous experiment help debunk spontaneous generation?
Two flasks are filled with broth that is then boiled. On one flask the neck of is heated bent into an S shape. The other is not. Air could reach the broth but micro-organisms and other particles would get caught in the s bend.
What other experiment involving Pasteur disproved spontaneous generation.
Making a nutrient broth of yeast and sugar. If the flask was sealed the broth remained unchanged and no fungi or other organisms emerged.
The study of cells
Cytology
Cell theory
All organisms are made up of one or more cells
cells are the smallest unit of life
All cells come from pre-existing cells
Sir Robert Hooke
Coined the word cell, developed the simple microscope. Studied many organisms and even plant material such as cork.
1665
Anton Van Leeuwenhoek
Improved the magnification and resolution of microscopes.
“The father of Microbiology”
First to study and document one celled organisms
term of organisms he observed where animalcules
1680s
Matthias Schleiden
Concluded that all plants are composed of cells
1838
Theodor Schwann
animal tissue consists of cells
1839
Rudolf Virchow
all cells are produced from division of pre-existing cells.
1855
The basic functions of life
homeostasis, reproduction, growth, response, metabolism. excretion, nutrition
Two main categories of cells
prokaryotic (before nucleus)
eukaryotic (true nucleus)
prokaryotic cells are _____ and ______ than eukaryotic cells, most are ________
smaller and simpler
less than 1 um in diameter
Prokaryotic cells are often called
bacteria
common structures of prokaryotic cells
plasma membrane, flagella, cell wall, pili, ribosomes, nucleoid region, plasmids
main form of reproduction in bacteria
asexual, specifically in bacteria called binary fission.
Binary fission
the single circular chromosome composed of DNA is replicated. The cell divides into two genetically identical daughter cells.
Bacterial conjugation
sexual reproduction involving a conjugation tube from the pili.
Eukaryotic cells
advanced cells that occur in organisms other than bacteria
eg. algae, protozoans, fungi, plants, animals
specialized structures within the cell area are called organelles and are surround by a membrane
A common characteristic of all cells is
they are small
all living organisms exchange nutrients and waste with their external environment through
the plasma membrane
What problem arises from geometry
as a cell enlarges its volume increases more rapidly than its surface area does.
most move into and out of a cell by
simple diffusion
if a cell is too large…
the distance for molecules to travel by diffusion would be too far and take too long for cell survival
External membrane which serves as a barrier to their envrionment
plasma membrane
The plasma membrane has a protective function and can control what goes into and out of a cell so it is
selectively permeable
helps to describe the structure of the plasma membrane
fluid mosaic model
the plasma membrane is composed of a special molecule called a
phospholipid
Phospholipids are composed of
a hydrophilic head, and a hydrophobic tail
hydrophilic
water soluble or polar (water loving)
hydrophobic
is not water soluble or nonpolar (water hating)
Because phospholipids have both a polar and nonpolar region they are called
amphipathic
The unique polarity causes phospholipid molecules to always align themselves in a ______ if they are present in a water environment
bilayer
What maintains the overall structure of the membrane?
the tendency water has to form hydrogen bonds
animal cells have _____ randomly embedded in the membrane
cholesterol
_______ prevents movement of phospholipid molecules, therefore _______ reduces the fluidity of the membrane
cholesterol
_______ reduces the permeability of the membrane to hydrophilic particles
cholesterol
Three major components of plasma membranes
protein, cholesterol, phospholipids
various types of proteins are embedded in the fluid matrix of the phospholipid bilayer. This creates the
“mosaic” effect of the phospholipoid bilayer
Two major types of membrane proteins
peripheral, integral
Two major types of membrane proteins
peripheral, integral
Peripheral
do not exist in the middle of the bilayer but remain bound to the surface of the membrane
can be attracted to glycoproteins
integral
have both hydrophobic and hydrophilic regions within the same protein
this property helps hold the protein in the place in the bilayer
integral
have both hydrophobic and hydrophilic regions within the same protein
this property helps hold the protein in the place in the bilayer
composed of carbohydrate chains attached to peripheral proteins
Glycoproteins
function in recognition of the like cells and immune response
glycoproteins
assist the movement of specific ions and carbohydrates across the membrane
transport or “Channel” proteins
six functions of membrane proteins
channels for transport
cell communication
enzyme function
hormone binding
cell adhesion
pumps
bacteria, atoms, membranes, organelles, viruses, molecules
Cells in decreasing order
organelles, bacteria, viruses, membranes, molecules, atoms
