REVIEWER IN BIOLOGY 1 ROBERT BROWN (1833)- Scottish Botanist

NOTE: THIS IS JUST A SUMMARY NOTE OF WHAT WE HAVE - Discovered the nucleus using ORCHID.
DISCUSSED FOR THE PAST WEEKS. THERE’S NO ASSURANCE MATTHIAS SCHLEIDEN (1838)- German botanist
- Discovered that plants are made up of cell.
THAT EVERYTHING I HAVE INCLUDED HERE WILL APPEAR IN
THEODOR SCHWANN (1839)- German Zoologist
YOUR PERIODICAL EXAM. I HAVE ALSO INCLUDED SOME
- Discovered that animals are made up of cell.
CONCEPTS THAT MIGHT APPEAR IN YOUR EXAM. RUDOLF VIRCHOW- German Scientist
- introduced the third tenet of the cell theory.
LESSON 1: CELL THEORY
“OMNIS CELLULA E CELLULA”
CHARACTERISTICS OF LIFE:
Cell theory is developed in the mid 1800’s as a result of
1. Reproduction - For something to be considered alive, various discoveries about cells, it is one of the basic principles
it must be able to reproduce and create offspring. of biology:
2. Heredity - Heredity is the ability to pass on genetic
material (DNA) from parent to offspring. 1. All living things are made up of cells.
3. Cellular Organization - All living things are composed 2. Cells are the basic unit of structure and function in an
of one or more cells. organism.
3. Cells come from pre-existing cells.
Atom → molecule → organelle → cell → tissue → organs →
organ system → organism LESSON 2: CELL PARTS AND THEIR CORRESPONDING
FUNCTIONS
4. Growth and Development - All organisms develop
over time to become more physically and mentally • UNICELLULAR- Composed of one Cell.
mature. • MULTICELLULAR- Composed of many cells that may
5. Adaptation Through Evolution - Every living thing has organize into tissues etc.
evolved at some point in time, and continues to do
so in order to adapt to an everchanging environment. Major Structures of Cell
6. Response to Stimuli - Living things respond to stimuli 1. Cell membrane- outer boundary of the cell.
in their environment. 2. Cytoplasm- material between the cell membrane and the
7. Homeostasis - Homeostasis is a living thing's ability to
nucleus.
maintain stable internal factors, such as blood
pressure, body temperature (thermoregulation), and
3. Nucleus- control center of the cell.
water balance within cells.
8. Metabolism - An organism must use chemical reactions CELL PARTS (ANIMAL AND PLANT)
to process and/or use resources from the
environment in order to continue functioning.

Cells- are the basic building blocks of all living things.

HISTORY OF CELL:

ROBERT HOOKE (1665)- Discovered the cell through “CORK”.

He also coined the term “cell” derived from “cellulae” which
means “little rooms”.
JANSSEN MICROSCOPE- Created by Zaccharias Janssen.
Modified and used by Robert Hooke.
ANTON VAN LEEUWENHOEK (1674)- discovered bacteria and
protozoa. First to witness living organism under the
microscope.
- Father of microbiology. 1. Nucleus- Stores the cell’s DNA; the control center
- He used his teeth plaque to discover bacteria and - Controls and regulates cell activities
freshwater/pondwater for protozoa. - Controls the synthesis of ribosomes and proteins
• Nucleolus- Spherical body found inside the nucleus
Animalcules- term used by Leeuwenhoek for his discovery. - Produces and assembles ribosomes
2. Ribosomes- large complex (Large and small subunit)
- protein factories of the cell.
3. Cytoplasm- Gel-like structure found in both animal LESSON 3: PROKARYOTIC AND EUKARYOTIC CELLS
and plant cell. Contains many organelles as well as
the cytosol. PROKARYOTIC CELL- “pro”- before; “Karyo”- nucleus
Cytosol- Liquid portion of the cytoplasm - lack true nucleus. No membrane-bound organelles
4. Mitochondria- First observed by Kolliker in 1850. ex. Bacteria
- Powerhouse of the cell. Has its own DNA. Archaebacteria- “Archae”-primitive/ancient
- A double membraned rod-shaped organelle - can live in extreme conditions
COMPONENTS OF MITOCHONDRIA Eubacteria- “Eu”- true; “Karyo”- nucleus
- Outer membrane - true bacteria, can live in normal environment/conditions.
- Inner membrane
- Intermediate space EUKARYOTIC CELL- contains true nucleus.
- Cristae - With membrane-bound organelles. Ex. Nucleus, ER,
- Matrix Mitochondria etc.
Ex. Protists, fungi, plants and animals
5. Endoplasmic Reticulum
➢ Smooth ER- No attached ribosomes DISTINGUISHING FEATURES OF PROKARYOTIC AND
- Production of carbohydrates, lipids and steroids EUKARYOTIC CELL

