On National Teacher Day, meet the 2024-25 Kenan Fellows
Cell structure
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3. • The cell (from Latin cella, meaning "small room" )
is the basic structural, functional, and biological
unit of all known organisms.
• Cells are the smallest units of life, and hence are
often referred to as the "building blocks of life".
• The study of cells is called cell biology, cellular
biology, or cytology.
INTRODUCTION:
6. TYPES OF CELL:
PROKARYOTIC CELL
• A prokaryotic cell is a type
of cell that does not have a
true nucleus or membrane-
bound organelles.
• Organisms within the
domains Bacteria and
Archaea are based on the
prokaryotic cell
EUKARYOTIC CELL
• Eukaryotic cells are the cells
that are complex in
structure and function as
they have a membrane-
bound well-defined nucleus
and other membrane-
bound organelles.
• The term “eukaryote” is
derived from Greek words,
“eu” meaning ‘true’ and
“karyon’ meaning ‘nucleus.
11. TYPES OF CELLS ON THE BASIS OF
FUNCTIONS:
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37. FUNCTIONS OF CYTOPLASM:
• It is the site of many biochemical reactions that are vital and
crucial for maintaining life.
• It is the place where the cell expands and the growth of the
cell takes place.
• It provides a medium for the organelles to remain
suspended.
• The cytoskeleton of the cytoplasm provides shape to the cell
and it also facilitates movement.I
• It also aids in the movement of the different cellular
elements.
• The enzymes in the cytoplasm metabolize the
macromolecules into small parts so that it can be easily
available for the other cellular organelles like mitochondria.
38. • It is a means of transport for genetic material.
• It also transports the products of cellular respiration.
• The cytoplasm acts as a buffer and protects the genetic
material of the cell and also the cellular organelles from
damage caused due to movement and collision with other
cells.
• The cytoplasmic organelles are specialized structures that
have their own functions like cellular respiration, protein
synthesis, etc.
• The cytoplasmic inclusions are non-soluble molecules, they
are seen floating in the cytoplasm, they act as stored fats
and sugars that are ready for cellular respiration.
• The cytoplasm and the proteins prevent the grouping of
organelles in place due to gra
39. Cytoplasmic Structure
• The protoplasm is generally composed of water (water is the largest
component). With the exception of water, sugars, inorganic salts and
different organic elements are present. the protoplasm is additionally
composed of many organelles.
• The Endomembrane system consists of:
• Golgi Apparatus
• Endoplasmic reticulum
• Endosomes
• Lysosomes
• Vacuoles
• The cytoskeleton consists of:
• Microtubules
• Microfilaments
• Intermediate filaments
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50. • The function of ER are as follows:
• 1. Mechanical support
• The ER forms a network like structure in the cytoplasm that gives mechanical
support to the cytoplasmic matrix.
• 2. Formation of other organelles
• ER helps in the origin of nuclear membrane, Golgi body and microbodies.
• 3. Exchange of materials
• The tubular network of ER is continuous externally with the cell membrane, and
extracellular fluid (ECF) flows within it. Thus, the ER provides an 'intracellular
circulatory system' that ensures a far greater surface of exposure of the cytoplasm
to the extracellular environment. This facilitates exchange of materials between
cytoplasm and ECF.
• 4. Protein synthesis
• Protein synthesis is a great function of endoplasmic reticulum. Due to the presence
of ribosomes in them, the RER functions as the site of protein synthesis
51. • 5. Lipid synthesis
• ER takes part in synthesis of various lipids e.g., fats (triglycerides),
steroids, lipoproteins and phospholipids. This function is attributed
to SER.
• 6. Carbohydrate metabolism
• The SER is also believed to be involved in glycogenolysis.
• 7. Detoxication
• The SER is probably concerned with detoxication of drugs and
toxins.
• 8. Transport of information
• It is another very important function of endoplasmic reticulum. The
SER is especially important for transmission of impulse from the cell
membrane into the interior of the cell. Particularly in muscle fibers,
the SER is modified into sarcoplasmic reticulum which transmits the
impulse received by the cell membrane to the contractile machinery
for excitation-contraction coupling system
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56. This Photo by Unknown Author is licensed under CC BY-SA-NC
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58. PEROXISOMES:
• Peroxisomes are membrane-bound organelles in most
eukaryotic cells, primarily involved in lipid metabolism
and the conversion of reactive oxygen species such as
hydrogen peroxide into safer molecules like water and
oxygen.
• Peroxisomes are organelles that can vary in shape, size
and number depending on the energy needs of the cell.
• These organelles are made of a phospholipid bilayer
with many membrane-bound proteins – especially
those that act as protein transporters and translocators
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80. FUNCTIONS OF NUCLEUS:
• It controls the hereditary characteristics of an
organism.
• The organelle is also responsible for protein
synthesis, cell division, growth, and differentiation.
• Storage of hereditary material, the genes in the
form of long and thin DNA (deoxyribonucleic acid)
strands, referred to as chromatin.
• Storage of proteins and RNA (ribonucleic acid) in
the nucleolus.
81. • The nucleus is a site for transcription in which
messenger RNA (mRNA) are produced for protein
synthesis.
• During the cell division, chromatins are arranged
into chromosomes in the nucleus.
• Production of ribosomes (protein factories) in the
nucleolus.
• Selective transportation of regulatory factors and
energy molecules through nuclear pores.
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