GEN BIO THE CELL THEORY

CELL THEORY - All living organisms are composed of

cells.
- Basic unit of life.
Zacharias Janssen and Hans - All cells arise from pre-exisiting cells
- Hereditary information is passed on
- contributor on the discovery of the cell from one cell to cell (DNA)
- invented the microscope in 1590 - Energy flows within the cell (ATP)
(compound optical) - All cells have the same chemical
Robert Hooke composition.

- earliest scientist to study living things

under microscope Biomolecules – Micromolecules
- British scientist who discovered the cell
- “cellulae” or “cell” Latin word means  Protein – Amindo Acid
“little rooms”  Nucleic acid – nucleotides
 Carbohydrates – glucose
Anton Van Leeuwenhock  Lipids – fats
- Enhanced the microscope magnifying
270-300x
- Discovered(?) bacteria, protozoa

Matthias Schleiden

- botanist
- cell is the basic building block of all
plant matter
- biogenesis (spontaneous generation)
was rejected

Theodore Schwann

- zoologist
- concluded that both plants and animals
were composed of cells
- biogenesis (spontaneous generation)
was rejected

Rudolf Virchow

- the father of modern pathology

- “All cells arise from pre-existing cells”
1. Cilia – movement or locomotion 17. Golgi vesicles – packaging and secretion of
2. Mitochondria – powerhouse of the cell proteins
3. Cytoplasm – holds the organelles 18. Ribosomes – source of protein (factory)
4. Ribosome – source of protein (factory) 19. Smooth endoplasmic reticulum – production
5. Rough endoplasmic reticulum – protein of hormones/ lipid synthesis
synthesis 20. Nucleus – contains genetic information
6. Nucleolus – source of ribosomes (DNA)
7. Nucleus – contains genetic information (DNA) 21. Nucleolus – source of ribosomes
8. Golgi apparatus – processing the protein 22. Rough endoplasmic reticulum – protein
9. Cell membrane – controller of the molecules/ synthesis
protection/ adhesion 23. Plasmodesmata – acts as a channel
10. Microfilament/Cytoskeleton – provides the 24. BONUS
shape of the cell 25. Cell wall shape – protection/ for strength/
11. Lysosome – digest food or suicide bags of the shape of the plant (KUNG WALA NI NAA’Y
the cell NAG KAMANG2 RON NA PUNO HAHAHAHAHA)
12. Smooth endoplasmic reticulum – production 26. Peroxisome – metabolism/ breaks down
of hormones/ lipid synthesis proteins and lipids
13. Secretory vesicle – serves as a 27. Golgi apparatus – processing the protein
passage/storage 28. Central vacuole – water storage
14. Peroxisome – metabolism/ breaks down 29. Chloroplast – responsible for color/
proteins and lipids photosynthesis
15. Centriole – responsible for cell division 30. Cytoplasm – holds the organelles
16. Flagella – responsible for locomotion 31. Mitochondrion – powerhouse of the cell
32. Cell membrane – controller of the
molecules/ protection/ adhesion

Nerve Cells/ Neurons

- Send and receive signals

Epithelial Cells – covers inside and outside the Sperm cell – male reproductive cell
surfaces of the body.

Bone cell – storage of calcium

Egg cells – female reproductive cell

Fat cell – storage of fats or energy

Red blood cells- carrier of oxygen.

Flagella – locomotion
Muscle cells – contract or shorten (ambot kung
naa pa ba ni sumpay mao ran aa sa notes nako)
 Hemidesmosomes – contributes to attachment
of epithelial cell

Cilia – locomotion

Tight junction – cell adhesion

Extracellular matrix – physical maintenance

Adhering junction – cell to cell communication

Microvilli – supports digestion and absorption

Pseudopod – locomotion/ engulfing of foods Gap junctions – serve as a channel/ entry & exit
and bacteria of molecules
Characteristics of prokaryotic cell

- No nucleus
- Small
- Unicellular
- Binary fission, buddings
- DNA – circular
3. Metaphase
- Line up in the equator
Characteristics of Eukaryotic cell - Mitotic spindle (formation)
- Has a nucleus - Mitotic spindle (attach to the sister
- Large chromatids)
- Multicellular
- Meiosis & Mitosis
- DNA – Linear