➢ Rough ER- With ribosomes attached to its surface

- Modifies proteins synthesized by ribosomes Features Prokaryotic Cell Eukaryotic Cell
- Site of protein synthesis, processing and packaging 1. Nucleus - no nucleus - with NUCLEUS that
6. Golgi Bodies- Sort, tag package and distribute lipids - genetic material contains genetic
of protein found in the NUCLEOID material/DNA.
region.
- Site of formation of lysosomes
2. Cell wall and Cell Cell wall Cell wall
7. Lysosome- “suicidal bags”
membrane - present in almost all - present in most
- Digest cellular nutrients prokaryotic cells. eukaryotic cells (not
- Breaks down worn out or damaged organelles - cell wall is found in animals and
- Aids in Apoptosis (programmed cell death) peptidoglycan most protists)
8. Chloroplast- Site of photosynthesis. Contains - cell wall is Cellulose
pigment chlorophyll. Cell membrane
- Chlorophyll- Green pigment that gives color to the - They do not have Cell membrane
plant. sterols. - cholesterol (animals)
9. Vacuole- Stores nutrients and waste products - Sterol-like lipid called - Phytosterol (plants)
- Present in both animal and plant cell hopanoid. - ergosterol (fungi)
10. Cell wall- Supports and protects cell 3. Endomembrane - lacks endomembrane - with endomembrane
- Found outside the cell membrane and other system. system.
11. Cytoskeleton- Provides shape and structure organelles - rough and smooth
endoplasmic
- Network of protein filaments or fibers
reticulum, Golgi
- Allows movement
apparatus, lysosomes.
- Microtubules, Microfilaments and intermediate
4. Ribosomes - can be found in the - found in cytoplasm,
filaments. cytoplasm (free ribosome) Rough
12. Centrioles- (pair) are found within the centrosome. - 70s ER, Mitochondrion,
- Each is composed of nine sets of triplet S (svedburg unit) outer nuclear
microtubules arranged in a ring. - Sedimentation membrane and
coefficient. Rate at chloroplast.
ENDOMEMBRANE SYSTEM- includes the nuclear which particles settle - 80s
envelope, lysosomes, vesicles, the ER, and Golgi at the bottom.
apparatus, as well as the plasma membrane. 5. Shape of DNA - closed, circular DNA - linear
- These cellular components work together to modify, 6. Chromosome - one chromosome - more than one with
package, tag, and transport proteins and lipids that number (NUCLEOID) histones.
form the membranes. - PLASMID- circular ex. 46 in human
extra-chromosomal
DNA.
 Histones- packages DNA. Helps DNA to condense into 2 TYPES OF EPITHELIAL TISSUE
chromatin. SIMPLE EPITHELIUM STRATIFIED EPITHELIUM
PLASMID AND NUCLEOID (BACTERIAL DNA) - One layer, all cells - Multilayered.
rest on basement a. Transitional
membrane epithelium
a. SQUAMOUS - Lines organ that is
EPITHELIUM distensible (can be
- Flattened and fish stretched)
scale like. ex. Urinary bladder
- Allows rapid b. Stratified
exchange of squamous non-
substances. keratinized
ex. Lining of alveoli epithelium
b. CUBOIDAL - Cells are columnar
FEATURES PROKARYOTIC EUKARYOTIC CELL EPITHELIUM - No keratin
CELL - Cube/square-like ex. Lining of
7. Cell size - Smaller - ranges from 10 - Nucleus is central esophagus
- 1 micron to 100 micron and round. c. Stratified
8. Mode of - binary fission - mitosis and - Absorption and squamous
reproduction meiosis secretion. Keratinized
ASEXUAL ASEXUAL ex. Thyroid gland epithelium
REPRODUCTION REPRODUCTION c. COLUMNAR - With keratin
- Binary fission - budding, binary EPITHELIUM (protection against
fission, multiple - Rectangle-like with abrasion)
SEXUAL fission, cilia ex. Skin (epidermis)
REPRODUCTION fragmentation - Nucleus is basal
- Bacterial and regeneration. and elongated.
Conjugation For protection,
(sharing of SEXUAL secretion and
plasmid) REPRODUCTION absorption
- fusion of ex. Lining of
gametes (egg and fallopian tube.
sperm cell) d. PSEUDOSTRATIFIED
9. DNA - can occur in two - unidirectional EPITHELIUM
Replication opposing Telomerase- Pseudo- false
directions at the replenishes Stratified-
same. telomeres. multilayered.
- continuously Telomeres- seals - It appears multi-
replicate their chromatin. layered because of
DNA. - replicate their the differences in
DNA during the cell’s height.
S-phase ex. Epithelial lining
10. Transcription - both happens in TRANSCRIPTION of trachea
and Translation the CYTOPLASM - nucleus
TRANSLATION
- Cytoplasm. 2. CONNECTIVE TISSUE- connects different component
of the body. Made up of cells, Fibers and matrix.
LESSON 4: TISSUES, TYPES AND FUNCTIONS Function:
- Providing support to different parts of our body.
4 TYPES OF TISSUES - connects different components of our body.
- medium for exchange of nutrients, metabolites, and
1. EPITHELIAL TISSUE- It lines external and internal oxygen between blood and cells
surfaces of the body. CELLS
Function: A. Fibroblast- cells which synthesize collagen fibers,
- protection, absorption, secretion and forms glands elastic fibers and lays down matrix.
and ducts. - Fibrocytes- matured fibroblasts
b. Adipose/fat cells- stores fat Structure of a Neuron: Axon, Dendrite, Cell body
c. Plasma Cells- synthesize immunoglobulins
d. Mast cells- involve in inflammatory reactions
e. Macrophages- engulf various foreign particles
f. Leucocytes- white blood cells (neutrophils, lymphocytes,
eosinophils, basophils and monocytes)
g. Pigment cells- gives color to the skin when present.
h. Mesenchymal cells- undifferentiated cells. Can differentiate
into a variety of cell types

