BIOLOGY HANDOUT

BY: MAYA SOFIANA

CELLS

Cell is the smallest unit that makes up all living organisms. Because the cell is
the smallest unit of en organism, we need a microscope to see it. Cells that make
organisms can consist of a single cell (unicellular) or many cells (multicellular). Based
on knowledge development, the cells theory that used today are as follows:

1. Every organism consists of one or more cells. Life processes such as

metabolism and heredity occur in the cell.
2. Cells are the structural and functional unit of living things.
3. Cell come from preexisting cells. These cells carry the genetic material from
previously cells during cell division.

Development of Cells Theory

Cell comes from the Latin word cellula, meaning small room. The term cell was
first used by Robert Hooke in the 17th century. He studied the thin cross-sectional
slices of cork under a microscope. Mathias J. Schleiden and Theodor Schwann found
that every plant and animal tissue composed of cells. Max Schultze argued that the
protoplasm is an important part of the cell because inside it lasts the entire process of
life. Rudolf Virchow argued that the cells come from preexisting cells.
Chemical Components, Structure, and Functions of Cells
Prokaryotic cell do not have nucleus membrane, so its genetic material is mixed with
cytoplasm (bacteria and cyanobacteria). Eukaryotic cell is a cell that has nucleus
membrane so there separation between the nucleus and cytoplasm (animal and plant
cell). Part complier of animal and plant cells has some similarities, there are:

1. Cell Membrane: each cell is covered by cell membrane. Cell membrane has primary
function as a protective. So the cell contents do not come out. In addition, the cell
membrane also has the following functions such as, as receiver of outside stimulation
(hormones and other chemicals), control the substances that enter or exit cell, as the
site of biochemical activities.
The complete structure of cell membrane can be explained by using the fluid mosaic
model. In fluid mosaic model, the cell membrane consists of lipid layers and protein
molecules. Lipid layer is composed of phospholipids , which is lipid-containing
phosphate group. Phospholipids are amphypatic, means a molecule that contains the
“head” is hydrophilic and a molecule that contains the “tail” is hydrophobic. One
unit of phospholipids coupled with other phospholipids units is the opposite position,
so it forms two layers of phospholipids (phospholipids bilayer).
Cell membranes are selectively permeable, means the membrane only can be
passed certain molecules, such as glucose, amino acids, glycerol and various ions.
How do substances transport through the cell membrane? Based on energy demand,
there are two kinds of transport through the cell membrane as follows:
a. Passive transportation, means the transport of molecules or compounds does
not require energy, such as diffusion and osmosis.
b. Active transportation, means to carry molecules or compounds into the
membrane require energy, such as active transport, endocytosis and
exocytosis.
 Differences of Transport Through the Cell Membrane

Method Through
Process Mechanism Example of Events
the Membrane
Simple Diffusion Direct Random molecular movement Gas exchange at the
causes the displacement of alveoli in the lungs, O2
molecules from regions of high molecules from air to
concentration toward regions of blood.
lower concentration
Facilitated Carrier protein Molecules are bound by carrier Glucose inclusion into cell
diffusion proteins in the membrane and
passed through a membrane by a
transmembrane protein
Osmosis Direct Water diffusion or molecules water Water molecules
movement through a inclusions into red blood
semipermeable membrane from cells
hypotonic to hypertonic solution.
Active transport Carrier protein Carrier protein provides the energy Re-absoption of glucose,
(pump Na+, K+) to move Na+ against a amino acid and salts by
concentration gradient, the nephron in kidney
Endocytosis
-Phagocytosis Vesicle membrane Particles surrounded by a vesicle Ingestion of bacteria by
membrane and inserted into the cell leukocytes cell
-Pinocytosis Vesicle membrane Solution encloses with vesicle Ingestion of nutrients in
membrane and inserted into the cell the egg cells animal
Exocytosis Vesicle membrane Plasma membrane vesicles that Mucus secretion
carry molecules, unify with the cell
membrane and release moleculles

2. Cytoplasm: is everything in the cell except the nucleus. In addition, the cytoplasm is
the substance that fills the nucleus and cell membrane (liquid of cell). Cytoplasm has
function as a source of important chemicals for the cell because inside it there are
essential compounds or molecules for cell metabolism.
ORGANELLES CELL

1. Nucleus: the most important cell part because it serves as the cell control activity. In
general, organisms cell have a single nucleus, but some have more then one
nucleus.
2. Endoplasmic Reticulum: there are two type of ER, rough ER (granular) and smooth
ER (agranular). Rough ER plays role in protein synthesis, whereas the smooth ER
has function to synthesize lipids, phospholipids and steroids.
3. Ribosome: the smallest organelle structure. Ribosome involves in protein synthesis.
4. Golgi Apparatus: place of polysaccharides synthesis, place of plasma membrane
formation.
5. Lysosomes: are produced by the Golgi apparatus filled with protein. Lysosome have
several function as follows; intracellular digestion, exocytosis, destroy carcinogenic
compound.
6. Mitochondria: are energy forming cell organelles. In connection with those function,
mitochondria are often the power house of cells.
7. Plastids: found in plant cells. Based on the pigment that contain, plastids divided into
three. Chloroplasts (green pigment called chlorophyll as a photosynthesis pigment),
Leucoplast (colorless plastids), Chromoplast (contain non photosynthesis pigment
such as carotene, xanthophylls, etc).
8. Microbody (Peroxisome and Glyoxysome): Peroxysome play a role in substrate
oxidation. The fuction of glyoxysome is to oxidize fatty acids to sugar that are useful
for plant growth.
9. Vacuole: place of accumulation metabolic waste, food substance storage.
10. Microtubules: play a role in cell division.
11. Centrioles: play a role in cell division.
12. Cilia and Flagellum: in microorganism, cili and flagella serve as motion tools.
 Differences of Plant Cells with Animal Cells

No Cell Parts Plant Cells Animal Cells

1 Cell membrane √ √
2 Cell wall √ -
3 Nucleus √ √
4 Cytoplasm √ √
5 Endoplasmic reticulum √ √
6 Ribosome √ √
7 Golgi apparatus Exist, less clear √
8 Lysosomes - √
9 Mitochondria √ √
10 Plastids √ -
11 Vacuole √
12 Centrioles - √
13 Centrosome - √

PICTURE: PLANT CELL AND ANIMAL CELL