Mitosis

- One single cell

- Divides two identical cells
- Growth and repair
4. Anaphase
- Pulling (sister chromatids)

1. Interphase
- DNA replication

5. Telophase
- Full set of xsomes
- Cell pinches in the middle

2. Prophase
- Xsomes pair up 6. Cytokinesis
- Formation of sister chromatids
- Condense into x shape
- Nuclear membrane dissolves
Meiosis - The pairs of chromosomes may then
exchange bits of DNA in a process called
- Produces 4 haploid cells
recombination or crossing over.
- Single cell divides twice to produce 4
- At the end of Prophase I the membrane
cells containing only half genetic
around the nucleus in the cell dissolves
information.
away, releasing the chromosomes.
- The meiotic spindle, consisting of
microtubules and other proteins,
extends across the cell between the
centrioles.
3. Metaphase I
- The chromosome pairs line up next to
each other along the centre (equator)
of the cell.
- The centrioles are now at opposites
poles of the cell with the meiotic
spindles extending from them.
- The meiotic spindle fibres attach to one
chromosome of each pair.
4. Anaphase I
- The pair of chromosomes are then
pulled apart by the meiotic spindle,
which pulls one chromosome to one
pole of the cell and the other
chromosome to the opposite pole.
- In meiosis I the sister chromatids stay
Meiosis I together. This is different to what
happens in mitosis and meiosis II.
1. Interphase 5. Telophase I and cytokinesis
- The DNA in the cell is copied resulting in - The chromosomes complete their move
two identical full sets of chromosomes. to the opposite poles of the cell.
2. Prophase I - At each pole of the cell a full set of
- The copied chromosomes condense chromosomes gather together.
into X-shaped structures that can be - A membrane forms around each set of
easily seen under a microscope. chromosomes to create two new nuclei.
- Each chromosome is composed of two - The single cell then pinches in the
sister chromatids containing identical middle to form two separate daughter
genetic information. cells each containing a full set of
- The chromosomes pair up so that both chromosomes within a nucleus. This
copies of chromosome 1 are together, process is known as cytokinesis.
both copies of chromosome 2 are
together, and so on.
Meiosis II - in males, these four cells are all sperm
cells
6. Prophase II
- in females, one of the cells is an egg cell
- Now there are two daughter cells, each
while the other three are polar bodies
with 23 chromosomes (23 pairs of
(small cells that do not develop into
chromatids).
eggs).
- In each of the two daughter cells the
chromosomes condense again into Cell Membrane Structure
visible X-shaped structures that can be
- Primarily composed of a mix of proteins
easily seen under a microscope.
and lipids
- The membrane around the nucleus in
- Works as a barrier between the inner
each daughter cell dissolves away
and outer surface of the cell
releasing the chromosomes.
- In animal cell, the plasma membrane is
- The centrioles duplicate.
present in the outermost layer of the
- The meiotic spindle forms again.
cell
7. Metaphase II
- In plant cell it is present just beneath
- In each of the two daughter cells the
the cell wall
chromosomes (pair of sister
chromatids) line up end-to-end along Cell Membrane Lipids
the equator of the cell.
- The centrioles are now at opposites - Phospholipids form a lipid layer in
poles in each of the daughter cells. which hydrophilic (attracted to water)
- Meiotic spindle fibres at each pole of head areas spontaneously arrange to
the cell attach to each of the sister face the aqueous cytosol and the
chromatids. extracellular fluid
8. Anaphase II - Hydrophobic (repelled by water) tail
- The sister chromatids are then pulled to areas face away from the cytosol and
opposite poles due to the action of the extracellular fluid.
meiotic spindle. - Lipid layer is semi-permeable, allowing
- The separated chromatids are now only certain molecules to diffuse across
individual chromosomes. the membrane.
9. Telophase II and cytokinesis - Phospholipids are considered
- The chromosomes complete their move amphipathic molecules.
to the opposite poles of the cell. o Cholesterol
- At each pole of the cell a full set of  Keep cell membranes
chromosomes gather together. from becoming stiff by
- A membrane forms around each set of preventing
chromosomes to create two new cell phospholipids from
nuclei. being too closely
- This is the last phase of meiosis; packed together.
however cell division is not complete  Not found in the
without another round of cytokinesis. membranes of plant
- Once cytokinesis is complete there are cells.
four granddaughter cells, each with half
a set of chromosomes (haploid):
 o Glycolipids antigens, are found in plasma
 Help the cell to membrane
recognize other cells of - Proteins like glycolipids are attached to
the body. phospholipids along with the sugar
chains
Cell membrane proteins
- Lipids with short chain of carbohydrates
o Structural proteins are attached on the extracellular size of
 Give the cell support the membrane
and shape - Cholesterol maintains the fluidity of the
o Receptor proteins cell surface membrane.
 Help the cells
communicate with their
external environment
o Glycoproteins
 Help in cell to cell
communications and
molecule transport
across the membrane.

