77 terms

Biology Chapter 7 Study Guide

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Cytoskeleton
gives cells its characteristic shape
Jans and Zacharia Janssen
spectacle makers
Combined 2 lenes to produce primitive compound microscope
Robert Hooke
Englishman who used primitive microscope to view thin sections of cork
discovered tree bark composed of "a great many little boxes"
said that these boxes resemble the cells occupied by monks called cellulare
cork was a nonliving material
later while looking at live plants, he discovered that cells contain "juices in them"
Anton Von Leewenhoek
Dutch inventor
mastered art of lens grinding
credited for developing imporved microscope and microscopic study of living things
Robert Brown
resolved that the cell had a nucleus
Mathias Schleiden
botanist
noted that all plants are composed of cells
Theodor Schwann
zoologist
studying animal tissue (cartilage) discovered that it is made of cells
by 1840 Schleiden and Schwan simultaneously published:
cell unit of organization and composition of all living things
fundamental unit of life
The Cell Theory
Rudolf Virchow was a pathologist
wrote that...
all living things are composed of cells
cells are the simplest unit of structure and function of a living organism
all cells come from pre-existing cells
Light Microscopes
most common one, the one used in class during the lab
allows light to pass through specimen
used 2 lenses to form an image
the 2 lenses are ocular and objective
light waves scatter as they pass through matter to produce clear images of objects up to 1000x
Why is a Cell Stain necessary...
with light microscopy, living cells transparent, difficult to see structures
chemical stains/ dyes: specific and reveal compounds/ structure within the cell
Cell Stain
Iodine was the one we used in the lab
some dyes give off light of particular color, fluorescence
Fluorescent dyes attach to specific molecules and are visible using fluorescence microscope
fluorescence microscopy makes it possible to ID structures
Electron Microscopes
use beams of electrons, not light, that are focused magnetic fields
off highter resolution than light microscopes
two major types:
transmission (TEM)
scanning (SEM)
Transmission Electron Microscopes
Transmission electron microscopes make it possible to explore cell structures and large protein molecules.
But because beams of electrons can only pass through thin samples, cells and tissues
must be cut into ultra thin slices before they can be examined.
This is the reason that such images often appear flat and two dimensional.
Scanning Electron Microscopes
Pencil- like beam of electrons canned over surface of specimen
image is of surface
specimens do not have to be cut into thin slices
Produce 3- dimensional images of specimen's surface
Prokaryotes ( (what makes them different)
do not possess a membrane- bound nucleus
Genetic material found in cytoplasm, not nucleus
Believed to be the most primitive of all cells
Eukaryotes (what makes them different)
true cells
have a defined nucleus bound by a membrane
have membrane bout organelle in the cytoplasm
What Prokaryotes and Eukaryotes have in Common
cell membrane: outer cell boundary
cytoplasm- all the material found between cell membrane and nucleus
DNA/ Nucleus- cells blueprint/ control center respectively
...
...
Prokaryotes and Eukaryotes Size:
Prokaryotes: 1-5µm and Eukaryotes 10-100 µm
µm
microns, what is used to measure minuscule stuff (i.e. cells)
Example/Characteristics of Prokaryote
generally smaller than Eukaryotic
think of bacteria
Example of Eukaryote
generally larger and more complex
plants, animals, fungi
we are made up of Eukaryote cells
The Cell (7-2)
...
Organelle
Small membrane- bound structures in cells
perform specific functions
found in the cytoplasm
"little organs"


think of the cell as a factory and organelles as the different machines and characteristics of a factory
Cytoplasm
Material within the cell/ plasma membrane
includes everything in the cell except the nucleus
nucleus
control center of cell
region isolated from the remainder of the cell by the nuclear membrane
most conspicuous of all cell structures
contains all of the cell's DNA
https://www.youtube.com/watch?v=gGeC0ntvxR8
video on nucleus and everything else found in the nucleus
DNA
molecule that houses genetic information
carries instructions for production of 100s of molecules for cell function and directing cell activities
Nucleolus
found in most cells
contains RNA
RNA
messenger for DNA
protein production
Chromatin/ Chromosomes
hereditary material of the cell
consists of DNA and proteins+ chromatin
in prep. for cell division:
Chromatin condenses
coils around proteins
becomes organized into chromosomes
mitochondria/ mitochondrion
"cell organelle that converts the chemical energy stored in food into compounds that are more convenient for the cell to use"

power house of the cell
endoplasmic reticulum
internal membrane system found in eukaryotic cells; place where lipid components of the cell membrane are assembled
Rough ER
the presence of ribosomes
Smooth ER
there is no presence of ribosomes
Chloroplasts
organelle found in cells of plants and some other organisms that captures the energy from sunlight and converts it into chemical energy
Golgi Apparatus
organelle in cells that modifies, sorts, and packages proteins and other materials from the endoplasmic reticulum for storage in the cell or release outside the cell
centriole
"structure in an animal cell that helps to organize cell division"
Cytoskeleton
Network of filaments in cytoplasm
Give cells characteristic shape
Enables movement of organelles & materials throughout cell
Nucleoplasm
found within nuclear membrane
term to describe contents
of nucleus
Vacuole
sac- like structure
single membrane
function in food and water storage (salt, proteins, and carbohydrates)
controls water regulation
provides support for cell- hydrostatic pressure
Vesicles
smaller membrane enclosed structures
used to store and move materials
between cell organelles
to and form the cell surface
Lysosomes
contain digestive enzymes and break down compounds

