Download Biology Mid-Term Study Guide 6: Cells Cell Theory All living things

Biology Mid-Term Study Guide 6: Cells
I. Cell Theory
a. All living things are composed of cells
b. Cells are the basic units of structure and function in living things
c. New cells are produced from existing cells
II. Basic Cell Structure
a. Cell Membrane
i. Thin, flexible barrier around the cell
ii. Strong layer around the cell membrane called the cell wall
1. Both protect the cell and allow it to interact with its surroundings
b. Nucleus
i. A large structure that contains the cell’s genetic material and controls cell
activities
c. Cytoplasm
i. Material inside the cell membrane but not the nucleus
III. Two Types of Cells
a. Prokaryotes
i. Do not have nucleus
b. Eukaryotes
i. Have nucleus
ii. Most contain organelles
1. Perform important cellular function
IV. Cell Wall
a. Found in organisms such as plants, algae, fungi, and most prokaryotes
b. Not found in animals
c. Main function is to provide protect and support for the cell
d. Made from fibers and carbohydrates
i. Substances produced by cells, released at cell membrane and assemble to
form cell walls
e. Plant cell walls are made up of cellulose and carbohydrate fibers
V. Nucleus
a. Controls most cell processes and contains hereditary information of DNA
b. Contains nearly all DNA
c. Holds coded instructions for making proteins and other important molecules
VI. Chromatin and Chromosomes
a. Chromatin
i. Granular material visible within the nucleus
ii. Consist of DNA bound proteins
iii. Spread through nucleus
b. Chromosomes
i. When a cell divides the chromatin condenses to form chromosomes
ii. Distinct thread-like structures containing the genetic information that is
passed from one generation of cells to the next
VII. Nucleolus
a. Small dense region in nucleus
b. Assembles Ribosomes
VIII. Nuclear Envelope
a. Surrounds nucleus
b. Thousands of nuclear pores
i. Allow material to move into and out of the nucleus
ii. Nucleus sends a steady stream of RNA and other information carrying
molecules to the rest of the cell through these
IX. Cytoskeleton
a. Network of protein filaments that help the cell to maintain shape
b. Involved in cell movement
c. Made up of important structures
i. Microtubules and microfilaments
1. Microtubules
a. Hollow tubes of protein about 25 nanometers wide
2. Microfilaments
a. Long, thin fibers that function in the movement and support
of cells
X. Organelles in the Cytoplasm
a. Ribosomes
i. Proteins are assembled on ribosomes
ii. Follow coded instructions from nucleus
b. Endoplasmic Reticulum
i. Organelle in which components of the cell membrane are assembled and
some proteins are modified
ii. Rough Endoplasmic Reticulum
1. Modifies proteins
iii. Smooth Endoplasmic Reticulum
1. Contains collections of enzymes that perform specialized tasks
c. Golgi Apparatus
i. Sends proteins to final destination
ii. Enzymes in Golgi apparatus attach carbohydrates and lipids to proteins
d. Lysosomes
i. Small organelles filled with enzymes
ii. Breakdown lipids and carbohydrates and proteins from food particles that
can be used by the rest of the cells
iii. Used to break down organelles that have outlived usefulness
e. Vacuoles
i. Store water, salts, proteins and carbohydrates
ii. Pressure in vacuoles allows support of heavy structures
f. Chloroplasts
i. Use energy from the sun to make energy-rich food molecules
1. Photosynthesis
g. Mitochondria
i. Use energy from food to make high-energy compounds that the cell can
use to power growth, development and movement
XI. Organelle DNA
a. Chloroplasts and mitochondria contain DNA that is essential for function of
normal organelles
XII. Cell Membrane
a. Regulates what enters and leaves the cell and also provides protection and support
b. Core of cell membranes is a double layered sheet called a lipid bilayer
i. Form when certain lipids are dissolved in water
XIII. Diffusion
a. Works for dynamic equilibrium
b. High to low concentration
c. Does not require energy
XIV. Osmosis
a. Movement of water molecules
b. Moves water through selectively permeable membrane
c. Move from low to high concentrations of sugar
i. Until dynamic equilibrium
d. Isotonic Solution
i. Equal concentrations
e. Hypotonic Solution
i. Cell expands due to water move into cell
f. Hypertonic
i. Cell shrinks due to water leaving the cell
XV. Facilitated Diffusion
a. Protein channels in membrane
i. Molecules move through the protein channel from high to low
concentration
XVI. Active Transport
a. Movement from low to high concentration
b. Requires energy
c. Endocytosis
i. Making material into the cell by means of infoldings, or pockets, of the
cell membrane
1. Pockets that results break loose from out portion of cell membrane
and form vacuole within cytoplasm
d. Phagocytosis
i. Large particles are taken up by endocytosis
ii. Extensions of cytoplasm surround and engulf large particles
e. Exocytosis
i. Removing of large particles
ii. Membrane of the vacuole surrounding the material fuses with the cell
membrane
iii. Forcing contents out of the cell
XVII. Unicellular Organisms
a. Do everything a living thing does
b. Bacteria and Prokaryotes
c. Some eukaryotes
d. Used in daily life
i. Yeast
XVIII. Multicellular Organisms
a. Specialized to perform particular functions within the organism
XIX. Levels of Organization
a. In Multicellular organisms
i. Individual cells, tissues, organs, and organ systems
b. Cells
i. Division of labor among cells that make multicellular life possible
c. Tissues
i. A group of cells that perform particular functions
ii. Collection of cells
d. Organs
i. Many groups f tissue working together
e. Organ Systems
i. A group of organs working together to perform specific functions