Download CHAPTER 7 STUDY GUIDE

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CHAPTER 7 STUDY GUIDE
HOW WE STUDY CELLS
a. Microscope:
i. Developed by Anton van Leeuwenhoek o study cells.
ii. Robert Hooke modified and advanced the microscopes
and studied the cells in a cork.
iii. Magnification: how much larger an object appears.
iv. Resolution: how clear an object appears.
v. Light microscopes: visible light is passed through the
specimen and through glass lenses. Magnifies about
1000 times. Used to see live cells.
vi. Electron microscope: focuses and electron beam
through a specimen. Magnification of over 100,000x.
1. Transmission electron microscope (TEM): used to
study interior of cells. The images are flat and 2dimensional.
2. Scanning electron microscope (SEM): used to
study the fine details of cell structures. Uses
stains with heavy metals (ex: gold) which kills
cells. Images are 3-dimensional.
3. Phase contract microscopes: used to examine
unstained living cells and cell growth in tissue
culture.
b. Other tools for studying cells:
i. Cell fractionation: taking cells apart, separating major
organelles so that their individual functions can be
studied. Ultracentrifuges are used to spin the materials.
The process begins with homogenization (disruption of
cells) and centrifuging (separating the parts of the cells).
(page 105)
ii. Freeze fracture: used to study details of membrane
structure.
iii. Tissue culture: study properties of specific cells in a lab.
COMPARING PROKARYOTES AND EUKARYOTES
EUKARYOTIC
PROKARYOTIC
Founding kingdoms: protista,
1. Found in kingdom:monera
fungi, plantae, and animalia.
true nucleus, envelope
2. no true nucleus, envelope
genetic material in nucleus
3. genetic material in nucleoid
contains cytomplasm with
4. no membrane bound
membrane bound organelles.
organelle.
multicellular
5. unicellular
only in eukarya
6. only in archea and bacteria
ribosomes are bigger
7. ribosomes are smaller
cells size: 10-100 microns
8. cell size: 1-10 microns
9. metabolism is aerobic
III.
9. metabolism is aerobic and
anaerobic.
STRUCTURE AND FUNCTION OF THE CELL
a. The major theme of biology is “function dictates form and
vice-versa.
b. Nerve cell is the longest cell. It functions to send electrical
impulses.
c. A human body has 200 different types of cells with different
function, therefore different forms.
d. NUCLEUS: contains chromosome, which are wrapped with
special proteins into a chromatin network.
i. Surrounded by a nuclear envelope that contains pores
to allow for the transport of molecules like RNA (mrna),
which are too large to diffuse directly through the
envelope.
ii. It is well known as the “control center of the cell.”
iii. Site for replication and transcription.
iv. Nucleolus: site of ribosome synthesis. Produces 10,000
ribosomes per minute. Present in the nucleus of cell that
is not going under mitosis. Not a membrane bound
structure but a tangle of chromatin and unfinished
ribosome precursors.
e. RIBOSOMES: it is a cytoplasmic organelle which is the site for
protein synthesis. (refer notes)
f. ENDOMEMBRANE SYSTEM: (notes)
g. ENDOPLASMIC RETICULUM: means a network with in the
cytoplasm and used to carry and transport materials, the
freeway of the cell. Has a network of tubules and sacs.
i. Smooth er: connects rough err o the golgi apparatus.
Contained a lot in liver cells. (notes)
ii. Rough er: notes
h. GOLGI APPARATUS:
i. Def: notes
ii. Function: package substances (proteins, lipids and
other macromolecules) produced in rough er and
secrete them to other cell parts or cell surface to export.
The substances are modified by the addition of sugars
and other molecules to form glycoproteins. Products are
then sent to other parts of the cell in vesicles, directed
by the particular changes made by the Golgi. The Golgi
apparatus can be considered as a post office of the cell
where packages get dropped off by customers, golgi
adds the appropriate postage and zip code to make sure
that the package reaches the proper destination of the
cell.
i. LYSOSOMES:
i. Def: notes
ii. Sacs of hydrolytic (digestive) enzymes surrounded by a
single membrane.
iii. “Stomach of the cell”, “Suicide sacs (example: cells of
the tail of a tad pole, which are digested as the tadpole,
which are digested as the tadpole changes into a frog)”.
iv. Functions: notes
j. MICROBODIES (notes)
i. Peroxisomes: found in both plant and animal cells.
Contains catalase, which converts hydrogen peroxide
into water with the release of oxygen atoms also
detoxify alchohol in liver cells.
ii. Glyoxisomes: notes
k. VACUOLES (notes)
i. Large in plant cells but small in animal cells.
l. ENERGY TRANSDUCERS: (notes)
m. MITOCHONDRIA: notes
i. “power plants of the cell”
ii. site of cellular respiration
iii. all cells have many mitochondria, very active cell could
have 2,500 of them.
iv. Also contains their own DNA and can self replicate..
n. CHLOROPLAST: notes
IV.
CYTOSKELETON (notes)
a. Intermediate cells: constructed form a class of proteins called
keratins.
b. Microtubules: notes
i. Aids in the structure of cilia, flagella, spindle fibers.
ii. Cilia and flagella which move cells around consist of 9
pairs of microtubules organized around 2 singlet
microtubules.
iii. Spindle fibers help separate chromosomes during
mitosis and meiosis and consist of microtubules
organized into 9 triplets with no microtubules in the
center.
c. microfilaments: (actin filaments)
i. functions: animal cells to form a cleavage furrow during
cell division.
ii. Amoeba to move by sending out pseudopods.
iii. Skeletal muscle to contract as they slide along myosin
filaments.
V.
CENTRIOLES, CENTROSOMES, AND THE MICROTUBULE
ORGANIZING CENTERS.
a.
b.
c.
d.
VI.
VII.
All lie outside the nuclear membrane
Organize spindle fibers.
Give rise to the spindle appearances required for cell division.
Plant cells lack centrosomes but have microtubule organizing
centers.
PLANT CELL vs. ANIMAL CELL
a. Plant cells have large vacuoles.
b. Animal cells do not contain cell walls and chloroplast.
Vacuoles are small.
CELL SURFACE
a. Cell wall:
i. Def (notes)
ii. Plants and algae have cell walls made of cellulose and
fungi’s cell walls are made up of chitin.
iii. Primary cell wall: immediately outside the plasma
membrane.
iv. Secondary cell wall: produced by some cells outside the
primary cell walls.
v. Middle lamella: thin gluey layer formed between the 2
new cells (when a plant cell divides)
b. cell or plasma membrane:
i. selectively permeable membrane that controls what
enters and leaves the cell.
ii. Glycocalyx: notes