FIBERS
Collagen Fibers- flexible and offer tensile strength. Found in LESSON 5: CELL MODIFICATIONS
tendons, ligaments and all kinds of connective tissues
Elastic Fibers- can be stretch and come back to its normal CELL MODIFICATION- process that occur after cell
size. Ex. Walls of large arteries division where newly formed cells are structurally
Reticular Fibers- special type of collagen fibers. Can be seen in modified to perform their function effectively and
spleen and liver lymph nodes. efficiently.
3 TYPES OF MODIFICATION
GENERAL CONNECTIVE TISSUE: APICAL LATERAL BASAL
A. Loose connective tissue- composed mainly of densely -found on -found at the -found at the
packed collagen fibers. Ex. Tendons and ligaments apex/top. side of the cell base of the
B. Dense connective tissue- the most widely distributed of all A. Cilia- hair- A. Tight cell.
connective tissues. It is the predominant type of connective like structure. Junction- Desmosomes
tissue that joins the cells in the other main tissues For movement barrier that - rivet-like
C. Mucoid tissue- a gelatinous tissue primarily composed of a and transport. regulate structure that
ground substance with few collagen or reticular fibers. B. Flagella- movement of links
D. Adipose Tissue- body fat whip-like; for water and cytoskeleton
locomotion. solutes; and
SPECIALIZED CONNECTIVE TISSUE: C. Villi and connects the extracellular
A. Cartilage- Hyaline cartilage (Joints), Elastic Cartilage Microvilli- cell to its matrix
(supports parts that need to be bend), Fibrocartilage (can finger-like; it neighboring components.
withstand considerable pressure) increases cell. - anchors
B. Bone- hard connective tissue that consists of living cells and surface area for B. Adhering basal surface
mineralized matrix. faster and Junction- of the cell.
C. Hemolymphoid tissue- Blood and lymphatics fall into this efficient Fasten cells to
group. absorption. one another
Ex. Intestines C. Gap
3. MUSCULAR TISSUE- ability to contract, or shorten, D. Pseudopods Junction-
making movement possible. a.k.a false feet. a.k.a
- allow the body to move voluntarily or It moves the communicating
involuntary. cell or engulf junction
3 Types of Muscles prey. - connects the
a. Skeletal Muscle- helps in locomotion; Most abundant E. Extra-cellular cytoplasm of
in the human body; Voluntary matrix (ECM) adjoining cells.
ex. Biceps Femoris - secreted by - allows direct
b. Smooth Muscle- walls of hollow organs and tubes, cell on its apical exchange of
Involuntary. surface. Cell chemicals and
Ex. Muscles in the stomach wall. wall is the ECM materials
c. Cardiac Muscle- seen ONLY in HEART. Allows heart to in plants. between cells.
contract and pump blood throughout the body.
Involuntary movement. LESSON 6: CELL CYCLE AND CELL DIVISION, MITOSIS
AND MEIOSIS
4. NERVOUS TISSUE- forms the brain, spinal cord and
nerves. Helps in sending different kind of information Cell Cyle- series of events that occur from the time
to brain and bringing its responses back from brain to the cell is first formed until its own division into two
the effector organ. daughter cells.
Neuron- responsible for conducting action potential
 Cell Cycle is generally divided into two: STAGES OF MITOSIS
Interphase- cells are non-dividing, preparing for cell 1. PROPHASE
division; Longest which covers 90% of the cell cycle. - Chromatin condenses into chromosomes
Mitotic phase- cells are dividing, covers 10% of the - Nuclear envelope disintegrates
cell cycle. - Centrosome (pair of centrioles) moves to the
opposite poles and spindles form at opposite poles.
3 STAGES IN THE INTERPHASE: 2. METAPHASE (middle)
1. G1 PHASE or GAP 1- cell increase in size and - Nuclear membrane completely disappears
