organelles and their role on the over-all cellular activities. Single brick= CELL Building block?
CELL- building blocks of the body - basic unit of life - able to control & execute several functions in all types of organism Cell Structure and Function
Cells are basic structural and functional units of life. No matter how widely diverse in structure and function cells
are, they share common characteristics.
Most of them have three main parts, namely:
A. Cytoplasm the part where the main life activities occur
B. Cell Membrane which protectively envelops the cytoplasm
C. Nucleus ( nuclei ) the part of the cell where the genetic material is found. A. Cytoplasm
Early cytologists referred to the cytoplasm as complex fluid .Suspended in this fluid are the different kinds of structures called
organelles which enable the cell to perform the metabolic life
processes. 1. Mitochondrion/Mitochondria
A mitochondrion consists of an outer
membrane, and inner membrane which is folded inward, and a liquid which fills the cavity.
The liquid and membranes of a
mitochondrion contain respiratory
enzymes.
These enzymes promote chemical reactions that lead to the release of energy in stored food, making it available for use by the cell.
powerhouse or energy factories
ATP (Adenosine Triphosphate)
production 2. Lysosomes
They are structurally similar to the mitochondria except that their inner walls are not thrown
into folds.
They contain enzymes that promote the breakdown or
digestion of carbohydrates, fats
and proteins. 3. Peroxisomes
small round organelles (single membrane) that carry out
oxidation reaction that break down fatty acids and amino
acids.
oversee reactions that neutralize free radicals, which cause cellular damage and cell death.
> - In plants: Glyoxysomes fat sugar
## 4. Golgi bodies
Consists of short bands of very
fine parallel cavities or flat sacs.
They are rich in fatty material.
They are largely found in cells
which secrete certain
substances, or those that make up gland cells. 5. Endoplasmic Reticulum
The electron microscope has revealed that the cytoplasm has an
intricate system of very fine tubes
or cavities, the endoplasmic reticulum .
It is a network of pathways through
which materials flow to different
parts of the cytoplasm.
The endoplasmic reticulum consists of a double layer of fats
and proteins .2 Parts of Endoplasmic Reticulum
1. The Rough Endoplasmic Reticulum (RER) is associated with tiny spherical structures called
ribosomes . Other ribosomes float in
the cytoplasm. 2. The Smooth Endoplasmic
Reticulum (SER) has no ribosomes.
It is a site for lipid metabolism and detoxification of drugs. Ribosomes
- protein factories of the cell
-synthesize proteins during DNA transcription & RNA translation into a specific order of amino acids in protein -appear either as clusters, single, tiny dots that floats freely in the cytoplasm. Endoplasmic Reticulum
Vacuoles which are the membranous storage sacs in
cells, usually serves as storage
and transport of food or water
In some protists, contractile vacuoles rid the cell of excess water.
Vesicles store and transport materials between organelles. Cell Membrane B. Cell Membrane
The cell membrane consists of a double layer of fats and proteins.
It is elastic . The elasticity of the cell membrane is
due to the structure of protein molecules
They are relatively long molecules which can
easily be folded. The cell membrane is also
differentially permeable .
> This means that it permits some substances to pass through readily, others slowly, and still others not at all.
# Nucleus
Cell Structure and Function C. Nucleus
The nucleus is covered by a membrane called nuclear membrane.
Like the cell membrane, it consists of a
double layer of fats and protein and associated short chains of sugars.
However, it differs from the cell membrane in that it has many holes or pores. Nucleus
Inside the nucleus is a fluid, the nuclear sap (also
> called nucleoplasm or karyoplasm ).
Several structures are suspended in this fluid. One of these is the nucleolus (nucleoli).
Some cells have two or more nucleoli. Besides the nucleoli, the nucleolus also contains
chromosomes .
These are long threadlike structures which are made up of molecules of protein and DNA.
The chromosomes are responsible for the next transmission of traits from one generation to then next. The DNA makes up the genes. D. Cytoskeleton
Responsible for cell shape, motility of the cell as a whole, and motility of organelles within a cell.
Types: 1. Microfilaments 2. Microtubules
3. Intermediate filaments 1. Microfilaments narrowest among cell protein fibers; about 7nm in diameter - are flexible but still strong, resisting crushing and buckling while providing support to the cell - also known as actin filaments
- provide rigidity & shape to the cell 2. Microtubules
small hollow tube
about 25nm in diameter (widest components
of cytoskeleton)
help the cell resist compression, resist compression, provide a track along which vesicles move through the cell, pull replicated chromosomes to opposite ends of
a dividing cell.
can dissolve & reform quickly like microfilaments
structural elements of flagella, cilia,
centrioles, & centrosome Intermediate Filaments
is a fibrous cytoskeletal polymers intermediate in size between 6-nm actin filaments
and 23-nm microtubules that
form the structural framework of nearly all eukaryotic cells. E. Special Cell Structures
- specialized for PLANT ( cell wall, chloroplast, central vacuole ) / for
ANIMAL cell ( lysosome, centrosome ) only. 1. Centrosome
organelle that is found close to the nucleus within the cytoplasm of cells.
consists of two centrioles that are
orientated at right-angles to each other. Each centriole is a cylindrical array of 9 microtubules.
where microtubules originate, replicate itself before cell divides 2. Cell wall
rigid covering that protects the cell, provides structural support &
gives shape to cell.
found in plants, fungal & protista cells
Peptidoglycan chief component of prokaryotic cell wall
Cellulose major component of plant cell wall 3. Chloroplast
plant cell organelles which carry out photosynthesis.
like mitochondria they
- have their own DNA and ribosomes - has also an inner & outer membrane - contains chlorophyll - captures light energy - some photosynthetic protists also have chloroplasts & some bacteria (ex. Cyanobacteria) also perform photosynthesis, but their chlorophyll is not relegated to an organelle. 4. Central Vacuole
occupies most of the area of a plant cell.
ROLE: regulating the cells
concentration of water in changing environmental condition
supports cell expansion
cell gets larger when the vacuole holds more H 2O without investing a lot of energy in synthesizing new cytoplasm. Create a 3-D cell model base from the materials that you are going to provide from the list below.
What do I need?
Any fruit and vegetable materials at home. E.g. Watermelon, orange, apple, carrots, potatoes, cabbage etc. Make sure to prepare some flaglets to label your output.
What you have to do?
1. Gather all the needed materials, choose light materials as much as possible 2. Based from the images and visuals provided in this lessons, create a 3-D cell model with the following standards; diameter and height is 5-10 inches. 3. Work on the output following the rubrics on the next slide. Rubrics References:
Alberts, Bruce et. al. Molecular biology of the cell. (5th ed.). New York: Garland Publishing, 2007.
Reece, Jane. B. et. al. Campbell Biology (9th ed.). Boston: Pearson,
2011.
Department of Education. Bureau of Learning Resources (DepEd-BLR). (2017) First Edition. Chapter 2: Cellular structure General
Biology 1(p.51-66), Pasig City, Philippines.
Rea, Maria Angelica D. et.al. (2017) First Edition. General Biology 1(pp 4-14), Manila, Philippines: Rex Bookstore, Inc. End of
Presentation
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