Download Name - Humble ISD

Name _____________________________________________________________
Test Date _Block Day, 9/15 or 9/16___
UNIT II – INTRODUCTION TO THE CELL
http://learn.genetics.utah.edu/content/begin/cells/insideacell/
I. TYPES OF CELLS
(p.172, 173)
All living things are made of _cells____ and all cells can be divided into two groups
A. Prokaryotic – “_Before nucleus__”
Prokaryotic cells lack a true _nucleus___ and other _membrane__- bound internal structures.
Prokaryotic cells do contain _DNA_____, usually concentrated in a particular region of the cell. All
prokaryotes are _bacteria___ and all _bacteria are prokaryotes____.
B. Eukaryotic – “_True___ _nucleus___”
Eukaryotic cells contain a _nucleus_______ and other membrane-bound structures. Eukaryotic organisms
may be _unicellular (single-celled)_____ or _multicellular____. In multicellular organisms, cells become
_specialized______.
II. DISCOVERY OF CELLS
(pp.169-172)
A. History of Microscopes
The invention and development of the microscope in the 1600s enabled scientists to discover and study cells.
1. Anton van Leeuwenhoek - Was the first to try stacking several _lenses____ together to view tiny objects. He
looked at _pond water________ through his lenses and became known as the first scientist to
describe living cells as seen through a microscope.
2. Robert Hooke - Used a microscope to examine thin slices of cork. He called the tiny boxes he saw
_cells_________. He chose the name "cells" because the chambers he saw reminded him of the small
rooms in a _monastery_______, which were called cells.
B. Cell Theory
The discoveries and observations of scientists such as _Schleiden____, _Schwann_______, and
_Virchow___ led to the development of the _Cell Theory____________ in the mid 1800s.
The Cell Theory states that:
1. All _living things _ are composed of cells.
2. Cells are the _smallest working unit of life_______.
3. All cells come from _other cells___ through _cell division____.
C. Modern Microscopes
There are several types of modern microscopes:
1. Compound light microscope – Contain more than one _lens___ and uses _light rays____ bent through
_glass__ to magnify objects. Type of microscope used in the classroom.
2. Electron microscope – Uses a beam of _electrons_____. Specimen must be kept in a
_vacuum_____. Offers the advantage of much greater _magnification____ but specimen must be
_non-living_______. There are 2 types of electron microscopes:
a. scanning electron microscope or _SEM__________ - traces the _surface________ of the
specimen and forms a 3D image
b. transmission electron microscope or _TEM_________ - aims electron beam through specimen.
Used to examine _internal___ cell structures.
III. CELL BOUNDARIES
(pp.182-183)
A. Cell Wall
Cell walls are the outermost boundary in _plants____, _fungi________, and _bacteria___________.
They are not found in _animal cells________________. The primary function of the cell wall is to provide
_structure and support________. The cell wall does not regulate what _enters and leaves___________
the cell.
1. Cell walls of plants are composed of _cellulose_________________
2. Cell walls of fungi are composed of _chitin____________________
B. Cell Membrane
Every cell is surrounded by a cell membrane made of ___________________. The cell membrane is selectively
permeable which means _it only allows certain substances in and certain substances out________. This
characteristic is critical in helping the cell maintain _homeostasis____. The cell membrane is also called the
_plasma_____ membrane.
IV. INSIDE A EUKARYOTIC CELL
(pp. 174-181)
The inside of the cell consists of the:
A. Nucleus
B. Cytoplasm – Includes the _cytosol__________ or “cell gel” and the _organelles________, which
means “_little organs____”
V. EUKARYOTIC CELL STRUCTURES
Illustration
Structure
Nucleus
Nucleolus
Nuclear
Envelope
Ribosomes
Rough
Endoplasmic
Reticulum
Smooth
Endoplasmic
Reticulum
Plant
Animal
Characteristics & Function
_Control center___ of the cell. Genetic information
stored as _chromatin______, which is _DNA________
wrapped in _protein____.
Small, dense region in the nucleus. Site of
_ribosome____ production.
Double _phospholipid______ membrane. Has nuclear
_pores_____ which allow _RNA______ to leave the
nucleus
Tiny, granular organelles located on _endoplasmic
reticulum_____ or suspended in _cytosol_______. Site
of _protein production_____. All cells (pro & euk) have
ribosomes.
Extensive network continuous with _nuclear
envelope_____. Called “rough” because it has
_ribosomes___ all along the membrane. Function of the
rough ER is to _modify & transport proteins_____. Most
of these proteins are packaged into _vesicles______
(like bubbles or sacs) and shuttled to the __Golgi
apparatus________
Similar to rough ER in structure, except that it lacks
_ribosomes__. The smooth ER manufactures
_lipids____, breaks down _glycogen___, detoxifies
_poisons__, and _stores calcium_____.
Golgi
apparatus
Lysosome
Vacuole
Mitochondria
Found in _animal__ cells only. Round sacs containing
_enzymes___ that _break down___ and _recycle_____
used cell components. Also used as defense against
_bacteria_____ and _viruses__
Sacs that may be used as storage for _water___,
_molecules__, _molecules__, or wastes. Plants have a
large central vacuole.
Double-walled organelle with inner folds _to increase
surface area____. Uses _glucose_____ to manufacture
energy in the form of _ATP____. Mitochondria have their
own _DNA____.
Chloroplast
Found in _plant____ cells. Contain _chlorophyll_____
(green pigment) and their own _DNA______.
Chloroplasts harvest energy from the _sun___ to
produce _ATP___ through _photosynthesis___.
Centrioles
Found in _animal____ cells only. Bundles of
_microtubules_______ that play a role in _cell
division_____
Cytoskeleton
VI. THE PROKARYOTIC CELL
Flattened, round sacs that look like a sack of
_pancakes_____. Receives, modifies, and ships
products by way of _vesicles____ into the _cytosol →
cell membrane_______
Composed of protein fibers known as _microtubules____
and _microfilaments_______. Anchor _organelles_____
and provide _structure_____. Also provide motility for
some cells in the form of _cilia___ or _flagella____. More
extensive cytoskeleton found in _animal___ cells.
VII. THE EUKARYOTIC CELL