LAB (1) - BIOCHEMICAL SYSTEMS AND LIVING CELLS Flashcards
What are the cell theory?
- All living organisms are made up of one or more cells.
- The cell is the basic unit of life.
- All cells come from the division of pre-existing cells.
Who was the English scientist that first described the cells from his observations of cork slices and the first who used the word “cell”?
Robert Hooke (1665)
Who was the first to document the structure of red blood corpuscles and the nature of the circulatory system?
Anton Van Leeuwenhoek
accurately described the life cycles of many types of insects
Anton Van Leeuwenhoek
invented the compound microscope
Hans Jansen (1595)
designed a two-lens microscope
Robert Hooke (1667)
developed the microscope with single lens
Antonie van Leeuwenhoek (1670)
constructed the set of color-corrected lenses
Benjamin Martin (1774)
solved the spherical aberration problem
Jackson Lister (1830)
produced a paper on dark-ground illumination
Francis Wenham (1850)
improved the composite lens
Ernest Abbe (1857)
developed the apochromatic system of lenses
Carl Zeiss (1868)
developed the luminescence microscope
August Kohler (1908)
invented the phase contrast microscope
Frits Zernike (1932)
invented the confocal scanning optical microscope
Davidovits and Egger (1969)
were the first to say that all organisms are made of one or more cells
German scientists Schleiden and Schwann (1830)
stated that all cells come from the division of pre-existing cells
German biologist Virchow (1858)
are the building blocks of life; comes in many shapes and sizes, although most are microscopic
Cells
- Most cells are small, about 0.001 cm in length (1/100 of a mm, or 10 micrometer)
* smallest cells of the microorganism mycoplasma are .3 micrometer in size - Some are large
* giant algal cells may be several cm long - A chicken’s egg is a single cell
- Multicellular organism (us) have at least 10^14 cells
limited by the wavelength of light to a resolution limit of about 200 nm
Light microscope
limited by the design of the electromagnetic lenses to a resolution of about 0.2 nm
Electron microscope
Light microscope
Illuminating source = light
Max magnification = 1000x
Specimen type = live and dead
Lenses material = glass
Image = colored
Field of use = study of internal structure
Electron microscope
Illuminating source = electron
Max magnification = 2,000,000x
Specimen type = dead or dried
Lenses material = electromagnetic
Image = black and white
Field of use = study of internal surface, cell structure, and small organisms
What are the applications of TEM (Transmission electron microscope)?
- Morphological studies
- Cytochemistry/Histochemistry
- Autoradiography
- Immunolabelling
- Elemental analysis
e.g. flagellar attachment, details of cell parts, etc.
Morphological studies
e.g. study of enzyme-substrate complexes: acid-phosphatase etc.
Cytochemistry/Histochemistry
e.g. how a certain vitamin is transported into tissues
(labelling)
Autoradiography
e.g. study of antiserum – antigen complexes made possible by gold labelling
Immunolabelling
determination of different elements present in a
specimen region; quantitative analysis of water and air, etc.
Elemental analysis
include bacteria, blue-green algae, and archaea
all single-celled organisms that lack both a true nucleus and other membrane-bounded cellular substructures
DNA is usually circular
Prokaryotes
cells of this lack a nucleus ad ither organelles; unicellular
memorize parts of the prokaryotes
include plants, animals, protozoa, and fungi
these cells contain nuclei and other membrane-bound organelles; genetic material is organized into chromosomes
Eukaryotes
Why do we need to study organelles of the
living cell in relation to biochemical
systems?
- Structure
- Function
- Composition of each part
- Relationship of organelles to biochemical systems
specialized structure within the cell which contains DNA and controls cell functioning and reproduction
Nucleus
small bodies with
specific structures and functions within the cell.
Organelle
the liquid substance between the nucleus and the cell membrane, in which the organelles are located
Cytoplasm
the thin layer which separates the cell contents from it’s environment
Plasma membrane
Plants cells also have a cell wall surrounding the cell
Membrane-bound structures that usually contain chloroplasts and give their colors (i.e. green pigment)
Plastids
contains the cell’s genetic information
Nucleus
dark void objects spreads throughout the cell; produce energy for the cell
Mitochondria
small black dots; storage form of glucose
Glycogen granules
Animal cell:
Magnification: x8,500 when printed at 10 cm tall
a dangerous form of the normally benign E. coli bacteria which live in the intestine.
usually transmitted by food poisoning; can cause life threatening diarrhea, intestinal bleeding, kidney failure, and disturbance to blood.
no effective cures for this, but there are treatments for dealing with the symptoms
Another strain of EHEC bacteria is E. coli O157:H7.