http://highered.mheducation.com/olc/dl/120067/bio01.swf
Nuclear Membrane/ Nuclear Envelope
made up of 2 membrane layers
possess many highly selection nuclear pores
Cell Membrane
Both eukaryotic and prokaryotic cells has one of these. It is a thin flexible barrier that is made to protect the cell, give it structure and monitor all cellular contents that enter and leave the cell.
Selectively permeable membranes
some substances can pass across them and others cannot. Selectively permeable membranes are also called semipermeable membranes.
Cell wall
Strong, supporting layer around the cell membrane in some cells
Supports and protects cells
Prevents over-expansion when water enters the cell
Cell Membrane: lipid bilayer
all cells contain cell membranes which are made up of a double- layered sheet called a lipid bilayer- "flexible double-layered sheet that makes up the cell membrane and forms a barrier between the cell and its surroundings"
"The cell membrane regulates what enters and leaves the cell and also protects and supports the cell. "
cont. Cell Membrane: lipid bilayer
Cell membranes are made up of a lipid bilayer in which proteins and carbohydrates are embedded
The layered structure of cells membranes reflects the chemical properties of the lipids that make them up
Cell Membrane: Aquaporins
The inside of a cell's lipid bilayer is hydrophobic or water hating. Because of this, water molecules have a tough time passing through the cell membrane. However, many cells contain water channel proteins, known as aquaporins (ak wuh pawr inz), that allow water to pass right through them. The movement of water through cell membranes by facilitated diffusion is an extremely important biological process—the process of osmosis.
Fluid Mosaic Model
embedded in the lipid bilayer of most cell membranes are protein molecules. Carbohydrate molecules are attached to many of these proteins.
Cytoskeleton
Network of filaments in cytoplasm
Give cells characteristic shape
Enables movement of
organelles & materials throughout
cell (endocytosis & exocytosis)
Microfilaments & microtubules, 2
principal protein filaments that make
up cytoskeleton
Microfilaments
Threadlike made of protein actin.
Form extensive networks
Produce tough, flexible framework
Allows cells and cytoplasmic movements (amoebas)
Microtubules
Hollow structures/Protein tubulin/maintains cell shape
cell division, mitotic spindle which separates chromosomes
Build projections from cell surface, cilia and flagella enable swimming "9+2" pattern
Centrioles
Structure in an animal cell that helps to organize cell division
The difference of plant and animal cells
Plant cells include chloroplasts, the cell wall, and vacuoles.
Passive transport
Movement of materials across cell membrane without using energy
Important fnx. of membrane to keep internal conditions constant
Regulates movement of molecules from one side to other
Diffusion
Process by which particles tend to move from an area that has high concentrated to an area where it is less concentrated
Facilitated diffusion
Process of diffusion in which molecules pass across the membrane through cell membrane channels

Many molecules transported across membrane with aid of transport proteins
(proteins are specific to molecule)
Aquaporins
Water channel proteins allow water to pass, otherwise water would diffuse very slowly
Osmosis
Diffusion of water through a selectively permeable membrane
isotonic
"when the concentration of two solutions is the same"
hypertonic
"when comparing two solutions, the solution with the greater concentration of solutes"
hypotonic
"when comparing two solutions, the solution with the lesser concentration of solutes"
Active Transport
The movement of materials against a concentration difference. This requires energy.
Endocytosis
Wrapped around cell membrane waiting to be brought in cell. Transports in cell, in pocket
http://highered.mheducation.com/olc/dl/120068/bio02.swf
Exocytosis
Releases, exports materials and transports out of cell, vessels, contains wastes.
http://highered.mheducation.com/olc/dl/120068/bio02.swf
Tonicity
A measure of the effective osmotic pressure gradient of two solutions separated by a semipermeable membrane.
Osmoregulation
adaptations for control of
water balance.
Hypertonic
Water moves in direction of hypertonic solution
Cell in this sol. would shrink/shrivel
Hypotonic
Has fewer solutes then cell
Water will be drawn into cell
Cell will gain water, swell, & possibly lyse
Isotonic
Cell will neither gain or lose water
Concentration of solutes is = on both
sides of membrane
Water moves at the same rate in both
directions
Cell size is not altered
Phagocytosis
form of endocytosis
pseudopodia wrap around food particle
creates vacuole/vesicle that then fuses
with lysosome for breakdown
Protein Pumps
Protein, made by DNA. ATP helps push/release.
http://highered.mheducation.com/olc/dl/120068/bio05.swf
Pinocytosis
Droplets of extracellular fluid are taken into cell in small vesicle
Plant Cell diagram
Animal Cell diagram
cell membrane diagram

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