volume, cell produces proteins and energy in - Spindle fibers continue to extend from the poles to
preparation for the next stage. the center of the cell.
G1 CHECKPOINT- checks for damages in DNA, - Spindle fiber interacts and attaches to the
sufficient cell size, energy and proteins. kinetochore of the chromosomes.
STIMULATING PROTEIN- signals “go” to the cell. - The chromosome aligns at the equatorial plate.
- GROWTH FACTORS- production of cyclin and Terminologies:
CDK. CENTROMERE- joins two sister chromatids together.
- CYCLIN AND CYCLIN DEPENDENT KINASES- CENTROSOME- pair of centrioles. Forms spindle fiber
regulators of the cell cycle KINETOCHORE- protein located at the centromere
INHIBITING PROTEIN- signals “stop”. Inhibits the region in which the spindle fiber attaches.
cell to proceed with the cell cycle. 3. ANAPHASE (away)
- P53 PROTEIN- checks the DNA - Sister chromatids separate and move away from each
- RETINOBLASTOMA PROTEIN- checks sufficient other.
protein, nutrients, size - It ends when each pole contains a complete set of
2. S-PHASE or SYNTHESIS PHASE- DNA is duplicated. chromosomes.
3. G2 PHASE or GAP 2- cell grows more in 4. TELOPHASE
preparation for cell division. Replenishment of - Nuclear envelope and nuclear membrane start to re-
energy. appear
G2 CHECKPOINT- ensures that all DNA are - Chromatid starts to uncoil
correctly replicated. Cell proceeds if cell size and - Nucleolus also starts to reappear in each cell.
nutrients are sufficient. - Pinching of cell. Cleavage furrow forms.
CYTOKINESIS- division of the cytoplasm, forming 2
G0 or GAP 0- resting phase. Cells are inactive. If the cell does daughter cells.
not receive a “go-ahead signal” it may exit the cell and enter Cleavage- forms 2 daughter cells in animal cell.
G0 phase. Cell plate- formation of cell plate forms 2 daughter
cell in plant cells.
- Most cells of the human body are in the G0 phase.
Example: mature nerve cells and muscle cells STAGES OF MEIOSIS
never divide.
- Other cells, such as liver cells, can be “called back” MEIOSIS 1- REDUCTIONAL DIVISION
from the G0 phase to the cell cycle by external 1. PROPHASE 1
cues, such as growth factors released during injury. - Chromatin condenses into chromosome.
- Nuclear membrane and nucleolus start to disappear
DIFFEENCES OF MITOSMIS AND MEIOSIS - SYNAPSIS or pairing of homologous chromosome
MITOSIS MEIOSIS takes place.
-takes place in somatic -takes place in sex cells Homologous chromosome- they have the
cells (body cells) (egg cell and sperm same length, pattern, position of centromere
cell) -composed of four sister chromatids called
Results in Diploid Results in haploid TETRAD or BIVALENT.
(complete set) chromosome number - next is the crossing over between two non -sister
Chromosome number (half of the chromatids along the point called CHIASMA/CHIASMATA.
chromosome number) - crossing over results to genetic diversity.
Involves one cellular Involves two cellular
division: PMAT division: MEIOSIS 1 and
MEIOSIS 2
Produces 2 daughter Produces 4 daughter
cells cells
No synapsis and There is synapsis and
crossing over crossing over
 2. METAPHASE 1
- Homologous chromosomes (tetrads) line up along
the metaphase plate or equatorial plate of the cell.
- Spindle fibers attaches to one of the kinetochores of
each homologous chromosome.
3. ANAPHASE 1
- Homologous chromosome migrates and separate
toward their respective poles
- In humans, since there are 46 chromosomes, 23 will
move to the poles; this means that only half of the
number of chromosomes will remain in each cell
hence, MEIOSIS 1 is known as reductional division.
4. TELOPHASE 1 and CYTOKINESIS
- 2 daughter cells are completely divided.
- Nuclear envelope and nuclei reappear.