Magnification: x160,000 at 8x10 inch size.
Enterohaemorrhagic E.coli (EHEC)
Cells are surrounded by a thin membrane of lipid and
protein, about 100 angstroms (1.00 x 10-8 m) thick.
functions in transport of materials in and out of the cell, recognition, communication, and homeostasis
Cell membrane/plasma membrane
remarkable structure that has properties of a solid and liquid
Cell membrane/plasma membrane
It forms a “fluid sea” in which proteins and other molecules like other lipids or carbohydrates are suspended
(like icebergs) or anchored at various points on its surface.
Cell membrane/plasma membrane
“sea” or “fluid” = composed of side by side phospholipids arranged in a bilayer (lipid bilayer)
is the variety of proteins and other molecules embedded in the bilayer
the solid part or “mosaic”
Each phospholipid has a?
a hydrophobic tail and a hydrophilic head
has consistency of a light machine oil
selectively permeable (will let some substances in but not others of the same size)
Cell membrane/plasma membrane
The plasma
membrane that
surrounds
eukaryotic cells is
a dynamic
structure
composed of [ ]
interspersed with
[ ]
two layers of
phospholipid
molecules
cholesterol and
proteins
composed of a hydrophilic (water-loving) head, and two tails which are hydrophobic (water-hating)
Phospholipids
anchor the membrane to the cytoplasm, (the watery fluid inside the cell) and also to the water surrounding the cell.
Water-attracting heads
block large
water-soluble molecules from passing through
the membrane while permitting fat-soluble
molecules, including medications such as
tranquilizers and sleeping pills, to freely cross the membrane.
Water-hating tails
embedded in the
plasma membrane carry out a variety of
functions, including
transport of large water soluble molecules such
as sugars and certain
amino acids
Proteins
(proteins bonded
to carbohydrates) serve in part to
identify the cell as belonging to
a unique organism, enabling the
immune system to detect foreign
cells, such as invading bacteria,
which carry different
glycoproteins.
Glycoproteins
in the plasma membrane act as stabilizers that limit the movement of the two slippery phospholipids
layers, which slide back and forth in the membrane.
Cholesterol molecules
Tiny gaps in the
membrane enable small molecules such as oxygen (upper right) to diffuse readily into and out of the cell.
Since cells constantly use up oxygen, its concentration
decreases within the cell. The higher concentration of
oxygen outside the cell causes a net flow of oxygen into
the cell.
The steady stream of oxygen into the cell enables it to
carry out aerobic respiration continually.
a process that provides the cell with the energy needed to carry out its functions
Aerobic respiration
is made up of a large number of cellulose fibers cemented together (like the cellulose fibers in paper)
semi-permeable
Cell wall
Small molecules have little difficulty
penetrating the cell wall, while larger
molecules may not be able to pass
through.
What are the characteristics of a cell wall?
relatively rigid
lends shape to plant cell
does not participate in cell activity
is made up of cellulose (long molecule of carbohydrate)
Plant cell wall
is made of chitin (amino sugar glucosamine)
Fungi cell wall
is made of murein (polysaccharide chain linked by amino acid)
Bacteria cell
found in plant cells only
Membrane-bound structures that
usually contain pigments and
give plant cells their colors.
most prominent plastid
Chloroplasts
Some plastids are storage bodies
for starch, proteins, oils.
colored plastids
chlorophyll bearing plastids (green color)
Chloroplasts
yellow or orange pigments, cream, red and brown
Carotenoids/xanthrophylls
are white or colorless plastids
Leucoplasts
Inside the chloroplast are membranous stacks of thylakoids (look like pancakes) where the chlorophyll
is located.
Each pancake is called a granum (grana).
are the double-membrane bound organelles in which photosynthesis (the conversion of light energy to carbohydrates) occurs.
Chloroplasts
is the chemical that absorbs the energy of the sun to provide the
energy required for reducing CO2
to Glucose
Chlorophyll
a small cellular container used for transport and storage of materials
Vesicle
Vacuoles and vesicles are formed by:
- pinching off from the Golgi apparatus
- endocytosis of the cell membrane
- extension of the ER membrane
Plant cells usually have one large Central
Vacuole.
