Biology notes 10-09-07 through 10-15-07
10-09-07
The size of an organism is determined by the number of cells not the
size of its cells.
The six levels of a cell “cell specialization”
1.
2.
3.
4.
5.
6.
Cell
Cells
Tissues
Organs
Organ systems
Complete organism
11 process of a cell:
1. Nutrition: food getting processes
2. Digestion: enzymes
3. Absorption: take in food requirements
4. Synthesis: convert inorganic substances to organic (protoplasm)
5. Respiration: Breathing processes of a cell
6. Excretion: getting rid of waste materials (digested particles)
7. Egestion: getting rid of non digested particles that are eliminated
8. Secretions: discharged substances from a cell (vitamins and
hormones)
9. Movements: cellular contractions (muscle cells)
10. Response: can respond to an external environment (example:
goose bumps)
11. Reproduction: mitosis
DANS SMEERRR
Properties of Protoplasm
1. Irritability: able to respond to stimuli
2. Conductivity: able to transmit impulses
3. Maintain Metabolism: use food to provide energy and synthesis
complex compounds
4. Reproduce: made more of its own kind
Robert Hooke discovered cells in 1665 he hooked a piece of cork
under a microscope he saw a little division he called “cells”
10-10-07
in 1839 Schleidon and Schwan proposed the cell theory
-there are two steps they proposed
1. All living things substances are composed of cells
2. the cell is the basic unit of life
Biology notes 10-09-07 through 10-15-07
An outline of the structures that make up a cell
1. Plasma membrane “animal cell” and Cell wall “plant cell”
2. Cytoplasmic organelles
a. Endoplasmic Reticulum
b. Golgi body
c. Mitochondria
d. Lysosomes
e. Ribosomes
f. Centrosomes
3. Nucleus
a. Chromosomes
b. DNA
4. Nucleolus
a. Chromatin materials
b. RNA
Cytoplasm: It is the part of the cell between its membrane and its
nucleus
*see sketch
The two regions are Ectoplasm (outside) and Endoplasm (to
the center)
The cytoplasm consists of 1000’s of well organized structures called
organelles.
Protoplasm: the material substance composing every cell (this
substance provides a living condition)
13 elements that make up protoplasm:
1. C carbon 18%
2. H hydrogen 10%
3. O oxygen 65%
4. P phosphorus
5. K potassium
6. I iodine
7. N nitrogen 3%
8. S sulfur
9. Ca calcium
10. Fe iron
11. Mg magnesium
12. Na sodium
13. Cl chlorine
The 4 main elements of protoplasm are C H O N are 96% (3 are
gasses)
All the rest of the elements make up the other 4%.
The main compounds that are unique to all living matter.
1. Proteins
Biology notes 10-09-07 through 10-15-07
2. Carbohydrates
3. Fats
4. Acids
These make living conditions so the cell can survive.
Plasma membrane: (animal cell) thickness 3/10 millionths of an inch
thick.
2 substances that make up the membrane
1. Proteins
2. Lipids
*see sketch
10-11-07
Functions of a plasma membrane:
1. Protects the inner cell structures
2. firm enough to keep the cell structures arranged for carrying on
activities that maintain life
3. It serves as a barrier and yet as a gateway.
Barrier- it separates the living substances of the cell from its fluid
environment
Gateway- It lets the following substances through
1. Oxygen
2. Water
3. Waste
4. Food products
PLANT CELL WALL *see sketch
Primary cell walls composed of a cellulose substance. Fibrous (celery
materials)
Middle Lamella is made of a protein substances
Secondary cell walls composed of more cellulose substances
PLANT CELL *see sketch
3 Functions of a plant cell
1. Protects inner cell structures
2. Regulates transpiration of water and respiration of gases
3. Controls Turgor pressure
ANIMAL CELL*see sketch
ENDOPLASMIC RETICULUM *see sketch
Snake-like or ribbon like
The are scattered within the endoplasmic region of the cytoplasm.
Biology notes 10-09-07 through 10-15-07
They consist of numerous tubules and vesicles.
Function: A passageway through which proteins pass from the
ribosomes (where they are made) to the Golgi bodies (where they are
stored)
There are 265 different proteins in a cell.
GOLGI BODIES *see sketch
A three-layer cake or a crown a king would wear
It is composed of vesicles or tubules located in the endoplasmic region
of the cytoplasm.
Function: They condense substances before they leave the cell as a
secretion (waste products)
MITOCHONDRIA *see sketch
Shaped like a little sausage
They are located in both the endoplasmic and ectoplasmic regions of
the cytoplasm.
These enzymes generate power for the cell to work.
The amount of mitochondria in a cell is proportional to its amount of
activity. (The more active the cell is the more mitochondria it
contains.)
A human skin cell has about 50 mitochondria.
A rat liver cell has about 2500 mitochondria.
The rat liver cell is much more active because it works much harder.
Function: These enzymes break up chemical substances and create
chemical reactions that provide energy for the cell to live. “the
powerhouse of the cell”
10-15-07
LYSOSOMES *see sketch
Closed sacs or bags
They are formed in both the ectoplasmic and endoplasmic regions of
cytoplasm.
White blood cells contain large amounts of lysosomes.
Function: 1. They digest contain large molecules and large particles
like bacteria that find their way into the cell. 2. They contain enzymes
which can dissolve all compounds present in cells. They can actually
digest any part of the cell that dies.
Called “suicide bags” or “digestive bags”
RIBOSOMES *see sketch
Spherical shaped like little bb’s
They are located in both the endoplasmic and ectoplasmic regions of
the cytoplasm.
They are small structures composed of DNA and proteins.
Biology notes 10-09-07 through 10-15-07
Some are connected to the endoplasmic reticulums
Function: They are the protein factories of the cell. Every cell
contains 265 different proteins.
Special enzymes make possible the many chemical reactions that have
to go in cells to keep them alive, and all enzymes are proteins.
Proteins are vitally important compounds to a cell.
CENTROSOMES *see sketch
Spherical shaped and granulated
Located in the endoplasmic region of the cytoplasm
These dots reveal tiny cylinders where cells reveal 9 groups of tubules
or (18 in total) connected to each centrosome.
Function: When cell division is about to occur 2 centrosomes will line
up on each side of the nucleus and they pull the cell apart.
They control polarization. *see sketch
NUCLEUS: *see sketch
Spherical shaped
Located in the center of the cell.
Double layered pore-containing busy highway (2 protein layers)
Within the nucleus are tiny structures called chromosomes
(chromotin material,
granuales,
chromatin fibers,
chromatides,
chromosomes)
Humans have 23 pairs of chromosomes.
23 pairs: Analogous chromosome pairs
1 pair sex-somatic cells
Male XY
Female XX
So if an X and an X pair up the offspring will be a female.
If an X and a Y pair up the offspring will be a male.
¾ of the materials of a chromosome is composed of DNA which is
protein strands.
There are 10 amino acids added to the DNA ribbon to form each
segment.
146 amino acids make up a protein molecule.
The cytoplasmic organelles are the energy supplies of the cell.
The nucleus of the cell is the control center of the cell, and it contains
all the heredity materials of a cell.
Function: It houses the DNA materials that formulate chromosomes
that directs the making of each new generation of cells to each new
generation of human beings.
Biology notes 10-09-07 through 10-15-07
The DNA molecule is a giant one. The largest in the human body (3
feet long).