MEIOSIS II: EQUATIONAL DIVISION

- The two cells produced in MEIOSIS 1 with haploid

chromosome number will both undergo MEIOSIS II,
to complete the whole process.

1. PROPHASE II
- Nuclear envelope and nucleolus disappear
- The centrioles move to opposite poles and spindle
fiber forms in preparation for the coming metaphase
2. METAPHASE II (middle)
- The spindle fiber from opposite poles attaches to the
kinetochore of chromosomes.
- Chromosomes line up at the equatorial plate.
3. ANAPHASE II (away)
- Spindle fiber pull the sister chromatids apart.
- Sister chromatids move toward the opposite poles.
4. TELOPHASE II and CYTOKINESIS
- Chromosome uncoils
- Nuclear envelope reform and the cleavage furrow
eventually produces two daughter cells, each with
haploid set of chromosomes.
- Since there are two cells undergoing meiosis II, at the
end of this process, four new cells with haploid
chromosomes are produces.

*To help you remember which is which, never forget the

mnemonic devices MiSo and MeGa. “IF YOU FAIL TO PLAN, YOU ARE PLANNING TO FAIL”
- BENJAMIN FRANKLIN
MiSo: Mitosis for Somatic Cells
MeGa: Meiosis for Gametes
GOOD LUCK ON YOUR REVIEW AND EXAM!