The plant cell’s central vacuole functions in:
water storage
food storage
waste storage
cell support
thought to be an extension of the ER membrane
Central vacuole
membrane-enclosed, fluid filled spaces
membrane = tonoplast cell sap (fluid) - water with dissolved substances (sugar, salt, and other organic acids)
Central vacuole
processing centers
Food vacuoles
contains finished products such as fat
Storage vacuoles
elimination of waste
Excretory vacuoles
are single-membrane organelles.
Peroxisomes
remove hydrogen atoms from small
molecules and join the
hydrogen atoms to oxygen to form hydrogen peroxide, and then break it down into water and oxygen.
Peroxisomal enzymes
control center of the cell
contains the DNA and is the of manufacture of RNA
large, centrally located organelle surrounded by nuclear envelope
Nucleus
is a double membrane (2 phospholipid bilayers thick) that has nuclear pore in it for molecules to enter and exit
Cell membrane
allow selected molecules into and out of the nucleus
It is also believed that these pores are the routes by which genetic messages
(RNA) pass into the
cytoplasm.
Nuclear pore
The DNA is contained by a number of chromosomes, which
consist of long strands of DNA tightly wound into coils with
proteins called histones.
The combination of DNA and histone proteins is known as
Chromatin
function in packaging of DNA during nuclear division and control of gene expression
Chromosomes
determines the metabolism,
growth, differentiation, structure,
and reproduction of cell
Nucleus
The nucleus contains one or more
DARK-STAINING discrete
structures, known as [ ] which are sites of ribosomal ribonucleic acid rRNA synthesis
Nucleolus
is a system of
MEMBRANOUS TUBULAR CANALS that beginsnjust
outside the nucleus and branches throughout the
cytoplasm
Endoplasmic reticulum (ER)
ribosomes attached to the ER
protein synthesis
Rough endoplasmic reticulum
no ribosomes attached
synthesis of lipids
Smooth endoplasmic reticulum
consist of rRNA and proteins
is made of 2 non-identical subunits: the LARGE and SMALL
SUBUNITS.
site of protein synthesis
Ribosomes
is produced in the nucleolus
and joined with proteins – then
migrate through the nuclear pore to
the cytoplasm for final assembly.
rRNA
is a stack of flattened,
hollow cavities enclosed by
membranes, which is often continuous
with the membranes of the endoplasmic
reticulum
also called the Golgi complex/Golgi body
located near to the nucleus and ER
functions in modification, assembly, packaging, storage, and secretion of substances
Named after Camillo Golgi
Golgi apparatus
each sac on the Golgi apparatus contains enzymes that modify proteins as they pass through
Special vesicles which are formed by the Golgi apparatus.
They contain powerful
hydrolytic/digestive
enzymes
Lysosomes
What are the functions of lysosomes?
1) cellular digestion
2) autodigestion or disposal of
damaged cell components like
mitochondria
3) breakdown of a whole cell (by
releasing their contents into the
cell cytoplasm)
suicide sacs
Lysosomes
are known to contain over 40 different enzymes that can digest almost
anything in the cell, including proteins, RNA, DNA, and carbohydrates
Lysosomes
also appear to perform other digestive processes, such as those connected
with phagocytosis and pinocytosis.
Lysosomes
help destroy foreign microorganisms
and invading bacteria
Lysosomes
are the largest
organelles in an animal cell, after the nucleus.
Mitochondria
Are sausage-shaped or
filamentous structures
surrounded by a double-layered membrane
Mitochondira
vary in diameter
from 0.5 to 1 micrometer and in
length up to 7 micrometers.
(about the size of bacteria).
Mitochondria
2 membranes of mitochondrion: inner and outer membranes
The inner is convoluted into shelf-like folds called
where energy is produced
Cristae
functions in AEROBIC ENERGY METABOLISM (also called CELLULAR
RESPIRATION); converts glucose and fatty acids to ATP, the cell’s primary energy molecule, as well as lesser amounts
of other energy rich molecules.
Mitochondrion
The overall formula for cellular respiration is:
Carbohydrate + O2 -> CO2 + H2O + ENERGY (i.e. ATP)
38 molecules of ATP
also help control the concentration of water, calcium, and other
charged particles (ions) in the cytoplasm.
Mitochondria
have some of their own DNA molecules
and ribosomes that resemble those of prokaryotic cell
are also self-replicating. They
“reproduce” by splitting in half
Mitochondria