Plasma Membrane

- Biological membrane or an outer

membrane of a cell
- Composed of two layers of
phospholipids and embedded with
proteins
- Thin semi-permeable membrane layer
which surrounds the cytoplasm and
other constituents of the cell
- Boundary which separates the living cell
from their non-living surroundings
- Phospholipid bilayer
- Plasma membrane is an amphipathic
which contains both hydrophilic heads
and hydrophobic tails
- Fluid mosaic of lipids, proteins and
carbohydrates
- Lipid bilayer which contains two layers
of phospholipids, phosphate head is
polar (water loving), fatty acid tails non-
polar (water fearing) and the proteins
embedded in membrane
- Proteins like glycoprotein, used for cell
recognition and act as receptors and
Simple Diffusion

- form of diffusion that does not require

the assistance of membrane proteins
- he particle or substance moves from
higher to lower concentration
- major type of passive transport

Facilitated Transport

- a type of diffusion in which the

molecules move from the region of
higher concentration to the region of
lower concentration assisted by a
carrier.
- passive movement of molecules along
the concentration gradient
- membrane allows only selective
molecules and ions to pass through it
- Hydrophilic, polar or charged molecules
cannot cross the membrane

Transmembrane proteins

- proteins present in the cell membrane

that facilitate the movement of certain
molecules across the membrane
Channel Protein Active Transport

- These help in the entry and exit of - Process of transferring substances into,
substances in the cell. out of, and between cells, using energy.
- There are two types of channel - requires energy to move substances
proteins, open channel proteins, and from a low concentration of that
gated channel proteins. substance to a high concentration of
- Open channel proteins create a pore in that substance, in contrast with the
the cell membrane and allow the process of osmosis
charged molecules to pass through.
- The gated channel proteins are either
closed or open and regulate the entry
and exit of substances.
- Transports faster at a rate of tens of
millions per second.

Endocytosis

- dinako mag copy paste

- basta endocytosis pasulod ang mga
substance sa cell
- ta sang mahitabo kay murag gahimo
siyag bulsa frak para kaunon ang naa sa
Carrier Proteins labas then iyahang I close para masulod
sa cell
- These are present on the cell
membrane.
- They carry the molecules, change the
confirmation of the molecules and
release the molecules to the other side.
- Temperature and saturation affect the
carrier proteins.
- Transports slower at a rate of thousand Exocytosis
to million per second.
- kabaligtaran sa endocytosis meaning
pasulod siya
- kani kay ang mga dili na kailangan sa
cell kay I circle napud sa sulod tas iyang
ibuga palabras
- #ilabasangtoxicity
- #letgooftoxic
Bulk Transport

- Active transport siya nga dagko nga

substances ang ginapasulod

Two types of endocytosis

o Phagocytosis
 Ang ginapasulod niya
kay solid bay
 Usually transported by
lysosome
o Pinocytosis
 Kani bay kay liquid or
kanang dissolved
substances iyang gina
transport
 Liquid ha kanang dili
solid
 Allows faster entry via
channel protein